Biology 182 Exam 2

Homologous structures

"Common Ancestry" with the same character or character state (Ex: The forelimbs of all mammals constructed from the same skeletal elements.)Used for building phylogenic trees

Heterosis

"Hybrid vigor"; A cross between two different true-breeding homozygotes can result in offspring with stronger, larger phenotypes (Ex: bigger corn). Exaggeration in both alleles in heterozygoates

Mesophyll cells

"Middle leaf" Near the upper surface of the leaf have a columnar arrangement that maximizes light interception. close to the stomata have a honeycomb-like arrangement to allow CO2 to spread easily throughout the leaf and has loosely packed photosynthetic cells.

Evolution

"descent with modification" the change in the genetic makeup of a population from generation to generation. Explains the unity and diversity of life.

Ecological defenses

"employ" animals as bodyguards in exchange for shelter or nourishment, much the way that many plants provide food or other rewards to animals that transfer pollen and disperse seeds (ants who live in plants will protect it from creatures trying to eat it)

angiosperms

"enclosed seed" The flowering plants; they are a monophyletic group of seed plants characterized by transporting water through the xylem(which may not have evolved initially for this), flowers, double fertilization which results in the formation of a triploid tissue, and fruits. (Nearly 90% of all flowers) They evolved from both squeezing out other plants and increasing in the species that can coexist

analogous structures

"evolved independently" similarity that results from convergent evolution; Describes similar characters that evolved independently in different organisms as a result of adaptation to similar environments. (Ex: the wings of a bat and a bird)

epiphyte

"on plant" A bryophyte plant that grows high in the canopy of other plants, or on branches or trunks of trees, without contact with the soil.

sympatric

"same place" When populations are in the same physical area. But natural selection must act strongly to counteract the homogenizing effect of the gene flow (EX: polyploidy) Or behavioral or other isolating mechanisms such as pre-zygotic isolating mechanisms at a faster rate than allopatric species (Ex: mating patterns, feeding behavior) so it becomes genetically isolated by genetic events. Other factors cause them not to reproduce Populations are split by genetic or behavioral patterns while living in the same physical area

Frequency of that allele

(alleles)/(total) Include B, b

gymnosperms (big strong plants)

(ginkgos, cycads, redwoods, pines, conifers, evergreens) gnetophytes) "Naked" Seed plants whose ovules are not enclosed in a carpel;. meaning the ovules and seeds are not protected by ovary or fruit tissue

Frequency of that genotype

(number of individuals of a certain genotype)/(total) Include BB, Bb, or bb

What is the probability that a family of 3 children has at least 1 boy?

0.5 X 0.5 X 0.5 = 0.125 1-0.125=0.875

Genetic example 1: Mendel crossed two heterozygous smooth, yellow-seeded F1 plants. What's the probability that the offspring was smooth-, green-seeded?

3/4 X 1/4 = 3/16

What's the probability of obtaining a wrinkled-, green- seeded, tall, purple-flowered offspring from a self-cross of heterozygous round-seeded, yellow-seeded, tall, purple- flowered F1 pea plants?

3/4 X 3/4 X 1/4 X1/4 = 9/256

In a population of organisms with 4 alleles, how many homozygous genotypes are possible? How many heterozygous genotypes are possible?

4;6

CLICKER: What is the probability of Enzo's sister with a dad that is color blind but his mom is not.

50%

In the previous cross, what's the probability that the offspring is heterozygous for at least three of the four traits?

8(1/2)^3 (1/4) +(1/2)^4 = 5/16

synapomorphy

A "shared derived character"; a homology shared by some, but not all, members of a group. (The hoof developing from five toes in a horse and a donkey). This helps identify sister groups

environmental risk factor

A characteristic in a person's surroundings that increases the likelihood of developing a particular disease.

hormone

A chemical signal that influences physiology and development. Decides: How are leaves arranged? Where do branches form? How much do internodes elongate? Second, they coordinate growth in different parts of the plant in response to both internal and external environmental factors.

ecological niche

A complete description of the role a species plays in its environment.

quantitative trait

A complex trait in which the phenotype is measured along a continuum with only small intervals between similar individuals.

Cork cambium

A cylinder of meristematic tissue in plants that produces cork cells to replace the epidermis during secondary growth

Contingency Table

A data matrix that displays the frequency of some combination of possible responses to multiple variables; cross tabulation results

phylogenetic tree

A diagrammed hypothesis about the evolutionary history, or phylogeny, of a species. It does NOT in any way imply that more recently evolved groups are more advanced than groups that arose earlier.

meristem

A discrete population of actively dividing and totipotent cells,

normal distribution

A distribution whose plot is a bell-shaped curve.

thallus

A flattened photosynthetic structure produced by some bryophytes.

X-linked gene

A gene in the X chromosome with a unique pattern of inheritance; provided the first experimental evidence that chromosomes contain genes.

hemizygous

A gene present on the X chromosome that is expressed in males in both the recessive and dominant condition

meristem identity gene

A gene that contributes to meristem stability and function.

Y-linked gene

A gene that is present in the region of the Y chromosome that shares no homology with the X chromosome.

A‐Type Blood Type

A glycoprotein on blood cell

norm of reaction

A graphical depiction of the change in phenotype across a range of environments. (environmental factors fall on the x-axis, and phenotypes fall on the y-axis)

population

A group of individuals from the same species that can interbreed Living in the same place at the same time

species

A group of individuals that can exchange genetic material and sharing alleles through interbreeding to produce fertile offspring. OR A population or group of populations whose members have the potential to interbreed in nature and produce viable, fertile offspring that are reproductively isolated from other such populations

shoot apical meristem

A group of totipotent cells near the tip of a stem or branch that gives rise to new shoot tissues in plants. (like embryonic cells in mammals)

strigolactone

A hormone, produced in roots and transported upward in the xylem, that inhibits the outgrowth of axillary buds.

auxillarly buds

A meristem that forms at the base of each leaf. Have the same structure and developmental potential as the apical meristem and express the same meristem identity genes

genetic test

A method of identifying the genotype of an individual.

ferns and horsetails

A monophyletic group of vascular plants that have leaves and disperse by spores; not capable of secondary growth and therefore they have slender stems and frequently grow underground

lycophytes

A monophyletic major group of spore-dispersing vascular plants that are the sister group to all other vascular plants.

CLICKER: Mrs. Cala is in a traffic accident and needs blood transfusion. She remembers her blood type is A but can't remember which blood types she could ask for. What are the viable alternatives?

A or B

crisscross inheritance

A pattern in which an X chromosome present in a male in one generation is transmitted to a female in the next generation, and in the generation after that can be transmitted back to a male.

adaptive radiation

A period of unusually rapid evolutionary diversification in which natural selection accelerates the rates of both speciation and adaptation in a single lineage.

Natural Theology

A philosophy (1700s Europe) dedicated to discovering the Creator's plan by studying nature. No genetic relationship as God has formed all species just as they appear and to do a certain job.

auxin

A plant hormone that causes and controls shoots to elongate and guides vascular differentiation. It underlies how shoots bend and grow toward light and establishes spatial patterns of shoot development. Moves from the stem to the tip of a leaf back to the stem.

cytokinin

A plant hormone that stimulates cell division and are found in plant meristems. Promote shoot growth by increasing the number of dividing cells in the apical meristem and, when applied directly to axillary buds, can stimulate them to develop into branches

gibberellic acid

A plant hormone that stimulates the elongation of stems.

necrotrophic pathogen

A plant pathogen that kills cells before drawing resources from them.

biotrophic pathogen

A plant pathogen that obtains resources from living cells. They produce chemicals that stimulate the host cells to secrete compounds that the pathogen can use as food (EX: viruses)

host plant

A plant species that can be infected by a given pathogen.f

Reduced hybrid viability

A post-zygotic barrier in Hybrids fail to develop or reach sexual maturity (Ex: Mules)

Basal resistance

A receptor protein in the plant cell's plasma membrane binds with a pathogen-derived molecule and triggers a defense response.

Immune System with no infection

A receptor protein in the plant cell's plasma membrane binds with a pathogen-derived molecule and triggers a defense response.

HW: A virus

A researcher comes across a plant that has been infected by a pathogen. As a result of the infection, the plant has undergone a systemic acquired resistance (SAR) response and has also generated several siRNAs. This takes about

Founder effect

A sample of the population colonize a new region, and it is random which alleles followed the colonizers (Ex: founding Pitcairn Island)

Evolutionary arms race

A series of reciprocal adaptations that can lead to The evolution of traits that increase the fitness of a predator or parasite exerts selection pressure on its prey or host species to counter the consumer's adaptation (EX: Herbivores becoming more used to poisons and plants become more poisonous.)

Pleiotropic effects

A single allele can have multiple phenotypic effects (ex: siamese cats or red heads)

peripatric speciation

A specific kind of allopatric speciation in which a few individuals from a mainland population disperse to a new location remote from the original population and evolve separately.

