Final

map distance (% recombination) =

# recombinant progeny / total progeny x 100

animals prevent of limit infection by:

(1) preventing pathogen entry (physical barriers) (2) mounting immune responses that destroy the invaders

action potentials

A rapid depolarization followed by repolarization that is propagated with fidelity along the axon of the nerve cell. These depend on voltage dependent changes in the gates of the ion channels, and result in long-distance signaling. In mammals,the threshold for an action potential is -55mV

alcohol inhibits

ADH production, contributing to dephydration

triploidy

(3n); three sets of chromosomes

most cell functions are limited to the range of

0 C to 45 C

total requency of all genotypes is

1

1 map unit =

1 % recombination = 1 centimorgan

differences in the end results (between mitosis and meiosis)

1) mitosis produces diploid cells whereas meiosis produces haploid cells 2) mitosis, not meiosis, produces genetically identical cells

how do cells begin to differentiate in the embryo?

1. cytoplasmic determinants 2. induction by nearby cells 3. cell determination

yeast mating

1. exchange of mating factors 2. mating 3. new a/A cell

what our genome is made up of

1.5% exons, 5% regulatory sequences, 20% introns, 15% unique noncoding DNA, 14% repetitive DNA unrelated to transposable elements, 44% repetitive DNA that includes transposable elements and related sequences

extracellular concentration Cl-

120 mM

Eion=

62 mV (log([ion]outside/[ion]inside))

the theory of plate tectonics

Earth's crust is composed of plates floating on Earth's mantle

Neurons that carry information into and out of the CNS form the

PNS

Ca2+

a 2nd messenger in both GPCR and RTK pathways; concentration in the cytosol is much lower than outside the cell or in the ER

polytomy

a branch from which more than two groups emerge

point mutation

a change in one base in a gene; in noncoding regions, generally result in neutral variation

cladogram

a diagram that only indicates relationships between species

karyotype

a display of the chromosome pairs of a cell, arranged by size and shape

a distribution of environments will be reflected biologically as

a distribution of phenotypes

the vas deferens joins

a duct from the seminal vesicle and becomes an ejaculatory duct prior to joining the urethra, which traverses the pensis

pedigree

a family tree that describes the interrelationships of parents and children across generations; can trace and describe inheritance patterns of particular traits

non-tropic hormone

a hormone that directly influences non-endocrine tissues

tropic hormone

a hormone that has an endocrine gland or endocrine cell as the target

if the receptor is a sensory neuron

a larger receptor potential results in more frequent action potentials

long term potentiation

a lasting increase in the strength of synaptic transmission

selection coefficient (s)

a measure of the relative intensity of selection against a given genotype

syndrome

a set of symptoms

allopolyploid

a species with multiple sets of chromosomes derived from a different species

fruit fly courtship

a stimulus-response chain, in which the response to each stimulus is the stimulus for the next behavior

"the morning after pill"

a type of progestin that prevents ovulation. it is unclear how it works

integration

The nervous system processes sensory input.

vagina

a muscular but elastic chamber where the male penis is inserted and sperm is deposited. it opens to the outside at the vulva

the relative fitness W of the most fit genotype in a population is

W=1

hybrid zone

a region in which members of different species mate and produce hybrids; can occur in a single band where adjacent species meet. for example, two species of toad in the genus Bombina interbreed in a long and narrow hybrid zone

S=

cA^z

chronic myelogenous leukemia (CML)

caused by translocations of chromosomes

cleavage

cell division to produce the blastula

local signaling

cell junctions, cell-cell contacts, paracrine signaling, synaptic signaling

mutations

changes in the nucleotide sequence of DNA; cause new genes and alleles to arise; a random change in nucleotide sequence of DNA

extinction can be caused by

changes to a species' environment

five mass extinctions

characterized by more than 75% of species loss in a very short time period- have punctuated the history of life, shaping biodiversity by elminating whole groups of organisms while fostering the subsequent diversification of others

earth is changing rapidly as a result of human actions

climate change; nutrient enrichment; toxins; ozone hole

homeobox genes

code for a domain that allows a protein to bind to DNa and to function as a transcription regulator

eustachian tube

connects to the pharynx and equalizes pressure between the middle ear and the atmosphere

conserving biodiversity

conservation of populations and species focuses on population size, genetic diversity, and critical habitat; also focused on sustaining biodiversity of entire communities, ecosystems, and landscapes

moto unit

consists of one motor neuron and the muscle fibers it controls

c

constant

cerebrum

controls skeletal muscle contraction and is the center for learning, emotion, memory and perception

plasmodesmata

cytoplasmic channels through cell walls that connect cells; allow the movement of cytoplasm between cells

if fertilization does not happen, the corpus luteum

degenerates, and a new follicle matures during the next cycle

breakage of a chromosome can lead to four types of changes in chromosome structure

deletion, duplication, inversion, translocation

logistic growth model assumptions

density-dependent factors affect population; populations adjust growth instantaneously and smoothly approach K; each individual added to the population has the same negative effect on its growth rate

the bipolar cells that transmit a signal in the presence of light

depolarize in the absense of glutamate

evolution

descent with modification or change in the genetic composition of a population from generation to generation

electromagnetic receptors

detect forms of electromagnetic energy, such as light, electricity, and magnetism. They are used in vision, to detect prey, to guide migratory patterns...

thermoreceptors

detect heat and cold. they are used for detecting prey, for thermoregulation...some are also activated by chemicals in our diet (capsaicin in hot peepers, and cooling menthol)

norm of reaction

determines the way in which the environmental distribution is transformed into the phenotypic distribution for a given genotype

diabetes mellitus

diabetes mellitus is caused by a deficiency of insulin (type 1) or a decreased response to insulin by target cells (type 2); type 1 diabetes is an autoimmune disorder in which the immune system destroys the beta cells of the pancreas. usually appears during childhood, and eliminates the ability to produce insulin. treat by injecting insulin; type 2 diabetes is more common and manifests itself in persons with excess weight and lack of exercise. it generally appears after the age of 40. inflammation likely plays a role. treat by diet and exercise. 7th most common cause of death in the US

genetic variation among individuals is cased by

differences in genes or other DNA segments

what might predispose a species to drift?

different taxa vary greatly in terms of population size; larger organisms typically have smaller populations; microbes typically have large population size, small role for drfit

different types of cells arise as a result of

differential gene expression

systematics compare each ingroup species with the outgroup to

differentiate between shared derived and shared ancestral characteristics

lipid soluble hormones

diffuse out of the endocrine cell, bind transport proteins that keep them soluble in the blood, diffuse into the target cell, bind to receptors in the cytoplasm or nucleus, and trigger changes in gene transcription

the movement of O2 and CO2 across respiratory surfaces takes place by

diffusion, from regions of high partial pressures to regions of low partial pressure

R is the

discrete growth factor

lambda =

e^r

antigen recognition by B cells and antibodies:

each B cell antigen receptor is Y-shaped, consists of two heavy chains and two light chains that are linked by disulfide bonds (bridges), and is anchored in the membrane. each heavy chain and each light chain have a constant (C) region which is similar between receptors. at the tips of the Y-shape, variable (V) regions form an asymmetric binding site for the antigen. there are two per receptor. all receptors within a cell are the same. There are 5 types of antibodies. IgG is most common. binding of a B cell receptor to an antigen activates the cell, leading to the formation of cells that secrete a soluble form of the receptor: the antibody (also known as immunoglobin). these receptors bind intact antigens on pathogens or in circulation. the amino acid sequences of the variable regions dictate the specificity. difference in these regions (in different cells) allow different B cells to recognize different epitopes.

NGSTs

each DNA template is sequenced directly

hemoglobin and gas exchange:

each hemoglobin molecule can bind four O2 molecules, via hemes. binding to one O2 molecule causes a conformational shift that assists in loading the others. release of one O2 molecule causes a conformational shift that assists in releasing the others. low pH (high CO2) decreases the affinity of hemoglobin to O2, inducing its release (Bohr shift)

trait

each variant for a character, such as purple or white color for flowers

the high rate of species extinction is largely a result of

ecosystem degradation by humans

embryonic germ layers

ectoderm (outer layer), mesoderm (forms between the ectodoerm and the endoderm), endoderm (lines the embryonic gut - Archenteron)

long distance signaling

endocrine signaling

Origin of Species

focused biologists' attention on the great diversity of organisms

lens

focuses; divides the aqueous and vitreous humors

organogenesis

formation of organs and tissues

the chromatids are sorted into

four haploid daughter cells

each spermatocyte gives rise to

four spermatids via meiosis

pus

a whitish fluid filled with white blood cells, dead pathogens, and debris. a minor injury or infection leads to localized inflammation. systemic inflammation results in additional release of WBC from the bone marrow. during certain infections, substances released by activated macrophages cause the body's thermostat to rest to a higher temperature: fever. an overwhelming systemic inflammatory response can lead to life-threatening septic shock (very high fever, low blood pressure, poor blood flow through capillaries). chronic inflammation is also disruptive: Chrohn's disease, ulcerative colitis.

in sexual reproduction, haploid gametes fuse to form

a zygote

examples of cellular response pathways

activation of cellular response via a cell surface receptor (epinephrine via a GPCR); direct regulation of gene expression by a steroid hormone receptor (estradiol, which is a kind of estrogen)

motor output

activation of muscle, gland, etc

activation of complement system

activation of the complement cascade, thus forming membrane attack complexes

different cells have different mixes of

activators that turn on the expression of specific sets of genes

enteric division

active in the digestive tract, pancreas, and gallbladder

Darwin percieved ________ as closely related processes

adaptation to the environment and the origin of new species

indirect fitness

additional reproduction by relatives that is made possible by an individual's helpful actions

proximate causation

addresses "how" a behavior occurs or is modified, including Tinbergen's uestions 1 and 2

ultimate causation

addresses "why" a behavior occurs in the context of natural selection, including Tinbergen's questions 3 and 4

high reproduction

advantages of birth rate (e.g. if offspring have low survival, more is better)

high growth

advantages of body size (e.g. greater survival)

general rules about pedigrees for rare recessives:

affected people usually have two parents who are not affects; in affected families, about one fourth of the children of unaffected parents are affected; the phenotype usually occurs equally in both sexes

gastrulation (long)

after cleavage, the cell cycle is restored, and cell division slows; then, gastrulation begins, where a set of cells at or near the surface of the blastula moves to an interior location; this is a morphogenetic process; cell layers are established, and the three-layered embryo is called a gastrula. the cell layers are collectively called the embryonic germ layers

fever

an elevation in body temperature, can develop during certain bacterial or viral infections. fever may be beneficial because: some immune reactions speed up at higher temperature, soem pathogens may be maladapted to high temperatures

anterior pituitary

an endocrine gland that secretes hormones in response to hypothalamic hormones

polygamy

an individual of one sex mates with several individuals of the other sex

pathogen

an organism or virus that causes diease

heterozygous

an organism that has two different alleles for a gene

homozygous

an organism with two identical alleles for a character for a gene controlling that character

the chromosomal basis of sex

an organism's sex is an inherited phenotypic character determined by the presence or absence of certain chromosomes. the sex chromosomes have genes for many characters unrelated to sex.

exoskeletons

an outer body shell. msucles attach to this outer covering. in arthropods it is jointed and called the cuticle. in bivalves it is made of calcium carbonate.

stem cell

an unspecialized of relatively unspecialized cell that can replicate itself indefinitely, and can differentiate into specialized cells of one or more types

menopause

an unusual phenomenon. in most species, adults can reproduce throughout their life. during menopause, ovaries lost responsiveness to LH and FSH, thus reducing estradiol production

acute allergy can lead to

anaphylactic shock. epinephrine counteracts symptoms

homologous structures

anatomical resemblances that represent variations on a structural theme present in a common ancestor

cloning of mammals (CC)

another example of cloning of a mammal is CC (Carbon Copy), the first cloned cat; but in CC's case, the coat pattern and temperament were different from that of the mother's; historically, cloned animals have been more prone to health problems, probably due to epigenetic modification that affect gene expression patterns; methylation of DNA; acetylation of histones (reprogramming of donor nuclei requires accurate chromatin restructuring)

pupil

aperture

in development, programmed cell death via

apoptosis

density-dependent birth and death rates

are an example of negative feedback that regulates population growth

the basic model

area and distance to a migrant pool, by influencing immigration and extinction rates, determines the number of species on an island

A

area of the habitat

in the motor cortex (frontal lobe) and somatosensory cortex (parietal lobe), neurons are

arranged by the region of the body that they serve. the size of the region is proportional to the amount of activity needed

arterioles

arteries branch into

reproduction can be

asexual or sexual

two principle ways to not have random mating

assortative mating; small populations (these can result in inbreeding)

in birds/reptiles, divisions take place

at one end of the yolk

cell signaling occurs in unicellular organisms (examples)

bacterial fruiting body formation; yeast mating

assumptions of the model

birth and death rates are constant over time and resources are abundant; no age or size structure, and no differences in birth and death rates among individuals; population is closed; no emigration or immigration; no time lags (for continuous model); no genetic structure

density-independent populations

birth rate and death rate do not change with population density

phylogram

branch lengths are proportional to the amount of inferred evolutionary change since the last common ancestor

chronogram

branch lengths are proportional to time

afferent neurons

bring information to the CNS

endoskeleton

internal skeleton buried within soft tissues. in chordates, it is typically composed of cartilage and bone. ligaments hold bones together at a joint. tendons attach muscle to bone

terrestrial mammals fertilize eggs _________

internally

chromosomes duplicate during

interphase

carolus linnaeus (1707-1778)

interpreted organismal adaptations as evidence that the Creator had designed each species for a specific purpose; accepted that species are fixes; was the founder of taxonomy, the branch of biology concerned with classifying organisms; he developed the binomial format for naming species; in contrast to scala naturae, Linnaeus' system was not linear but nested

Linnaeus

introduced a system for grouping species in increasingly exclusive categories

autonomic nervous system

involuntary processes

dispersive mutualisms

involve animals that transport and disperse seeds in return of the nutritional value of fruits or other structures associated with seeds

example: bicoid (two-tailed) in drosophila melanogaster

maternal effect genes; bicoid sets the A/P axis; a larvae with mutated bicoid gene lacks an anterior end and instead has a posterior in both ends; bicoid sets up the anterior end of the body (it follows the morphogen gradient hypothesis, where gradients of substances called morphogens establish the axes and other features)

egg-polarity genes

maternal genes that control the orientation of the egg

maternal effect genes

maternal genes that encode cytoplasmic determinants

hormones secreted during puberty trigger....

maturation and the development of sexual characteristics

jasmonates

mediate plant defenses against insect herbivores; regulate a wide range of physiological processes

ethylene

mediates fruit ripening and the triple response

fertilization stimulates completion of

meiosis II, after which the egg and sperm (both haploid) fuse to produce the zygote (diploid)

PNS has two efferent components

motor system and ANS

auditory canal

sound waves travel through

sexual selection

natural selection for mating success; can result in sexual dimorphism

somatic cells

non-reproductive cells

how many human genes are under balancing selection

not that many protein-coding genes (<100). many are involved in immunology and some are associated with disease

primary succession

occurs where no soil exists when succession begins

cardiac cycle

one complete cycle

average mutation

one mutation in every 100,000 genes per generation

Alfred Sturtevant

one of morgan's students, constructed a genetic map, an ordered list of the genetic loci along a particular chromosome. sturtevant predicted that the father apart two genes are, the higher the probability that a crossover will occur between them, and therefore the higher the recombination frequency

X inactivation

one of the two X chromosomes in each cell is randomly inactivated during embryonic development

the diploid zygote contains

one set of chromosomes from each parents

menstruation (final notes)

only humans and some primates undergo menstruation. other animals have estrous cycles, where the uterus reabsorbs the endometrium

sympatric speciation

speciation takes place in geographically overlapping populations; can occur if gene flow is reduced by factors including habitat differentiation, polyploidy, and sexual selection

great chain of being or scala naturae

species are arranged on a ladder of increasing complexity

facilitation

species can have positive effects on the survival and reproduction of other species without necessarily living in the direct and intimate contact of a symbiosis

spatially partition

species can spatially partition their ecological niche

the testes produce _______ in ____________

sperm; highly coiled tubes called the seminiferous tubules

large-scale chromosomal alternations in humans and other mammals often lead to

spontaneous abortions (miscarriages) or cause a variety of developmental disorders

thick filaments

staggered arrays of myosin

rule of addition

states that the probability that any one of two or more exclusive events will occur is calculated by adding together their individual probability; can be used to figure out the probability than an F2 plant from a monohybrid cross will be heterozygous rather than homozygous

cytokinins

stimulate plant cell division; promote later bud growth; slow organ death

auxine

stimulates cell elongation; regulates branching and organ bending

immature eggs form in the ________ of the female embryo and undergo ___________

ovaries; developmental arrest

changes in allele frequency are proportional to

strength of selection

genomic information shows that minor differences in gene sequence or regulation can result in

striking differences in form

the oldest known fossils are

stromatolites, rocks are formed by the accumulation of sedimentary layers on bacterial mats; date back 3.5 billion years ago; prokaryotes were earth's sole inhabitants for more than 1.5 inhabitants for more than 1.5 billion years

exaptations

structures that evolve in one context but become co-opted for a different function

studying processes in one species can inform on the biology of seemingly disparate species (examples)

studies in the fruit fly informed on, among other things, the molecular basis of immunity in humans; studies in giant squid illuminated how nerve cells generate action potentials; studies on the marine slug, Aplysia, informed on how memories are formed and stored

natural selections increases and maintains the frequencies of alleles that enhance

survival and reproduction

species can also partition their ecological niches

temporally

it should not be assumed (taxons)

that a taxon evolved from the taxon next to it

neutrophils

phagocytic cells that circulate with the blood and are attracted by infected tissues

macrophages

phagocytic cells that migrate throughout the body (monocytes) or reside in organs (e.g. spleen)

dendritic cells

phagocytic cells that populate tissues that contact the environment (e.g. skin). they stimulate adaptive immunity

chloroplast

photosynthetic organelle; site of photosynthesis; located in the mesophyll cells of leaves

morphogenesis

physical processes take place that give an organism its shape, including the organized distribution of differentiated cells

choroid

pigmented layer

ecological succession order

pioneer stage, Dryas stage, alder stage, spruce stage

true breeding

plants that produce offspring of the same variety when they self-pollinate

abscisic acid

promotes stomatal closure in response to drought; promotes seed dormancy

the packaging of these macromolecules into

protocells (droplets with membranes that maintained a different internal chemistry)

ventricles

pump blood out of the heart

atria

receive blood entering the heart

in asexual reproduction, no

fusion of gametes occurs (the offsprings are usually clones)

plants tolerate ____________ better than animals do

genetic changes

sexual replication facilitiates

genetic variation, at a reproductive cost (hypothesis: aids in overcoming changes in environmental conditions)

threats of biodiversity

habitat loss and fragmentation; invasive species; overhavesting/poaching; global change

monosomic zygote

has only one copy of a particular chromosome

trisomic zygote

has three copies of a particular chromosome

homeotherms

have relatively constant body temperature

backflow causes

heart murmurs

single circulation

hearts with two chambers: an atrium and a ventricle. The blood passes through two capillary beds, which significantly reduces blood pressure

double circulation

hearts with two pumps. the first delivers blood to the oxygenating tissues. the second receives oxygenated blood and delivers it to the internal tissues

the blastocyst secretes

homan chorionic gonadotropin (hCG) which maintains the corpus luteum

erthropoietin (EPO)

hormone that stimulates erthrocyte (RBC) production

strigolactones

regulate apical dominance, seed germination, and mycorrhizal associations

antidiuretic hormone (ADH or vasopressin)

regulates kidney function (increases water retention) and modulates behavior

oxytocin

regulates milk secretion by the mammary glands. it also triggers uterine contraction during birthing, and influences maternal behaviors

when closely related species meet in a hybrid zone, there are three possible outcomes

reinforcement, fusion, stability

innate immunity

relies on molecular recognition of pathogens using a small set of receptors that bind to molecules or structures that are absent from animal bodies but common to a group of viruses, bacteria, or other microbes. the internal defenses elicited are active against a broad range of pathogens. found in all animals

deletion

removes a chromosomal segment

iteroparity

repeated reproduction; produce offspring repeatedly

branch point

represents the divergence of two species

where reinforcement occurs,

reproductive barriers should be stronger for sympatric than allopatric species. for example, in populations of flycatchers, males are more similar in allopatric populations than sympatric popuations

stem cell practical applications

reproductive cloning, therapeutic cloning, induced pluripotent stem cells (iPS)

external signals are converted into

responses inside the cell

sickle cell anemia

results from abnormal polymerization of hemoglobin in RBCs

male gonads and sex hormones

hypothalamus -> GnRH -> anterior pituitary -> FSH and LH -> testes -> testosterone -> reproductive processes and 2ry sexual characteristics

the coordinated actions of the ________, _______, and _______ govern reproduction

hypothalamus, anterior pituitary, and gonads

phylogenies

hypotheses about gene/organism relationships that are constantly updated with new data

function of sex hormones

reuglate gametogensis, promote the appearance of primary sex characteristics, induce the formation of secondary sex characteristics (males: voice deepens, facial and pubic hair develop, muscle grows) (females: breast and pubic hair develop, fat is deposited in the breasts and hips, water is retained, etc)

the testes are in the ________ which is ____________

scrotum; 2 degrees cooler than the body

vestibular glands

secrete lubricating mucus that facilitate intercourse

natural selection and hardy-weinberg

selection can cause allele frequencies to change from generation to generation; selection can cause deviation from H-W genotype frequencies; selection is deterministic (predictable); selection can be a strong evolutionary force (compared to mutation)

efferent neurons

send out instructions from the CNS

there is a _______ cell and a _________ cell

sender; receiver

cloning of mammals (dolly)

in 1997, dolly was born. she was a lamb cloned from an adult sheep by nuclear transplantation from a differentiated cell; but, at 6 years old, dolly was arthritc and had to be euthanized because of a lung condition usually only seen in much older sheep

what hardy realized that other famous biologists of the day did not:

in a given population where gametes contribute to the next generation randomly, allele frequencies will not change

natural selection

increases the frequencies of allele that enhance survival and reproduction

vasodilation

increases the transfer of body heat to the environment through conduction, convection and radiation

how does genetic variation arise in sexual cycles?

independent assortment of chromosomes, crossing over, random fertilization

although natural selection occurs through interactions between individuals and their environment

individuals do not evolve. it is the population that evolves over time

black circles

individuals whose relatedness you are interested in

retina

innermost layer with photoreceptors

two general classes of secreted signal molecules

signal molecules that are unable to cross the plasma membrane and signal molecules that cross the plasma membrane

coordination of the endocrine and nervous systems (example)

insects molt in order to grow, and holometabolous insects undergo metamorphosis in order to reach sexual maturity; neurosecretory cells in the corpora cardiaca release PTTH. PTTH reaches the prothoracic gland, which in response releases ecdysteroid, inducing a molt; at the same time, JH is released by the corpora allata. When JH levels are high, ecdysteroid induces molting. But when JH levels are low, ecdysteroid induces metamorphosis

monogamy rare in

insects, fishes, reptiles, amphibians

Igf2

insulin growth factor 2. hormone that promotes fetal growth during pregnancy; is imprinted with expression deriving from the paternal allele

in a synapse prior to LTP

the NMDA glutamate receptor opens in response to glutamate but is blocked by Mg2+

adrenal hormones and stress

the adrenal medulla responds to short term stress (flight or fight) using two hormones, epinephrine and norepinephrine, that are secreted after nervous input from the hypothalamus; both are catecholamines synthetized from tyrosine, and function via GPCR's; the adrenal cortex responds to long term stress via mineralocorticoids and glucocorticoids (corticosteroids) that are produced following stimulation by hypothalamic adrenocorticotropic hormone (ACTH)

a life history entails three main variables

the age at which reproduction begins, how often the organism reproduces, and how many offspring are produced per reproductive episode

the production of mature gametes ceases at around

the age of 50

differentiation and organogenesis: the chick wing

the apical ectodermal ridge (AER) and zone of polarizing activity (ZPA) are regions that are important for proper win development; implanting another ZPA induces the development of two posterior structures; this is due to a ZPA- produced protein signal, called Sonic hedgehog

whether to model population growth with the continuous or discrete models depends on

the biology of the organism; if it has overlapping generations, we must use the continuous model

zero population growth (ZPG) occurs when

the birth rate equals the date rate (r=0); populations grow when r>0, shrink when r<0

deuterostomes

the blastopore becomes the anus

imprinting

the establishment of a long-lasting behavioral response to a particular individual or object. imprinting only takes place during a specific period of development, called the sensitive period. in some birds, imprinting can take place only during the first two days after birth, and bonding is usually via visual cues. imprinting between the parent and the offspring forms a bond that facilitates the learning of basic behaviors

spatial learning

the establishment of a memory that reflects the environment's spatial structure

evapotranspiration

the evaporation of water from soil and plants

macroevolution

the evolutionary processes that occur slowly, where the hisotry of life is written both in the fossil record and in the relationships of living species

macroevolution

the evolutionary processes that occur slowly, where the history of life is written both in the fossil record and in the relationships of living species

trophic structure

the feeding relationships between organisms in a community - key for community structure

lambda is

the finite rate of increase

mitosis during and after cleavage

the first few cell division are cleavage events, where little or no protein synthesis takes place and there is no increase in mass; only S phase (DNA synthesis) and M phase (mitosis) takes place; at the beginning, the little amount of DNA in the egg (one nucleus) is not sufficient to produce the mRNA and proteins needed to cellular processes. thus, the embryo relies on maternal RNA and proteins

thermogenesis

the generation of heat. it is increased by muscle activity such as moving or shivering. can also occur by the of burning brown fat, which is rich in mitochondria (non-shivering thermogenesis)

STR- and TR-containing genes are directly involved in

the generation of phenotypic variation

the hardy-weinberg theorem

the hardy-weinberg theorem describes a population that is not evolving. it states that frequencies of alleles and genotypes in a population's gene pool remain constant from generation to generation, provided that only Mendelian segregation and recombination of alleles are at work. Mendelian inheritance preserves genetic variation in a population. this theorem establishes the genotype frequencies we would expect in a population that would be produced by pure chance, given known allele frequencies.