Bryophyte stomata

A sporophyte with open stomata will dry out quickly, so its spores are more easily released into the air.

desiccation tolerance

A suite of biochemical traits that allows cells to survive extreme dehydration without damage to membranes or macromolecules until the proper amount of water is returned and the plant can begin the process of photosynthesis again

single-gene trait

A trait determined by Mendelian alleles of a single gene with little influence from the environment.

incomplete penetrance

A trait that could or could not be expressed based on other genes or the environment

complex trait

A trait that is influenced by multiple genes as well as by the environment. The genes and the environment are equal contributors.

inbred line

A true-breeding, homozygous strain.

small interfering RNA (siRNA)

A type of small double-stranded regulatory RNA that becomes part of a complex able to cleave and destroy single-stranded RNA with a complementary sequence. Molecules move through plasmodesmata, enter the phloem, and from there spread throughout the plant.

Viral Defense against Hypersensitive Response

A virus infects the host plant cell by injecting its single-stranded RNA* (ssRNA) genome --> During the replication of the viral genome, double- stranded RNA molecules (dsRNA) are formed. -->The plant cell recognizes dsRNA as foreign and cleaves it into fragments of 20-25 nucleotides called small interfering RNA (siRNA). --> siRNA bind to a plant protein complex, which retains only one of the RNA strands. --> ssRNA molecules that bind to the protein-bound siRNA strand are destroyed.

CLICKER: You and your mom both have blood type O. What are the possible types your dad can have?

A, B, and O (not AB)

Which is dominant: A/B or O

A/B

Diversification of land plants

According to fossil record: Green algae --> nonvascular plants --> seedless vascular plants --> seed plants Further evidence: Molecular phylogenies

key features of the inheritance of traits due to rare X-linked recessive alleles

Affected individuals are usually males because males need only one copy of the mutant gene to be affected, whereas females need two copies to be affected. Affected males have unaffected sons because males transmit their X chromosome only to their daughters. A female whose father is affected can have affected sons because such a female must be a heterozygous carrier of the recessive mutant allele.

What is complexity?

All creation gradually evolved to a higher, more perfect state. A combination of Multicellular, Many different cell types, Many different structures, Internal specialization, Number of functions, And this must have a genetic basis, as it has evolved.

Evolutionary constraints on Developmental processes also constrain evolution

All evolutionary innovations are modifications of previously existing structures (ex: fish eye migration). We have to have an organism that has the existing characteristics to get an beneficial trait.

Alternation of generations

All land plants have a life cycle with alternation of generations (Includes multicellular diploid (sporophyte) and multicellular haploid (gametophyte) individuals)

Moving from single crosses to populations

All populations have genotype frequencies, and all populations have allele frequencies. When 2 heterozygous individuals mate, they each make a pool of gametes, which essentially pair up randomly. We will assume the same thing happens within populations. Start by crossing Aa with Aa

HOMEWORK: gene pool

All the alleles at all the gene loci in all the individuals in a population or species

When a population is genetically stable:

Allele frequencies (p and q) predict genotypic frequencies (p2 + 2pq +q2)

subspecies

Allopatric populations that have yet to evolve even partial reproductive isolation but which have acquired population-specific traits.

allele frequency

Among all the alleles of a gene in a population, the proportion that are of a specified allele.

coevolution

An adaptation in one species that leads to the evolution of an adaptation in a species it interacts with (Ex: Hummingbird and red flowers, yucca and yucca moth)

Rh+/- or D antigen

An additional blood system describing many antigens on the blood cells; In general, Rh- blood is given to Rh- patients, and Rh+ blood or Rh- blood may be given to Rh+ patients

How do "bad" alleles happen?

An allele can mutate and become a different allele; mainly are undesirable but not always "bad"

protease inhibitor

An antidigestive protein that binds to the active site of enzymes that break down proteins in a herbivore's digestive system.

island population

An isolated population.

Recombinant

An offspring with a different combination of alleles from that of either parent, resulting from one or more crossovers in prophase I of meiosis.

polymorphism

Any genetic difference among individuals sufficiently common that it is likely to be present in a group of 50 randomly chosen individuals.

sex chromosome

Any of the chromosomes associated with sex.

phenol

Any one of a class of compounds, produced by some plants as a defensive mechanism.

terpene

Any one of a group of compounds that do not contain nitrogen and are produced by some plants as a defensive mechanism.

alkaloid

Any one of a group of nitrogen-bearing compounds that damages the nervous system of animals, produced by some plants as a defensive mechanism.

tannin

Any one of a group of phenols found widely in plant tissues that bind with proteins and reduce their digestibility.

R protein and gene

Any one of a group of receptors in plant cells, each expressed by a different gene, that function as part of the plant's immune system by each binding to a specific pathogen-derived protein. Can result in an evolutionary arms race

X-linked recessive phenotypes

Appear much more often in males than females Daughters who are heterozygous are carriers Mutant phenotype can skip a generation if it passes from a male to his daughter

Scale of Nature

Aristotle's chart that organized by complexity with humans on top

B‐Type Blood Type

B glycoprotein on blood cell

Do individual organisms evolve?

Because evolution is "in the genes", changes in an individual's phenotype are not passed on to offspring. Evolution must be any change in allele frequencies, genotype frequencies, or both

what do we think the advantge that led to the evolution of 'cup eyes' in Planaria

Being able to detect the direction of light so they can detect where a predator is

Evolutionary constraints on Adaptations involve both fitness costs and benefits

Benefit must outweigh the cost if adaptation is to evolve the trade-offs must be worthwhile. (Ex: Species in which males have multiple mates are polygynous. Males are usually larger than females and often have weapons—horns, antlers, etc.)

Morgan looked at what two traits

Body color (gray dominant) and wing shape (large wings dominant) and back crossed

AB Blood type

Both the A and B glycoproteins

Cladogenesis (branching evolution)

Branching off of one or more new species from a parent species that continues to exist. A new species is invented (Ex: adaptive radiation)

What is the anatomy of a root (CREEPRX)

Casparian strip, Root hairs, Epidermis, Endodermal cells, Phloem, Root cortex, Xylem

What are three functions of the shoot apical meristem? (CIM)

Cell division (source of all the cells that make up a stem), initiates leaves, and produces new meristems (allows stems to branch)

Evolutionary constraints on Evolution must work within the boundaries of universal constraints such as what

Cell size, constrained by surface area-to-volume ratios. Protein folding, constrained by types of bonding that can occur. Laws of thermodynamics that constrain energy transfers

totipotent

Cells with the potential to become one of many different cell types

Kin selection

Certain genotypes may code for behaviors that help close relatives raise more offspring than they would without help These alleles would be favored by selection, provided that their close relatives are likely to have copies of the same alleles. You want your genes to be passed on. Our behavior comes from the environment and genetics. So sociality may be passed on through genes.

Microevolution

Change in allele frequencies in a population over generations.

parsimony

Choosing the simplest hypothesis to account for a given set of observations. Each node corresponds to a mutation (or mutations) in an ancestral species, and the more changes or steps we propose, the more independent mutations we must also hypothesize. It's important to note that the branching patterns are not meant to suggest that multiple species diverged simultaneously,

Parapatric speciation

Contiguous (large and spread out) populations; But individuals more likely to mate with local neighbors making gene flow limited, varying selection pressures, and Helped by heterogeneous environment and disruptive selection

polygenic inheritance

Controlled by many genes; additive effect of 2+ genes on a single character (Ex height or skin color) can be affected by the environment

When and where does recombination occur?

Crossing over takes place at the four-strand stage of meiosis

origin of species

Darwin's book about means of natural selection and evolution. He waited to publish this because he was worried that he would receive backlash from the public for saying humans were only a branch of tree of life. The whole point of his revolution is species are not fixed. However, natural selection may or may not play a role in speciation

Expressivity

Degree to which genotype is expressed in an individual (Ex: polydactyly in cats)

fixed

Describes a population that exhibits only one allele at a particular gene.

homozygous

Describes an individual who inherits an allele of the same type from each parent, or a genotype in which both alleles for a given gene are of the same type.

heterozygous

Describes an individual who inherits different types of alleles from the parents, or genotypes in which the two alleles for a given gene are different.

post-zygotic isolation

Describes factors that cause the failure of the fertilized egg to develop into a fertile individual. If fertilization occurs, it presents hybrids from developing into a viable, fertile adult

pre-zygotic isolation

Describes factors that prevent the fertilization of an egg. Impede mating between species or hinder fertilization if mating is attempted

monophyletic

Describes groupings in which all members share a single common ancestor and all of its descendants. They evolved after the divergence of the group from its sister group.

polyphyletic

Describes groupings that do not include the last common ancestor of all members.

paraphyletic

Describes groupings that include some, but not all, the descendants of a common ancestor.

virulent

Describes pathogens that are able to overcome a host's defenses and lead to disease. In the absence of a matching R protein, the AVR protein blocks the plant's basal resistance.

partially reproductively isolated

Describes populations that have not yet diverged as separate species but whose genetic differences are extensive enough that the hybrid offspring they produce have reduced fertility or viability compared with offspring produced by crosses between individuals within each population.

Synapomorphy of plants

Develop from an embryo protected by tissues of the parent plant (embryophytes)

genetic variation

Differences in genotype among individuals in a population.

map unit/centimorgan (cM)

Distance between genes which is = recombinant frequency of 0.01( X 100)

reproductive features that contributed to angiosperm diversity and success

Double fertilization, Production of endosperm, Ovules and seeds enclosed in a carpel, Flowers/Fruits, Phloem with companion cells, and Reduced gametophyte stage; only ones to have triploid endosperm

Sexual dimorphism

Dramatic differences between sexes are known; mainly the result of sexual selection

What were the ideas before Darwin?

Earth was young (only a few thousand years old) All creatures were unchanging and created in their current forms

A bacteriologist is studying two asexually reproducing strains of E. coli. The two require different amounts of trace minerals for survival; on these grounds, the bacteriologist determines that they are separate species. In making his determination, he is using which species concept or concepts?

Ecological Species Concept; adapted to resources/niches

Vegetable

Edible parts of a plant originating from stems, leaves, roots, flowers, flower buds etc.

a multicellular seed

End product of the diploid zygote where the growth is suspended and the embryo enters a dormant stage. Can be spread to new locations

CLICKER: two white corn with AAbb and aaBB genes produce a purple corn with AaBb?

Epistasis; these genes suppress the expression of another gene usually in a biochemical pathway. The genotypes expressed with one enzyme is white and when they are expressed together is purple

The features of the pedigree that immediately suggest dominant inheritance/Autosomal Dominant inheritance

Every affected person has an affected parent (seen in every generation) Each gender is likely to receive it (the success rate determines how often the trait appears) "Dominant" means that a person has the gene if they have even one copy of the allele in their genes There is a 50% probability that any child he/she has will inherit the trait

CLICKER: The role of evolution in shaping complex organisms

Evolution is a non-directional process increased complexity is a common effect But, there is no reason why evolution cannot move towards simplicity if that makes an organism better suited to its environment Selection has no memory, no plan, and no goal they are only looking for advantageous traits.

process

Evolutionary process whereby an organism becomes better able to live in its habitat

X chromosome

Female chromosome

Floral meristems vs shoot meristems

Flowers develop from floral meristems formed by the conversion of shoot meristems. Floral meristems have cells that differntiate and therefore lose the capacity for continue growth, floral organs (sepals, petals, stamens, and carpels) develop from primordia and occur in whorls (each consisting of only a single organ type), an arrangement differs from the placement of leaves along the sems

Directional Selection

Form of natural selection in which the entire curve moves; Selection moves the average phenotype in one direction or the other, depending on what the actual effect is. Genetic variation is reduced

Frequency of a dominant allele

Frequency(A) = frequency(AA) + ½ frequency(Aa)

CLICKER: the sperm of one species of sea urchin is chemically incompatible what type of example is this

Gametic isolation

Minimalistic gametophyte generation

Gametophyte generation is reduced even further than it is in ferns Haploid gametophyte develops partly or entirely while attached to the sporophyte

Which animal predator can tolerate the neurotoxin produced by the rough-skinned newt and what does this represent?

Garter snake; evolutionary arms race

Deviations from Mendel's standard crosses

Gene interactions, Incomplete dominance, Pleiotropism, Epistasis, Heterosis, Incomplete penetrance and expressivity, Quantitative trait loci, and Epigenetics

When does Absolute linkage

Genes may recombine during prophase I of meiosis by crossing over.

Sex linkage

Genes on sex chromosomes which don't follow Mendelian patterns

HW: Which one of the following BEST describes genotype-by-environment interactions?

Genetic and environmental factors combine to influence phenotype.

genetic incompatibility

Genetic dissimilarity between two organisms, such as different numbers of chromosomes, that is sufficient to act as a post-zygotic isolating factor.

Why is calculating the map unit important?

Get an understanding of the probability of the genotype

sister groups

Groups that are more closely related to each other than either of them is to any other group.

What relies on fertilization through seeds

Gymnosperm and angiosperm

Reproduction for seedless vascular plants

Haploid spores form on the sporophyte (2n) of a fern Spore mother cells in sporangia form haploid spores by meiosis Spores can be blown by wind and develop into gametophyte far from parent plant

What was Morgan's model for Linkage

He integrated his models of the fruit fly Drosophilia melanogaster with Mendel's idea with chromosome theory and everything made sense

Darwin's Voyage 1831 - 1836 on the HMS Beagle

He made observations of the species and how they evolved based on their environment. He collected thousands of specimens, Examined many fossils (lots of South American), Made notes of innumerable adaptations to innumerable diverse habitats, Spent lots of time collecting and observing on the Galapagos especially the developed finches which he almost did not recognize

CLICKER: Enzo (a boy) is color blind. Enzo's dad is color blind but his mom is not. Why is Enzo color blind

His mom gave him the color blind allele; mom is a carrier and gave him the X-linked recessive gene

Mendel's three crosses

Homozygous parentals with different traits (phenotypically dominant x recessive) Crossed F1 x F1 (monohybrid cross) Crossed F1 back to recessive parental (backcross)

Which of the following research questions would a population geneticist be MOST likely to ask?

How much genetic variability is found in sperm whales? How can we explain the amount of genetic diversity in Adelie penguins? Why do some species have more genetic diversity than others?

Artificial selection

Humans Selecting individuals to breed can result in dramatic modifications over generations

Character Matric

Identify groups of taxa with shared characters.

What if a mother is Rh- and the fetus is Rh+

If a person is pregnant for the first time the blood will begin to create antibodies and during the second pregnancy the mother's antibodies will attack the baby

Tricks to identifying grouping

If in order to separate a group from the rest of the phylogenetic tree you need only to make one cut, the group is monophyletic. If you need a second cut to trim away part of the separated branch, the group is paraphyletic. Groupings that do not include the last common ancestor of all members are polyphyletic

Evolutionary constraints on When does Lack of genetic variation can prevent evolution of potentially favorable traits

If the allele for a given trait does not exist in a population, that trait cannot evolve, even if it would be favored by natural selection. If it is lost from the population once, it is unlikely that it will appear again though not impossible

Tricks for finding which equation to use

If the question asks what is the chance that it will be heterozygous then use 2pq If the question asks what are the chances that it will be recessive or dominant use p^2 or q^2 respectively. If it asks what are the chances there will be two of them just multiply the value of p^2 X p^2 or q^2 X q^2 If it asks for what are the chances of getting one gene on the first and another gene on the second multiply p^2 + 2pq + q^2 When we go from genotypes to alleles we take the square root

How do we see what blood type occurs

If there is an antigen then you will see clumping and the real blood type will remain constant

Multiplication Rule

If two random events are independent, then the probability that they both happen is the product product of the probability that each one happens alone.

Why do we choose not to produce offspring?

If you stick together they increase their chance that the population will survive. (Ex: prairie dogs signaling each other)

Alfred Russell Wallace

In 1858, nearly 20 years after his five-year voyage, Darwin received a manuscript. On July 1, 1858 Lyell presented both Wallace's paper and Darwin's work to the Linnaean Society of London

Growth and Defense Trade-off

In a high nutrient environment the plants worry less about defense and spend more time on growing because if they are injured they can just regrow it. In a low nutrient environment it will spend more time on protection.

cortex

In a stem, the region between the epidermis and the vascular bundles, composed of parenchyma cells.

pith

In a stem, the region inside the ring of vascular bundles. Connect the epidermis and the vascular bundles

CLICKER: Haploid spores

In nonvascular plants which of the following are produced by meiosis

node

In phylogenetic trees, the point where a branch splits, representing the common ancestor from which the descendant species diverged.

character

In the discipline of systematics, an anatomical, physiological, or molecular feature of an organism that varies among closely related species.

Inclusive fitness and kin selection

Inclusive fitness results from helping the survival of relatives with shared alleles from a common ancestor Behaviors have evolved to increase the fitness of close relatives.

For two genes that show independent assortment, what is the frequency of recombination?

Independent assortment means that a double heterozygous genotype like AB ab produces gametes in the ratio ¼ AB: ¼ Ab: ¼ aB: ¼ ab. The first and last are nonrecombinant gametes, and the second and third are recombinant gametes. The frequency of recombination is therefore ¼ + ¼ = ½, or 50%.

Convergent Evolution

Independently evolved traits subjected to similar selection pressures may become superficially similar (Ex: Agave and Aloe, and bryophytes)

Lamarck's Mechanisms of evolution

Individual lose unused characteristics and develop and pass on useful characteristics. Characteristics will be acquired through individuals lifetime. This hypothesis was supported by fossils and geology

Theory of Natural Selection

Individuals in a population vary phenotypically Some variants fit better into their (current) environment than others Those variants produce more offspring If there is genetic basis to the variation...then Those alleles will increase in the population over time

HW: Chemical defenses are an important part of plant-herbivore interactions. The production of these chemical defense compounds results in an energetic cost to the organism. Which of the following statements explains how natural selection resulted in the evolution of these chemical compounds?

Individuals that produce chemical compounds are better protected from herbivores and are able to produce more young than individuals that do not produce the compounds.

pedigree

Information about a family's history for a particular trait and assemble this information into a family tree describing the ancestor-descendent relationships among individuals.

hybridization

Interbreeding between two different varieties or species.

Stem elongation.

Internodal elongation results from cells increasing many times in length, but only a small amount in width.

key features of recombination

It can either change a previously recombinant chromatid into a nonrecombinant chromatid, or vice versa. No matter how many crossovers there may be (as long as there is at least one), the maximum frequency of recombination remains 50%

If there are so many restrictions in the Hardy-Weinberg theorem, what good is it?