F1 generation

the hybrid offspring of the P generation

egg activation and cleavage

the influx of Ca2+ into the cytoplasm also activates the egg. The nuclei fuse and cell division begins; the first few cell division are cleavage events, where little or no protein synthesis takes place and there is no increase in mass; these smaller cells are called blastomeres, and form a blastula that surrounds a fluid filled cavity known as the blastocoel

the size of a receptor potential increases with

the intensity of the stimulus

the phanerozoic eon includes

the last half billion years and is divided into three eras: the Paleozoic, Mesozoic, and Cenozoic

adaptive evolution occurs as

the match between an organism and its environment increases

speciation

the origin of new species, is at the key point where microevolution and macroevolution intersect

the female reproductive cycle involves the coordination of two organs

the ovaries and the uterus

evaporative cooling

the removal of heat from the surface of a liquid that is losing some of its molecules as gas. bathing, sweating, panting

mass extinction

the result of disruptive global environmental changes

hybrids

the result of mating between species with incomplete reproductive barriers; often have reduced fitness compared with parent species

specificity of cell signaling:

the same signal can induce different responses in different cells; this occurs because different types of cells have different collections of proteins, which lead to different cellular events (ex. epinephrine stimulates liver cells to break down glycogen. stimulates heart cells to contract more rapidly)

species richness

the total number of different species in the community

two important assumptions about phylogenetic characters

they are homologous and they are evolving independently from each other

characteristics that make fruit flies a convenient organism for genetic studies:

they breed at a high rate. a generation can be bred every two weeks. they have only four pairs of chromosomes.

pressure waves dissiplate when

they strike the round window, preventing reverberation

thyroid regulation: a hormone cascade pathway

thyroid hormone (T3 and T4, with the number of iodines) stimulate metabolism: blood pressure, heart rate, muscle tone, digestive and reproductive processes; hypothalamic thyrotropin-releasing hormone stimulates release of thyroid-stimulating hormone by the anterior pituitary, which stimulates the thyroid to release thyroid hormone

cornea

transparent layer that assists in focusing

spemann's organizer

transplanted the dorsal lip to the other side of another embryo induces gastrulation on that side as well

at the most basic level, all living organisms rely on the same

underlying mechanisms to survive, adapt, grow, and reproduce

quantitative variation

usually indicates polygenic inheritance

trophic mutualisms

usually involve partners specialized for obtaining energy nutrients

pollination mutualisms

usually pollen dispersal in exchange for nutrients

the ovaries flank the

uterus

changes in DNA arise via mutation but within a population...

variation, diversity, and resemblance are due in large part to meiosis followed by fertilization

veins

venules converge into

the only information in a phylogeny is on the

vertical axis. there is no information on the horizontal axis

lateral inhibition

when a photoreceptor is activated, horizontal cells inhibit distant photoreceptors and bipolar cells that are not illuminated this sharpens edges and gives you contrast. this is repeated by amacrine cells, at the level of the ganglion cells

reinforcement

when hybrids are less fit than parent species, reinforcement of reproductive barriers may occur through strong selection for prezygotic barriers. over time, the rate of hybridization decreases

symbiosis

when individuals of two or more species live in direct and intimate contact with one another; interactions among symbionts could be helpful, harmful, or neutral

in a log-log plot of S versus A

z is the slope of the line through the data points

species known to science

~2.3 million

the sliding-filament model of muscle contraction steps

(1) myosin head is bound to ATP and is in its low-energy configuration (2) the myosin head hydrolyses ATP to ADP and P, switching to a high-energy configuration (3) the myosin head binds to actin, forming a cross-bridge. (4) releasing ADP and Pi, mysoin returns to tits low-energy configuration while sliding the thin filament toward the middle of the sarcomere (5) binding of a new molecule of ATP releases the myosin head from actin, and a new cycle begins

tetraploidy

(4n); four sets of chromosomes

survivorship curve

(age against log survivorship); a graphic way of representing the data in a life table

the geologic record is divided into the

Hadean, Archaean, Proterozoic, and Phanerozoic eons

ovarian cycle (8)

LH stimulates the follicular tissue left behind to transform into a corpus luteum, which secretes progesterone and estradiol, which inhibits release of GnRH. this brings levels of LH and FSG to very low levels

(male) LH causes

Leydig cells in the connective tissue between the tubules to produce testosterone, which promotes spermatogenesis

neuron

The basic unit of the nervous system is the neuron. Neurons use pulses of electrical current to receive, transmit and regulate the flow of information over long distances within the body. In transferring information from one cell to another, neurons often rely on chemical signals that act over very short distances. Interpreting nerve impulses involves sorting paths and connections. In more complex animals this is carried out by groups of neurons organized into a brain or ganglia.

Capillary sequencing

all DNA templates are sequenced together to create a single consensus sequence

animal and plant responses:

at the levels of signal transduction and reception, animals and plant cells are quite similar. at the organismal level, the responses are very different; animals commonly respond by movement; plants respond by altering growth and development, and by adjusting to changes in time and seasons

protostomes

blastopore becomes the mouth

the genes of diverse organisms are

chemically identical

crossover points are visible as

chiasmata (singular: chiasma)

sclera

connective tissue

some populations increase or decrease each year by a

constant proportion (discrete growth - they do not have overlapping generations)

behavioral isolation

courtship rituals and other behaviors unique to a species are effective barriers to mating

reproductive cloning

create a clone, widely used in agriculture, has been used in animals

Mendel's experiment

crossed parents that differed in an obvious character; one parent's character had disappeared; the character reappeared in the next generation

the population growth equation can be revised

deltaN/deltat = bN-mN or deltaN/deltat = (b-m)N

r-selection

density-independent selection; selects for life history traits that maximize reproduction

species scale

different kinds of organism and size is relative to amount

different sites/characters may be evolving at

different rates

Mendel's work on pea plants provided evidence of

discrete heritable units (genes)

short tandem repeats

duplications of simple sets of DNA bases such as A, CA, CGG, etc

feedback regulation: simple endocrine pathway

endocrine cells respond directly to a stimulus by secreting a particular hormone; hormone travels via the bloodstream to the target cell, interacts with a receptor, and triggers a physiological response

adrenal medulla

epinephrine and norepinephrine: raise blood glucose level, increase metabolic activities, and contrict certain blood vessels

repeat-containing genes may act as

evolutionary "tuning knobs"

shared derived characters

evolutionary novelties unique to a particular clade

disruptive

favors individuals at both extremes of the phenotypic range

fusion of the nuclei of the sperm and the 2ry oocyte results in

fertilization (the polar bodies are discarded)

phenotype =

genotype x environment

hormonal regulation of growth

growth hormone (GH) is released by the anterior pituitary and stimulates growth via both trpoic and non-tropic effects (ex: the liver responds to GH by releasing insulin-like growth factors that sitmulate bone and cartilage growth)

female gonads and sex hormones

hypothalamus -> GnRH -> anterior pituitary -> FSH and LH -> ovaries -> estradiol

morphogenesis

in animals requires the movement of cells and the changing of cell shape; during neurulation, for example, changes in the organization of microtubules and apical actin allow the formation of the neural tube; similar cytoskeletal changes allow convergent extension, for example, as occurs for the formation of the archenteron of sea urchins; in animals, also requires cell migration; transmembrane glycoproteins called cell adhesion molecules (CAMs) promote the interaction between cells; cell migration via amoeboid-like movement also involves the extracellular matrix (ECM): the meshwork of secreted glycoproteins and other molecule that lie outside of the plasma membrane; specific components in the ECM guide specific cells

rooted tree

includes a branch to represent the last common ancestor of all taxa in the tree

dependable environments favor

iteroparity

populations shrink when

lambda < 1

the joining of these smaller molecules into

macromolecules, such as proteins and nucleic acids

Nearly a third of all metabolic energy expended by the human body is used to

maintain electrical imbalances between the inside and outside of the membranes of excitable cells.

x-linked recessive disorders are much more common in

males than in females

new genes and alleles can arise by

mutation or gene duplication

endocrine glands

often ductless organs and secrete hormones directly into the surrounding fluid

metaphase I

pairs of homologous chromosomes attach to metaphase plate

iris

part of the choroid that regulates pupil size

postzygotic barriers

prevent the hybrid zygote from developing into a viable, fertile adult

"the abortion pill"

prevents the activation of the progesterone receptor of endometrial cells, and thus, this stimulates menstruation

Vm

primarily determined by the membrane's permeability to K+

frequency of aa offspring is

q^2

inversion

reverses orientation of a segment within a chromosome

water soluble hormones

secreted by exocytosis, travel in the blood, bind to cell surface receptors on target cells, and induce changes to cytoplasmic molecules and sometimes alter gene transcription

muscle

sensory inputs to the nervous system result in specific behaviors, some of which are driven by nervous system motor output. Thus, these behaviors require muscle activity. Muscle contraction relies on the interaction between thin and thick filaments. muscle contraction results from filament movement powered by chemical energy. muscle contraction is active whereas muscle extension is passive

r =

sum of (0.5)^L

land plants enable the survival of all other life forms that live on land by

supplying oxygen, supplying most food eaten by terrestrial animals, creating habitats by stabilizing the soil, etc

hCG

the basis for pregnancy tests

telophase I and cytokinesis

the cytoplasm divides and the cleavage furrow forms

in vertebrates, coordination of endocrine signaling relies heavily on

the hypothalamus

secondary immune response

the immune repsonse during a subsequent exposure to the same antigen. peaks 2-7 days after exposure. this is because of the clonal expansion of memory cells. (basis for vaccination)

egg activation and cleavage

the influx of Ca2+ into the cytoplasm also activates the egg, and the nuclei of the gametes fuse and cell division begins; the first few cell divisions are cleave events, where little or no protein synthesis takes place and there is no increase in mass; these smaller calls are called blastomeres, and form a blastula that surrounds a fluid filled cavity known as the blastocoel; cleavage furrows form when divisions begins. the manner in which the furrows form affects the size of the blastomeres

innate immunity in invertebrates: insects as an example

the insect exoskeleton is the first line of defense. insects use pattern recognition receptors to specifically recognize marcromolecules that are characteristic of a broad class of pathogen. once recognized in the hemocoel, immune cells called hemocytes kill pathogens via phagocytosis and other mechanisms. hemocytes and other cells also release antimicrobial peptides that disrupt the plasma membrane microbes (lysis). different types of pathogens elicit different types of immune responses

lateralization (for cognition)

the left side is more adept to language, math and logical operations. the right side is more adept to recognize faces and patterns, spatial relations, and non-verbal thinking

lateralization (for motor and sensory functions)

the left side of the brain controls the right side of the body and the right side of the brain controls the left side of the body

the energetic hypothesis

the length of the food chain is limited by the inefficiency of energy transfer along the chain; only ~10% of the energy stored in the organic matter at one trophic level is converted to organic matter at the next trophic level

for any character, dominance/recessiveness relationships of alleles depend on

the level at which we examine the phenotype

inbreeding depression

the loss of fitness (the ability to make babies that make more babies) that takes place when homozygosity is increased for deleterious alleles

mating systems

the mating relationships between males and females

pleiotropy

the property that genes have multiple phenotypic effects

because gas exchange is via diffusion, this limits

the size of the organism

specific receptors (chemo)

transmit information about specific molecules (glucose, oxygen, CO2, amino acids, volatiles, pheromone)

cell-cell contacts

two cells in an animal may communicate via the interaction of molecules protruding from their surfaces

Mendel used the scientific approach to identify

two laws of inheritance

Mendel chose to track only those characters that

varied in an "either or" manner

change in allele frequency due to gene flow

within a population, it can introduce or reintroduce alleles, increasing its genetic variation; by moving genes around, it can make distant populations genetically similar to one another, hence reducing the chance of divergence; gene flow has resulted in the introduction of a new allele and 15-20% change in allele frequency in the last 300 years

within a species, genetics influences innate behavior:

within a species there is a significant amount of genetic diversity. this diversity can impact innate behavior. in this example, blackcap warbles were collected in two regions of Europe where the birds migrate in different directions. The young of the British blackcaps and the young from the German blackcaps were raised under similar conditions but showed different migratory orientations

Why is there variation? how is variation inherited?

"fleeming Jenkin has given me much trouble but has been of more real use than any other essay or review" - letter of Darwin to J.D. Hooker, 1869. in response, Darwin proposed the pangenesis hypothesis, in which hereditary substances called gemules or pangenes are shed by all parts of the organism and carried in the bloodstream

four concepts for mendel's model

#1 genetic information is particulate, does not blend #2 for each character an organism inherits, one from each parent #3 dominance and recessiveness #4 the law of segregation

regulation of skeletal muscle contraction steps

(1) acetylcholine is released at the synapse by a motor neuron and triggers an action potential on the muscle fiber (2) the action potential propagates along the plasma membrane and T tubules (3) this triggers the release of Ca2+ from teh sarcoplasmic reticulum (4) Ca2+ binds to troponin, exposing the myosin-binding sites (5) cycles of myosin cross-bridge formation, coupled with ATP hydrolysis, slide thin filaments toward the center of the sarcomere (6) when action potentials end, Ca2+ is moved back to the sarcoplasmic reticulum by active transport (7) tropomyosin blocks myosin-binding sites, and the muscle fiber relaxes

hyperthyroidism

(excessive thyroid hormone) can lead to high body temperature, sweating, weight loss, irritability, and high blood pressure

oviduct

(fallopian tube) extends from the uterus to a funnel-like opening at each ovary

hypertension

(high blood pressure); damages blood vessels and contributes to heart attack and stroke

industrial melanism

(in the peppered moth) - classic study in the development of the theory of natural selection and evolution

heart attack

(myocardial infarction); the damage or death of cardiac muscle from blockage of one of more coronary arteries (these supply O2 to the heart)

during the most drastic extinction event

(the Permian-Triassic extinction), 80-96% of global biodiversity was lost

Patau syndrome

(trisomy 13); 1:5,000. serious eye, brain, circulatory defects as well as cleft palate. children rarely live more than a few months.

Edward's syndrome

(trisomy 18); 1:10,000. almost every organ system affect. children generally do not live more than a few months

down syndrome

(trisomy 21); an aneuploid condition that results from three copies of chromosome 21. it affects about one out of every 700 children born in the US. only viable autosomal trisomy. the expression of many genes is higher on trisomy chromosome 21 relative to normal; no mechanisms for autosomal inactivation. the frequency of Down syndrome increases with the age of the mother, a correlation that has yet to be explained

H =

-(pAlnpA + pBlnpB + pClnpC) where A,B, C are the species, p is the relative abundance of each species)

For a resting neuron (one not sending a signal), the resting potential is between

-60 and -80 mV.

three events unique to meiosis

1) crossing over in prophase I 2) homologous chromosomes pair at the metaphase plate (metaphase I) 3) separation of homologs (anaphase I)

at birth, the ovaries contain

1-2 million primary oocytes, of which about 500 fully mature between puberty and menopause

the time between when sperm contacts the membrane and depolarization is______ and this depolarization lasts about _____

1-3 seconds; 1 minute

s =

1-W

The resting potential (unequal distribution of charge) is a result of two factors:

1. ATP-dependent ion pumps create concentration gradients across the plasma membrane. 2. The plasma membrane, because of ion channels, is more permeable to potassium than it is to sodium or chloride.

The resting potential (unequal distribution of charge) is a result of two factors: (revisited)

1. ATP-dependent sodium potassium pumps maintain the Na+:K+ chemical gradient across the membrane. 2. Potassium channels allow the free movement of K+ across the membrane, thus creating the resting potential.

ion channel receptors:

1. gate is closed 2. ligand binds to the receptor and the gate opens. specific ions flow through the channel, inducing a cellular response 3. the ligand dissociates from the receptor, the gate closes, and ions no longer enter the cell

G-protein coupled receptors

1. inactive GPCR (no ligand) and inactive G protein (GDP is attached) 2. ligand binds GPCR activating it via a conformational change. GPCR binds a G protein causing the GDP in the A subunits to be displaced by GTP, and thus activating the G protein 3. the activated A subunit of the G protein dissociates from the B and Y subunits and diffuses along the plasma membrane until it binds to a specific enzyme. the enzyme changes conformation and becomes active, leading to a cellular response 4. the A subunit of the G protein hydrolyzes GTP to GDP, inactivating both itself and the enzyme. the A subunit of the G protein re-associates with the B and Y subunits, and the process is free to start again

bacterial fruiting body formation

1. individual rod-shaped cells 2. aggregation in progress 3. spore-forming structure (fruiting body)

evolution by natural selection - Darwin's postulates

1. individuals vary 2. at least some variation is heritable 3. some individuals leave more progeny than others 4. the variation in survival and reproduction is not random, but depends on heritable trait variation outcome: (genetic) variants with higher survival and/or reproduction increase n frequency in population

short-term stress response and the adrenal medulla

1. the hypothalamus activates the adrenal medulla via nerve impulses 2. the adrenal medulla secretes epinephrine and norepinephrine, which act on target cells via GPCRs

long-term stress response and the adrenal cortex

1. the hypothalamus secretes corticotropin releasing hormone, which induces the anterior pituitary to release adrenocorticotropic hormone (ACTH) 2. the adrenal cortex recieves ACTH and secretes corticosteroids, which act on target cells via intracellular receptors

meiosis was discovers in

1875-1885

in ____________, August Weismann

1883; germ plasm theory separates germ cells from somatic cells and claims that only the first are involved in inheritance

by ____, the concept of nucleus as the basis for heredity is

1885; well established. Theodor Boveri is the first to propose that chromosomes are the physical basis of inheritance

frequency of Aa offspring is

2pq

skin color

3 loci, with alleles additively controlling the amount of melanin (darkness)

the egg's journey from the ovary to the uterus takes

3-4 days

what is the probability of getting at least 2 recessive traits in a cross PpYyRr x Ppyyrr?

3/8

tetrapods evolved from lobe-finned fishes around

365 MYA

earth formed about

4.6 billion years ago, along with the rest of the solar system

vascular tissue in plants appeared by about

420 MYA

extracellular concentration K+

5 mM

_______ of recombination is observed for any two genes on different chromosomes

50%

frequency of heterozygotes never exceeds

50%

the maximum frequency of observed recombinants between two genes is

50%

_____ of all mammals are monogamous

< 10%

axon

A neuron has a single axon, which transmits signals to other cells. Axons are longer than dendrites. The axon hillock is where signals that travel down the axon are generated. Each branched end of an axon transmits information to another cell at a junction called a synapse. These branches are called synaptic terminals. At synapses, chemical messengers called neurotransmitters pass information from the transmitting neuron (presynaptic cell) to the receiving cell (post-synaptic cell).

Spinal and bulbar muscular atrophy

AR locus, normal (CAG)9-37, repeat sequence mutated (CAG)38-62

light reactions produce

ATP, NADPH, and O2

major NTs

Ach is involved in muscle stimulation, memory formation, and learning. at the neuromuscular junction, it binds an ionotropic receptor and induces skeletal muscle contraction. it is degraded by Ach. in cardiac muscle, it binds a metabotropic receptor and reduces the heart rate. glutamate is involved in teh formation of long-term memory. dopamine and serotonin affect sleep, mood, attention, and learning. nitric oxide relaxes smooth muscle

births and deaths can be expressed as the average number of births and deaths per individual during the specified time interval

B= bN D= mN

Neurons communicate with each other at synapses:

Between cells, information is transmitted at synaptic terminals. Electrical synapses are composed of gap junctions that allow electrical current to flow from one neuron to another. These mediate rapid, unvarying behaviors like escape. Chemical synapses, which are more common, involve the release of chemical neurotransmitters by the presynaptic neuron and their reception by the post-synaptic cell.

Neurons that carry out integration are organized in the

CNS

parathyroid and thyroid regulation of blood calcium

Ca2+ levels msut be carefully regulated. if Ca2+ levels are too low, muscles contract convulsively. if too high, calcium phosphate causes organ damage; when Ca2+ levels fall too low, the parathyroid gland releases parathyroid hormone (PTH). PTH raises blood Ca2+ levels via direct and indirect effects; when levels are too high, thyroid-produced calcitonin inhibits hone breakdown and enhances Ca2+ excretion by the kidneys

dentatoribral-pallidoluysian atrophy

DRLA locus, normal (CAG)6-35, repeat sequence mutated (CAG)49-88

direct observation

Darwin's finches (beak size varied based on diet), mantids (coloring varied based on environment), artificial selection (using wild mustard to create kale, brussels sprouts, cabbage, broccoli, and kohlrabi), invasion event (soapberry bug has shorter beak in areas where goldenrain tree is more popular than balloon vine)

fragile X syndrome

FRM1 locus, normal (CGG)6-53, repeated sequence mutated (CGG)60-over 230

sensory input

For example, sensing the external environment (e.g., light) or sensing internal conditions (e.g., blood pressure)

three main types of cell surface receptor proteins

G protein-coupled receptors, receptor tyrosine kinases, and ion channel receptors

ovarian cycle (2)

GnRH stimulates the anterior pituitary to release FSH and LH

Huntington's Disease

HD locus, normal (CAG)6-35, repeat sequence mutated (CAG)36-121

types of Abs

IgA, IgD, IgG, IgM

the behavior of chromosomes during meiosis was said to account for

Mendel's laws of segregation and independent assortment

neurotransmitters

NT can often bind to multiple receptors, exerting very different effects. receptor activation ceases when NTs are cleared from the synaptic cleft. the stoppage of the signal can occur by: enzymatic hydrolysis of the NT, recapture by the presynaptic neuron, simple diffusion

Nt+1 =

Nt + RNt or (1+R)Nt

lambda =

Nt+1/Nt

(male) FSH causes

Sertoli cells in seminiferous tubules to nourish the developing sperm

graded potentials

Small changes in membrane potential that can either depolarize or hyperpolarize. By themselves, they propagate a few millimeters before dying out.

Chemical synapses: Generation of post-synaptic action potentials.

The arrival of an action potential to the synaptic terminal (1) depolarizes the plasma membrane, opening voltage-gated ion channel that allow Ca2+ into the cell (2) Elevated Ca2+ causes synaptic vesicles to fuse with the plasma membrane, releasing a neurotransmitter into the synaptic cleft (<50 nm) (3) Neurotransmitter binds to ligand-gated ion channels in the post-synaptic membrane, which in this example allow Na+ and K+ to flow through (4) At many chemical synapses, the receptor that binds and responds to the neurotransmitter is a ligand-gated ion channel, also known as an ionotropic receptor. Binding results in a graded potential called a postsynaptic potential. When the channel is permeable to both K+ and Na+, it depolarizes: excitatory postsynaptic potential (EPSP). When the channel is permeable to only K+ or Cl-, it hyperpolarizes: inhibitory postsynaptic potential (IPSP).