It explains how genetic variation is preserved and provides a benchmark to compare to other populations. It outlines exactly what processes are essential to prevent evolution and how it can happen.

Which of the following may be a characteristic of a beneficial mutation?

It facilitates successful reproduction.

X-linked dominant inheritance in female

It is said to express dominant inheritance, it means that a single dose of the allele will affect the phenotype of the female A recessive X-linked gene requires two alleles to affect the female phenotype

Explain how genetic variation arises and why it is essential for natural selection

It is the source material for natural selection.

What are the possible effects of a mutation that occurs in the coding sequence of a gene

It may have no effect on the amino acid sequence, or it may result in a change in the amino acid sequence, introduce a stop codon, or shift the reading frame

Why worry about genetics of a population?

It provides a foundation for studying evolution. Genes are the smallest units of evolution

genetic divergence

Key to speciation and is the accumulation of different mutations in genetically separated populations

Land plants phylogeny

Land plants are monophyletic - all descend from a single common ancestor (green algae)

Mechanical and Chemical Plant Defenses

Latex, which is sticky and toxic, and thick plant hairs exudes from damaged areas and protects milkweeds from many herbivores. Small monarch caterpillars dig trenches that prevent latex from flowing into the feeding area. Large monarch caterpillars sever the midvein. The production of these chemical defense compounds results in an energetic cost to the organism.

Which of Mendel's findings is not applicable when predicting the results of crosses involving genes that are closely linked?

Law of independent assortment; genes that are closer together are less likely to separate than those farther apart

FOSSILS and GEOLOGY

Layers that show a succession of organisms have populated Earth throughout time

sexual selection vs natural selection

Look for "Counteracting forces" A male with more conspicuous coloration or behavior is more vulnerable to predation Even if the trait causes males to die earlier, the trait is still beneficial as long as males with the trait produce more offspring than males lacking the trait

What relies on fertilization through dispersement by spores and rely on swimming sperm?

Lycophytes, ferns, horsetails, and bryophytes

Y chromosome

Male chromosome

Which animal has the most complex eye

Mantis Shrimp;it has 12 photoreceptors where human only has 3

non-random mating

Mate selection biased by genotype or relatedness.

How does natural selection work?

Members of the population vary. This variation is heritable. Not all individuals survive. Survival depends on inherited trait. Survivors reproduce

Dry fruits

Mesocarp completely dry at maturity (EX: Follicles, Legumes, Siliques, Capsules, Nuts, Grain, Samaras)

what can cause taxon

Migration, Mutation? Stochastic events? Genetic drift, Natural selection

Monocots

Monocots produce only a single cotyledon(one embryonic seed leaf); monocot roots are produced continuously directly from the stem; many monocots produce creeping stems; and the strap-shaped leaves of many monocots elongate from a zone of cell division located at the base of the leaf creating a protective sheath, which surrounds the stem to form a sheath. Monocots do not form a vascular cambium; instead, radial growth occurs in a narrow zone just below the shoot apical meristem. In most monocot stems, the vascular bundles are distributed throughout the cross section, as opposed to being arranged in a ring.

Angiosperm phylogeny

Most angiosperm species belong to the monocots and eudicots.

Edicots

Most diverse angiosperms; they are easily distinguishable from the three openings in the pollen tube. They produce two cotyledons highly conductive xylem with higher rates of water transport and higher rates of photosynthesis (EX: parasitic/carnivorous plants, cactus, and roses)

Genetic variation has two sources:

Mutation generates new variation, and recombination followed by segregation of homologous chromosomes during meiotic cell division shuffles mutations to create new combinations.

Which is not part of the Hardy-Weinberg equilibrium

Mutations create genetic variation

What can the Hardy-Weinberg theorem tell us?

Mutations occur at a slow but steady rate in all known populations, Many organisms enter and leave populations, Most populations are not large enough to be unaffected by random changes in allele frequencies, Survival is virtually never random, Reproduction in organisms that can choose their mates is also virtually never random

Which evolutionary mechanisms would contribute to anagenesis and cladogenesis and is it possible for both of these to occur at the same time?

Mutations, sexual reproduction, gene flow, directional selection, and adaptive radiation cause the anagenesis and cladogenesis can be caused by environmental speciation, allopatric speciation, disruptive selection, artificial selection, founder effect Yes and No They can occur at the same time in two different paces

autosome

NOT a sex chromosome

Sympatric speciation by disruptive selection

Natural selection eliminates individuals in the middle of the spectrum meaning that while there is still gene flow it does not effect the divergence of the two populations because it does not survive to reproduce (more common in plants)

Snapdragon color: Incomplete dominance

Neither color completely dominates the other, Is not "blending inheritance", Genes remain distinct units, Result is a mixture—pink, Do not get ever-finer varieties of pink. The white and red flowers return in the second generation.

Many SNPS are regarded as "neutral" in the sense of having little or no effect on the likelihood of survival or the reproduction of the different genotypes. Could you ever say for certain that a particular SNP neutral?

No because any effect may be too small to detect

O Blood Type

No recognizable glycoprotein from this group on blood cell

Are reciprocal crosses along the X and Y chromosome equivalent?

No; they do not produce the same types or numbers of progeny

creating recombinants

Nonrecombinant chromosomes can also be the result of two crossover events occurring between two genes

Nondisjunction as evidence that genes are present in chromosomes

Normal chromosome separation yields expected progeny. Nondisjunction yields exceptional progeny.

Somatic mutations

Not transferred to the next generation. Mutations in the somatic cells can be caused by environmental toxins such as UV Radiation

What happens if you are type A and you receive O blood?

Nothing type O does not have antigens to for the A antibodies to attack

What blood type are most Americans

O+

procambial cell

Occurs after the primordia; A cell that retains the capacity for cell division and gives rise to both xylem and phloem (elongation of the plant).

CLICKER: Hybrid breakdown

Offspring of hybrids have reduced viability or fertility. It is not a pre-zygotic reproductive isolating barrier

Cryptospores

On Earth, 475 mya something that resembles liverworts (algal) are the oldest land plant fossils yet found (Superman spores)

bud scale

One of many like structures formed from leaf primordia that, together, protect shoot apical meristems from desiccation and damage due to cold.

pedigree characteristics of Y-linked inheritance

Only males are affected with the trait. Females never inherit or transmit the trait, regardless of how many affected male relatives they have. All sons of affected males are also affected.

Why is the upper limit of recombination 50% rather than 100%?

Only two of the four products (frequency = 50%) of meiosis are recombinant because crossing over takes place at the four-strand stage of meiosis

Changes in the atmosphere

Oxygen levels have increased (overall) (oxygen revolution caused by cyanobacteria) as a result of photosynthetic organisms which then resulted in the evolution of more complex, multicellular organisms

AVR Protein

Pathogens secrete AVR proteins that can enter plant cells.

Epistasis

Phenotypic expression of one gene is influenced by another gene (Ex: puppy coat color). One gene will silence or inhibit another

CLICKER: What is considered the transitional form of Seahorses?

Pipefish; they have similar noses though their subtle structures that would be more advantagous. This show s that complex organisms can be produced from simple ones but they must be derived from pre-existing structure

Hypersensitive Response

Plant is trying to stop biotropic pathogens by killing off a certain part. A type of plant defense against infection in which uninfected cells surrounding the site of infection rapidly produce large numbers of reactive oxygen species, triggering cell wall reinforcement and causing the cells to die, thus creating a barrier of dead tissue.

CLICKER: If plant life was never subjected to herbivores/predators, how would plant diversity be affected

Plant life would likely be less diverse; When herbivores and plant pathogens began populating land, land plants had selective pressures to evolve more complex defense mechanisms (Ex: become more poisonous)

Why was it a huge advantage for plants to move from water to land? Which challenges did they meet on land?

Plants evolved techniques for hydration, support, and protection from ultraviolet radiation and temperature fluctuations, and they needed a way to transport water to transport water to all parts of the plant, the support and methods to disperse gametes other than water currents to transport sperm and disperse offspring. Surviving on land required the evolution of new ways of growing including photosynthesis (early plants could only do this when the land was wet), getting more CO2, minerals from the soil, avoiding predators and reproducing.

Bottleneck event

Population is dramatically reduced in size due to an external cause, and it is random which alleles survive (Ex: northern elephant seal)

allopatric

Population splits into two geographically isolated groups. Genetic changes accumulate. Cumulative differences prevent breeding (reproductively isolated) between the two new species Facilitated by natural selection Two species have evolved

How species arise

Populations become physically separated. They diverge genetically in different habitats Until they are no longer likely to interbreed if they overlap

Habitat isolation

Pre-zygotic barriers in which Two species live in different habitats (in the same area) and rarely meet

behaviorally isolated

Pre-zygotic isolation between Species do not recognize signals or mating cues of other species

ecological isolation

Pre-zygotic isolation between individuals that specialize ecologically in different ways.

temporal isolation

Pre-zygotic isolation between species that breed at different times (times of day, seasons)

gametic isolation

Pre-zygotic isolation of Incompatibility between the gametes of two different species.

mechanical isolation

Pre-zygotic isolation of Structural configuration of the genitalia that prevents mating with another species; anatomically incompatible. (only certain pollinators can fit in a flower)

Prophylactic mastectomy

Procedure is used as a preventative measure against breast cancer if the patient have BRCA1 and BRCA2 mutations in their genes

How do plants Reproduce in dry conditions

Produce gametes in protected structures, Retention of the embryo, Alternation of generations

Seedless fruits

Produced on triploid plants; three sets of chromosomes prevent meiosis from taking place => plants cannot produce fertile gametes. Generally propagated vegetatively from cuttings, resulting in identical clones, or crossing diploid and tetraploid lines creating sterile triploid offspring

Nonrecombinant

Progeny in which the alleles are present in the same combination as that present in a parent.

Penetrance

Proportion of individuals in a population with a certain genotype that show the phenotype, (Ex: Huntington's and Incomplete penetrance = BRCA1 gene)

Non-photosynthetic functions of leaves

Protection (bud scales); climbing (tendrils); trapping insects (spines); and attracting pollinators (color).

You are examining a human pedigree for a trait. You notice that an offspring can be affected even if neither parent is affected. This immediately tells you that the trait is:

Recessive

hemophilia

Recessive mutation that does not allow encoding for a protein necessary for blood clotting

genetic maps

Recombinant frequencies can be used to show the arrangement of genes along a chromosome

recombinant frequencies

Recombinant offspring phenotypes (non-parental) Divide number of recombinant offspring by total number of offspring. Recombinant frequencies are greater for loci that are farther apart. These frequencies can be used in calculating genetic distance and gene maps.

Closed, low-volume state Stomata and Guard Cells

Release of solutes causes water to flow out of the guard cells, closing the stoma. This can help retain solutes and water

Simple fleshy fruits

Resulting from a single pistil; ovary can be simple or compound

Melanocortin 1 receptor (MC1R) gene

Same gene, just slightly different alleles. (Most alleles that generate red hair also generate freckles Produces pheomelanin more than euomelanin.)

density-dependent mortality

Seedling recruitment is often negatively density-dependent; High species density = lower seedling recruitment of that species. This can allow many species to co-exist. Density-dependent mortality of seedlings can be due to species- specific predators or pathogens. May be an explanation only for plants

Angiosperm reproduction

Seeds surrounded; Not only are animal-pollinated plants able to reduce their production of pollen, but also double fertilization reduces the costs of reproduction by allowing angiosperms to delay provisioning their offspring until after fertilization (reproduce quickly with minimal resources).

what must be occurring in order for natural selection to take place?

Selection acts ONLY if the trait has a genetic basis (somatic mutations are not applicable) Selection acts ONLY if there is variation present Selection does NOT CREATE new genes or alleles, nor does it create variation (the genes must already exist to adapt) Selection DOES produce ADAPTATION

Examples of complex systems

Shapes of nature and evolution of the eye

Linkage maps are not physical maps

Should be used with caution, Describe only the relationship between the genes considered, Ignore other genes, Do not tell the actual physical length of the chromosome

Phloem with companion cells

Sieve? tube elements so reduced that they need companion cells to provide for major metabolic functions

homoplasies/homoplastic traits

Similar traits generated by convergent evolution

Pomes

Simple fleshy fruit in which Most of the fruit developed from the floral tube and/or receptacle; endocarp papery or leathery includes Apples, pears, quinces

Drupes

Simple fleshy fruit that Contain a single seed (pit); hard endocarp Coconuts, apricots, cherries, peaches, plums, olives, almonds, walnuts, pecans

True Berries

Simple fleshy fruit that developed from a compound ovary, most contain more than one seed; entire pericarp is fleshy. Includes Tomatoes, grapes, persimmons, peppers, eggplant, dates, gooseberries, bananas, cranberries, blueberries, avocados

Hesperidium

Simple fleshy fruit that include Oranges, lemons, limes, grapefruits, tangerines, kumquats

Pepos

Simple fleshy fruit that include Watermelons, pumpkins, cucumbers, squash

Group selection

Simply put; individuals staying together helping each other have a better chance of survival than single or few individuals. Best group is selected for Alleles can become "fixed or spread" in a population because of the "benefits" they give on groups

the nonmutant allele of the BRCA1 gene helps to suppress tumor formation in women who are heterozygous for the mutation. Women homozygous for BRCA1 nevertheless have a 50%-70% chance of developing breast cancer before age 70 and the usual reason is that the nonmutant allele is lost or inactivated in a lineage of cells. One possible mechanism for such loss of the heterozygosity is

Somatic mutation in a breast cell inactivates the nonmutant BRCA1 allele

Why is genetic variation critical for evolution?

Source of natural selection

instantaneous speciation

Speciation that occurs in a single generation.

ring species

Species that contain populations that are reproductively isolated from each other but can exchange genetic material through other, linking populations. (Ex: greenish warbler)

Benefits of having seeds

Spores are not dispersed; instead, they germinate and develop into morphologically distinct male and female gametophytes while still attached to the sporophyte. Male and female gametes are brought together by the transport of the male gametophyte, which is so small that is fits within the spore wall, forming a pollen grain. Following fertilization, the embryo and surrounding tissues develop into a seed, a multicellular structure that replaces unicellular spores as the dispersal unit.

What if there were unequal number of A vs. a alleles in the population? How many AA, Aa and aa would you expect in the next generation? How do you solve for this?

Step 1: find p (0.9) and q (0.1) Step 2: Find the frequency for AA: p^2 = 0.81 Step 3: Find the frequency for aa: q^2 = 0.01 Step 4: Find the frequency for Aa: 2pq = 2(0.9)(0.1) = 0.18 (Hint: these values should equal 1)

biological species concept (BSC)

Stresses separateness, As described by Ernst Mayr, the concept that "species are groups of actually or potentially interbreeding populations that are reproductively isolated from other such groups." If they do interbreed than the offspring will not be fertile. However this cannot be applied to Bacteria, extinct creatures, or Archaea.

Phylogenetic trees of DNA sequences based on what?

Synapomorphies and overall similarity. Molecular data are often combined with morphological data, and each can also serve as an independent assessment of the other.

In an experiment, you find that exposing leaves to methyl salicylic acid vapor prior to exposing them to a pathogen results in an avirulent infection, whereas exposing untreated control leaves to the same pathogen results in virulent infection. This is likely an example of:

Systematic Acquired Response Fights viruses

CLICKER: What are the possible genotypes for a person who is not affected by the trait whose parents genotypes are Tt and Tt

TT or Tt

Roots

Take up all the nutrients and minerals (Except for carbon dioxide)

Changes in the Earth's land masses (plate tectonics)

The Earth's crust consists of plates floating on viscous magma. Convection currents move the plates. This causes continental drift, changed the location and size of the Earth's continents over geologic time, and is an ongoing process

hemizygous male

The Y chromosome carries few genes; the X chromosome carries many Thus, males have only one copy of these gene

systemic acquired resistance (SAR)

The ability of a plant to resist future infections, occurring in response to a wide range of pathogens.

importance of geographic separation (allopatry) in speciation

The availability of islands provides opportunities for populations to become isolated from one another, allowing speciation.

mainland population

The central population of a species.

Linkage and Recombination

The closer together that genes Genes are on the same chromosome the more likely they are to remain together in inheritance

shoot

The collective name for the leaves, stems, and reproductive organs, the major aboveground organ systems of vascular plants.

where were angiosperms and gymnosperms believed to have originated

The common ancestor was believed to have originated in the shady understory of tropical forest a bout 300 mya

The gray wolf is though to be the ancestor of all dog breeds. Which statement must be true

The early gray wolf population had great genetic variation, for which many phenotypes were not expressed. This gave the variation to give the ability to artificial selection

phenotype

The expression of a physical, behavioral, or biochemical trait; an individual's observable phenotypes include height, weight, eye color, and so forth. (9:3:3:1)

Vascular Wilt disease

The first leaf exposed to TMV shows necrotic resulting from aregions hypersensitive response. The second leaf exposed to TMV shows no visible sign of infection or disease. The plant has built a resistance against the infection

Forces that Pull Water from the Soil

The forces that develop in leaves must be large enough to overcome the *capillary forces in the soil. --> Hydrogen bonds (cohesion) that form between water molecules allow water to be pulled through the xylem rather than be pulled out through diffusion --> The evaporation and photosynthesis of water from leaves causes water to flow from the soil

Hardy-Weinberg theorem

The frequency of alleles and genotypes in a population's gene pool remain constant from generation to generation

genotype

The genetic makeup of a cell or organism; the particular combination of alleles present in an individual.

Stabilizing Selection

The graph becomes narrower Natural selection that favors intermediate variants by removing extreme variants from the population. Reduces phenotypic variation and Genetic variation is reduced

Bryophytes Reproduction

The haploid gametophyte produces gametes in specialized sex organs. Female archegonium produces one egg and Male antheridium produces many sperm with two flagella each which is transferred through water

Camouflage

The hiding of something as a result of its appearance to avoid predation. Survive to reproduce

phylogenetic species concept (PSC)

The idea that members of a species all share a common ancestry and a common fate.