Ion pumps and ion channels establish the resting potential of a neuron

The inside of a cell is negatively charged relative to the outside of the cell. The attraction of opposite charges across the plasma membrane is a source of potential energy, and this charge difference, or voltage, is called the membrane potential. For a resting neuron (one not sending a signal), the resting potential is between -60 and -80 mV. Input from other neurons or a specific stimulus causes changes in the neuron's membrane potential, and this acts as a signal that transmits information.

the first solid evidence associating a specific gene with a specific chromosome came from

Thomas Hunt Morgan, an embryologist (experiments with fruit flies provided convincing evidence that chromosomes are the location of Mendel's heritable factors)

The preservation of genetic variation

Udny Yule - how could Mendelism work - shouldn't all population be composed of dominant alleles over time? Why don't recessive alleles disappear (especially if they are bad for you?) If they don't disappear, then why not? How is variation maintained?

dopamine

a NT that is essential for proper brain function; both schizophrenia (overactive) and Parkinson's disease (death of neurons that normally release DA) result from improper dopamine signaling

antigen recognition by T cells:

a T cell receptor is composed of an a chain and B chain, linked by a disulfide bond. the constant (C) region anchor the receptor to the membrane. the variable (V) regions of the a and B chains form the antigen binding site. These receptors bind epitopes that are being presented on major histocompatibility complex (MHC) molecules on the surface of host cells. host cells enzymatically cleave antigens in the cytoplasm, load them on MHC molecules, and display them on their surface (antigen presentation)

blood clotting

a break in a blood vessel exposes proteins that attract platelets and initiate coagulation: the conversion of liquid components of blood into a solid clot. platelets release clotting factors that leads to the formation of thrombin, which converts plasma fibrinogen to fibrin

senescence

a burst of ethylene is associated with the apoptosis of cells during senescence

microevolution

a change in allele frequencies in a population over generations

animal hormone

a chemical signal that is secreted into the circulatory system and communicates regulatory messages within the body (types include small peptides, proteins, glycoproteins, steroids, and amines)

circulatory systems:

a circulatory system is composed of circulatory fluid, interconnecting vessels, and a heart. the main driver of circulation is the muscular heart. the heart drives circulation by elevating the circulatory fluid's hydrostatic pressure, powering it to flow through the vessels and back to the heart

the duffy antigen

a classical blood polymorphism with three main alleles (FYA, FYB, and FY*BES) - historically these alleles were population-specific

thrombus

a clot formed in the absence of injury

polyploidy

a condition in which an organism has more than two complete sets of chromosomes

blood

a connective tissue composed of cells suspended in a fluid matrix called plasma

type II

a constant death rate over the organism's life span; some parental care, more offspring, smaller body size

continental drift has many effects on living organisms

a continent's climate can change as it moves north or south; separation of land masses can lead to allopatric speciation

for a recessive X-linked trait to be expressed

a female needs two copies of the allele (homozygous); a male needs only one copy of the allele (hemizygous)

But the resting potential is between -60 and -80 mV and not -90mV. This is because

a few Na+ ions leak across the membrane. Neither K+ or Na+ is at true equilibrium potential, but Vm is much closer to EK

polyandry

a form of polygamy where one female mates with many males; females are often more showy than the males; better for females = many male parents

polygyny

a form of polygamy where one male mates with many females; males are usually more showy and larger than the females; better for males = many mates

all other genotypes are scaled as

a fraction of the fitness of the most fit genotype

The Hardy-Weinberg Theorem

a fundamental principle in population genetics stating that the genotype frequencies and gene frequencies of large, randomly mating population remain constant provided immigration, mutation, and selection do not take place

epistasis

a gene at one locus alters the phenotypic expression of a gene at a second locus.

master regulators

a gene at the top of a gene regulation hierarchy; for example, the master regulator MyoD drives the differentiation of muscle cells

sex-linked gene

a gene located on either sex chromosome; follow specific patterns of inheritance

SRY

a gene on the Y chromosome that is responsible for development of the testes in an embryo (sex-determining region on the Y)

linkage map

a genetic map of a chromosome based on recombination frequencies

cohort

a group of individuals from birth to death

population

a group of individuals of a single species living in the same general area

just as a population increases in size when births > deaths,

a group of organisms increases when more new species are produced through speciation than are lost to extinction

character

a heritable feature that varies among individuals (such as flower color)

if the receptor is not a sensory neuron

a larger receptor potential usually causes more NT to be released

population

a localized group of individuals capable of interbreeding and producing fertile offspring

callus

a mass of dividing, undifferentiated cells formed at the cut end of the shoot

recombination frequency

a measure of the distance between genes; the higher the frequency of recombination between two genes, the more distant the genes are from each other

neuroendocrine signaling

a nerve cell releases or induces the release of neurohormones that diffuse into the bloodstream and trigger responses in target cells elsewhere in the body (epinephrine, oxytocin, etc)

hypothalamus

a neurosecretory gland located in the brain; it recieves information from nerves throughout the body, and then initiates endocrine signaling appropriate for those conditions (ex. it controls the release of reproductive hormones); signals from the hypothalamus travel to the pituitary, which is located at its base

when a new colony is started by a few members of the original population, the small population size of the colony means that it may have

a non-random sample of the genes present in the original population, reduced genetic variation from the original population

planarians detect light via

a pair of ocelli. Comparing the rate of action potentials coming from the two ocelli allows the planaria to move toward shade

torpor

a physiological state of decreased activity and metabolism, enables animals to save energy. more common in smaller animals, and is most often accompanied by a significant drop in body temperature

natural selection

a process in which individuals with favorable inherited traits are more likely to survive and reproduce

migration

a regular, long-distance change in location. during migration, many animals pass through environments they have never encountered before. environmental cues guide migration. some animals track their position relative to the sun or the North Star, adjusted by their circadian clock. time-compensated sun compass. some animals track their position relative to the earth's magnetic field. yearly cycles follow a circannual rhythm. these are influenced by the periods of daylight and darkness in the environment

autocrine signaling

a secreted molecule diffuses locally and triggers a response in the cell that secretes it

paracrine signaling

a secreting cell acts on nearby target cells by secreting molecules of a local regulator (growth factors, nitric oxide, etc.)

fixed action pattern

a sequence of unlearned acts that is directly linked to a simple stimulus, called a sign stimulus (example: stickleback fish attacking anything with a red underside); this behavior is unlearned and genetically fixed, and is known as innate behavior (other examples of innate behavior are migration, the courtship-stimulus responses chain, and pheromone signaling)

example of behavior

a single master regulatory gene can control many behaviors. one transcription factor, fruitless (fru), controls many behaviors of the male fruit fly courtship ritual. mutant males don't court. there are male and female splice variants; male splice variants in females can cause sex roles reversal (as does female splice variants in males

outgroup

a species or group of species that is closely related to the ingroup; a groups that has diverged before the ingroup

each genes resides at

a specific locus on a specific chromosome

bottleneck effect

a sudden change in the environment that may drastically reduce the size of a population; the resulting gene pool may no longer be reflective of the original population's gene pool

culture

a system of information transfer through social learning or teaching that influences the behavior of individuals in a population

taxon

a taxonomic unit at any level of hierarchy

the prostate gland produces

a thin, milky fluid: anticoagulant enzymes and citrate (nutrient)

phagocytosis

a type of endocytosis in which large particulate substances or small organisms are taken up a cell. it is carried out by some protists and by certain immune cells of animals. in insects, these cells are the hemocytes. in mammals, these cells are mainly the macrophages, neutrophils, and dendritic cells

monophyletic

a valid clade signifying that it consists of the ancestor species and all its descendants

example: Ca2+, nitric oxide, cGMP, and vasodilation

acetylcholine binds its GCPR receptor; Ca2+ activates nitric oxide synthase which produces nitric oxide (NO); NO activates guanylyl cyclase in muscle cells, creating a new 2nd messenger: cyclic GMP; cGMP activates PKG, which relaxes muscles and allows more blood flow (vasodilation)

behavior is an essential part of

acquiring nutrients and finding a mate, and contributes to homeostasis

intracellular receptors

act as transcription factors and alter gene expression

selection favors certain genotypes by

acting on the phenotypes of certain organisms

regional adaptive radiations

adaptive radiations can occur when organisms colonize new environments with little competition; the hawaiian islands are one of the world's great showcases of adaptive radiation

life tables

age-specific summaries of the survival patterns of populations, summarize some of the vital statistics; follow the fate of a cohort; built by determining the number of individuals that die in each age-group and to calculate the proportion of individuals surviving from one age class to the next

different shapes of trees

all show genealogical relationships but can be used to address different questions

species richness is positively correlated with

amount of sunlight and water

individual behavior

an action carried out by muscles under control of the nervous system

polygenetic inheritance

an additive effect of two more genes on a single phenotype (e.g. skin color)

reproductive tables

an age-specific summary of the reproductive rates in a population; demographers generally ignore males and focus only on females bc they are the producers of offspring; two key parameters are number of breeding females, age of reproductive females

TEs are a source of phenotypic variation

an initial insertion of a Gret1 LTR retortransposon (not present in the Cabernet variety) resulted in a loss-of-function allele of the Vvmby1 A gene, leading to a loss of color in the fruit of the Chardonnay variety. a subsequent rearrangement in Gret1 results in revertant, colored grapes in varieties such as Ruby Okuyama

commensalism (+/0 interaction)

an interaction between species that benefits one of the species but neither harms nor benefits the other; is difficult to document in nature because any close association between two species is likely to affect both of them, even if only slightly

characters shared by the outgroup and ingroup

ancestral characters that predate the divergence of both groups from a common ancestor

the main sex hormones are steroids called

androgens (testosterone) and estrogen (estradiol) and progestins (progesterone)

testes

androgens: support sperm formation, promote development and maintenance of male secondary sex characteristics

to avoid damage to host,

animals protect themselves by means of their immune system

exchange with the environment:

animals require mechanisms for the exchange of molecules into and out of the body: gases, nutrients, wastes. because diffusion is rapid over short distances, one adaptation is to place many or all cells in direct contact with the outside environment. this could be in for of a gastrovascular cavity. another form is a circulatory system that moves fluid between each cell's immediate surrounding and the body tissues where exchange with the environment occurs.

pathogens make

animals sick

proliferation of B and T cells:

apoptosis kills lymphocytes with self-reactive receptors prior to their release into circulation (self-tolerance). activated lymphocytes multiply, producing clones (clonal selection). Some are effector cells that immediate action. B cells: plasma cells. T cells: helper T cells (CD4+) and cytotoxic T cells (CD8+). some are memory cells that increase the speed and strength of the response upon subsequent exposure.

light reactions

are carried out by molecules in the thylakoid membranes; convert light energy to the chemical energy of ATP and NADPH; split H2O and release O2 to the atmosphere

capillaries

arterioles branch into; form capillary beds, are thin and microscopic vessels with porous walls. this is where chemical exchange take place

induction by nearby cells

as cells divide, cytoplasmic determinants become diluted and degraded. then, a process called induction becomes more important (cell-cell signaling); inductive signals from nearby embryonic cells, either via direct contact or via soluble secreted growth factors, induce the target cell to turn on or off specific sets of genes

seedless bananas

bananas are seedless because a chromosomal imbalance; bananas are triploid, having inherited two sets of chromosomes from one original parent and one set from other; because of this odd number, homolgous chromosomes cannot pair properly during metaphase I, and meiosis fails; no gametes are formed; but bananas are parthenocarpic, so fruit can develop without fertilization. thus, the fruit is seedless. propagation is via side shoots; the problem with commercial banas (Cavendish strain) is that they are all clones. there is not genetic variation (monoculture); now, the fungus "Tropical Race 4" is threatening the Cavendish with extinction

polyphyly

based on convergent characters

secondary succession

begins in an area where soil remains after a disturbance

the nervous system

can be as simple as a nerve net; can also involve cephalization, where sensory neurons and interneurons are clustered in the anterior of the body; it can be divided into a central nervous system (CNS) and a peripheral nervous system (PNS); in vertebrates, the brain and spinal cord form the CNS, and nerves and ganglia are the key components of the PNS

dominantly inherited disorders

can be homozygous or heterozygous. (~3700 autosomal dominant diseases are known); examples include archondroplasia, a form of dwarfism that is lethal when homozygous for the dominant allele. neurological diseases (ataxias, paraplegia, dystonia, inherited dementia)

venules

capillaries converge into

arteries

carry blood from the heart to organs throughout the body

immune system problems: transplantation

cells from another person can be recognized as foreign and attacked by immune defenses. for blood transfusions, blood types must match. for organ transplants, MHC molecules (encoded in several loci, each with many alleles) must match as closely as possible between the donor and recipient. even then , the recipient receives immunosuppressants.

"target cells"

certain types of cells that are equipped to respond to hormones because they have the appropriate receptors

microevolution

change in the genetic makeup of a population from generation to generation

inbreeding

changes genotype frequencies by increasing the proportion of homozygotes and reduces the proportion of heterozygotes in any population in which it occurs. in the most extreme case (selfing), it has effects just like positive assortive mating

nonsynonymous mutations

changes in nucleotides that change amino acids

basilar membrane

changes in thickness along the length of the cochlea. this accounts for pitch reception

morphological species concept

characterizes species by body shape and other structural features. it applies to sexual and asexual species but relies on subjective criteria

phylogenetic trees are built from

characters

meiosis results in

chromosome reduction from diploid to haploid. If meiosis did not happen, fertilization would keep doubling the number of chromosomes

metaphase II

chromosomes attach to the metaphase plate. because crossing over took place, the two sister chromatids are not identical

interphase (S phase)

chromosomes duplicate during this, yielding sister chromatids

example of unity of life

cilia of paramecium and cilia of windpipe cell

natural killer cells

circulate throughout the body and detect and kill infected cells

sister chromatids are held together by

cohesins

polyploidy is

common in plants, but not animals. more normal in appearance than aneuploids

endocrine system

communicates via hormones, many of which act as long distance chemical signals

nervous system

communicates via long-distance electrical signals and short distance chemical signals

why do we care about species diversity?

communities with higher diversity are: more productive (they yield more biomass) and more stable in their productivity, better able to withstand and recover from environmental stresses, and more resistant to invasive species, organisms that become established outside their native range

comparative embryology

compartive embryology reveals anatomical homologies not visible in adult organisms. for example, all vertebrate embryos have a post-anal tail and pharyngeal arches

examples of interspecific interactions

competition, predation, herbivory, symbiosis (parasitism, mutualism, and commensalism), and facilitation

totipotent stem cells

completely undifferentiated and can give rise to any cell type. these must be collected at the blastocyst stage or earlier

myofibrils

composed of repeating sections called sarcomeres. the sacromeres line up in adjacent myofibrils, giving an organization called striated muscle

ventricles (brain)

contain cerebrospinal fluid

acrosome

contains enzymes that help the perm penetrate the egg

organ of corti

contains the mechanoreceptors of the ear, with hairs projecting into the cochlear duct. the hairs project into the cochlear duct and attach the tectorial membrane. sound waves make the basilar membrane vibrate, which bends the hairs and depolarizes the hair cells

systole

contraction

muscle and the skeletal system:

converting muscle contraction to movement requires a skeleton. movement occurs by contraction of msucle connected to two parts of the skeleton. in vertebrates, msucle is anchored to bone via a tendon. usually, to move a body part back and forth, two muscles attached to the same section of the skeleton must be sequentially contract. skeletons also function in support and protection

cerebellum

coordinates motor commands to muscles

instantaneous growth rate can be expressed as

dN/dt = rinst*N

fast twitch

dark meat (bc of myoglobin)

"carbonaria"

dark, melanic, dominant; cryptic against the polluted background

stroke

death of nervous tissue in the brain due to a lack of O2

pitch

determined by the frequency of the sound wave, and different areas of the cochlea are receptive to different pitch

each sexually reproducing species has a characteristic

diploid and haploidd number

the number of possible combinations increases with the ______ number of the organisms, and equals _____, where ____ is the __________

diploid; 2n; n; haploid number

intrasexual selection

direct competition among individuals of one sex (often males) for mates of the opposite sex

inclusive fitness

direct fitness + indirect fitness

support for evolution

direct observations, homology, fossil record, biogeography

systematics

discipline that classifies organisms an determines their evolutionary relationships

map units

distances between genes; one map unit or centimorgan, represents a 1% recombination frequency; indicate relative distance and order, not precise locations of genes

convergent evolution

distantly-related organisms resemble each other because of convergent evolution; the independent evolution of similar features in different lineages; such features area analogous and not homologous (i.e. sugar gliders and flying squirrel)

basal taxon

diverges early in the history of a group and originates near the common ancestor of the group

pattern formation

driven by positional information; begins in the early embryo; cytoplasmic determinants and inductive signals contribute to developing the spatial organization for tissues and organs; for example, in Drosophila melanogaster, cytoplasmic determinants localized in the unfertilized egg provide positional information for the three axes

cytoplasmic streaming

driven by the cytoskeleton and circulates cytoplasm within a cell

most imprinted genes are critical for

embryonic development

when a population becomes crowded and resource competition increases

emigration often increases

corpus callosum

enables the right and left cerebral cortices to communicate

amnion

encases the fluid that protects the embryo

labia majora

encloses the vulva; within are the labia minora and the clitoris, which together with the vagina, engorge with blood during sexual arousal

yolk sac

encloses the yolk in the ehh of reptiles, and in mammals is a site for the early formation of blood cells

genes

encoded in DNA, and nuclear DNA is packed into chromosomes

the two major communication systems of animals

endocrine system and nervous system

kinases

enzymes that catalyze the transfer of phosphate groups, turning a hydrophobic residue into a hydrophilic one

protein tyrosine phosphates

enzymes that remove phosphate groups from phosphorylated tyrosine residues on proteins. they turn off RTKs

sperm traverses the _______ and completes maturation

epididymis

the sperm travel to the _________ and they become ________

epididymis; motile

dosage compensation

equalization of gene expression between the males and females of a species

the origin of self-replicating molecules that

eventually made inheritance possible

general rules about pedigrees for rare dominants:

every affected person has an affected parent; about half of the offspring of an affect parent are also affected; the phenotype usually occurs in both sexes

variation in heritable traits is a prerequisite for

evolution

Darin developed three main ideas

evolution explains life's unity; evolution explains life's diversity; natural selection is the cause of adaptive evolution

keystone species

exert strong control on e a community by their ecological roles, or niches (not necessarily abundant in the community)

the muscular uterus can

expand to contain a fetus

motor neurons

extend out of the processing centers and trigger a response in the form of muscle or gland activity.

astrocytes

facilitate information transfer at the synapse. participate in the forming of the blood-brain barrier

re-arrangements of genetic material can lead to

false conclusions

fast oxidative

fast contraction speed, aerobic respiration, intermediate rate of fatigue, many mitochondria, high myoglobin content (red muscle)

fast glycolytic

fast contraction speed, glycolysis, fast rate of fatigue, few mitochondria, low myoglobin content (white muscle)

tay sachs disease

fatal; a dysfunctional enzyme causes an accumulation of lipids in the brain. at the organismal level, the allele is recessive. at the biochemical level, the phenotype (i.e. the enzyme activity level) is incompletely dominant. at the molecular level, the alleles are codominant

hydrostatic skeleton

fluid held under pressure in a closed body compartment. these animals control their movement by changing the shape of their fluid-filled compartments. found in cnidarians, flatworms, nematodes, and annelids.

lymphatic system:

fluid lost by the capillaries is returned to the blood by the lymphatic system. this fluid is called lymph. the lymphatic system drains into large veins at the base of the neck. the mechanics flow via lymph vessels is similar to that of veins. along the lymph vessels are the lymph nodes, which are filled with white blood cells and play critical roles in defense. blockage of lymph flow results in edema.

the visual field: focus

focusing occurs by changing the shape of the lens. at the fovea, there is a high density of cones but no rods. this is the region with the sharpest receptive field, but it provides less sensitivity to light. the ratio of rods to cones increases with distance from the fovea.

beginning at puberty, _________ periodically stimulates a small group of follicles to resume growth and developmetn

follicle stimulating hormone (FSH)

often, it is the ________ of action potentials that encodes the signal

frequency

the frizzled gene in chickens

frizzled feathers, abnormal body temperatures, higher metabolic and blood flow rates, greater digestive capacity. lay fewer eggs

cell junctions

gap junctions in animals cells and plasmodesmata in plant cells allow molecules to pass readily between adjacent cells without having to cross plasma membranes

chorion

gas exchange

phylogenetic analyses use molecular data

genetic basis of characters knows. larger amount of phylogenetic information. any groups of organisms can be compared. different rates of evolution. mathematical modelling. character delimitation is straightforward. DNA is the ultimate level of information. aligning DNA data.

three levels of biodiversity

genetic diversity in a population; species diversity in an ecosystem; community and ecosystem diversity across a region

effects of genetic drift summary

genetic drift is significant in small populations; genetic drift can cause allele frequencies to change at random; genetic drift can lead to a loss of genetic variation within populations; genetic drift can cause harmful alleles to become fixed

effects of epinephrine and norepinephrine

glycogen broken down to glucose; increased blood glucose; increased blood pressure; increased breathing rate; increased metabolic rate; change in blood flow patterns, leading to increased alertness and decreased digestive, excretory, and reproductive system activity

FSH and LH are called

gonadotropins because they act on the gonads (male and female) and support gametogenesis

Changes in charge distribution due to ion flow through gated channels cause changes in membrane potential. There are two types of changes:

graded potentials, action potentials

morphogen gradient hypothesis

gradients of substances called morphogens establish the axes and other features

metapopulations

groups of populations linked by immigration and emigration

cladistics

groups organisms by common descent

homologous chromosomes

have the same length, centromere position, and gene arrangment (this is true for the autosomes but not for the sex chromosomes)

pangenesis hypothesis

hereditary substances called gemules or pangenes are shed by all parts of the organism and carried in the bloodstream

heterozygote advantage (overdominance)

heterozygote has greater fitness either homozygote. results in a balanced polymorphism

HDL

high-density lipoprotein

temporal and spatial expression of hox genes

homeotic genes that control A/P structures occur in the same linear sequence in fruit flies and mice; most of these genes are evolutionarily conserved, and their temporal and spatial expression follows the same pattern as the linear order on their chromosomes; they all include a sequence that encodes a homeodomain that binds to DNA (transcription factor)

z

how many species should be found in a habitat as its area increases

types of skeletal systems

hydrostatic and exoskeletons and endoskeleton

positive assortative mating

if the phenotype is under genetic control, positive assortative mating decreases heterozygosity for the genes affecting the trait; on average heterozygotes decreases if similar genotypes are pairing. note that heterozygotes are decreased by half each generation with complete positive assortative mating

microglia

immune cells in the CNS

lack of iodine

impedes production of active T3 and T4. this induces overproduction of TSH, and results in goiter and other problems

example of epistasis

in dogs and many other mammals, coat color depends on two genes. one gene determines the pigment color (with alleles B for black and b for brown). the other gene (with alleles E for pigment color and e for no pigment color) determines whether the pigment will be deposited in the hair

inheritance of sex-linked genes

in humans and other mammals, there are two varieties of sex chromosomes, X and Y. other animals have different methods of sex determination. genes on sex chromosomes (X-linked) exhibit a different pattern of inheritance than autosomal genes.

membrane potential (Vm)

in millivolts, where the electrical gradient is "strong enough" to attract the ions back across the membrane, thereby stopping the net flow of ions driven by the chemical gradient.

eosinophils

in mucosal surfaces an discharge enzymes that damage multicellular parasites

innate immunity in vertebrates:

in vertebrates, innate immunity co-exists with adaptive immunity. barrier defenses include: the skin, the mucous membranes lining the digestive, respiratory, urinary, and reproductive tracts (mucus traps particles that are then swept away). lysozymes in tears, saliva, and mucous secretions destroy the cell walls of some bacteria. the acidic environment of the stomach lyses many ingested pathogens. secretions from oil and sweat glands acidify the skin, preventing the growth of many bacteria.

FLO1

in yeast, variation in the number of TR repeats in the FLO1 gene, which encodes for a cell surface antigen, can make yeast cells stick to each other or be loose in the liquid culture

many species have mechanisms that help avoid or prevent

inbreeding

pancreas

insulin: lowers blood glucose level; glucagon: raises blood glucose level

Changes in charge distribution due to

ion flow through gated channels cause changes in membrane potential.

signals are

ions or molecules that directly or indirectly regulate protein function (Ca2+, amines, peptides, steroids)

positive feedback in the case of oxytocin

is because milk release induces more suckling, which induces the production of more oxytocin

negative feedback in the case of secretin

is due to the alkalinization of the duodenum, which decreases the production of secretin

locus

is fixed if all individuals in a population are homozygous for the same allele

endometrium

is rich in vasculature

cell determination

is the point where the cell is irreversibly committed to become a particular cell type; at this point the differentiation is set, even if the cell is transplanted; this is marked by the presence of tissue-specific proteins

what determines the number of species on an island?

islands are good "experimental models" to understand area effects if we can understand what determines diversity on islands, then we can generalize to how area affects diversity; we need to consider: the size of the island, distance from mainland, immigration, extinction; the equilibrium model of island biogeography maintains that species richness on an ecological island levels off at a dynamic equilibrium point

when isolation occurs

isolated populations may diverge genetically because of mutation, drift, and/or natural selection

because norms of reaction curves of different genotypes often cross each other,

it is not possible to predict the phenotypes of different genotypes in new environments (except for genotypes so defective that they will not survive in any environment)

zero population growth occurs when

lambda = 1

populations grow when

lambda > 1

in sexual reproduction, the egg is

large and non-motile

ependymal cells

line the ventricles of the brain

CNVs

loci where some individuals have one or multiple copies of a particular gene or genetic region, rather than the standard two copies (one on each homolog); many stem from segmental duplications

leaf abscission

loss of leaves prevents desiccation during periods of low water availability. a decreases in auxin renders the cells of the abscission layer more sensitive to ethylene, inducing abscission

mutations rates are ____ in animals and plants

low

social learning

many animals learn to solve problems by observing the behavior of other individuals; social learning forms the roots of culture

environment

many environmental conditions can directly increase the mutation rate

sexual dimorphism

marked differences between the sexes in secondary sexual characteristics

in humans, germ cells (2n) divide by

meiosis and result in gametes that contain a single set of chromosomes. gametes are haploid (n)

pineal gland

melatonin: participates in regulation of biological rhythms

biological species

members are reproductively compatible, at least potentially; they cannot interbreed with other populations

g-proteins

membrane proteins that bind energy-rich guanine nucleotides: GDP and GTP; composed of A subunit (binds GDP/GTP), and B and Y subunits

mutations are more rapid in

microorganisms

mesoderm

middle layer of embryo; skeletal and muscular systems; circulatory and lymphatic systems; excretory and reproductive systems (Except germ cells); dermis of skin; adrenal cortex

in humans, the zygote divides by

mitosis

in humans, somatic cells divide by ______ and contain ________ and are _______

mitosis and contain 23 pairs of chromosomes (46 in total)- a maternal and paternal set- and are diploid

in insects, multiple rounds of

mitosis occurs without cytokinesis; the nuclei then migrate to the outer edge of the embyro, and the plasma membrane form

DNA replication (comparison of mitosis and meiosis)

mitosis: occurs during interphase before mitosis begins meiosis: occurs during interphase before meiosis I begins

monozygotic twins

monozygotic twins results from the split of a blastocyst or early stage embryo; cell must be totipotent; the timing of the split impacts the nature of the placenta or placentas

most genes exist in populations in

more than two allelic forms

Morgan's experiment

morgan mated male flies with white eyes (mutant) with female flies with red eyes (wild type). the F1 generation all had red eyes. the F2 generation showed the 3:1 red:white eye ratio. morgan determined that the white eye mutant allele must be located on the X chromosome. morgan's finding supported the chromosome theory of inheritance

mechanical isolation

morphological differences can prevent successful completion of mating

characters can be

morphological, behavioral, physiological, or molecular

DNA transponsons

move through a DNA intermediate; "cut-and-paste" or "copy-and-paste"

Retrotransposons

move through a RNA intermediate; always "copy-and-paste"; most abundant

translocation

moves a segment from one chromosome to another

skeletal muscle

moves the bones and the body and is progressively broken down into: a bundle of muscle fibers, a multinucleated muscle fiber, a myofibril that contains thin and thick filaments. thin filaments attach at the Z lines (the edge of the sacromere). thick filaments are anchored in the M-lines (the middle of the sarcomere). during rest, the thin and thick filaments partially overlap.

genetic diversity arises via

mutations and recombination

oligodendrocytes

myelinate axons in the CNS

schwann cells

myelinate axons in the PNS

the rapid evolution of antibiotic resistance in Staphylococcus aureus

natural selection can only act on variation with a genetic component. the bacterium Staphylococcus aureus is commonly found on people. one strain, methicillin-resistant S. aureus (MRSA) is a dangerous pathogen. when exposed to methicillin, MRSA strains are more likely to survive and reproduce than nonresistant S. aureus strains. MRSA stains are now resistant to many antibiotics

When bundled together, the axons of neurons form

nerves

major kinds of innate immune cells

neutrophils, macrophages, dendritic cells, eosinophils, mast cells, natural killer cells

nonparental phenotypes

new combinations of traits

what happens to allele frequencies under inbreeding each generation, for alleles with no effect on fitness?

no change in allele frequencies in large populations

wild type

normal

genes imprinted in the germ line are

not expressed early in fetal develpoment

telophase II and cytokinesis

nuclei form, the chromosomes begin to de-condense, and cytokinesis occurs

founder effect

occurs when a few individuals become isolated from a larger population (a form of bottleneck); allele frequencies in the small founder population can be different from those in the larger parent population

balancing selection

occurs when natural selection maintains stable frequencies of tow or more phenotypic forms in a population; includes heterozygote advantage and frequency-dependent selection

when a stem cells divides

one daughter remains a stem cell while the other one specializes. lymphoid stem cells. myeloid stem cells.

there are two normal exceptions to Mendelian genetics

one exception involves gene located in the nucleus, the other involves genes located outside the nucleus. in both cases, the sex of the parent contributing an allele is a factor in the pattern of inheritance

monogamy

one male mates with one female; males and females typically have similar external morphologies

Elvis monkey

one of more than 1,000 new species discovered this century in the Greater Mekong region of southeast Asia

genes can be transferred horizontally from

one organism to an unrelated one

parasitism (+/- interaction)

one organism, the parasity, derives nourishment from another organism, its host, which is harmed in the process, but is usually not lethal

cervix

opens into the vagina

a couple of examples of amazing adaptations

orchids that mimic female wasps; shape shifting octopus

equilibrium

organs in the inner ear detect body movement, position, and balance. the utricle and saccule detect position in terms of gravity or linear movement. These chambers contain hair cells that project into a gel that contains calcium carbonate particles called otoliths. Bending of hair by the otoliths signals the angle of the head. Three fluid-filled semicricular canals connected to the utricle detect turning of the head and rotational acceleration

antidiuretic hormone and the posterior pituitary

osmoreceptors in the hypothalamus monitor blood osmolarity. when too increased (too salty), ADH is released; this induces thirst and increased water reabsorption by the kidneys; when back to normal, ADH release ceases

mitosis of stem cells can give rise to

other stem cells, precursor cells that differentiate further

because signaling by neurons can regulate the release of hormones, the nervous and endocrine systems often...

overalp in function

frequency of AA offspring is

p^2

hardy-weinberg rule

p^2 + 2pq + q^2 = 1

biological clocks and circadian rhythms are maintained by the phytochrome switch

plants use light to maintain their biological clocks; however, if you place a plant in the dark, it maintains its clock, although it starts to drift; the environment stimulus that plants use most often to determine the time of year is photoperiod, which is determined by night length; controls flowering and other processes

receptor Tyrosine kinases (RTKs)

plasma membrane receptors with enzymatic activity; RTKs catalyze the transfer of a phosphate group from aTP to tyrosine residues on a substrate protein; unlike a GPCR, which activates a single pathway, an RTK can simultaneously activate multiple signal transduction pathways; abnormal RTK function is associated with several types of cancer

patterns of diversity have been influenced by large-scale processes such as

plate tectonics, mass extinctions, and adaptive radiations

types of mutualisms

pollination, trophic, defensive, dispersive

complete nondisjunction leads to

polyploidy, a condition in which an organism has more than two complete sets of chromosomes

dynamic biological processes influence

population density, dispersion, and demographics

natural selection is a

process of selection. it is not a creative mechanism

multipotent stem cells

produce blood cells and are located in the red marrow inside bones

crossing over

produces recombinant chromosomes: individual chromosomes that carry DNA derived from two different parents (in humans, meiosis results in 1 to 3 crossover events per chromosome pair); the orientation of chromosomes at metaphase II is random, further increasing variations (for humans, this is 2^23 x 2^23 or 70 trillion)

fertilization

produces the zygote

primary immune response:

production of effector cells from a clone of lymphocytes during the first exposure to antigen. peaks 10-17 days after the initial response.

parasympathetic division

promotes calming and a return to self-maintainence; most nerves exit at the base of the brain, form synapses near or within an internal organ; Ach

william hamilton

proposed a quantitative measure for predicting when natural selection would favor altruistic acts among related individuals

the per capita rate of increase (r) is

r = b-m

natural selection favors altruism when

rB > C (or rb-c>0)

plants that can move

rapid movements (at least for a plant) can occur when there is rapid loss of turgor within pulvini, which are specialized motor organs at the leaf joint. stimulation causes cells of the pulvini to lose potassium and a s a consequence water leaves the cells (vacuoles) by osmosis; when it happens in response to touch it is called thigmotropism

genes undergoing selection can be

rapidly evolving and contain many convergently evolving sites

tay-sachs

rare autosomal recessive; completely lethal before reproduction

diencephalon

receives sensory input going to the cerebrum (thalamus), has neuroendocrine function (hypothalamus), and is sthe source of melatonin (pineal)

three stages of cell signaling

reception, transduction, response

two general kinds of receptors

receptors on the cell membrane and intracellular receptors

g-protein coupled receptors

receptors with seven transmembrane domains that work with the help of g proteins (over 700 GPCRs are encoded in the human genome); hormones such as epinephrine and many neurotransmitters function via GPCRs; GPCRs function in embryonic development, sensory reception, and many other processes; GPCRs are a frequent target of drugs; malfunction or interference results in disease

the X __________ when in females by the male-limited Y is ___________

recombines; nonrecombining

RBC

red blood cell = erythrocyte

gene flow tends to

reduce variation among populations over time

What determines variation in biological diversity?

relatively small-scale or local factors that influence the diversity of communities (e.g. the effects of species interactions, keystone species, disturbances); large scale biogeographic factors also contribute to the tremendous range of diversity observed in biological communities; two key factors: latitude of a community and the size and location of the area a community occupies

diastole

relaxation

vasodilation

relaxing of smooth muscle, via nitric oxide

mast cells

release histamine

evaporation

removal of what from the surface of a liquid (e.g. sweat) that is losing some of its molecules as gas

cri du chat

results from a specific deletion in chromosome 5. a child born with this syndrome is severely intellectually disabled and has a catlike cry; individuals usually die in infancy or early childhood.

aneuploidy

results from the fertilization of gametes in which nondisjunction occurred and results in monosomic (2n-1) and trisomic (2n+1) individuals

effects of mineralocorticoids

retention of sodium ions and water by kidneys; increased blood volume and blood pressure

interspersed repeats

retrotransposons and DNA transposons

frequency-dependent selection example

scale-eating fish of Lake Tanganyika; attack other fish by sneaking up, rushing them, biting off a moutfulof scales; those with mouths that curve to the right attack the left side of victims and vice-versa; handedness of mouth determined by a single locus with 2 alleles; right-handedness is dominant

examples of neurological disorders

schizophrenia, depression, drug addiction, alzheimer's disease, parkinson's disease

______, ________, and _______ produce secretion that combine with the sperm to form the semen

seminal vesicles, prostate gland, and bulbourethral glands

chemoreceptors

sense chemical cues; there are two main kinds: general receptors and specific receptors

pain receptors (nocireceptors)

sense extreme conditions and trigger defensive reactions, such as withdrawal from danger

mechanoreceptors

sense physical deformation caused by mechanical energy (pressure, touch, stretch, motion, sound). these are typically ion channels that are linked to external or internal structures. bending or stretching alters the permeability of ion channels. They are usually embedded in connective tissue

Information processing in the nervous system occurs in three stages

sensory input, integration, motor output

a cascade of developmental regulation

sequential (hierarchial) expression of genes is controlled by transcription factors that bind to enhancers upstream of promoters of the controlled genes; maternal effect genes; gap genes; pair-rule genes; segment polarity genes; homeotic (Hox) genes

basal nuclei

serve as centers for planning and learning movement sequences

mutations rates may be affected by

sex, generation time, the environment, and physiological stress

recessively inherited disorder

show up only in individuals homozygous for the allele (~4000 autosomal recessive diseases known); carries are heterozygous individuals who carry the recessive allele but are phenotypically normal. albinism is a recessively inherited phenotype. (cystic fibrosis, hemochromatosis, phenylketonuria, spinal muscular atrophy)

biochemical processes in diverse organisms are

similar

homology

similarity resulting from common ancestry

anaphase II

sister chromatids separate and move toward opposite poles

haplodipoidy means

sisters share 75% of their genes, compared to normal 50% between females and their offspring

slow oxidative

slow contraction speed, aerobic respiration, slow rate of fatigue, many mitochondria, high myoglobin content (red muscle)

types of skeletal muscle fibers

slow oxidative, fast oxidative, fast glycolytic

altruism

some animals even behave in ways that reduce their individual fitness but increase the fitness of other; in species like ants and naked mole rats, nonreproductive individuals may sacrifice thier lives protecting their reproductive queen and king from predators

experience and behavior:

some behaviors vary with experience, and thus, differ between individuals. experience during development can modify physiology in a way that alters parental beahvior, extending the influence of environment to a subsequent generation. (example mice)

hybrid breakdown

some first-generation hybrids are fertile, but when they mate with each other or with either parent species, offspring of the next generation are feeble or sterile

heterozygote advantage

some individuals who are heterozygous at a particular locus have greater fitness than homozygotes; natural selection will tend to maintain two or more alleles at that locus when heterozgyote advantage occurs; can result from stabilzing or directional selection

temporal isolation

species that breed at different times of the day, different seasons, or different years cannot mix their gametes

steps in fertilization

sperm dissolve or penetrate any protective layer surrounding the egg, and reaches the plasma membrane; molecules on the sperm surface bind to receptors in the egg surface (ensures species compatibility); changes at the surface of the egg precent polyspermy (only one sperm is allowed to enter)

gametic isolation

sperm of one species may not be able to fertilize eggs of another species

the spermatids differentiation into

sperm, with an acrosome and a motile tail

feedback regulation: simple neuroendocrine pathway

stimulus is received by a sensory neuron; the neuron stimulates a neurosecretory cell, which secretes a neurohormone; the neurohormone travels via the bloodstream to the target cell, interacts with a receptor, and triggers a physiological response

cells of diverse organisms are

structurally similar

behavior is subject to

substantial evolutionary selection over time, which affects anatomy

if there are rare deleterious recessive alleles, most individuals will not

suffer from deletertious effects because they are most likely to be found in heterozygotes (2pq is much greater than q^2 when q is small)

intermediate disturbance hypothesis

suggests that moderate levels of disturbance can foster greater diversity than either high or low levels of disturbance; high levels of disturbance exclude many slow-growing species; low levels of disturbance allow dominant species to exclude less competitive species

ethylene and the triple response to mechanical stress

the "triple response" allows growing shoots to avoid obstacles. when the tip of the plant contacts an obstacle the plant produces ethylene which triggers the triple response: slowing of stem elongation, thickening of the stem (Strength), a curvature that causes the stem to grow horizontally (to avoid the obstacle)

Ras/MAPK pathway

the Ras family is composed of about 30 "small G-proteins"; small G-proteins ("small GTPases") are similar in function to the A subunits of G-proteins. they are activated by the exchange of GDP for GTP, which is promoted by Guanine Exchange Factors (GEF). GEFs can be activated by a variety of pathways such as by binding cAMP; ~30% of all cancers contain mutations in the genes that encode for Ras proteins

associative learning

the ability to associate one environmental feature with another. blue jays, for example, avoid eating monarch butterflies. this is because they associate monarch butterflies with vomiting and indigestion (vomiting is due to substances that the monarch butterflies accumulate from the milkweed plants they eat)

bioinformatics

the application of computational methods to the storage and analysis of biological data

organogenesis: neurulation in chicks

the archenteron forms when lateral folds pinch the embryo away from the yolk; the notochord, neural tube and somites develop much like in the frog; by 3 days, and 2-3 mm in length, rudiments of most major organs are visible

transduction

the binding of the signaling molecule alters the receptor and initiates an intracellular signal transduction pathway. transduction often occurs in a series of steps

limitations of the biological species concept

the biological species concept annot be applied to fossils or asexual organisms (including all prokaryotes). the biological species concept emphasizes absence of gene flow. however, gene flow can occur between distinct species. for example, grizzly bears and polar bears can mate to produce "grolar bears"

at ovulation, the oocyte is released into

the body cavity and cilia on the epithelial lining of the oviduct help collect it by drawing fluid from the body cavity into the oviduct

the evolutionary or modern synthesis of Darwin and Mendel

the body of work that reconciled the sciences and findings of genetics, systematics, and paleontology with Darwin's theory of evolution by natural selection

prophase I

the centrosomes move, the spindle forms, and crossing over occurs

closed circulatory system

the circulatory fluid is called blood. it is confined to the veseels and is distinct from the interstitial fluid (annelids, cephalopods, vertebrates)

open circulatory system

the circulatory fluid is called hemolymph which is also the intersitial fluid that bathes the cells (anthropods and some mollusks)

testing genetic equivalence in plants

the cloning of a whole carrot plant from a single carrot root cell; in this example, differentiated cells taken from the root grew into normal adult plants; these new adults plants are all genetically identical: organismal clones

example of patition ecological niches temporally

the common spiny mouse and the golden spiny mouse show temporal partitioning of their niches. both species are normally nocturnal (active during the night). where they coexist, the golden spiny mouse becomes diurnal (active during the day)

relative fitness

the contribution of a genotype to the next generation, compared with contributions of alternative genotypes for the same locus

carbon fixation

the conversion of inorganic carbon (CO2) into organic compounds

sensory reception and transduction

the effect of sensory reception is to open or close ion channels, resulting in a change in the membrane potential. For example, when a substance binds a chemical receptor. The conversion of a stimulus to a change in the membrane potential is called sensory transduction, and the change in the membrane potential itself is called receptor potential.

in sexual reproduction, the female gamete is called

the egg

cytoplasmic determinants

the egg's cytoplasm contains RNA and proteins encoded in the mother's DNA; these factors, called cytoplasmic determinants, are unevenly distributed in the cytoplasm, and cell divisions partition them unevenly into different cells; the collection of cytoplasmic determinants in a cell controls the cell's fate by regulating the expression of specific sets of genes; cytoplasmic determinants are especially important early in development

de-etiolation (greening)

the elongation of stems slows, leaves expand, and chlorophyll is produced; induced by the light-mediated activation of a phytochrome receptor; a signal transduction pathway involving a receptor, ion channels, second messengers, protein kinases and transcription factors leads to the greening response

phylogeny

the evolutionary history of a species of group of related species

oogenesis

the formation and development of oocytes, and it occurs in the ovaries

spermatogenesis

the formation and development of sperm; it occurs in the seminiferous tubules contained within the testes

interactions between plates cause

the formation of mountains and islands, and earthquakes

oogenesis begins with

the formation of oogonia from primordial germ cells

theory of evolution

the genetic composition of a population changes over time; the process of evolution is primarily driven by natural selection (descent with modification)

atherosclerosis

the hardening of arteries by fatty deposits. this is caused by the accumulation of cholesterol into a plaque, followed by inflammation. exercise decreases LDL:HDL (decreasing risk), whereas smoking and trans-fats increases it

the mammalian heart:

the heart is made of cardiac muscle. diastole (relaxation) of the atria allows most blood to enter the ventricle. the rest is transferred during atrial systole (contraction). systole of the more muscular ventricles pumps blood out of the heart. one complete cycle is called the cardiac cycle. Pulmonary circuit and systemic circuit. the cardiac output (5 L/min) is dependent on the heart rate (72) and the stroke volume (70 mL). four heart valves prevent backflow. backflow results in a heart murmur

advantages of a closed circulatory system

the higher blood pressure means more effective delivery of O2 and nutrients to the cells. this type of system is particularly well suited for larger and more active animals. it is better suited for regulating the distribution of blood different organs

HIV

the human immunodeficiency virus (HIV) both escapes and attacks the adaptive response. HIV infects helper T cells by binding CD4, and replicates within. This kills the cell, which with time impairs both humoral and cellular immune responses, resulting in acquired immunodeficinecy syndrome (AIDS). those afflicted often succumb to an opportunistic infection. HIV escapes the immune response because of a high mutation rate.

in mammals, thermoregulation is controlled by

the hypothalamus; warm sensors signal the hypothalamic thermostat when the temperature of the blood increases, activating cooling mechanisms. likewise, cold sensors activate heating mechanisms

"particulate" hypothesis

the idea that parents pass on discrete heritable units (genes); Mendel documented a particulate mechanism through his experiments with garden peas

hemophilia

the inability to properly form clots

example of signaling pathway complexity

the insulin pathway regulated glucose levels in the blood via a receptor tyrosine kinase. Insulin: activates glucose transporters, initiates glycolysis, inhibits glycogen breakdown, promotes glycogen synthesis, alters gene transcription, and initiates the synthesis of new proteins

advantages of an open circulatory system

the lower hydrostatic pressure means that they are less energetically costly (but they are not well suited for gas exchange)

Equilibrium Potential (E)

the magnitude of a cell's membrane voltage at equilibrium; calculated using the Nernst equation.

phylogenetic tree

the mathematical structure used to depict the evolutionary history of a group of organisms or genes; show historical relationships, not similarities; represents a hypothesis about evolutionary relationships

ovarian cycle (7)

the maturing follicle enlarges and ~1 day after the LH/FSH surge the follicle ruptures, releasing the 2ry oocyte to the outside of the ovary (this begins the luteal phase)

carrying capacity

the maximum population size that a particular environment can sustain' varies over time and space as limiting factors vary (e.g. energy, shelter, predation, nutrient availability, water, suitable nesting sites)

extracellular matrix (ECM)

the meshwork of secreted glycoproteins and other molecules that lie outside of the plasma membrane; specific components in the ECM guide specific cells

imprinting if often the result of

the methylation (addition of CH3) of cysteine nucleotides

some prey species gain significant protection through mimicry,

the mimicking of the appearance of another species (Batesian and Mullerian)

gene flow

the movement of alleles among populations; the transfer of alleles into or out of a population due to the movement of fertile individuals or their gametes, can also change allele frequencies

alleles can be transferred through

the movement of fertile individuals or gametes (i.e. pollen)

the nervous system

the nervous system recieves (sensory input), processes (integration), and rapidly transmits information directing the appropriate physiological or behavioral response (motor output) with a provision for modifying the response with experience (learning and memory). these processes involve changes in the difference in the electrical potential (voltage) across the plasma membrane that arise from the regulated movement of ions across the membrane

behavior

the nervous system;s response to a stimulus and is carried out by the muscular or the hormonal system; subject to natural selection; have a genetic basis, are heritable, and can evolve by natural selection

realized niche

the niche actually occupied by a species

fundamental nich

the niche potentially occupied by that species

determining microbial diversity using molecular tools

the number of abundance of the different sequences of a particular gene (e.g. ribosomal DNA) in a sample can be used to approximate the number and abundance of microbial species in a sample; through PCR and sequencing samples from different microbial communities, we can estimate and compare their diversities

allele frequencies

the number of copies of an allele in a population

genotype frequencies

the number of copies of different combinations of alleles (genotypes) in a population

L is

the number of generation links between the individuals

population density

the number of individuals per unit area or volume

the theory of island biogeography summary

the number of species on an island should be at equilibrium (roughly constant over time); this equilibrium is dynamic (i.e. the result of continual turnover of species; some become extinct, and new ones arrive); large islands should support more species relative to smaller islands at equal distances; distant islands should have fewer species relative to close islands of equal size; large, close islands will have the most diversity; small, distant islands the least

because genes are inherited from two parents...

the offspring has a unique combination of genes. this uniqueness is in large part due to meiosis followed by fertilization

the most parsimonious tree

the one with the smallest number of changes

diversity through gene duplication

the origin of the gamma fetal Hgb coincides with the origin of the placental mammals. gamma Hgb binds oxygen with a higher affinity, enabling efficient transfer of oxygen from the bloodstream of the mother to the fetus

(spermatogenesis) stem cells are on

the outer edge of the seminiferous tubules. as the progeny develops, they move inward, and sperm are released into the lumen

the uterine cycle is controlled by

the ovarian cycle (hormonal activity links the two cycles)

fertilization usually occurs in

the oviduct

logistic growth model

the per capita rate of increase declines as carrying capacity is reached; starts with the exponential model and adds an expression that reduces per capita rate of increase as N approaches K; rather than a J-curve, we get a symmetrical S-shaped cruve with an upper asymptote; growth rate declines when the population size gets large

incomplete dominance

the phenotype of F1 hybrids is somewhere between the phenotypes of the two parental varieties

polyploidy

the presence of extra sets of chromosomes due to accidents during cell division; much more common in plants than in animals; can produce new biological species in sympatry within a single generation

thermoregulation

the process by which animals maintain their body temperature within a normal range

cognition

the process of acquiring knowledge that involves awareness, reasoning, recollection, and judgment. problem solving is evidence of cognitive learning. (experiment: (1) train bees in the color maze (2) test bees in the pattern maze; result: bees can distinguish "same" from "different")

gene annotation

the process of identifying all protein-coding genes in a genome sequence and ultimately their functions

apoptosis is essential for

the proper development of the nervous and immune systems, and for the formation of the hands and feet

relative abundance

the proportion each species represents of the total individuals in the community

adaptive radiation

the rapid evolution of diversely adapted species from a common ancestor; may follow mass extinction, the evolution of novel characteristics, the colonization of new regions

age structure

the relative number of individuals at each age in the population; predict a population's growth trends and can illuminate social conditions

klinefelter syndrome

the result of a extra chromosome in a male, producing XXY individuals. 1:500-1,000. unusually small testes, sterile. breast enlargement and other feminine body characteristics.