What does a recombinant frequency of 50% mean

The independent assortment is observed for genes that are far apart in the same chromosome as well as for genes in different chromosomes

HW: Reproductive isolation

The key to speciation: the inability of two different species to produce viable, fertile offspring

Which of the following is an adaptation The lion's speed, which enables the animal to capture its prey process by which a lion's speed has increased over many generations The increase in speed from young to adult lion

The lion's speed, which enables the animal to capture its prey and the process by which a lion's speed has increased over many generations. The last is Lamarck's idea

X-linked dominant inheritance in male

The male will still exhibit the characteristics

What does the frequency of recombinant genes indicate?

The measure of how far apart the genes are along the chromosome; the closer the genes are along the chromosome the less likely they are to cross over

wild type

The most common allele, genotype, or phenotype present in a population; nonmutant.

the evolution of alternation of generations

The multicellular haploid generation alternates with a multicellular generation composed of diploid cells.

What does migration among populations cause?

The mutation to spread further until all individuals within the species have it. The mutation spreads within the species but, with some exceptions, cannot spread beyond it.

Absolute linkage

The opposite of independent assortment. It is rare—genes at different loci on the same chromosome do sometimes separate. Chromosomes exchange corresponding segments. The exchange involves two chromatids i the tetrad; both chromatids become recombinant.

Angiosperm carpels

The ovules and seeds are enclosed in a modified leaf. (pistil) for protection and self-pollination, Have the ability to block the growth of pollen from different species and from closely related individuals (including self) suggests that these genetic recognition systems contribute to the reproductive isolation required for speciation

haplotype

The particular combination of alleles present in any defined region of a chromosome.

The test cross with a 1:1 offspring with a trait means what?

The person is heterozygous

two important principles governing the inheritance of X-linked genes

The phenotypes of the XX offspring indicate that a male transmits his X chromosome only to his daughters. The phenotypes of the XY offspring indicate that a male inherits his X chromosome from his mother.

reinforcement

The process by which diverging populations undergo natural selection in favor of enhanced pre-zygotic isolation to prevent the production of inferior hybrid offspring.

vicariance

The process in which a geographic barrier arises within a single population, separating it into two or more isolated populations. We can sometimes use this to study the timing of peripatetic speciation

dispersal

The process in which some individuals colonize a distant place far from the main source population.

speciation

The process whereby new species are produced. It is the branching on the phylogenic trees

Autosomal Recessive traits

The recessive allele is located on one of the autosomes A person who has only one recessive allele is a "carrier" (heterozygous) for the trait, but does not express the trait Most people do not know that they carry a recessive allele until they have a child with the trait/disease

selection

The retention or elimination of mutations in a population of organisms.

re-creating nonrecombinants

The reversed actions of creating recombinants by a second crossover

internode

The segment between two nodes on a shoot.

Cladistics

The study of building a phylogeny based on synapomorphy

Epigenetics

The study of heritable changes in gene expression or cellular phenotype, caused by mechanisms other than changes in the underlying DNA sequence

Probability Theory

The sum of all the probabilities of all the possible outcomes of an event must be one

Apical dominance results because of what?

The suppression of growth of axillary buds by the shoot apical meristem. chemical signals (Ex: auxin) from the shoot tip control the growth of axillary buds

conifers

The tallest and oldest trees which have strong apical dominance, and develop a single straight stem from which extend much smaller horizontal branches. Its xylem consists almost entirely of tracheids (this is how it gets water), and so its wood is strong for its weight. Many produce resin canals in their wood, bark, and leaves that deter insects and fungi and produce important chemicals esp. for medicines. Called gymnosperms, Sporophyte is the dominant stage, Adapted to cooler climates, and called evergreens (pine, cedar, spruce, fir...)

variable expressivity

The trait is always expressed though in varying severity

Key features of pedigree

The trait is never passed from father to son All sons of an affected male and a normal female are normal All daughters of an affected male and a normal female are affected Mating of affected females and normal males produce ½ the sons affected and ½ of the daughters affected

the principal pedigree characteristics of autosomal recessive traits

The trait may skip a few generations. However, the parents must both carry the recessive genes Affected individuals are equally likely to be either gender Affected individuals with a recessive trait that is sufficiently rare may have unaffected parents. Affected individuals often result from mating between relatives, typically first cousins. About ¼ of the children of unaffected parents are affected

CLICKER: Ginkgo trees grow in Asia and North America and thus are divided into 2 groups that are geographically separated. Using the biological species concept we find that these populations belong to the same species. How?

The two populations are potentally capable of exchanging genes and produce fertile offspring

How is it possible that there are multiple different alleles in a population and yet any individual can have only two alleles?

There are many copies of each chromosome, however, there are only two copies of any chromosome, so any individual can have no more than two different alleles.

Hardy-Weinberg equilibrium is only met when:

There are no mutations, There is no gene flow, The population must be very large and stay the same (no migration), Survival is random, and Reproduction is random. When one of these conditions are not met there is evolution

Which of the following principles of Darwin's theory were guided by his reading of the economist Thomas Malthus

There must be some control of survival and reproduction in nature, or else the world would become overcrowded

Plato and Aristotle's ideas

There were two worlds: an ideal world where organisms were unchanging and perfect and illusionary world where imperfections are seen only because we perceive them so

Nonvascular plants

These plants are thought to be similar to the first land plants. (they evolved) They grow in moist environments in dense mats. They are Small, no system to conduct water from soil to plant body parts

What are freckles

They are a high concentration of MC1R gene that are more common in fair skinned people

Which is dominant: A/B

They are co-dominant

How did plants prevent water loss

They formed waxy cuticle and stomata Encased spores

Cycads anatomy

They have low photosynthetic rates and they grow slowly. Although they have large stems, their vascular cambium produces little additional xylem, and most of their bulk is made up of unlignified (nonwoody) cells in the center of the stem (pith) and surrounding the vascular tissues (cortex).

Would you expect a recessive gene to disappear over generations?

This assumes that populations are NOT evolving, The organism is diploid, Reproduction is sexual, Generations are non-overlapping, Mating is random, Population size is very large, Migration in negligible, Mutation can be ignored, Natural selection does not affect the alleles under consideration, The alleles under consideration are not on the sex chromosomes

Prediction for Morgan's experiment ???

This is basically a test-cross, so we expect equal distribution among the four different genotype/phenotype combinations

Changes in the climate

Throughout earth's history, the mean global temperature has shifted from hot/humid periods to cold/dry periods. Why? Catastrophic events e.g., meteors, Geologic factors e.g., reflectivity of the earth's surface, Human activity "Greenhouse Effect"

how do we create many medicines and how does grasshoppers contribute to this

Tropical plants make several medicines and grasshoppers create pressure so they reproduce more

CLICKER: What are the possible genotypes for a person whose phenotypes is similar to the siblings Mom: TT Dad: Tt

Tt

CLICKER: What are the possible genotypes for this person who mates with a Tt and has a tt

Tt

multiple alleles

Two or more different alleles of the same gene occurring in a population of organisms. (Ex a rabbit can have 1 gene, four alleles, any rabbit with the C allele is dark gray, and a rabbit with cc is albino sometimes the rabbit can be light gray and be incomplete dominance)

How do groups become reproductively isolated?

Two populations become so different that they are considered different species OR A population becomes so different from its ancestral state that it is considered another species

What is the concentration difference driving the diffusion of CO2 into the leaf?

Typically 100 times smaller than the concentration difference driving the diffusion of water vapor out of the leaf.

genotype-by-environment interaction

Unequal effects of the environment on different genotypes, resulting in different phenotypes.

CLICKER: What if a mother is Rh+ and the fetus is Rh-

Unless there is blood exchange, there is no problem.

Biogeography

Unrelated organisms evolved similar adaptive solutions to the same problem and tend to be found in the same geographic area. This is an example of conversion evolution or the ability to have a favorable allele to thrive. It also supports that they must stay in one certain space to evolve.

Open, high-volume state in Stomata and Guard Cells

Uptake of solutes by guard cells causes water to be drawn in by osmosis (diffusion). As the guard cells swell, they bow apart, opening the stoma.

peat bog

Wetland in which dead organic matter accumulates. These mosses play a key role in creating wet and acidic conditions that slow rates of decomposition. This is an exception to other bryophytes which only make up a small contribution to the total biomass

Moving from single crosses to populations

When 2 heterozygous individuals mate, they each make a pool of gametes, which essentially pair up randomly •We will assume the same thing happens within populations •Start by crossing Aa with Aa

When do nonrecombinant configurations occur

When crossing over occurs at the four-strand stage of meiosis (when each homologous chromosome is a pair of sister chromatids), but only two of the four strands (one sister chromatid from each homologous chromosome) are included in any crossover.

CLICKER: seedless plants are monophyletic

Which is an incorrect interpretations of this phylogeny There was only one successful transition from freshwater environments to land, the nonvascular plants are paraphyletic, seeds evolved once , or seedless plants are monophyletic

CLICKER: A free-living sporophyte

Which of the following traits would never be found in a bryophyte (GOING to be in the exam)

Genetic diversity

With many loci and additive effects. Selection can result in new allele combinations (such as extreme phenotypes) that previously would be rare. Selection that reduces other alleles (a,b,c,d,e) makes it more possible

CLICKER: The royal family of Great Britain is well known for a having genetic disease called hemophilia. Looking at their much simplified pedigree, which type of inheritance pattern is most likely?

X-linked recessive; only male carriers (heterozygous)

Gnetophytes vs angiosperm

Xylem vessels evolved convergently in gnetophytes and angiosperms; insect pollination evolved convergently in cycads and angiosperms; fleshy tissues to facilitate seed dispersal evolved convergently in early seed plants (reflected today in ginkgo and cycad seeds), conifers such as juniper and yew, and flowering plants. Double fertilization evolved independently in gnetophytes and in flowering plants.

How to read epigentics

Yellow shows where the twins have epigenetic tags in the same place. Red and green show the differences based on the environmentf

Can you get reproductive isolation without complete geographic isolation?

Yes: in a heterogeneous environment or when genetics helps isolate individuals.

Tricks for probability: If you see the word or

You are going to add the probabilty

Tricks for probability: If you see the word and

You are going to multiply the probability. (ex: getting heads on two coins is 1/2 x 1/2 = 1/4

Sex-linked inheritance

a character is controlled by loci on the sex chromosomes

ingroup

a group that is being studied because they are believed to be closely related

vascular cambium

a layer of actively dividing and differentiating cells that surrounds stems and allows them to increase in diameter; gave the ability to produce secondary xylem and phloem

nondisjunction

a pair of chromosomes fails to separate normally during anaphase of cell division. Can occur in either gender

Fruit

a part of a flowering plant derived from specific tissues of the flower, mainly one or more ovaries, usually containing one or more seeds. Its main tasks are to Protect the seeds and Promote dispersal

Salicylic acid

a phloem mobile signal results in higher levels of salicylic acid its volatile ester and pathogenesis-related proeins

Flower

a reproductive structure and modified leaves that attracts animal pollinators, much more productive than wind. Are the only items t

sickle cell anemia

a single DNA nucleotide (A allele) is transferred with and S allele and people have difficult breathing because the hemoglobin to malfunction

HW: Which of the following would be good examples of genotype-by-environment interactions? a strain of corn whose yield varies with the amount of nutrients in the soil a line of dairy cows that increases milk yield in relation to feed amount a strain of mutant mice that becomes obese regardless of feed amount two different strains of corn that differ in height due to genotype a line of chickens whose eggshells are extra thick regardless of feed type two different mutants of mice that share similar fat metabolism abilities

a strain of corn whose yield varies with the amount of nutrients in the soil a line of dairy cows that increases milk yield in relation to feed amount

Taxonomic system

a system for naming and grouping similar organisms together. This provides us with a hierarchical classification of species in groups that are more and more inclusive, giving us a convenient way to communicate information about the features each group possesses.

Anagenesis (phyletic evolution)

accumulation of changes with the transformation of one species to another. These processes can lead to change within a population (or species) The total amount of species does NOT change

Eusociality

adults live in groups, individuals care for brood that is not their own, reproductive division of labor (not all individuals get to reproduce), and overlap of generations. Giving up one's reproductive potential is contrary to the basic premise of natural selection (to survive and reproduce). They all take an active part of division of labor.

Vascular plants

all living vascular plants have conducting cells called tracheids; all these constitute a clade. relating to or denoting the plant tissues (xylem and phloem) that conduct water, sap, and nutrients in flowering plants, ferns, and their relatives.

From individuals to populations

alleles are randomly distributed into gametes within individuals; It's assumed alleles are randomly distributed into gametes across individuals in a population

According to Mendel's law of independent assortment

alleles for different characteristics always assort independently (H0)

Why are recombinants important

allows any pair of parental genomes to form an almost limitless number of possible recombinant gametes, depending on where crossovers occur

Thomas Malthus

among the first to compare human populations with animal populations. Human populations increase faster than resources are produced and Suffering is the result

five major plant hormones

auxin, gibberellic acid, cytokinins, (establish the basic patterns of shoot development) ethylene, and abscisic acid

Rh-

blood cells do not have the D antigen

Rh+

blood cells have the D antigen

genetic drift

change in allele frequency due to random effect of a small population from one generation to next may over time result in large changes in frequencies

Mutation

changes in a genomic sequence. Humans are the product of of mutations

Sequence complexity

complexity of DNA sequences and the amount of information

Phloem

conducts products of photosynthesis through the plant

Xylem

conducts water and minerals from soil up to aerial parts of plant. Some cells have lignin - provides support and takes nutrients from the soil

Vascular system

consists of tissue specialized for the transport of materials. Arranged in a ring near the outside of the stem.

CLICKER: what type of evolution are the Euphorb from Africa and the cactus from america

covergent evolution

GENEALOGICAL SPECIES CONCEPT

defines a species as a set of organisms with a unique genetic history

ecological species concept (ESC)

defines a species in terms of it's ecological niche a species' niche depends on its unique adaptations to its role inthe biological community

morphological species concept

defines a species in terms of its unique structural features (its morphology)

Polar transport of auxin

depends on the difference in pH between the cell wall and the cytoplasm and results in the movement of this hormone from the tip of each developing leaf to the base of the plant.

autopolyploids

derived from an unusual reproductive event between members of a single species when an error of meiosis in one or both parents in which homologous chromosomes fail to separate, a gamete may be produced that is not haploid.

avirulent

describes pathogens that damage only a small part of the plant because the host plant is able to contain the infection. When an R protein binds with an AVR protein, it prevents the AVR protein from blocking the plant's basal resistance and directly activates defensive genes.

Chemical signals in plants

determine what sort of cell is formed. These signals provide information on both the identity of neighboring cells and the cell's position in the plant and sometimes affect the development of the of a specific part (EX: signals that cause cells to express meristem identity genes are restricted to the region close to the shoot tip.)

Diploid zygote

divides to produce an embryonic sporophyte

Charles Lyell

effectively discredited the long-standing view that the earth was relatively young

outgroup

falls on an earlier branch in the same phyla

HW: Virulent bacteria are always damaging to plants and thus have no beneficial uses.

false; (EX: Rhizobium radiobacter is useful to humans)

primordia

form near the tips of shoot apical meristems and develop into leaves. (small leaf bumps). During the initial growth of this it will only use diffusion

Balancing selection

form of natural selection in which No single phenotype is favored in all populations of a species at all times. Genetic variation is maintained

Disruptive Selection

form of natural selection in which a single curve splits into two; occurs when Selection favors variants at each extreme Genetic variation is increased

p

frequency of the dominant allele

q

frequency of the recessive allele

Gnetophytes

gymnosperms that have independently evolved xylem vessels (which is higher than gymnosperms) and double fertilization (does not result in the formation of a triploid tissue) much like that of an angiosperm.

Sickle cell protects from malaria?

homozygous normal individuals die of malaria, homozygous recessive individuals die of sickle cell anemia, and heterozygote carriers are relatively free of both. The heterozygote carriers are more likely to reproduce.

Repeated independent fixations of different mutations in the two populations result in what over time and how can this be negated

in the genetic divergence of separated populations and it can be made ineffective through gene flow

sexual selection

influences reproductive success: fitness. Favors traits that increase reproductive success at potential cost to survival

Species concepts

is a population or group of populations whose members have the potential to interbreed in nature and produce viable, fertile offspring are reproductively isolated from other such populations

What happens when there are taxa "in the middle" that don't have the character?

leave the group at the end of the branch. As you move through the rest of the characters, you will be able to resolve situations like this.

Three clades of Nonvascular plants (three clades)/bryophytes?

liverworts, hornworts, and mosses; cannot pull water, CO2, or other nutrients from the soil so As the environment dries, so do they, and all metabolic activity ceases. To reproduce they must release swimming sperm (haploid) into the environment, their mode of fertilization also limits their size.

Darwin's ideas

living animals can be classified by similarities, fossil animals look different than living, the earth is old, small changes can add up to big changes

apical meristems

located at the tip of stems and roots and produce cells that allow plants to grow in length

dominant allele

located on one of the autosomes (chromosomes 1-22)

What are the only two groups of seedless vascular plants have living relatives today

lycophytes and ferns/horsetails; which have developed a vascular system with stems and roots giving them the ability to move on land and get taller and were the First plants that were able to grow tall. These large sporophyte is independent of the small, short-lived gametophyte. Must have water for part of the life cycle Flagellated swimming sperm

HOMEWORK: With few exceptions, we cannot use observable traits to measure the amount of genetic variation in populations because

many traits are encoded by large numbers of genes, and observable traits are products of the environment as well as the genotype.

Gene flow

migration of individuals between populations that may add new genes to the gene pool or change frequencies of alleles already present and maintains similarity among populations

Which of the following are not events in which genetic drift may play a key role?

migration, bottleneck effect, founder event. Which all have trouble with a small population as the lack of genetic variation gives increased

Gametes/Meiosis/germ gamates

mutations in the sperm or egg that will be transferred to the next generation

What are the possible effects of a mutation

no effect (neutral), create a different product or is helpful (advantageous), and prevent the gene from functioning or is harmful (deleterious)

HW: The failure of a pair of chromosomes to separate during anaphase is referred to as

nondisjunction

polyploidy and plants

nondisjunction of the whole genome - can double, triple, even quadruple the genome. Large genetic events could "instantly" isolate individuals. Unlike animals, polyploid plants can survive and reproduce. They may even do better than parental types!