Mendel's laws of segregation and independent assortment reflect

the rules of probabilty

biogeography

the scientific study of the geographic distribution of species, provides evidence of evolution. earth's continents were formerly united in a single large continent called Pangaea, but have since separated by continental drift; an understanding of continent movement and modern distribution of species allows us to predict when and where different groups evolved; Darwin's famous voyage on the Beagle allowed him to study the distribution of different organisms, and provided important clues about the origin of species

ecological succession

the sequence of community and ecosystem changes after a disturbance; succession is the result of changes induced by the vegetation itself

signals alter

the shape or conformation of target proteins, thus activating or inactivating them (allosteric regulation or covalent modification)

population dynamics

the size of populations doesn't always remain stable. some populations fluctuate in size. other populations experience regular cyclic changes. yet others are influenced by immigration and emigration. the study of population dynamixs focuses on the complex interactions between biotic and abiotic factors that cause variation in population size

cell differentiation

the specialization of structure and function

CNS (brain and spinal cord)

the spinal cord conveys information to and from the brain, and also acts independently from the brain to produce reflexes

prophase II

the spindle forms

speciation

the splitting of an ancestral lineage (species) into one or more descendants which ultimately means that all organisms on earth are related to each other via a gigantic 'tree' of common descent, the tree of life

homeostasis

the steady-state physiological condition of the body

sensory perception

the stimulus is processed when the action potentials reach the brain, generating the perception of the stimulus. These action potentials travel along neurons that are dedicated to a particular stimulus. The brain distinguishes between stimuli (e.g. sight or sound) by the path they take.

fossil record

the study of fossils helped to lay the groundwork for Darwin's ideas. Fossils are remains or traces of organisms from the past, usually found in sedimentary rock. the fossil record provides evidence of the extinction of species, the origin of new groups, and changes within groups over time

population ecology

the study of populations in relation to environment, including environmental influences on density and distribution, age structure, and population size

behavioral ecology

the study of the ecological and evolutionary basis for animal behavior

behavioral ecology

the study of the ecological and evolutionary basis of animal behavior

demography

the study of the vital statistics of populations and how they change over time

reception

the target cell detects a signaling molecule that binds to a receptor protein. binding of the signal (1st messenger or ligand) triggers a conformational change that activates the receptor

ecological niche

the total of a species' use of biotic and abiotic resources - an ecological niche can also be through of as an organisms' ecological role

life history

the traits that affect an organism's schedule of reproduction and survival; evolutionary outcomes reflected in the development, physiology, and behavior of an organism

response

the transduced signal triggers a specific response in the target cell. the cell signaling process helps ensure that crucial activities occur in the appropriate time and space

food chain

the transfer of energy up the trophic levels; are not isolated from each other but are linked together in food webs

short segments at the ends of the Y chromosome are homologous with the X, allowing

the two to behave like homologues during meiosis in males

gas exchange refers to:

the uptake of O2 from the environment and the discharge of CO2 into the environment

the penis contains

the urethra as well as three cylinders of spongy tissue that can fill with blood to form an erection

muscle and cilia action moves the egg toward

the uterus

mutation and sexual recombination produce

the variation that makes evolution possible

species diversity of a community

the variety of organisms that make up the community; two components: species richness and relative abundance

ingroup

the various species being studies

waggle dance of honeybees

the waggle dance informs the hive about the distance and direction to food. if the food is near (<50 m), the bee performs the "round dance". odor informs on the source. if food is far, the bee performs the "waggle dance". a half circle in one direction, a straight run with a waggle, and a half circle in the other direction. the angle of the straight run relative to the hive's vertical surface represents the horizontal angle of the food relative to the sun. the longer the straight run, the longer the distance

there is no systematic relationship between

their phenotypic effect and the needs of the organism in which they occur

cells receive signals from

their physical environment and from other cells

ecologically similar species can co-exist in a community if

there are one or more significant differences in their niches

variation in resistance to malaria

there are three genotypes: SS, SA, and AA. sickle cell carriers were 6.2% less likely to be infected by malaria than were normal normal homozygotes. SS homozygotes suffer from complications of anemia that, without treatment, increase mortality. SA heterozygote have the highest fitness in the presence of malaria. The S variant is caused by a mutation in the sixth position of the B-globin chain of hemoglobin. this results in the replacement of hydrophilic glutamic acid by hydrophobic valine.

dominant species

those that are most abundant or have the highest biomass

quantitative characters

those that vary in the population along a continuum

in males, the Y chromosome is ___________ than the X

three times less numerous

the land masses of Earth have formed a supercontinent

three times over the past 1.5 billion years: 1.1 billion, 600 million, and 250 million years ago

thyroid gland

thyroid hormone (T3 and T4): stimulates and maintains metabolic processes; calcitonin: lowers blood calcium level

adaptations

traits that have evolved through the mechanism of natural selection

in the nucleus, signaling pathways may end with the activation of

transcription factors that turn on or off the transcription of specific genes; example: transcription factor CREB is phosphorylated by PKA. it then binds CRE in DNA to activate transcription. CRE-activated genes are involved in gluconeogensis, memory, etc. a low level of CREB is associated with Alzheimer's

convection

transfer of heat by the movement or air of liquid past a surface

radiation

transfer of radiating (electromagnetic) heat

conduction

transfer of thermal motion (heat) between molecules of objects that are in contact with each other

sensory neurons

transmit information about external stimuli.

general receptors (chemo)

transmit information about total solute concentration (e.g. osmoreceptors)

middle ear

transmit vibrations to the oval window

PNS

transmits information to and from the CNS and plays a large role in regulating both an animal's movement and its internal environment

parkinson's symptoms are alleviated by

treatment with L-dopa; after it crosses the blood-brain barrier, L-dopa is converted to DA by the enzyme, dopa decarboxylase

there is more species diversity in the

tropics

Ca2+ and regulatory proteins regulate muscle contraction:

tropomyosin and the troponin complex are bound to the actin strands of thin filaments. at rest, tropomyosin covers the myosin binding sites. When Ca2+ accumulates, it binds to the troponin complex, which shifts the position of tropomyosin, exposing the myosin binding sites. motor neurons cause muscle contractions by triggering the release of Ca2+ into the cytosol of muscle cells with which they form synapses.

pituitary

two fused glands: the posterior pituitary and the anterior pituitary

sister chromatids

two identical copies of a single chromosome and are closely associated along their length

a dihybrid or other multicharacter cross is equilivalent to

two or more independent monohybrid crosses occurring simultaneously

habitat isolation

two species encounter each other rarely, or not at all, because they occupy different habitats, even though not isolated by physical barriers

tandem repeats

typically found at the centromeres and telomeres of chromosomes these are duplications of more complex 100-200 base sequences

stress

under some conditions, increased rates of mutation appear adaptive

X chromosomes have genes for many characters

unrelated to sex

therapeutic cloning

use stem cells to treat disease

the dihybrid cross

using a dihybrid cross, Mendel developed the law of independent assortment. it states that each pair of alleles segregates independently of each other pair of alleles during gamete formation. this law applies only to genes on different, nonhomologous chromosomes or those far apart on the same chromosome. genes located near each other on the same chromosome tend to be inherited together.

cognitive map

using spatial learning to form; stores the spatial relationship between objects

in sexual reproduction, the sperm is

usually much smaller and motile

kin selection

usually refers to natural selection favoring alleles that increase indirect fitness

because pressure in veins is relatively low,

veins have valves that prevent backflow

mark infected cells for destruction

viral-infected cells are recognized and marked for killing by natural killer

antimicrobial peptides and proteins and the antimicrobial response:

virus-infected cells secrete interferons that induce nearby cells to produce factors that inhibit viral replication. other interferons enhance phagocytosis by macrophages. the complement system consists of ~30 plasma proteins that are activated by microbes, resulting in a biochemical cascade that lyses pathogens. it is also involved in inflammation and in adaptive defenses. also antimicrobial peptides

endotherms

warm their body mostly be heat generated by mtabolism

"blending" idea

was common at the time of Mendel- ideas that genetic material from the two parents blends together

memories are stored in the cerebral cortex:

we hold information for a time in "short-term memory" and release it if it becomes irrelevant. this information is accessed via temporary links formed in the hippocampus (in the limbic system; at the medial temporal lobe). other information is held in "long-term memory". these are connections in the cerebral cortex itself, where new data is associated with already stored memory. memory consolidation is thought to occur during sleep, and be the basis of some of our dreams

two general questions about regulation of population growth

what environment factors stop a population from growing indefinitely? why do some populations show radical fluctuations in size over time, while others remain stable?

example using the model of discrete growth:

what is the population size in 10 generations? N0= 100, lambda = 1.15, t= 10 generations

Barr body

what the inactive X condenses into

inheritance of characters by a single gene may deviate from simple Mendelian patterns in the following situations:

when alleles are not completely dominant or recessive; when a gene has more than two alleles; when a gene produces multiple phenotypes

language

when repeating a spoken word, activity travels from the auditory cortex (temporal) to Wernicke's area (temporal) and tehn on to Broca's area (frontal_ and the motor cortex (frontal); when repeating a written word, the flow of activity is from the visual cortex (occipital) to Wernicke's area, then Broca's area to motor cortex

ectopic pregnancy

when the fertilized egg lodges in an oviduct

aneurysm

when the wall of a vessel weakens and balloons outward

facultative

where both species can survive alone

obligate

where one species cannot survive without the other

which mating system occurs depends upon

whether 1 or 2 parents can effectively raise offspring and whether mates are clumped or dispersed and can be economically defended

slow twitch

white meat

the human lineage of tetrapods evolved around

6-7 MYA

Modeling of the resting potential:

Resting potential can be modeled by an artificial membrane that separates two chambers: To start, the concentration of KCl is higher in the inner chamber and lower in the outer chamber. Because of K+ channels, K+ diffuses down its gradient to the outer chamber. Negative charge (Cl-) builds up in the inner chamber. At equilibrium, the electrical and chemical gradients balance each other.

spinocerebellar ataxia type 1

SCA1 locus, normal (CAG)6-44, repeated sequence mutated (CAG)39-82

machado-joseph disease

SCA3 locus, normal (CAG)12-40, repeat sequence mutated (CAG)55-84

diversity decreases as

latitude increases

_____________ govern Mendelian inheritance

laws of probability

anaphylactic shock

leads to constriction of bronchioles, dilation of peripheral blood vessels, and drop in blood pressure

excessive GH during development

leads to gigantism

excessive GH in adults

leads to growth of body parts still responsive to GH: face, hands, feet (acromegaly)

both the unfertilized egg and the sperm typically survive

2-3 days

retinal

light absorbing molecule

white matter (spinal cord)

makes up the outer layer

blood pressure steps

(1) pressure in cuff closes the artery (2) as pressure drops, blood passes during systole. this is the systolic pressure (3) pressure continues to drop, blood passes during both systole and diastole. this is the diastolic pressure

what affects the pacemaker:

(1) temperature (2) hormones (epinephrine) (3) sympathetic division (increases) (4) parasympathetic division (decreases)

mammalian cardiovascular system:

(1-3) the right ventricle pumps blood to the lungs via the pulmonary arteries. in the capillary beds it loads O2 and unloads CO2. (4) blood returns to the left atrium of the heart via pulmonary veins (5-6) oxygenated blood flows into the left ventricle, which pumps it into the systemic circuit via the aorta (7-8) the aorta delivers blood to capillary beads in the head and forelimbs, and capillary beds in the abdominal organs and legs (9-10) oxygen-poor blood is funneled into two large veins: the superior vena cava and the inferior vena cava (11) the two venae cava empty their blood into the right atrium, and blood moves to the right ventricle

foundation species

(aka "ecosystem engineers") exert their influence on the community by dramatically altering the physical environment

homology

(ancestral structures that have evolved different functions); mammalian forelimbs (same arrangement of bones in humans, cats, wales, bats); comparative embryology (human embryo and chick embryo both have pharyngeal arches and post-anal tails); genetics and genomics (organisms share a genetic code. many genes and biochemical pathways are conserved between species. generally, the more closely related the species are, the more closely related their genetic sequences are. alignment of the genetic sequence of the globin gene reveals the following differences: 0.08% among humans, 1.1% between humans and chimps, 1.5% between humans and gorillas, 1.6% between chimps and gorillas)

mating relationships

(called mating systems) are also shaped by natural selection

the degree of dominance

(the nature of the association between alleles in a given genotype) will determine the pattern of slection

hypothyroidism

(too little thyroid to function) can produce symptoms such as weight gain, lethargy, and cold intolerance

receptor tyrosine kinases:

1. inactive receptors exist as monomers. each has a ligand binding site, and A helix spanning the membrane, and an intracellular tail containing multiple tyrosine residues 2. binding of the ligand causes the monomers to dimerize 3. dimerization activates the tyrosine kinase region of each monomer. each tyrosine kinase adds a phosphate from an ATP molecule to a tyrosine on the tail of the partner monomer 4. the activated receptor is recognized by specific relay proteins inside the cell. each relay protein binds a specific phosphorylated tyrosine, inducing a conformational change that activates the protein. this induces a signal transduction pathway that leads to a cellular response

darwin's insight

1. individuals vary within populations 2. variants more or less suited to environment 3. differential survival and reproduction of individuals (variation is heritable) 4. favorable characters passed on, increase in frequency natural selection: differential success in reproduction results in certain alleles being passed to the next generation in greater proportions

three mechanisms leading to a skewed pattern of the x-chromosome inactivation in females

1. the normal, random process of X inactivation. maternally derived (blue) X chromosomes or paternally derived (purple) X chromosomes are inactivated at random independently in each cell early in embryogenesis 2. one X chromosome bears a mutation (green dot) that hinders cell survival in a particular tissue. the resulting selective disadvantage leads to a skewed pattern of X inactivation in mature tissue. 3. a mutation in the X-inactivation-specific transcript (XIST) gene results in the nonrandom selection of the X chromosome to be inactivated. the red arrows indicate the production of XIST RNA that spreads an inactivation signal up and down the X chromosome.

niko tinbergen identified four questions that should be asked about animal behavior

1. what stimulus elicits the behavior, and what physiological mechanisms mediate the response? 2. how does the naimal's experience during growth and development influence the response? 3. how does the behavior aid survival and reproduction? 4. what is the behavior's evolutionary history

epistasis occurs:

1. whenever two or more loci interact to create new phenotypes (e.g. plant pigments called anthocyanins) 2. whenever an allele at one locus masks the effects of alleles at one or more other loci (e.g. the malvidin pigment) 3. whenever an allele at one locus modifies the effect of alleles at one or more other loci (e.g. yellow kernels in corn)

the oldest fossils of eukaryotic cells date back

1.8 billion years

in a dihybrid cross YyRr, what is the probability of getting a genotype that is homozygous dominant for both traits?

1/16

What's the chances of getting YyRR in this dihybrid cross?

1/8

intracellular concentration Cl-

10 mM

intracellular concentration K+

140 mM

intracellular concentration Na+

15 mM

extracellular concentration Na+

150 mM

by _____, Mendel's paper had been

1900; rediscovered and his findings independently replicated by three different researchers

by _________, the parallels between Mendelian inheritance and

1902; chromosome behavior are well noted, giving rise to the chromosomal theory of heredity, under which Mendel's hereditary factors (genes) have specific loci

modern humans originated

195,000 years ago

planat pigments called anthocyanins

2 genes involved, C and P. dihybrid cross (CcPp) yields 9:7 phenotypic rations, either purple or white flowers. purple phenotype is the result of a 2 gene biosynthetic pathway. both genes must have a dominant allele in order to have a purple phenotype

for humans, the number of possible combinations is

2^23 or 8.4 million possibilities

small molecules act as 2nd messengers:

2nd messengers are water soluble molecules or ions that readily spread throughout the cell and activate cellular responses; 2nd messengers participate in pathways that are initiated by both GPCRs and RTKs

in humans, each somatic cell has

46 chromosomes, which are two chromosomes of each of 23 types

____% of above ground terrestrial plant productivity is consumed by herbivores

5-10

estimated actual number of species

5-100 million

in each of the five mass extinction events,

50% or more of marine species became extinct

fungi, plants, and animals began to colonize land about

500 MYA

the seminal vesicles produce

60% of the semen: yellowish mucus, protein, and fructose

larger and more diverse multicellular eukaryotes do not appear in the fossil record until

600 MYA - multicellularity in these lineages evolved independently, giving rise to plants, fungi, and animals

each sperm takes about _________ to develop

7 weeks

fossil evidence of early animals dates back to

710-560 MYA

the bottleneck effect - cheetahs

90-99% reduction in genetic variation compared to other cat species; populations bottleneck ~10,000 years ago

Conduction of action potentials:

Action potentials are initiated at the axon hillock and travel through the axon. Na+ influx during the rising phase depolarizes the neighboring region of the axon membrane, reaching threshold, and triggering an action potential. This process is repeated along the length of the axon, which results in the movement of the impulse from the cell body to the synaptic terminus. Inactivation of Na+ channels (refractory period) prevents backflow of information. Frequency of firing conveys the strength of the signal.

fragile XE mental retardation

FRM2 locus, normal (GCC)6-35, repeated sequence mutated (GCC)61-over 200

ovarian cycle (3)

FSH stimulates follicle growth (aided by LH)

Axon structure and conduction:

In invertebrates, continuous conduction is used. To increase speed, the diameter of the axon is increased. In vertebrates, saltatory conduction is used. Special cells called Schwann cells in the PNS and oligodendrocytes in the CNS insulate the axons using a lipid- rich, non-conducting myelin sheath. Voltage-gated ion channels are restricted to the gaps in the myelin sheaths, called nodes of Ranvier. Signal travels faster because fewer ion channels need to be activated and deactivated (120 m/sec).

Na+ and K+, moved by ion pumps, are key to the transmission of information

K+ and Na+ play an essential role in the formation of the membrane potential. K+ is higher inside the cell. Na+ is higher outside the cell. Sodium-potassium pumps maintain this gradient: Pump three Na+ out and two K+ in. Function by means of ATP hydrolysis. In addition, in a resting cell, Na+ channels are rarely open, but K+ channels are open. Thus, K+ flows out of the cell because of the chemical gradient and this stops because of the electrochemical gradient. (Ion channels have selective permeability.)

Action potentials are the signals conducted by axons:

Membrane potentials change when a neuron responds to a stimulus. Changes in membrane potential occur because of the opening of gated ion channels. When they open, ions flow across the membrane. Opening K+ channels increases the magnitude of the membrane potential (more negative; toward -90 mV): hyperpolarization. Opening Na+ channels decreases the magnitude of the membrane potential (more positive; toward +62 mV): depolarization.

the law of independent assortment

Mendel derived the law of segregation by following a single character. the F1 offspring produced in this cross were monohybrids, heterozygous for one character. a cross between such heterozygotes is called a monohybrid cross. mendel identified the law of independent assortment (his second law of inheritance) by following two characters at the same time. crossing two true-breeding parents differing in two characters produces dihybrids in the F1 generation, heterozygous for both characters.a dihybrid cross, a cross between F1 dihybrids, can determine whether two characters are transmitted to offspring as a package or independently

glial cells

Most neurons require supporting cells called glial cells. Glia: Nourish neurons. Insulate axons. Regulate the extracellular fluid surrounding neurons. Sometimes replenish certain neurons and transmit information. In the mammalian brain, there are 10 to 50 times more glia than neurons.

neuron cell body

Most of a neuron's organelles, including the nucleus, are in the cell body. The cell body along with branched extensions, called dendrites, receive signals from other neurons. A neuron has a single axon, which transmits signals to other cells.

major differences between spermatogenesis and oogenesis

S: all four products of meiosis develop into mature gametes O: cytokinesis during meiosis I and II is unequal, with almost all the cytoplasm segregated to a single daughter cell. thus, meiosis results in only one gamete S: occurs throughout adolescence and adulthood O: mitotic divisions are completed before birth, and the production of mature gametes ceases around 50 years of age S: gametes are produced from precursor cells in a continuous sequence O: developmental arrest leads to long interruptions in gamete production

in allopatric speciation involving vicariance,

a geographic barrier emerges that splits the ancestral population, and the two populations diverge

clade

a group of species that includes an ancestral species and all its descendants; can be nested in larger clades, but not all groupings of organisms qualify as clades

the bulbourethral glands produce

a secretion that neutralizes acidity in the urethra

in allopatric speciation involving dispersal,

a source population disperses to a geographic isolated area, and diverges over time

balancing selection leads to

a state called balanced polymorphism

signal

a stimulus transmitted from one organism to another

MyoD

a transcription factor that binds to specific control elements in the enhancers of target genes, driving gene expression. These targets are: other muscle-specific transcription factors (activate genes and proteins such as actin and myosin), MyoD (positive feedback maintain the cell's differentiated state)

nervous system example

a tropical cone snail surveys the environment, determines the presence and location of a fish, and initiates an attack

regulation of skeletal muscle contraction:

action potentials triggered by the motor neuron (via acetylcholine release) sweep across the muscle fiber and into it along the transverse tubules (T tubules are infoldings of the plasma membrane). this initiates the release of Ca2+ from the sarcoplasmic reticulum

receptors on the cell membrane

activate a signal transduction pathway that produces an intracellular signal or "2nd messenger". this signal or signal cascade alters gene expression and/or acts on cytoplasmic proteins to generate a response

phospholipase C

activated and cleaves the phospholipid PIP2, into DAG (another 2nd messenger that activates PKC) and IP3

when LTP is being established

activity at nearby synapses depolarizes the membrane of the post-synaptic cell. The NMDA receptor is unblocked (1), and responds to glutamate. This allows an influx of Ca2+ and Na+ (2), and the influx of Ca2+ induces the insertion of AMPA glutamate receptors into the membrane (3)

circulatory adaptations

adaptations that regulate the extent of blood flow near the body surface or that trap heat within the body care

mass extinctions can pave the way for

adaptive radiations by eliminating so many species

spermatogenesis occurs throughout

adolescence and adulthood

adrenal glands

adrenal medulla and adrenal cortex

gastrulation in humans

after cleavage, the embryo is called blastocyst (mammalian blastula); the trophoblast (outer epithelium) begins implantation within the endometrium; the inner cell mass divides into the epiblast and the hypoblast; the epiblast will form the embryo; the hypoblast will form the yolk sac; a primitive streak forms, and cells invaginate; when complete, cells on the outside will form the ectoderm and cells on the inside will form the mesoderm and endoderm; cells from the trophoblast, epiblast and endometrium form the placenta

neuronal plasticity

after embryogenesis, connections ebtween neurons can be modified. this capacity is called neuronal plasticity. much of this reshaping occurs at synapses. Connections between neruons can be strengthened or weakened in response to activity. the strength of the post-synaptic response can be strengthened or weakened in response to activity. in this way, circuits that link information are maintained whereas those that lack context are not

crossing over during prophase I

after interphase, sister chromatids are held together by cohesins; in early prophase I, the two pairs of homologous chromosomes loosely but precisely associate along their length (loci match up); enzymes create breaks in the DNA; a zipper-like synaptonemal complex holds one homolog tightly to the other (At which point the homologs are in synapsis), and DNA breaks are closed such that non-sister chromatids join. (a paternal chromatid is joined to a piece of maternal chromatid beyond the crossover point, and vice versa and crossover points are visible as chiasmata); at least one crossover event per chromosome is required for a homologous pair to migrate together to the metaphase I plate

genomic equivalence

all cells within an individual contain the same DNA

cell theory

all living organisms are composed of cells; all cells only arise from other cells

sensory processes

all sensory processes begin with a stimulus or stimuli. Sensory receptors convert stimulus energy to a change in membrane potential, thus regulating the output of action potentials to the CNS. Decoding of this information in the CNS results in sensation, which can yield a reflex or a more elaborate process. Basic functions common to sensory pathways: (1) sensory reception (2) transduction (3) transmission (4) perception

gene pool

all the alleles of all loci in all individuals in a population at one time

speciation can occur in two ways

allopatric speciation and sympatric speciation

direct mutual fitness benefit

allow animals to cooperate; i.e. foraging in groups, group defense, reproducing in groups

poikilotherms

allow their body temperature to vary with their environment

genomic imprinting

also called parent of origin effects. variation in phenotype depending on which parent passed along the alleles for those traits. involves the silencing of certain genes depending on which parent passes them on

alleles

alternative versions of a gene

hamilton's rule

an altruistic act will be favored when the indirect fitness benefits (rb) are greater than the direct fitness costs (c)

biological community

an assemblage of populations of various species living close enough for potential interaction

synaptic signaling

an electrical signal traveling across a nerve cell induces the release of neurotransmitters (serotonin, dopamine...) into a synapse, stimulating the target cell, such as muscle or nerve cell

disturbance

an event, such as a storm, fire, flood, drought, or human activity that changes a community by removing organisms from it or altering resource availability

sickle cell disease

an example of a recessively inherited disorder. affects one out of 400 African-Americans. the disease is caused by the substitution of a single amino acid in the hemoglobin protein in red blood cells. symptoms include physical weakness, pain, organ damage, and even paralysis

theory

an explanation that is broader in scope that a hypothesis, is supported by a large body of evidence, and generates new hypotheses

posterior pituitary

an extension of the hypothalamus; hypothalamic axons reach into the posterior pituitary and secrete neurohormones synthesized in the hypothalamus

autopolyploid

an individual with more than two chromosome sets, derived from a single species

mutualistic symbiosis or mutualism (+/+ interaction)

an interspecific interaction that benefits both species; can be obligate or facultative

The Voyage of the Beagle

as a boy and into adulthood, Charles DArwin had a consuming interest in nature. Darwin fist studied medicine and then theology and CAmbridge University. After graduating, he took an unpaid position as naturalist and companion to Captain Robert FitzRoy for a 5-year around the world voyage on the Beagle. During his travels, Darwin collected specimens of South American plants and animals. He observed that fossils resembled living species from the same region, and living species resembled other species from nearby regions. Darwin though that the eath was more than 6,000 years old. His interest in geographic distribution of species was kindled by a stop at the Galapagos Islands west of South America. He hypothesized that species from South America had colonized the Galapagos and speciated on the islands.

examples of how we use plant secondary metabolites

atropine (belladona) - pupil dilator digitalin (foxglove) - heart medicine menthol (eucalyptus) - cough medicine morphine (poppy) - pain reliever salicylic acid (willow) - aspirin quinine (cinchona) - anti-malarial polyterpenes (rubber tree) - rubber pyrethroids (chrysanthemums) - insecticides caffeine (coffee) - coffee nicotine (tobacco) - tobacco cocaine (coca) - cocaine

skeletal muscle

attached to bones. striated. voluntary: motor neuron input produces action potentials

evolution by natural selection:

attributes the unity of life to the descent of all organisms from an ancestor that lived in the remote past; descendants of the ancestral organism lived in various habitats, and those population gradually acquired modifications, or adaptations, that fit them to their specific ways of life, thus explaining the diversity of life

how does auxin promote growth?

auxin stimulates proton (H+) pumps in the plasma membrane, thus increasing membrane voltage and decreasing pH; this activates expansins that break bonds between cellulose microfibrils and other call wall components; the increased ion concentration in the cell causes the osmotic uptake of water and an increase in turgor, resulting in the elongation of the cell; auxin also alters gene expression and cell components are produced; the most important auxin is indoleacetic acid (IAA)

paraphyly

based on shared ancestral characters

monophyly

based on shared derived characters

Mendel discovered ________ by breeding garden peas in carefully planned experiments

basic principles of heredity

random fertilization

because of independent assortment and crossing over, variation in the genetic composition of the pool of gametes of an individual is immense (in humans, independent assortment by itself can result in millions of different chromosomal combinations); as a result of gamete diversity, the somewhat random nature of fertilization (a post meiosis event) creates additional variation

cytotoxic T cells

become activated by helper T cells (not shown). their receptors then specifically bind an antigen on MHC I molecules on the surface of an infected cell. this is assisted by the accessory protein, CD8. effector proteins like perforin disrupt the plasma membrane of the infected cell and triggered apoptosis.

integration of sensory information

begins in the sensory receptor cell by summation

prey display many defensive adaptations

behavioral defenses include hiding, fleeing, forming herds or schools, self-defense, and alarm calls; also have morphological and physiological defense adaptations

2ry oocyte

beings meiosis II but this is arrested at metaphase

sorting

beneficial alleles are favored by natural selection, whereas deleterious ones are removed. thus, and in contrast to all other forces, the outcome of natural selection is not random

three key variables in an altruistic act

benefit to the recipient (B), cost to the altruistic (C), coefficient of relatedness (the fraction of genes that, on average, are shared, r)

interfering with pattern formation has devastating consequences

between 1957 and 1961, the thalidomide was used to alleviate nausea and morning sickness in pregnant women; but thalidomide interfere with axes formation in the developing fetus, leading to death and malformation; 50% mortality; limb deformation in the survivors

interspecific competition

between members of different species

intraspecific competition

between members of the same species

semelparity

big-bang reproductive; reproduce once and die

molecular basis of the response to ethylene:

binding of ethylene to its membrane receptor, ETR1, inactivates CTR1; inactivation of CTR1 (a negative regulator), activates the membrane protein, EIN2; EIN2 acts through a second messenger to activate the transcription factor, EIN3; EIN3 turns on the genes that produce ethylene's effect in the cell

cortical reaction

binding of sperm to the egg activates a signal transduction pathway that triggers the release of Ca2+ into the cytosol from the ER; this causes cortical granules in the egg to fuse with the plasma membrane, and the contents of these granules clip off sperm-binding receptors and cause the fertilization envelope to form; takes less than 1 minute, and is the slow block to polyspermy

neutralization

binding to viral proteins, thus preventing infection of a host cell. toxins can also be neutralized

IP3

binds to Ca2+ channels in the endoplasmic reticulum, opening them; Ca2+ flows into the cytosol, activating various proteins and inducing signal transduction pathways and cellular responses

density-dependent populations

birth rates fall and death rates rise with population density

the 4 factors that determine population size

births, deaths, immigration, and emigration

change in population size =

births- deaths; or births + immigrants - deaths - emigrants

the zygote divides to become a

blastocyst and moves down the oviduct

prezygotic barriers

block fertilization from occurring by impeding different species from attempting to mate, preventing the successful completion of mating, hindering fertilization if mating is successful

blood pressure and flow velocity:

blood flows from areas of higher pressure to areas of lower pressure. arterial pressure is greatest during ventricular systole (systolic pressure; felt as a pulse) and lowest during ventricular diastole (diastolic pressure). the total cross-sectional area of the capillaries is much greater than that of the arteries, which results in a decrease in pressure and flow velocity at the locations of chemical exchange

blood vessel structure and function:

blood vessels contain a central lumen lined by an endothelium. the diameter of capillaries is slightly greater than an RBC, and the endothelium is surrounded by a basal lamina. this is where chemical exchange takes place. the endothelium of arteries and veins is surrounded by a layer of smooth muscle and a layer of elastic connective tissue. the walls or arteries are much thicker than those veins, and recoil between contractions, maintaining blood pressure.

photoreceptors and the response to light:

blue light photoreceptors (e.g. cryptochromes) and phytochromes to detect the presence, intensity, wavelength and direction of light; blue light photoreceptors drive phototropism, the opening of the stomata, etc; blue light activates phototropin, leading to the redistribution of auxin and phototropic curved growth; phytochromes drive seed germination, de-etiolation, flowering, and shade avoidance; red light activates the response and far-red light represses it, with the last exposure determining the effect

stability and fluctuation

both weather and predator population can affect population size over time. Example: the moose population on Isle Royale collapsed during a harsh winter, and when wolf numbers peaked

populations are described by their

boundaries, size, and changes in size

control of breathing:

breathing is an involuntary process. neurons in the medulla oblongata form a pair of "breathing control centers" that establish the breathing rhythm. these centers use a negative-feedback mechanism to prevent overexpansion of the lungs. they also use the pH of blood and other fluids to determine the rate of breathing. increase in CO2 concentration decreases the pH

animals with effective chemical defense often exhibit

bright warning coloration, called aposematic coloration (predators often avoid them)

food webs

can be simplified by: grouping species with similar trophic relationships into broad functional groups (e.g. phytoplankton); isolating portions of the web that do not interact much with the rest of the web

pluripotent stem cells (embryonic stem cells)

can give rise to many, but not all, cell types. they are partially differentiated

disruptive selection

can increase variation by favoring extreme phenotypic values even if the mean of the distribution does not change

B cells

can only present the antigen that they can specifically bind, and they do so via the following sequence: A helper T cell becomes activated, the T helper cell activates a B cell, and the B cell produces thousands of (1) plasma cells that secrete antibodies, and (2) memory cells

sexual reproduction

can shuffle existing alleles into new combinations; in organisms that reproduce sexually, recombination of alleles is more important than mutation in producing the genetic differences that make adaptation possible

mimic octopus

can take the appearance of more than a dozen marine animals; used to approach prey as well as to scare predators

recessively inherited disorders are more common than dominantly inherited disorders because

carries of recessively inherited disorders are phenotypically normal

the history of the earth since life first appeared has been marked by

cataclysms and dramatic changes in chemistry and temperature

small populations

causes relatives to mate with each other

cell differentiation

cells become specialized: structure and function

cell division

cells divide by mitosis

gastrulation in frogs

cells from the animal pole invaginate to form a crease (blastopore); the part above the crease is the dorsal lip; cells from the animal pole begin to spread over the outer surface; the blastopore extends around both sides and moves downward as more cells invaginate. the blastocoel shrinks; cell layers are determined

organogenesis: neurulation in frogs

cells in the dorsal mesoderm associate into a cylinder called the notochord. this holds the place of the future vertebral column; the notochord send inductive signals to the above ectoderm to form the neural plate; the neural plate rolls itself into a neural tube that runs along the A/P axis. this eventually becomes the central nervous system (brain and spinal cord); cells just above the neural tube become the neural crest. they migrate and become peripheral nerves, teeth, skull, and other cell types; simultaneously, strips of mesoderm lateral to the notochord separate into blocks of tissue called somites. these define segmentation of the embryo, and become vertebrae, ribs, and muscle (the notochord disappears before birth)

fate mapping

cells undergo determination, which differentiation; to study this process, it is useful to trace differentiated cells back to their origins in the embryo, which can be done by marking embryonic cells using dyes; adult C. elegans are composed of exactly 959 somatic cells, and the developmental origin of each cell has been determined; development includes 131 apoptotic events

tree branches can be rotated around a branch point without

changing the evolutionary relationships

ecological species concept

characterizes species in terms of their ecological niches. it applies to sexual and asexual species and emphasizes the role of disruptive selection

homologous characters

characters present in a group of species due to shared ancestry.

analogous or homoplastic characters

characters present in certain species that have evolved independently (convergent evolution)

shared ancestral characters

characters shared beyond the taxon we are trying to define

brassinosteroids

chemically similar to the sex hormones of animals; induce cell elongation and division

secondary metabolites

chemicals that are not used for cellular metabolism. instead, they are involved in long term survival (i.e. attract pollinators, repel predators); they are frequently stored in the central vacuole; humans use them as fungicides, insecticides, rodenticides, pharmaceuticals, and recreational chemicals

gastrulation in chickens

chickens have a huge amount of yolk; the embryo is formed from cells of the epiblast; the bypoblast forms part of the sac that surrounds the yolk; during gastrulation, a primitive streak forms along the midline of the blastoderm; at this location, epiblast cells migrate inward and down to form the cell layers

apoptosis process involves

chopping up the DNA, organelles and other cytoplasmic components; blebbing (cell shrinks and becomes lobed); scavenger cells digest the blebs

thin filaments

composed of two coiled actin strands

neutral variation

conferring no selective advantage or disadvantage; mutations to genes can be neutral because of redundancy in the genetic code

circadian clocks (also known as biological clocks/circadian rhythms)

continuously oscillate in constant conditions with a period of approx 24 hours. run at about the same speed regardless of temperature, even in cold-blooded animals and plants. usually synchronized to the daily light/dark cycle of exactly 24 hours.

nervous control of muscle tension:

contraction of a muscle fiber is a brief all-or-none twitch. contraction of a whole muscle is graded; the extent and strength of the contraction can be altered. the nervous system accomplishes this by: varying the number of muscle fibers that contract and varying the rate at which muscle fibers are stimulated. each branched motor neuron may synapse with many muscle fibers, but each fiber is controlled by only one motor neuron. when a motor neuron produces an action potential, all the muscle fibers in its motor unit contract as a group. the strength of contraction depends on the number of muscle fibers the motor unit controls. as more motor neurons are activates (recruitment), the force (tension) developed by a muscle increases

vasoconstriction

contraction of smooth muscle, via endothelin

homeotic (Hox) genes

control pattern formation; regulate the development of anatomical structures; mutations in Hox genes can result in, for example, abnormal placement of structures

medulla and pons

control physical functions (e.g. breathing and circulation) and large scale body movements

sympathetic division

corresponds to arousal and energy generation (fight or flight); most nerves exit the CNS midway along the spinal cord and form synapses just outside the spinal cord; NE

binding of sperm induces the

cortical reaction, where the enzymes catalyze changes in the zona pellucida, which functions as the slow block to polyspermy

transgenic plants

created by biotechnology by introducing specific genes; reduce world hunger and malnutrition (examples: insect-resisteant maize via the production of Bt pro-toxin, beta-carotene producing rice (golden rice) and cassava, tomato plants that are environmentally adapted to grow in salty soil); reduce fossil fuel dependency: bio fuels (examples: higher ethanol-yielding or insect-resistant switchgrass and poplar); produce pharmaceuticals (bioreactors)

maximize benefits, minimize costs (b-c)

crows eat molluscs called whelks but must drop them from the air to crack the shells; optimal flight height is correlated with fewer drops; result of a trade-off between energy gained (food) and energy expended

evolutionary relationships:

data on direct observations, homology, the fossil record, biogeography, and other sources can be used to infer the evolutionary relationships between species; these inferences are often depicted in the form of evolutionary trees

stabilizing selection

decreases genetic diversity and stabilizes the mean of a trait in population around a particular, usually optimal, value

vasoconstriction

decreases the transfer of body heat to the environment through conduction, convection, and radiation

passive immunity

defenses that arise from transferring antibodies from a person/organism that is immune to one that is not. trans-placental transmission of antibodies. passage of antibodies in breast milk. administration of anti-toxins (e.g. anti-venoms)

active immunity

defenses that arise when a pathogen infects the body and prompts a primary or secondary immune response. infection. immunization (vaccination)

phylogenetic species concept

defines a species as the smallest group of individuals that share a common ancestor, forming one branch of the tree of life. it applies to sexual and asexual species, but it can be difficult to determine the degree of difference required for separate species

the permian extinction

defines the boudnary between the Paleozoic and Mesozoic era 251 MYA. this mass extinction occurred in less than 500,000 years and caused the extinction of about 96% of marine animal species

if immigration and emigration are ignored, a population's growth rate (per capita increase) equals

deltaN/deltat = B-D

change in population size can now be written as

deltaN/deltat = rN

K-selection

density-dependent selection; selects for life history traits that are sensitive to population density

volume

determined by the amplitude of the wave. higher amplitude result in a higher frequency of action potentials.

testing genetic equivalence in animales

differentiated cells in animals usually do not replicate in culture, so, in frogs, researchers transplanted nuclei into enucleated eggs; when the nuclei came from a frog embryo, most eggs developed into tadpoles; when the nuclei came from a tadpole, most embryos died; conclusion: the nucleus contains all the information needed to create a new copy, but something in the nucleus changes as a cell differentiates

the spemann-mangold experiment

differentiation (e.g. neurulation) depends on interactions between cells, a process called induction; in 1921, Spemann and Mangold demonstrated the inductive activity of the dorsal lip of the early gastrula: Spemann's Organizer; later, it was found the the dorsal lip cells secrete chordin and noggin, which inactivate BMP-4 that is released in the ventral side of embryo. this allows the formation of the notochord and neural tube

phototropism

directs shoot growth toward the sunlight, and this results from differential growth of cells in different sides of the shoot; the cells on the darker side grow faster; in 1880, charles darwin and his son, francis, observed that light on the tip of a coleoptile is required for phototropism, yet the growth response occurs far from the coleoptile; activation of photoreceptors on the coleptile tip drives production of auxin, which is moved in a polar manner by transport proteins; when light strikes a coleoptile from one side, auxin moves down the shaded side and growth on that side is increased, thus bending the seedling toward the light; lateral redistribution of auxin is also involved in gravitropism; roots respond to auxin in the opposite manner. At high concentration, auxin slows growth on the bottom side of the root, and this in part mediated by ethylene. grows down

dysfunction in cell signaling pathways is a major cause of

disease

allantois

disposes of wastes in reptiles and in mammals it joins the embryo to the mother via the umbilical cord

hallmarks of adaptive immunity:

diversity and specificity: there is an immense diversity of lymphocytes and receptors, enabling the immune system to specifically detect pathogens it has never encountered. self tolerance: "self" components are not attacked. clonal expansion: cell proliferation triggered by activated greatly increases the number of B and T cells specific for an antigen. immunological memory: a stronger and more rapid response to an antigen that has been encountered previously.

after interphase (s phase) the diploid cell then

divides twice - meiosis I and meiosis II - yielding four haploid daughter cells

(spermatogenesis) stem cells originate from

division and differentiation of primordial germ cells in the embryonic testes

meroblastic

divisions can also be meroblastic, where the large amount of yolk prevents the cleave furrows from passing through it. this happens in birds, reptiles, and insects.

taxonomic groups

domain, kingdom, phylum, class, order, family, genus, species

the sliding-filament model of muscle contraction

during contraction, the thin and thick filaments slide past each other, powered by the myosin molecules.

male hormones regulate the formation of reproductive structures:

during development, the presence of testosterone and anti-Mullerian hormone (AMH) directs the formation of sperm-carrying ducts and the degeneration of female ducts; in the absence of these hormones, the opposite is true

shaping the nervous system

during embryogenesis, nerons that do not reach an appropriate location undergo programmed cell death (apoptosis); half of the neurons formed in the embyro are eliminated; a developing neuron forms numerous synapses, and the activity of the neuron stabilizes some synapses and destabilizes others; by the end of embryonic development, more than half the synapses have been eliminated; this ensures effective circuitry

generation of B cell and T cell diversity

each person makes ~1 M different B cell receptors and ~10 M different T cell receptors, yet there are only ~20 K protein-coding genes in the human genome. diversity is created by VJ (light chain) and V(D)J (heavy chain; T cell receptor) recombination. example: a B cell receptor light chain is encoded by three components: a V segment, a joining (J) segment, and a C segment. The V and J segments encode the variable region. random linking of V and J segments providethe diversity. this linking remains for the lifetime of the cell, and its progeny. For the B cell light chain, there are 40 V, 5 J and 1 C gene segments, so 200 different combinations. the heavy chain contains even more diversity.

competitive exclusion

early in 20th century, G.F. Gause did a number of experiments using two Paramecium species, P. aurelia and P. caudatum; when he grew the two species separately, each population displayed logistic growth; when he grew the two species together, P. caudatum became extinct in the culture; two species competing for the same limiting resources cannot coexist permanently in the same place

cell signaling regulates

endocrine function, reproduction, growth, development, nervous system functions, immune system functions, circulatory system functions, metabolism

cell signaling occurs in multicellular organisms (example)

endocrine hormonal signaling (endocrine cell secretes into bloodstream, hormone travels through blood vessels to target cell)

birds and mammals are

endotherms

only the _____________ have regions that are homologous with corresponding regions of the chromosome

ends of the Y chromosome

plants are critical to energy flow in the ecosystem:

energy flows into an ecosystem as sunlight and ultimately leaves as heat, while chemical elements to life are recycled; photosynthesis converts light energy to the chemical energy of food

positive feedback

enhances the initial stimulus

ANS has three components

enteric division; sympathetic division; parasympathetic division

Cyclic AMP

epinephrine (1st messenger) binds GPCR; this activates a G protein (Gs); Gs activates adenyly cyclase, which converts ATP to cAMP (time ~100 ms; can amplify cAMP levels 20-fold in seconds); cAMP activates protein kinase A by binding regulatory subunits, thus releasing catalytic subunits; activated PKA phosphorylates other proteins, inducing a cellular repsonse; inhibitory GPCRs/G proteins block adenyly cyclase activity

a hormone can induce more than one effect example

epinephrine and the fight or flight response SEE GRAPH

termination of the signal: (example)

equally important as activation is the termination of the signal. this occurs when: the concentration of the signal (1st messenger) decreases, in the case of GPCRs when the G protein hydrolyzes its bound GTP to GDP, the enzyme phosphodiesterase converts cAMP to AMP, protein phosphatases inactivate phosphorylated kinases, receptors become desensitized via phosphorylation by G-protein receptor kinases, and receptors are internalized

semicircular canals

equilibrium

the theory of island biogeography

equilibrium number is intersection of immgration and extinction rates

apoptosis

essential for morphogenesis and other processes; in vertebrates, apoptosis disposes of: nerve cells that do not form synapses, auto-reactive immune cells (continues throughout adulthood), cells between the future digits, structures that are no longer needed (e.g., vestigial structures)

uterine cycle

estradiol secreted by growing follicles signal the endometrium to thicken, thus coordinating the follicular phase of the ovarian cycle with the proliferative phase of the uterine cycle; after ovulation, the estradiol and progesterone secreted by the corpus luteum stimulate maintenance and development of the endometrium, including the growth of arteries and endometrial glands (this begins the secretory phase); if an embryo is not implanted, low gonadotropin levels induce the corpus luteum to disintegrate. This decreases ovarian hormone levels, inducing the shedding of the endometrial lining (this begins the menstrual flow phase)

ovarian cycle (6)

estradiol stimulates a sharp increase in LH and FSH

ovaries

estrogens: stimulate uterine lining growth, promote development and maintenance of female secondary sex characteristics; progestins: promote uterine lining growth

ethylene: a gas that acts as a plant hormone

ethylene functions in three key areas: the triple response to mechanical stress, fruit ripening, leaf abscission, senescence (apoptosis)

reduced hybrid fertility

even if hybrids are vigorous, they may be sterile

allergies

exaggerated, hypersensitive, response to antigens called allergens.

inclusive fitness

explains cooperation between relatives; explains conflict in groups of unrelated individuals; explains why meerkats make risky alarm calls (turns out htye live in family groups); explains why male lions kill all of the offspring of females when they take over a pride (because they are not related to the cubs); explains why somatic cells of out body let the gametes have all the fun (because they are related); explains why disease more virulent when multiple serotypes infect the same host (because they compete with unrelated serotypes)

stability

extensive gene flow from outside the hybrid sone can overwhelm selection for increased reproductive isolation inside the hybrid zone

mammals underwent an adaptive radiation after the

extinction of terrestrial dinosaurs

evolutionary trends

extracting a single evolutionary progression from the fossil record can be misleading; apparent trends should be examined in a broader context. evolutionary trends do not imply an intrinsic drive toward a particular phenotype

extraembryonic membranes in amniotes

extraembryonic membranes are present in reptiles (including birds) and mammals; they evolved in response to reproduction in land; chorion: gas exchange; amnion: encases the fluid that protects the embryo; allantois: disposes of wastes in reptiles and in mammals it joins the embryo to the mother via the umbilical cord; yolk sac: encloses the yolk in the ehh of reptiles, and in mammals is a site for the early formation of blood cells; in amphibians and fish, only the yolk sac is present

inheritance of organelle genes

extranuclear genes (or cytoplasmic genes) are found in organelles in the cytoplasm. mitochondria, chloroplasts, and other plant plastids carry small circular DNA molecules. extranuclear genes are inherited maternally because the zygote's cytoplasm comes from the egg. the first evidence of extranuclear genes came from studies on the inheritance of yellow or white patches on leaves of an otherwise green plant. some defects in mitochondrial genes prevent cells from making enough ATP and result in diseases that affect the muscular and nervous systems. for example, mitochondrial myopathy and leber's heredity optic neuropathy

in males the Y is transmitted from

father to sons and the X from father to daughter

prolonged contraction can result in

fatigue because of (1) ATP depletion and (2) dissipation of ion gradients required from normal electrical signaling

directional

favors individuals at one end of the phenotypic range

stabilizing

favors intermediate variants and acts against extreme phenotypes

ants, bees, wasps (hymenoptera)

females help their mothers produce more sisters, and dont' reproduce themselves (why?) hamilton hypothesized that the reason was haplodiploidy. although we now know this isn't entirely true, it illustrates how kin selection works in principle;

the union of two gametes results in

fertilization

main stages of embryonic development:

fertilization, cleavage, gastrulation, organogenesis

evidence for allopatric speciation

fifteen pairs of sister species of snapping shrimp (Alpheus) are separated by the Isthmus of Panama formed and separated the Atlantic and Pacific waters

countercurrent exchange

fish use this to enhance the efficiency of gas exchange during ventilation

direct fitness

fitness from personal reproduction

a muscle twitch in a slow twitch fibers lasts

five times as long than in fast-twitch fiber (Ca2+ is pumped back to SR more slowly)

rubisco

fixes carbon in the calvin cycle of photosynthesis; constitutes 50% of all protein in a leaf; the most abundant protein on earth, and it catalyzes the most important reaction on earth

ovarian cycle (5)

follicle-produced estradiol rises steeply

pituitary gland (anterior)

follicle-stimulating hormone (FSH) and luteinizing hormone (LH): stimulate ovaries and testes; thyroid-stimulating hormone (TSH): stimulates thyroid gland; adrenocorticotropic hormone (ACTH): sitmulates adrenal cortex; prolactin: stimulates mammary gland cells; growth hormone (GH): stimulates growth and metabolic functions

the outer layer (ovaries) is packed with

follicles, each consisting of an oocyte (partially developed egg) and support cells

foraging

food-obtaining behavior, includes recognizing, searching for, capturing, and eating food items

sympatric speciation can also result from the appearance of new ecological niches

for example, the north american maggot fly can live on native hawthorn trees as well as more recently introduced apple trees. flies are diverging. flies that emerge from a given host generally return to mate and lay eggs on the same type of fruit. as apples mature more quickly than hawthorn fruit, apple-feeding populations now show temporal isolation from the hawthorn-feeding R. pomonella

the distribution of fossils and living groups reflect the historic movement of the continents

for example, the similarity of fossils in parts of south america and africa is consistent with the idea that these continents were formerly attached

tracheal systems:

for gas exchange, insects employ a tracheal system, which is a network of tubes that branch throughout the body. the largest tubes, the trachea, open to the outside. the smallest tubes, the tracheoles, extend to nearly every cell. this process is mostly independent of the circulatory systems

modification of crops

for thousands of years, humans have been modifying crop plants by selective breeding (artificial selection); modern maize was derived from teosinte (maize cannot spread its seeds); several crop plants were derived from the wild mustard plant; seedless fruits (reproduction problem means complete domestication)

vision: evolutionary conservation and eye spots

for vision, animals use photoreceptor cells that contain prigments that absorb light. light detectors in animals range from those that only detect the direction and intensity of light to those that form images. in animals, (1) the udnerlying mechanism for capturing light is the same, and (2) the genes that specify where and when photoreceptors arise is the same, suggesting a common evolutionary origin

gastrulation

formation of the germ cell layers and a primitive gut

central vacuole

functions in storage, and in the breakdown of wastes and macromolecules; enlargement is involved in plant growth; usually the largest compartment in a plant cell

ectotherms

gain most of their heat from external sources

what mendel called a heritable factor is what we now call a

gene

allopatric speciation

gene flow is interrupted or reduced when a population is divided into geographically isolated subpopulations. separate populations may evolve independently through mutation, natural selection, and genetic drift. reproductive isolation may arise as a by-product of genetic divergence.

where might the exponential model apply

generally, it might apply in cases where limits to growth do not exist or have been removed (in the lab, in nature for short periods, newly established populations with few predators, invasive species, pest outbreaks, populations recovering from catastrophic declines, humans)

parents endow their offspring with coded information in the form of hereditary units called

genes

reduced hybrid viability

genes of the different parent species may interact and impair the hybrid's development or survival in its environment

during bottlenecks

genetic drift may have substantail effect on the population becuase allele frequencies in the population are likely to change just b random chance and many genes may be lost from the population, reducing the population's genetic variation

diploidy maintains

genetic variation in the form of recessive alleles hidden from selection in heterozygotes

the four haploid daughter cells are

genetically different

in sexual reproduction, the offspring are usually

genetically distinct

variation in genome size

genomes vary in size, number of genes, and gene density. most bacteria and archea have small genomes. qukarytoic genomes are genrally larger and more gene-rich; much larger variation in both size and gene number

adrenal cortex

glucocorticoids: raise blood glucose level; mineralocorticoids: promote reabsorption of Na+ and excretion of K+ in kidneys

the pancreas and the control of glucose levels in the blood:

glucose homeostasis relies on the antagonistic effects of two hormones produced in the pancreas: insulin (produced in beta cells) and glucagon (produced in alpha cells); when blood glucose increases, secretion of insulin triggers the cellular uptake of glucose, decreasing levels in the blood; when blood glucose decreases, secretion of glucagon promotes the release of glucose into the blood, thus increasing levels in the blood

in a synapse exhibiting LTP

glutamate activates AMPA receptors (1), triggering depolarization (2). This unblocks the NMDA receptors (3). Together, the AMPA and NMDA receptors trigger postsynaptic potentials strong enough to initiate action potentials without input from other synapses (4). This is considered to be one of the fundamental processes by which memories are stored and learning takes place.