Endosperm

nourishes the embryo in its early development

Structural complexity

number of cell types, different limb-pair types, and fractal dimensions in ammonites

Functional complexity

number of functions an organism can perform

Parasitic plants

obtain resources by infecting other plants (EX: Mistletoe obtains water and nutrients from the xylem of the host plant without expending the costs of producing roots themselves)

Single Nucleotide Polymorphism (SNP)

occurring when a single nucleotide in a genome is altered

double fertilization

one sperm nucleus from the male gametophyte fuses with the egg resulting in the diploid zygote, and a second sperm nucleus fuses with two haploid nuclei from the female gametophyte giving rise to endosperm, which forms the nutritive tissue within the seeds of angiosperms. A consequence of double fertilization is that angiosperms do not expend resources for the next generation until the egg is fertilized. Two ♂ gametes in a microgametophyte fertilize in a megagametophyte One ♂ gamete combines with one egg diploid zygote The other ♂ gamete combines with two haploid ♀ gametes a triploid nucleus This nucleus divides to form triploid tissue, the endosperm

HW: Which of the following are points of entry through which viral and bacterial pathogens can infect plant tissues?*

open stomata and sites of herbivore damage; the viruses have adapted to open the stomata instead of having the plant naturally close when it finds a foreign material

Construction of a tree

outgroup/ingroup --> synapomorohy --> cladistic --> phylogeny

Alleles frequencies formula

p+q=1

genotypic frequencies

p2 (homozygous dominant) + 2pq (heterozygous) +q2 (homozygous recessive)

Beneficial mutations can

permit an organism to become adapted to its environment. protect from disease. be repaired.

Which of the following characteristics do land plants share with their closest algal relatives? (Select all that apply.)

populations of apical cells that maintain their meristematic identity cytoplasm that may be continuously connected between whole populations of cells

Equilibrium Population

populations that do not deviate significantly from the predictions of the Hardy-Weinberg theorem are said to be

allopolyploids

produced from hybridization of two different species.

pollen tube

produced that digests its way through the sporophyte tissue to the female gametophyte Sperm are released from the tube, and fertilization results in a diploid zygote

sporophyte (supported)

produces haploid spores; a multicellular spore-producing plant produced through meiosis that was the first diploid zygote developed by mitosis and to come up on land; may or may not be photosynthetic, but is always nutritionally dependent on the gametophyte, and is permanently attached

BRCA1 and 2

protect from cells to uncontrollably divide and grow

Rhynie cherts/ early Lycophyte

provide a window into the early evolution of vascular plants The fossil has helically arranged leaflike structures, Lobed cylinder of xylem, seen in cross section of the stem. adventitious roots (that is, roots that arise from the shoot and not from the root system), and a central strand of xylem, features much like those of living lycophytes (they also have one vein which is characteristic of lycophytes).

Linkage Mendel

published his work in 1865 and 1866, but his work was largely ignored. His theories were re-discovered in 1900 as highly controversial. Mendel was now given credit for his work!

Calculating genetic distance

recombinant phenotype over the total offspring

Angiosperm diversity

results from flowers and xylem vessels, among other traits, as well as coevolutionary interactions with animals and other organisms.

SRY

sex-determining region in the Y chromosome; for male development

Vascular system anatomy

simple water conducting cells elongate cells with little structural support (found in fossils and present day mosses), the first vascular tissue forms some structural support, Tracheids increased structural support which is now found in all vascular plants, and vessel elements were found in gnetophytes and angiosperms

HW: A key difference between single gene traits such as those Mendel studied and complex traits such as human height is that:

single gene traits are generally not significantly influenced by the environment, whereas complex traits have a significant environmental component.

Ti plasmid

small circular DNA molecule in virulent strains of R. radiobacter containing genes that can be integrated into the host cell's genome, as well as the genes needed to make this transfer.

From an evolutionary perspective, germ-line mutations are more significant than somatic mutations. This is because:

somatic mutations affect only one or a few cells and only germ-line mutations will appear in an individual's descendants.

Carl von Linné

sought to discover the diversity of life only "for the Greater Glory of God." His taxonomic system would become central to Darwin's ideas on evolution (did not believe in evolution)

What is the hierarchal classification

species --> genus --> family --> order --> class --> phylum --> kingdom --> domain

lateral meristems

surround stems and roots and produce cells that allow growth in diameter.

Conifer reproduction

tends to be slow; After pollination it can take more than a year for the pollen to be produced in small cones, and seeds to be put in larger cones which become woods, providing protection for the fertilized ovules to develop into seeds to be spread mainly by the wind. Have naked seeds that develop on scales of the female cones

trait

that fits an organism well to its environment (better than alternatives), and that has evolved for its current function

Mutant alleles

the DNA sequences are different, but each produces a protein product whose function is impaired under the usual environmental conditions

Normal alleles

the DNA sequences are different, but they all are able to produce functional protein.

if one branch is a sister group that contains 500 species and another has 6

the branches have experienced different rates of speciation, extinction, or both since they diverged

color-blindness

the chance of a female receiving two recessive alleles is less than the chance of a male receiving a single recessive allele therefore, males more likely to be colorblind

What happens to the X and Y chromosomes during metaphase and anaphase

the chromosomes align at metaphase I so that when their centromeres separate from each other at anaphase I the X and Y chromosomes go to opposite poles.

Carpel

the closed "vessel" in which seeds develop and that gives angiosperms their name, the pollen must grow through the carpel to reach the female gametophyte, interactions between pollen and carpel genotypes can affect the probability of fertilization. Believed to have evolved from leaves and flower petals folding in on each other

additive

the distances between adjacent genes can be added to get the distance between the genes at the ends

The term "genotype-by-environment interaction" applies to a situation in which:

the effects of genotype and environment on a phenotype are interdependent.

Four major transformations in life cycle

the evolution of alternation of generations, the evolution of vascular plants, through the evolution of pollen and seeds, and the evolution of the flowering plants (Angiosperms)

Natural Selection

the force behind adaptation to local conditions. Individuals with traits that enhance survival and reproduction will leave more offspring, who will inherit these traits. These traits will gradually become more common over the generations.

inclusive fitness

the genetic contribution of an individual to the next generation's gene pool relative to the average for the population, usually measured by the number of offspring or close kin that survive to reproductive age.

Genetic distance may also refer to what?

the genetic divergence between species or between populations (e.g., when creating phylogenies)

what does variable expressivity and incomplete penetrance express

the genotype does not always express the same phenotype

Antigens vs Antibodies

the glycoproteins are antigens that will be attacked by the antibodies if they enter a foreign body

gametophyte

the haploid gamete-producing plant that is photosynthetic; attaches and supports sporophytes

Independent Assortment

the hereditary transmission of one gene has no effect on a different gene

HW: Ten individuals of two inbred strains of mice, A and B, are fed identical diets. All have normal blood sugar as adults. The same mice are then fed diets high in sugar. Mice from strain B develop diabetes, but mice from strain A do not. Diabetes in strain B mice results from

the interaction of their diet with their genotype.

Pollen

the male gametophyte

character state

the observed condition of a character, (Ex: presence or absence of lungs or arrangement of petals.). They can form different structures based on homologous or analogous structures

epidermis

the outermost layer of cells in leaves, young stems (lacking secondary growth), and roots. Also, the outer layer of the cnidarian body. They have thick walls and waxy cuticles and is the first line defense against bacteria

Plant Node

the point on a shoot where one or more leaves are attached.

If you have + blood type what will happen if you receive a - blood type

the positive blood type antibodies will attack the blood type.

Crossover

the process in which DNA in the parental chromosomes break and rejoin in such a way that the ends exchange partners, but no genetic material is gained/lost

systematics

the study of evolutionary relationships among organisms

CLICKER: Vestigal characteristics

the traits are no longer needed (yellow dandelions even though it does not need pollinators to create seeds, blind cave dwelling fish still born with eyes even if they can't use them, and flightless beetles who still have wings, and wisdom teeth). There is no selection that is occurring therefore, it fulfills the HW theory

Co-dominance

the two alleles both affect the phenotype in separate, distinguishable ways

CLICKER: Linked genes

two genes that are on the same chromosome; will not separate in independent assortment

Co-speciation

two groups of organisms speciate in response to each other and at the same time, producing matching phylogenies.

VNTR

variable number tandem repeat; Some genes have so many alleles that they can be used for individual identification by means of DNA typing.

HW: The ability of plants to wall off infections through the coordinated death of a cordon of uninfected cells provides a first line of defense against

viruses, bacteria, fungi, nematode worms, other plants and oomycetes (Irish blight); each of these have the ability to grow on and in the tissues of plants, extracting resources to support their own growth and causing an array of diseases

Pollination

when a pollen grain lands near a female gametophyte

Advantages of being complex

you can eat larger things, you are harder to kill, and you are able to exploit new niche

Which of the three genes is between the other two?

you look at the distances of each of the genes and look which genes are the farthest away from each other and place the gene in the middle in between the others and