blood pressure and gravity:

gravity assists blood flow to areas lower than the heart. to efficiently circulate blood to areas higher than the heart, like the brain, significant pressure is required

sister taxa

groups that share an immediate common ancestor

myosin molecules

have a globular head region and a long tail region. the heads jot out, and all the tails adhere together

cochlea

hearing

almost all X-linked genes are _________ in males with normal chromosomes

hemizygous

heterozygote disadvantage (underdominance)

heterozygote has lower fitness than either homozygote

when an allele is rare, it is found in

heterozygotes

type III

high death rate for the young and lower death rate for survivors; no parental care, many offspring, very small body size

pineal gland the rhythmic hormones, melatonin:

homeostasis can be modulated rhythmically; melatonin is produced by the pineal gland in the brain, and regulates functions related to light and seasonality. it is secreted at night and promotes sleep. light inhibits its release. it regulates biological rhythms associated with reproduction and with daily activity levels. reproductive organs in some animals are seasonally controlled (by the length of the photoperiod). melatonin release is controlled by neurons in the hypothalamus

during interphase, __________________ are not associated with one another

homologous chromosomes

independent assortment of chromosomes

homologous chromosomes are randomly oriented during metaphase I. Thus, the first meiotic division results in each pair sorting its maternal and paternal homologs into daughter cells independently of every other pair (50% probability for each); this is called independent assortment, where each cell represents one outcome of all possible combinations of maternal and paternal chromosomes

anaphase I

homologous chromosomes separate and move toward opposite poles. the sister chromatids remain paired

under inbreeding, there is increased

homozygosity for these recessive deleterious alleles

paracrine and autocrine signaling

hormones acting over short distances, or locally (examples are cytokines, growth factors, and prostaglandins); these signals promote growth, division and development, and modulate processes such as blood pressure, inflammation, nervous system function, and reproduction

anterior pituitary

hormones produced in the anterior pituitary control metabolic, osmoregulatory, and reproductive processes; hormone production in the anterior pituitary is controlled by releasing hormones and inhibiting hormones secreted by the hypothalamus; hypothalamic hormones are released near capillaries, and travel via the blood to the anterior pituitary; because anterior pituitary hormones can act on other endocrine glands, they form hormone cascade pathways

hypothalamus

hormones released from posterior pituitary (oxytocin and vasopressin); releasing and inhibiting hormones: regulates anterior pituitary

endocrine signaling

hormones secreted into the extracellular fluid by endocrine cells reach target cells via the bloodstream; maintains homeostasis, thus regulating blood pressure, energy metabolism, and solute concentration in body fuilds; functions in the response to environmental stimuli, reuglates growth and development, and triggers sexual maturation and reproductive processes

two amino-acid changes in the human FOXP2 were positively selected during recent human evolution

humans and chimpanzees differ in the expression of the FOXP2 gene, whose product turns on genes involved in vocalization. differences in the FOXP2 gene may explain why humans but not chimpanzees communicate by speech. the FOXP2 gene of Neanderthals is identical to that of humans, suggesting they may have been capable of speech

taste in mammals

humans and other mammal perceive five tases: sweet, salty, sour, bitter, umami. each taste receptor cell (a modified epithelial cell) can detect tastants representing only one taste. Taste receptor cells are organized into taste buds, and each bud has cells that detect all five tastes. receptors for sweet, umami and bitter are GPCRs. the receptor for sour is a transient receptor potential (TRP) channel (an ion channel). the receptor for salty is a sodium channel (Detects the Na+ in NaCl)

Cholera toxin

humans become infected when they ingest water containing the bacterium, Vibrio cholera; in the intestine, cholera toxin enters the crypt cells and modifies a G-protein so that it cannot hydrolyze GTP, thereby irreversibly activating adenylyl cyclase, leading to constantly high levels of cAMP; ions are massively secreted into the lumen of the intestine, and water follows. this results in acute diarrhea and vomiting

ovarian cycle (1)

hypothalamus releases GnRH

disorders of the thyroid

hypothyroidism, hyperthyroidism, lack of iodine, thryoid hormone deficiency

cytoplasmic determinants

if cytoplasmic determinants are not properly distributed at the first cleavage, the totipotency of early embryonic cells is lost; in many organisms the first cleavage is asymmetrical, and totipotency is lost; in most mammals, totipotency is retained till the 8-16 cell stage

fusion

if hybrids are as fit as parents, there can be substantial gene flow between species. if gene flow is great enoguht, reproductive barriers weaken and the parent species can fuse into a single species

negative assortative mating

if the phenotype is under genetic control, negative assortative mating increases heterozygosity for the genes affecting the trait; on average heterozygotes increase if dissimilar genotypes are pairing

population differentiation

imagine you randomly sample from 7 'populations' of 20 yellow and green peas, choosing a small number of peas (say 10) each time to start your new 'population' and rebuilding them each time in proportion to the initial sample. over time, your populations will be very different

ethylene and fruit ripening

immature fruits are generally tart, hard and green, which protects them from predators; when the seeds have fully developed they ripen, and this attracts the animals that disperse the seeds; in many cases, a burst of ethylene in the fruit triggers the ripening process; breakdown of cell wall components softens the fruit, and the cconversion of starches and acids to sugars makes it sweet; ethylene triggers ripening, and ripening triggers more ethylene production; the signal spreads from fruit to fruit

sex

in humans, the rate of point mutations is ~5X higher in sperm than eggs, so dads contribute most harmful mutations

axis formation: bilateral symmetry

in many species (not humans), the A/P axis is determined prior to fertilization by the uneven distribution of substances in the cytoplasm including specific mRNAs, proteins, and yolk (stored nutrients); in the egg of the frog, a concentration of dark pigment granules at one pole (the animal pole), and a concentration of yolk at the other (the vegetal pole) make this uneven distribution of substances clearly visible; (in mammals, no polarity is obvious until after cleavage); in frogs, the D/V axis is established by rearrangement of the cytoplasm and the formation of the gray crescent; after fertilization the plasma membrane and cortex rotate (cortical rotation) toward the point of sperm entry (always in the animal pole) forming the gray crescent; the center of the rotated animal pole defines the anterior of the embryo; the grey crescent defines the dorsal side of the embryo; once the A/P and D/V axes are set, L/R axis is fixed-by the first cleavage, which bisects the grey crescent

the circadian clock and the sun defines the time-compensated sun compass:

in monarch butterflies and some birds, migratory patterns are dictated by the position of the sun relative to the time of day. the relative time of day is maintained by the circadian clock. for example, monarchs migrate southwest for the winter. if the clock of a monarch is shifted 6 hours by maintaining it in an artificially lit chamber, when released outside the monarch's migration will be off by 90 degrees.

smell in humans

in olfaction, sensory cells are neurons. olfactory receptor cells line the upper portion of the nasal cavity and send impulses to the olfactory bulb of the brain. the receptor cells extend cilia into the mucus and when an odorant binds, it activates a GPRC called an odorant receptor (OR). cAMP opens Na+ and Ca2+ channels, depolarizing the membrane. Signals are transmitted to the brain, and olfactory inputs are integrated into single sensations.

species with a large impact

in rocky intertidal communities of western North America, the relatively uncommon sea star Pisaster ochraceus preys on mussels such as Mytilus californianus, a dominant species and strong competitor for space

Chemical synapses: metabotropic receptors

in some chemcial synapses, the receptor that binds and responds to the NT is a matabotropic receptor. this receptor activates a signal transduction cascade that involves a second messenger. compared to the response of an ionotropic receptor, these responses are slower but last longer

developmentally programmed polyploidy

in some somatic cells, though, polyploidy increases the metabolic capacity of a tissue. hepatocytes and placental TGCs often provide nutrients and metabolites, whereas megakaryocytes can be viewed similarly as a stockpile of components needed to generate platelets

egg activation and cleavage (example)

in some species, like sea urchins and humans, division is uniform across the embryo; in others, like frogs, cleavage is asymmetric; for sea urchins, humans, and frogs, divisions are holoblastic, as the cleave furrows passes entirely through the cell

promiscuous

in some species, mating is promiscuous, with no strong pair-bond or lasting relationships

area effects

in the 1960's, two ecologists (MacArthur and Wilson) tested the predictions of the species-area relationship on different island chains; these as well as other studies have shown that z is usually between 0.2 and 0.4

natural selection can only improve a structure

in the context of its current utility

processing of visual information begins in the retina:

in the dark, rods and cones are depolarized and continuously release the neurotransmitter, glutamate. some bipolar cells depolarize and others hyperpolarize in response to the presence of absence of glutamate. when light strikes the rods and cones, they hyperpolarize and stop releasing glutamate. signals from rods and cones travel to bipolar cells and then to ganglion cells. signals also travel to other photoreceptor cells via horizontal cells and bipolar cells. when a photoreceptor is activates, horizontal cells inhibit distant photoreceptors and bipolar cells that are not illuminated. this is called lateral inhibition, and sharpens edges and gives you contrast. lateral inhibition is repeated by amacrine cells, at the level of the ganglion cells. The information recieved by a single ganglion defines the receptive field. the smaller this field, the sharper the image.

smooth muscle

in the walls of hollow organs (GI tract, blood vessels...). not striated (thick filaments are scattered). involuntary: contract either via stimulation from the autonomic nervous system or without nervous input.

the heart rhythm:

in vertebrates, the heartbeat originates within the heart. auto-rhythmic cells clustered in the sinoatrial (SA) node function as the pacemaker. this node produces electrical impulses that travel across the heart via gap junctions in cardiac muscle. impulses from the SA node trigger atrial contraction, and 0.1 sec later the atrioventricular (AV) node fires, contracting the ventricles.

limbic system

includes the amygdala, hippocampus, and parts of the thalamus; generating and experiencing emotion often requires the interaction between the limbic system and other regions of the brain; the amygdala is the most important structure involved in memory

mate showiness due to mate choice can

increase a male's changes of attracting a female, while decreasing his chances of survival

synthetic androgens

increase muscle mass by enhancing male 2ry characteristics; they also wreck havoc on the bodies of both men and women

observations -> inferences of evolution by natural selection

individuals in a population vary in thier heritable characteristics, and organisms produce more offspring than the environment can support -> individuals that are well suited to their environment tend to leave more offspring than other individuals, and over time, favorable traits accumulate in the population

gonadotropin-releasing hormone (GnRH)

induces the release of follicle-stimulating hormone (FSH) and luteinizing hormone (LH)

phenotype is the product of

inherited genotype and environment influences. some phenotypic differences are determined by a single gene and can be classified on an either-or basis. other phenotypic differences are determined by the influence of two or more genes are vary along a continuum within a population

botox

inhibits acetylcholine release

endoderm

inner layer of embryo; epithelial lining of digestive tract and associated organs (liver pancreas); epithelial lining of respiratory, excretory, and reproductive tracts and ducts; thymus, thyroid, and parathyroid glands

gene flow - insecticides

insecticides have been used to target mosquitoes that carry West Nile virus and malaria; alleles have evolved in some populations that confer insecticide resistance to these mosquitoes; the flow of insecticide resistance alleles into a population can cause an increase in fitness

vision: compound eyes

insects and crustaceans ahve compound eyes composed of many ommatidia, each with its own lens. Each ommatidium detects light from a small portion of the visual field, and together, the compound eye is very effective in detecting movement. information gathered from different intensities of light entering the ommatidia from different angles is used to form a visual image with each ommatidium giving a slightly different view. Insects have excellent color vision, and some can see into the UV spectrum

amacrine cells and horizontal cells

integrate information

Neurons in the brain

integrate the information. Most neurons in the brain are interneurons, which form local circuits in the brain.

social behavior

interactions with kin and conspecifics

species are groups of actually or potentially

interbreeding populations, which are reproductively isolated from other such groups

in sexual reproduction, fertilization can be

internal or external

Segmental duplications

intra-chromosomal and inter-chromosomal duplications are depicted for human chromosome 22q. Each horizontal line represents 1 Mb. the chromosome sequence is oriented from centromere to telomere

termination of hormonal signals:

intracellular termination of the hormone: degradation of the hormone, inhibition of transduction; extracellular degradation of the hormone: in the liver, spleen, blood, lymph; removal of the hormone: excretion via the kidneys

defensive mutualisms

involve species that receive food or shelter from their partners in return for a defensive function

gastrulation in seas urchins

involves cell migration and invaginantion; poles: the blastula has an animal pole and a vegetal pole. the animal pole will give rise to the anterior side and is less yolky; 1. mesenchyme cells migrate inward from the vegetable pole 2. cells at the vegatable plate invaginate into the blastocoel 3. cells form the archenteron (future digestive tract) 4. fusion of the archenteron with the blastocoal wall forms the digestive tube

signal transduction is a multi-step process:

it functions via the activation of proteins by the addition or removal of phosphate groups, and/or the release of 2nd messenger molecules; serine/threonine kinases (phosphorylation cascade; protein phosphatases dephophorylate and inactivate kinases); Cyclic AMP, Ca2+, IP3; allows for amplification; allows for tight regulation

for a pathogen, the internal environment of an animal is a wonderful place

it is full of nutrients, it is protected from outside sources, it is a means of transportation, it is climate controlled

vertebrate circulatory systems:

it is often called the cardiovascular system. arteries carry blood from the heart to organs throughout the body. within organs, arteries branch into arterioles, which branch into capillaries. capillaries, which form capillary beds, are thin and microscopic vessels with porous walls. this is where chemical exchange takes place. on their way back to heart, capillaries converge into venules, which converge into veins. the heart of vertebrates contains two or more muscular chambers. atria receive blood entering the heart. ventricles pump blood out of the heart. single circulation refers to hearts with two chambers: an atrium and a ventricle. The blood passes through two capillary beds, which significantly reduces blood pressure. double circulation refers to hearts with two pumps. the first delivers blood to the oxygenating tissues. the second receives oxygenated blood and delivers it to the internal tissues.

an organism's phenotype include

its physical appearance, internal anatomy, physiology, and behavior

acrosomal reaction

jelly coat on egg chemically attracts swimming sperm; sperm comes into contact with the egg, and enzymes released from the acrosome digest the jelly coat; the acrosomal process elongates, penetrates the coat, and binds to specific receptors on the egg; the sperm and egg fuse thier plasma membranes, and the sperm nucleus enters the egg cytoplasm; rapidly, ion channels on the egg open, sodium flows in, the membrane depolarizes, and this prevent polyspermy

CYP2D6

known to be involved in adverse reactions to or decreased drug effects of many drugs: antiarrhythmics, antidepressants, neuroleptics, opioids, amphetamines, and anticancer drugs (e.g. tamoxifen). many alleles, and variation across different human subpopulations

respiratory structures tend to be

large and thin

segmental duplications

large blocks of 10-300 kilobases that have been copied to another region of the genome

scaffolding proteins

large relay proteins to which several other relay proteins are simultaneously attached; enhances the speed and accuracy of the signal transfer

too little GH

leads to pituitary dwarfism, where the person is small but properly proportioned

in development, thyroid hormone deficiency

leads to retarded skeletal growth and poor mental development (called cretinism)

experience and learning:

learning is the modification of specific behaviors based on experience. learning involves the formation of memories by specific changes in neuronal connectivity

ion channel receptors

ligand-gated ion channels are membrane receptors containing a region that acts as a gate for ions when the receptor changes shape; at the level of the synapse between two nerve cells, ion channel receptors activated by neurotransmitters allow the influx of ions, triggering an electrical signal that propagates down the length of the cell; some ion channels are controlled by electrical currents instead of ligands, and are called voltage-gated ion channels

light reactions require

light and water

the eye detects light, the brain sees: sensory tranduction

light energy strikes a rod, shifting a single chemical bond in retinal, activating rhodopsin. active rhodopsin activates transducin (g protein). transducin activates phosphodiesterase. phosphodieterase hydrolyses cGMP to GMP, thus closing Na+ channels in the plasma membrane. The membrane's permeability to Na+ decreases, and the rod hyperpolarizes. in rods and cones, the receptor potential triggered by light is hyperpolarization, not depolarization

within a chloroplast

light reactions occur in the thylakoid membranes and the calvin cycle occurs in the stroma

"typica"

light, peppered, recessive; cryptic against the "typical" backgrond

assortative mating

like genotypes mate with each other, or avoid each other

earth's early atmosphere

likely contained water vapor and chemicals released by volcanic eruptions (nitrogen, nitrogen oxides, carbon dioxide, methane, ammonia, hydrogen)

the bottleneck effect- prairie chickens

loss of prairie habitat caused a severe reduction in the population of greater prairie chickens in Illinois; the surviving birds had low levels of genetic variation, and only 50% of their eggs hatched

type I

low death rate early and middle life and an increase in death rates among older age group; parental care, few offspring, territoriality, large body size

LDL

low-density lipoprotein ("bad cholesterol")

mammalian lungs

lungs are internal, localized respiratory organs. a system of branching ducts conveys air to lungs located in the thoracic cavity

cytogenetic maps

made using methods like chromosomal banding; indicate the positions of genes with respect to chromosomal features

fertilization

male and female gametes unite, passing genes from both parents to their offspring

lizards

male side-blotched lizards have either blue, orange, or yellow throat; each olor is associated with a specific strategy for obtaining mates; orange-throat males are the most aggressive, "usurpers", and defend large territories; blue-throats defend small territories and guard females; yellow-throats are nonterritorial, mimic females, and use "sneaky" strategies to mate; the success of each strategy depends on the frequency of all of the strategies; this drives frequency-dependent selection

mammals (XX/XY) sex determination means that

males and females differ in the number of copies of sex linked genes in cells (females =2; males = 1)

mammalian breathing

mammals employ negative pressure breathing, pulling air into the lungs. this is accomplished via the action of the diaphragm and rib muscles. tidal volume is the amount of air inhaled and exhaled with each breadth. the tidal volume during maximum inhalation is the vital capacity. residual volume is the amount of air that remains after forced exhalation. because of the residual volume, each inhalation mixes fresh air with oxygen-depleted air

cellular defenses and the lymphatic system:

many cellular defenses involve the lymphatic system. some macrophages reside in the lymph nodes, where they phagocytose pathogens. dendritic cells migrate to the lymph node after they encounters pathogens, and stimulate adaptive immune responses

ethylene and fruit ripening (at a commercial level)

many fruits are ripened in special chambers where ethylene levels are enhanced; many fruits are prevented from ripening by enhanced ventilation and increased CO2 (slows ethylene synthesis), or by the addition of scrubbers and absorbents that remove ethylene; plants are being genetically engineered such that ethylene production is inactivated, and thus, the fruits cannot naturally ripen. the fruits are then picked when green, transported to the site of sale, and exposed to exogenous ethylene to induce ripening

opsonization

mark bacteria for phagocytosis by macrophages and neutrophils. this leads to additional antigen presentation.

hybridization

mating two contrasting, true-breeding varieties

the study of the origin of species can be approached through the study of the

mechanisms that give rise to reproductive isolation

types of sensory receptors

mechanoreceptors (touch and hearing), chemoreceptors (taste and smell), electromagnetic receptors (vision - photoreceptors and electrical fields), thermoreceptors (heat), pain receptors (extreme conditions)

synapsis of homologous chromosomes (comparison of mitosis and meiosis)

mitosis: does not occur meiosis: occurs during prophase I along with crossing over between nonsister chromatids; resulting chiasmata hold pairs together due to sister chromatid cohesion

role in the animal or plant body (comparison of mitosis and meiosis)

mitosis: enables multicellular animal or plant (gametophyte or sporophyte) to airse froma single cell; produces cells for growth, repair, and, in some species, asexual reproduction; produces gametes in the gametophyte plant meiosis: produces gametes (in animals) or spores (in the sporophyte plant); reduces number of chromosome set by half and introduces genetic variability among the gametes or spores

number of divisions (comparison of mitosis and meiosis)

mitosis: one, including prophase, prometaphase, metaphase, anaphase, and telophase meiosis: two, each including prophase, metaphase, anaphase, and telophase

number of daughter cells and genetic composition (comparison of mitosis and meiosis)

mitosis: two, each genetically identical to the parent cell, with the same number of chromosomes meiosis: four, each haploid (n); genetically different from the parent cell and each other

the oogonia divide by ____ to yield _________

mitosis; primary oocytes

classes of local regulators

modified fatty acids such as prostaglandins; polypeptides such as cytokines and growth factors; amines such as serotonin; gases such as nitric oxide

blood pressure

modulated by cardiac output and also modulated by the state of the smooth muscle of arterioles

morgan linkage experiment

morgan crossed flies that differed in traits of body color and wing size. from the results, morgan found that body color and wing size are usually inherited together in specific combination. he noted that these genes do not assort independently, and reasoned that they were on the same chromosome. however, nonparental phenotypes were also produced. morgan discovered that genes can be linked, but the linkage was incomplete, as evident from recombinant phenotypes. morgan proposed that some process must sometimes break the physical connection between genes on the same chromosomes. that mechanism was the crossing over of homologous chromosomes.

how ecologically similar species co-exist: character displacement

morphological similarity and use of resources tend to be more divergent in sympatric populations of two species than in allopatric populations of the same two species; an example is variation in beak size between populations of two species of Galapagos finches

oxygenation of the planet

most atmospheric oxygen (O2) is of biological origin. by about 2.7 billion years ago, O2 began accumulating in the atosphere and rusting iron-rich terrestrial rocks. this "oxygen revolution" approximately 2.7 to 2.3 billion years ago caused the extinction of many prokaryotic groups. some groups survived and adapted using cellular respiration to harvest energy

are biological communities at equilibrium (traditional view)

most biological communities are in a state of equilibrium ("balance of nature" view); community functions as an integrated unit; following a disturbance, the community will bounce back

increasing cytosolic concentration of Ca2+ induces

muscle concentration, secretion of molecules, cell division, and other processes

summation of twitches and fatigue

muscle contraction is also modulated by varying the rate of muscle fiber stimulation, by summation. for example, if a second action potential arrives before relaxation, the two add together resulting in greater tension. too high of a rate results in tetanus

two processes that produce the variation in gene pools that contributes to differences among individuals

mutation and sexual recombination

sources of genetic variation summary

mutation is common on a per gamete (or per genome) basis, but rare per gene; most mutations with phenotypic effects are deleterious (bad) and recessive (hidden); mutation had little effect on HW equilibrium alone, but provides the ultimate raw material for selection and evolution; mutation rates may be affected by sex, the environment, and physiological stress; sexual reproduction can shuffle existing alleles into new combinations

three mechanisms cause allele frequency change

natural selection, genetic drift, gene flow

amino acide tyrosine

needed for general protein synthesis. precursor for several NTs the hormone thyroxine, and the pigment melanin

hormone pathways involves in homeostasis typically invovle

negative feedback in order to maintain the pre-existing state

synaptic signaling

neurons from junctions, called synapses, with other neurons or muscle; neurotransmitters are released and bind to receptors on target cells; neurotransmitters are central to sensation memory, cognition, and movement

drugs that stimulate the reward system also involve dopamine

neurons that function in the reward system release dopamine at synapses; as addiction to drugs that affect the reward system develops, there are long-lasting changes to the reward circuitry, resulting in craving independent of pleasure; addictive drugs include alcohol, cocaine, nicotine, and heroin

posterior pituitary hormones

neurosecretory cells of the hypothalamus synthesize the two posterior pituitary hormones; oxytocin and antidiuretic hormone (ADH or vasopressin)

five conditions for non-evolving populations

no mutations, random mating (if not, then inbreeding occurs), no natural selection (if not, then natural selection occurs), extremely large population size (if not, then genetic drift occurs), no gene flow (if not, then gene flow or migration occurs)

the five conditions for nonevolving population are

no mutations, random mating, no natural selection, extremely large population size, no gene flow

are biological communities at equilibrium (current view)

nonequilibrium model: most biological communities are chance assemblages of species, not integrated units; following a disturbance, the community will change and not return to the original state

capillary function

not all capillaries receive blood at the same time. this is controlled by: constriction of dilation of supplying arterioles and precapyllary sphincters. the smooth muscle of precaplyllary sphincters is controlled by nerve impulses, hormones and chemicals (e.g. vasodilating histamine). there is a net loss of fluid at the capillaries, which is mediated by two opposing forces: blood pressure (out; strongest force) and osmotic pressure (in; because of blood protein content)

sequence census assays

novel assays that harness the quantitative power of high throughput sequencing technologies are vastly increasing our ability to understand genome function; RNA-seq for transcriptome profiling; PCR-seq for metagenomics; ChIP-seq for protein-binding sites

more than 99% of all species that ever lived are

now extinct

synonymous mutations

nucleotide changes that don't result in amino acid changes

S

number of species in the habitat

effect of island size on species number

number of species is higher on large island

varicose veins

occur when the veins stretch and the valves no longer work

the cretaceous mass extinction

occurred 65.5 MYA. organisms that went extinct include about half of all marine species an dmany terrestrial plants and animals, including most dinosaurs

adaptive evolution

occurs as the match between an organism and its environment increases; a continuous process (because the environment can change)

hay fever

occurs when plasma cells secrete IgE antibodies specific for antigens on the surface of pollen. these antibodies interact with mast cells, which secrete histamine and other inflammatory molecules, yielding the symptoms of allergy.

competition

occurs when species compete for a resource in short supply

autoimmune diease

occurs when the immune system is active against particular molecules of the body. lupus - histones. diabetes (type 1) - insulin producing B cells. rheumatoid arthritis - joint linings. graves' disease - TSH receptor. multiple sclerosis - myelin sheaths around axons

complete dominance

occurs when the phenotypes of the heterozygote are identical

pheromones

odorants used in communication between members of a species. in social insects, they maintain social order (maintains the castes). in other insects, they are used to attracted mates. in fish and mammals, they can serve as danger signals

abiotic synthesis

of small organic molecules such as amino acids and nucleotides

parental types

offspring with a phenotype matching one of the parental phenotypes

recombinant

offspring with nonparental phenotypes

intersexual selection

often called mate choice, occurs when individuals of one sex (usually female) are choosy in selecting their mates; selection may depend on the showiness of the male's appearance

white matter (brain)

on the inside and is made primarily of bundles axons

grey matter (brain)

on the surface and is made primarily of neuron cell bodies

genetic drift

one of the basic mechanisms of evolution- is the evolutionary equivalent of a sampling error;random changes in allele frequencies from generation to generation; the smaller the population, the more important drift is; genetic drift tends to reduce genetic variation through losses of alleles, can result in fixation of some alleles and loss of others; can produce differences between populations by sampling error alone; important concern for conservation of species endangered due to small population size

ectoderm

outer layer of the embryo; epidermis of skin and its derivatives (including sweat glands, hair follicles); nervous and sensory systems; pituitary gland. adrenal medulla; jaws and teeth; germ cells

gills

outfoldings of the body surface that are suspended in the water. their surface area is usually much greater than the rest of the body's exterior

reduce world hunger and malnutrition by improving nutritional traits

over 30 million people die each year from malnutrition and associated diseases. more than 250,000 children go blind each year because of vitamin A deficiency; cassava is a primary food for 800 million of the world's poor. transgenic cassava plants are bigger and have enriched levels of protein, iron, and beta-carotene (vitamin A precursor). they also have reduced levels of cyanide; transgenic rice called golden rice is rich in beta-carotene

directional selection

over time, directional selection causes a change in the mean value of a character in a population that is either higher or lower than its current mean value, resulting in a shift in the plot of trait frequency

sperm joins the egg in the

oviduct, resulting in fertilization

pituitary gland (posterior)

oxytocin: stimulates contraction of smooth muscle cells in uterus and mammary glands; vasopressin (antidiuretic hormone, ADH): promotes retention of water by kidneys, influences social behavior and bonding

nondisjunction

pairs of homologous chromosomes do not separate normally during meiosis. as a result, one gamete receives two of the same type of chromosome, and another gamete receives no copy. sometimes nondisjunction at meiosis I is called "true nondisjunction"

ectoparasites

parasites that live on the external surface of a host

endoparasites

parasites that live within the body of their host

parathyroid glands

parathyroid hormone (PTH): raises blood calcium level

inferring phylogenies using maximum parisomy

parsimony uses only those characters/sites that are informative (i.e. have the same character in at least two different sequences)

lost worlds

part organisms were very different from those now alive. the fossil record shows macroevolutionary changes over large time scales, for example: the emergence of terrestrial vertebrates, the impact of mass extinctions, the origin of flight in birds

1900: the rediscovery of Mendel's laws of heredity

particulate, no blending, inheritance. maintains variation because character variation is discrete (3:1, 1:2:1, etc)

local populations occupy

patches of suitable habitat surrounded by unsuitabl ehabitat; they can be lost through extinctions; can be recolonized by immigration

evasion of the immune system:

pathogens and their hosts are involved in an evolutionary arms race, where hosts evolve mechanisms to kill pathogens and pathogens evolve mechanisms to survive those responses. for example, Mycobacterium tuberculosis is phagocytosed by macrophages, but is able to avoid degradation. instead, it replicates and kills this immune cell.

cellular innate defenses in vertebrates:

phagocytic cells use several types of receptors to recognize and destroy viruses, bacteria and fungi. examples are the toll-like receptors (TLR), which bind fragments of molecules normally absent from the vertebrate body but characteristics of a set of pathogens

classes of hormones

polypeptides such as insulin; cholesterol0derived steroids such as cortisol; amines (modified amino acids) such as epinephrine and thyroxine

the exponential model describes

population growth in an idealized, unlimited environment - not sustainable in the long term

exponential population growth

population increase under idealized conditions. under these conditions, the rate of increase is at its maximum, denoted as rmax (also known as intrinsic rate of increase) dN/dt = rmax*N

allee effects

positive effect of adding individuals at low densities; named after W.C. Allee; at some population sizes, growth rate increases with increasing density; potential mechanisms: problems finding mates at low densities and species that form groups (foraging success and predation avoidance)

estrogens and progestins

primarily produced in the ovaries; estrogens like estradiol maintain the female reproductive system and promote the development of 2ry female characteristics: breasts, widened pelvis, increases in body fat in certain areas (e.g. hips, buttocks, thighs); progesterone prepares and maintains the tissues of the uterus required for the growth and development of an embryo; these are components of hormone cascade pathways, controlled by follicle-stimulating hormone (FSH) and luteinizing hormone (LH). These are secreted in response to hypothalamic gonadotropin-releasing hormone (GnRH)

androgens

primarily produced in the testes; the primary androgen is testosterone, which function before birth by promoting the development of male reproductive organs; at puberty, androgens promote the development of 2ry sexual characteristics: low voice, hair patterns, muscle, bone mass

primary oocytes

prior to birth undergo developmental arrest in prophase of meiosis I; resides within a small follicle

only mutations in cells that __________ can be passed to offspring

produce gametes

F2 generation

produced by the F1 generation self-pollinating

monosomy X/Turner's syndrome

produces XO females, who are sterile. it is the only known viable monosomy in humans

placenta

progesterone released by the corpus luteum initiates the growth of the placenta and the enlargement of the uterus; the placenta provides for the diffusion of nutrients, the disposal of metabolic waste, and gas exchange; in the second trimester of pregnancy the placenta takes over the secretion of progesterone, which maintains the pregnancy; at the end of the third trimester, oxytocin released by the posterior pituitary initiates labor

the corpus luteum continues to secrete

progesterone, which maintains the endometrium (in the 2nd trimester, the corpus luteum disintegrates and the placenta takes over this job); also produces high levels of estrogens, which shuts down the ovarian cycle

gibberellins

promote stem elongation; help seeds break dormancy and use stored reserves

during ejaculation, sperm are

propelled via a muscular vas deferens that extends around and behind the urinary bladder

meiosis I

prophase I, metaphase I, anaphaseI, telophase I and cytokinesis

meiosis II

prophase II, metaphase II, anaphase II, telophase II and cytokinesis

survival rate

proportion of individuals alive at age x surviving to age x+1

mortality (or death) rate

proportion of individuals of age x dying by age x+1

survivorship

proportion of newborns (age = 0) surviving to age x

diffusion is

proportional to the surface area across which it occurs. inversely proportional to the square of the distance the molecules must move.

endosymbiont theory

proposes that mitochondria and plastids (chloroplasts and related organelles) were formerly small prokaryotes living within larger host cells

caspases

proteases that drive apoptosis; in C. elegans, death signals inactivate Ced-9, thus activating Ced-4, which initiates the apoptosis pathway via Ced-3 (the chief caspase); C. elegans has ~1,000 cells, and apoptosis occurs precisely 131 times during development

effects of glucocorticoids

proteins and fats broken down and converted to glucose, leading to increased blood glucose; partial suppression of immune system

the species-area curve

quantifies the idea that, all other factors being equal, a larger geographic area has more species

if population increases by 25% between years, then the factor by which a population grows is

r = 0.25

optic nerve fibers, ganglion cells, bipolar cells

receive information

insulation

reduces overall heat exchange: blubber, hair, feathers; can often be adjusted to thermoregulate, and this can either be rapid or seasonal. momentary: raising hair or feather. seasonal (acclimatization): changes in the composition of the insulating layer or layers

negative feedback

reduces the initial stimulus

sensory adaptation

refers to a decrease in responsiveness following continuous stimulation

herbivory (+/- interaction)

refers to an interaction in which an herbivore eats parts of a plant or alga

predation (+/- interaction)

refers to interaction where one species, the predator, kills and eats the other, the prey

amplification

refers to the strengthening of a sensory signal during transduction, and may involve enzymatically produced 2nd messengers

the cambrian explosion

refers to the sudden appearance of fossils resembling modern animal phyla in the cambrian period (535 to 525); provides first evidence of predator-prey interactions

most Y-linked genes are

related to sex determination

interspecific interactions

relationships between species in a community; can affect the survivla and reproduction of each species, and the effects can be summarized as positive (+), negative (-), or no effect (0)

adaptive immunity (acquired immunity)

relies on the molecular recognition of pathogens using a vast aresenal of receptors, each of which recognize a feature typically found only on a particular part of a particular pathogen. the internal defenses elicited are active against a specific pathogen or closely related pathogens. this immune response is enhanced by prior exposure to the infecting pathogen. found in vertebrates.

duplication

repeats a segment

the fossil record

reveals changes in the history of life on earth; shows changes in kinds of organisms on earth over time; is biased in favor of species that existed for a long time, were abundant and widespread, had hard parts

cell wall

rigid outer layer that maintains the cell's shape and protects it from damage

photoreceptors

rods = monochrome and cones = color

structure of the human eye

rods are more sensitive to light but do not distinguish color. they are most useful at night. cones provide color vision, but are less sensitive to light (less useful at night). there are three types of cones, which are sensitive to red, green, or blue light, respectively. three different visual pigments, called photopsins, that absorb light at different wavelengths.

if fertilization happens, the corpus luteum

secretes estradiol and progesterone, maintaining the uterine lining during pregnancy

highly variable or unpredictable environment favor

semelparity

direction of information

sensory information arrvie into primary sensory areas of the cortex via the thalamus; once processed, information moves to the prefrontal cortex for decision making; then, for example, motor commands may be generated via the motor cortex

sensory transmission

sensory information travels through the nervous system as action potentials (nerve impulses). many sensory neurons transduce the energy in a stimulus into a receptor potential, which initiates an action potential that is transmitted to the CNS. Non-neuronal sensory receptor cells form chemical synapses with afferent neurons and respond to stimuli by increasing the rate at which the neuron initiates action potentials (NTs).

gonads and sex hormones

sex hormones are primarily produced in the gonads and affect growth, development, reproductive cycles, and sexual behavior; adrenal glands are minor producers of sex hormones; there are three major types of sex hormones: androgens, estrogens, progestins; sex hormones act via intracellular receptors

sympatric speciation via sexual selection

sexual selection can drive sympatric speciation. sexual selection for mates of different colors has likely contributed to speciation in cichlid fish in lake victoria

If a female is heterozygous for a particular gene located on the X chromosome,

she will be a mosaic for that character

advantages of pea plants for genetic study

short generation time, large number of offspring, many varieties with well-described characters (such as color), mating could be controlled, plants could be allowed to self-pollinate or could be cross pollinated

four categories of repetitive DNA

short tandem repeats, tandem repeats, segmental duplication, interspersed repeats

cell signaling can regulate the activity of proteins:

signal transduction following the binding of epinephrine to a GPCR induces the conversion of glycogen to glucose; amplification occurs in many steps. thus, a small number of epinephrine molecules can trigger a huge response

regulation of the response:

signaling pathways generally amplify the cell's response to a single signaling event; the many steps in a multistep pathway provide control points where the cell's response can be further regulated (this contributes to the specificity and allows for the coordination with other signaling pathways); the overall efficiency of the response is enhanced by the presence of scaffolding proteins; all signals are terminated

motor system

signals skeletal muscles for both voluntary and involuntary movements

generation time

single-celled organisms and viruses have many more generations per unit of time than larger ones

vision: single-lens eyes

single-lens eyes are found in vertebrates and some invertebrates. the light enters through a pupil that changes in diameter via the action of the iris. behind the pupil, a lens directs light onto layer of photoreceptors. In invertebrates like jellies, polychaete worms, spider and mollusks (e.g. octopus), as well as in fish, movement of the lens forward and backward focuses the light. In mammals and other animals, focusing is achieved by changing the shape of the lens

sister chromatid cohesion

sister chromatids resulting from chromosomes duplicating during interphase and are associated along their lengths

mammals only employ the ___________ to polyspermy

slow block

the oldest known fossils of multicellular eukaryotes that can be resolved taxonomically are

small algae that lived about 1.2 BYA

pheromones

small molecules released into the external environment, and function in the communication between members of the same species (in animals, pheromones act like hormones, and influence physiology and behavior)

in arteries and aterioles, contraction of

smooth muscle impacts blood flow

population cycles

some populations undergo regular boom-and-bust cycles. Example: lynx populations follow the 10-year boom-and-bust cycle of hare populations; driven by the availability of prey; when prey become scarce, predator species begin to prey on one another, accelerating the collapse of predator populations

apoptosis functions in the formation of

some three dimensional structures

endocrine (hormonal) signaling

specialized endocrine cells (sender cells) secrete hormones (insulin, glucagon, etc) into body fluids, often blood. hormones travel via the circulatory system and reach virtually all cells in the body, but are bound only by some cells (target cells)

neuroendocrine signaling

specialized neurons called neurosecretory cells secrete neurohormones, which enter the bloodstream; many neurohormones regulate endocrine signaling

resource partitioning

species evolve to minimize competition by "partitioning" their resources

(spermatogenesis) mitotic divisions give rise to

spermatogonia and then spermatocytes

multiplication rule

states that the probability that two or more independent events will occur together is the product of their individual probabilities; can be used to determine the genotype probabilities in a cross between F1 and monohybrids.

law of segregation

states that the two alleles for a heritable character separate (segregate) during gamete formation and end up in different gametes; thus, an egg or a sperm gets only one of the two alleles that are present in the somatic cells of an organism; this segregation of alleles corresponds to the distribution of homologous chromosomes to different gametes in meiosis

competitive exclusion principle

states that two species competing for the same limiting resources cannot coexist in the same place

induced pluripotent stem cells (iPS)

stem cells that have been created from adult differentiated cells. they were cerated by the introduction of four stem cell master regulators into the genome of the differentiated cell

feedback regulation: hormone cascade pathway

stimulus is recieved by a sensory neuron; the neuron stimulates a neurosecretory cell, which secretes a neurohormone; the neurohormone travels via the bloodstream to an endocrine cell, interacts with a receptor, and triggers the release of another hormone; that hormone interacts with a receptor on a target cell, which triggers a cellular response

"good genes" hypothesis

suggests that if a trait is related to male genetic quality or health, both the male trait and the female preference for that trait should increase in frequency

support cells of the developing follicle ________ the egg

surround

behavior enhances

survival and reproductive success in a population

in populations now experiencing immigration or emigration, two key factors determine changes in population size

survivorship and reproduction rates

"the pill"

synthetic estrogens and progestins that prevent pregnancy by inhibiting the production of GnRH, LH and FSH. Thus, the ovarian cycle does not take place

calvin cycle reactions

take place in the stroma; use ATP and NADPH to convert CO2 to the sugar G3P; return ADP, inorganic phosphate and NADP+ to the light reactions

process of continental drift

tectonic plates move slowly

fast twitch fibers develop

tension two to three times faster than slow twitch fibers

(male) negative feedback:

testosterone inhibits release of GnRH, FSH, and LH; inhibin inhibits release of FSH

similarities in cell signaling suggest

that ancestral signaling components that evolved in prokaryotes and single-celled eukaryotes were adopted for use in their multicellular descendants

the fossil record shows that most species

that have ever lived are now extinct

adaptive immunity:

the adaptive responses relies of two types of lymphocytes: T cells and B cells. lymphocytes originate in the bone marrow. those that mature there are B cells, whereas those that mature in the thymus are T cells. Any substance that elicits a B cell or T cel response is called an antigen, which is bound by an antigen receptor. Each antigen receptor binds only one part of one molecule of a specific pathogen, and all the receptors within a single B or T cell are identical. These cells exhibit specificity. The portion of the antigen that is bound by the receptor is called an epitope.

adrenal glands

the adrenal glands sit atop the kidneys, and are composed of two glands: the adrenal cortex (endocrine; on the outside) and the adrenal medulla (neuroendocrine; on the inside);

the fundamental unit of life in all organisms is

the cell

ovarian cycle (4)

the cells in the follicles begin to make estradiol (this begins the follicular phase, when follicles grow and oocytes mature; several follicles grow but usually only one matures; low levels of estradiol keep levels of FSH and LH in check)

the cerebral cortex controls voluntary movement and cognitive functions:

the cerebrum is the larges structure in the human brain; it is essential for language, cognition, memory, consciousness, and awareness of our surroundings; cognitive functions resdie in the cortex: the outer layer of the cerebrum; each side of the cerebrum has frontal, temporal, occipital, and parietal lobes; within the cortex are sensory, association, and motor areas

the calvin cycle uses

the chemical energy of ATP and NADPH to reduce CO2 to sugars

why are leaves green?

the chlorophyll molecules of chloroplasts absorb violet-blue and red light, which are the colors most effective in driving photosynthesis. They reflect or transmit green light, giving the leaves their color; they also reflect or transmit far-red light, which is at the extreme end of the visible spectrum)

the return of venous blood to the heart is assisted by

the contraction of smooth muscle, and during exercise, of skeletal muscle

fitness

the contribution an individual makes to the gene pool of the next generation

after ovulation, the ruptured follicle develops into

the corpus luteum

reproductive isolation

the critical issue is the reduction of gene flow between populations, so that populations can diverge in allele frequencies (by genetic drift or by natural selection) and become reproductively isolated; hybrids are the offspring of crosses between different species; the existence of biological factors (barrier) that impede two species from producing viable, fertile hybrids

menstruation

the cyclic shedding of the blood rich endometrium (lining of the uterus) which flows through the cervix and vagina; it is also called the uterine cycle and in humans averages 28 days

sensory reception

the detection of stimulus by sensory cells. sensory receptors can be: a sensory neuron or a non-neuronal cell that regulates a neuron. Sensory receptor cells exist: singly or collected in a sensory organ. Sensory cells recieve: stimuli from outside the body (heat, light, pressure, chemicals) or stimuli from inside of the body (blood pressure, body position)

arteries and veins are distinguished by

the direction in which they carry blood

systematics

the discipline that focuses on inferring the phylogenetic relationships of organisms and creating classifications based on their evolutionary histories

sickle cell anemia

the disease is caused by the substitution of a single amino acid in the hemoglobin protein in red blood cells. symptoms include physical weakness, pain, organ damage, and even paralysis.

development

the events involved in an organism's gradual changing from a simple to a more complex or specialized form

microevolution

the evolutionary processes that occur rapdily within populations and change thier genetic makeup from one generation to the next

microevolution

the evolutionary processes that occur rapidly within populations and change thier genetic makeup from one generation to the next

sperm must traverse this cellular layer (support cells) before reaching

the extracellular matrix of the egg, called the zona pellucida

conflict theory for genomic imprinting in pregnancy

the fetus is selected to extract more from the mother than the mother is selected to give. fetal tissue in the placenta can manipulate maternal physiology via hormone production. there are two main paths to increasing fetal provisioning: increase maternal blood pressure (-> pre-eclampsia) and increase the sugar concentration of maternal blood (-> pregnancy related diabetes). the father turns off genes that downregulate growth. paternally-expressed transcripts thus enhance growth. the mother turns off genes that upregulate growth. maternally-expressed transcripts thus inhibit growth. the normal state is an equilibrium in which both mother and offspring are in reasonably good condition.

how do we fight pathogens?

the first lines of defense seek to keep pathogens from entering the body. if a pathogen subverts these physical barriers then the body must detect such foreign invader and get rid of it. it must be able to differentiate self from non-self by means of molecular recognition. innate immunity. adaptive immunity

Jean Baptiste de Lamarck

the first to propose a coherent theory of evolution. 1st law: use and disuse leads to acquired traits. 2nd law: acquired traits can be inherited; these "laws" are unsupported by evidence

frequency-dependent selection

the fitness of any morph declines if it becomes too common in the population; another mechanism that can preserve genetic variation

fossil record

the fossil record documents the pattern of evolution, showing how past organisms differed from present-day organisms. it also shows that many species have gone extinct. the fossil record fills gaps in the "living" record

ABO blood group

the four phenotypes of the ABO blood group in humans are determined by three alleles for the enzyme (I) that attaches A or B carbohydrates to red blood cells: IA, IB, and i. the enzyme encoded by the IA allele adds the A carbohydrate, whereas the enzyme encoded by the IB allele adds the B carbohydrate; the enzyme encoded by the i allele adds neither

cardiac muscle

the heart. striated, involuntary: ion channels in the plasma membrane cause rhythmic depolarizations in the absence of nervous input. cells are electrically connected by intercalating discs

inherited disorders show quite variable frequency in different human populations due to

the historical geographic isolation of different human populations

processing of visual information continues in the brain:

the optic nerves from the left and right eyes meet at the optic chiasm near the center of the base of the cerebral cortex. axons are routed such that sensations from the left visual fields of both eyes are routed to the right of the brain and vice versa. so, the right and left visual fields involve input from both eyes. ganglion cell axons lead to the lateral geniculate nuclei, which have axons that reach the primary visual cortex

thomas malthus

the power of population is indefinitely greater than the power in the earth to produce subsistence for man; inspired darwin

biogeography

the scientific study of the geographic distribution of species; accounts for geographic distance and continental drift

sickle cell anemia

the sickle-cell allele (b-globin; HBS) causes changes in hemoglobin that confers malaria resistance; heterozygotes are mostly resistant to malaria, and asymptomatic. homozygous recessive are severely anemic, and SCA is usually fatal before age of 5 without treatment; it exemplifies heterozygote advantage and balancing selection

pathogens can enter the body via:

the skin, the digestive system, the respiratory system, the urgoenital tract

in sexual reproduction, the male gamete is called

the sperm

genomics

the study of whole sets of genes, their products, and their interactions; a field that encompasses transcriptomics, proteomics, metabolomics, and various other -omics approaches

countercurrent exchange

the transfer of heat (or solutes) between fluids that are flowing in opposite directions. allows for heat exchange between arteries and veins that are traveling in opposite directions

communication

the transmission and reception of signals between animals, often has a role in the causation of behavior

P generation

the true-breeding parents

mass extinctions can change

the type of organisms found in ecological communities; for example, the percentage of marine organisms that were predators increased after the Permian and Cretaceous mass extinctions

gametes

the vehicles that transmit genes from one generation to the next in plants and animals that reproduce sexually

if a sperm penetrates the 2ry oocyte,

then meiosis II resumes, resulting in an egg and a polar body

signal molecules that cross the plasma membrane

these signals cross the plasma membrane and interact with a receptor in the cytoplasm of the target cell (ex: steroid hormones like testosterone or aldosterone, thyroid hormones, nitric oxide

signal molecule that are unable to cross the plasma membrane

these signals interact with a receptor on the cell membrane, which then transmits the signal to the interior of the cell. (ex: peptide hormones, biogenic amines like epinephrine, and amino acids)

the testcross

to determine the genotype we can carry out a testcross: breeding the mystery individual with a homozygous recessive individual. if any offspring display the recessive phenotype, the mystery parent must be heterozygous

shannon diversity index

to directly compare species diversity across communities (in time or space), we can use indices of diversity;

in the uterus, the blastocyst attaches

to the endometrium, which stimulated by estrogen, nourishes the embryo (pregnancy)

in some animals, all cells are close enough

to the outside environment that no dedicated respiratory structures exist

organisms have finite resources which may lead to

trade-offs between survival and reproduction

mutant phenotypes

traits alternative to the wild type

making transgenic plants

transgenes are inserted into Ti plasmid, and reinserted into the bacterium Agrobacterium; the Ti plasmid is transferred to the plant via infection with Agrobacterium; transformation is done on shoot or leaf tissue that forms a callus when grown on agar medium (alternately, the Ti plasmid can be electroporated into the plant)

helper T cells

trigger both humoral and cellular immune responses. become activated when their receptors specifically bind an antigen on MHC II molecules on the surface of an antigen presenting cell (macrophage, dendritic cell, B cell). This is assisted by the accessory protein, CD4

codominance

two dominant alleles affect the phenotype in separate, distinguishable ways. occurs when the phenotypes of both parents are simultaneously expressed in the same offspring

why does species diversity decrease as latitude increases?

two key factors in equatorial-polar gradients of species richness are evolutionary history and climate; evolutionary history: tropical environments tend to be older and the growing season is longer in the tropics, which means that biological time is faster; climate: two climatic factors (sunlight and precipitation, both high in tropical environments) are positively correlated with species richness

(oogenesis) each month,

typically one follicle matures and completes meiosis I, resulting in a secondary oocyte and a polar body

for most of human history, species were assumed to be

unchangeable

cooperation

under threat from a predator, individual meerkats make an alarm call to warn others, even though calling increases the chances that the caller is killed

inflammatory response

upon injury, histamine is released by mast cells in the connective tissue, dilating the capillaries and making them more permeable. this causes swelling. macrophages and neutrophils release cytokines that increase blood flow to the site of injury, resulting in redness and increased T. activated complement promotes further release of histamine, attracting ore phagocyctic cells. increased blood flow delivers additional antimicrobial peptides, and pus accumulates.

some times of aneuploidy appear to

upset the genetic balance less than others, resulting in individuals surviving to birth and beyond.

bombardment of earth by rocks and ice likely

vaporized water and prevented seas from forming before about 4 billion year ago

hearing

vibrating objects create pressure waves in the surrounding air. The ear tranduces this mechanical stimulus into nerve impulses that the brain perceives as sound. Moving air in the outer ear makes the tympanic membrane vibrate, and the three bones of the middle ear transit these vibrations to the oval window. When the stapes vibrates against the oval window, it creates pressure waves in the fluid inside the cochlea (inner ear). Pressure waves push on the cochlear duct and basilar membrane. The attached hair cells, which also attach to the tectorial membrane, vibrate up and down. With each vibration, the hair cells bend in one direction and then the others, causing ion channels in the hair cells to open and close. Bending in one direction depolarizes the cells, thus releasing more NTs. Bending the other hyperpolarizes the cells, thus reducing the release of NTs

five modes of communication

visual, chemical, tactile, auditory, electric

how are biological communities structured?

what factors determine how many species are there, which particular species are present, and their relative abundances? in general, a few species in a community exert strong control on that community's structure. two fundamental features of community structure are species diversity and trophic structure (feeding relationships)

example using the model of continuous growth:

what is the population size in 10 years? N0= 100, r = 0.1398, t = 10 years

modeling natural selection

you can build a simple population genetic model of how natural selection works at a single Mendelian locus. for example, AA, Aa, and aa could each be assigned different relative fitnesses, and you can study directional, stabilizing and diversifying selection in the easiest possible case