BSC 196 FINAL EXAM STUDY GUIDE

What are the four main steps that are believed to have led to the origin of life on Earth?

1. Abiotic synthesis of small organic molecules (Amino acids, nitrogenous bases) 2. Joining of these small molecules into macromolecules (proteins, nucleic acids) 3. Packaging of molecules into protocols (Membrane bound droplets with different internal chemistry) 4. Origin of self replicating molecules made inheritance possible

What are the major trends in the evolution of animals?

1. All animals share a common ancestor 2. Sponges are basal animals 3. Eumetazoa ("true animals") is a clade of animals with true tissues 4. Most animal phyla belong to the clade Bilateria 5. There are three major clades of bilaterian animals, all of which are invertebrates, animals that lack a backbone, except Chordata, which are classified as vertebrates because they have a backbone

What are the three possible outcomes when two incipient species come into secondary contact?

1. Reinforcement: 2. Absence of reproductive barriers: Fusion leads to hybrid speciation. If hybrids are as fit as parents. 3. Selection favors hybrids in transitional zones: Stability leads to a stable hybrid zone

What kinds of testable predictions can be derived from the theory of evolution as it applies to the fossil record

2.Simple life should be found in the oldest strata. more complex forms should only occur in recent strata. Before radioactive dating, relative time scale based on geographical column 3. Transitional forms: There should be intermediate forms between major taxonomic groups. Best tested in groups likely to fossilize

What are the different organ, and cell types that are found in plants? What is the function of each?

3 basic organs: Roots (roots and shoots. Major site of CO2, O2, and light uptake. Major site of water and mineral uptake. Roots anchor the plant store carbohydrates. primary root branches to form lateral roots. Absortion occurs near tip of roots. Root hair increases the surface area of the root. Taller plant have taproot system develops from primary root, increase stability, not used for nutrient absorption. Shorter plants have fibrous root system. Adventituous roots are from stems or leaves) stems: Organ consisting of nodes which is the point that leaves are attached and internodes. Many plants have modified stems leaves Main photosynthetic organ. Flattened blade and a stalk called the petiole which joins the lead to the node of the stem. Monocots have parallel veins and eudicots have branching veins.

What is adaption?

A trait which fosters the survival/reproduction of an individual within a particular environment. Selection acts on individuals it is a process of populations

What essential macro- and micro-nutrients are required for plants? How do plants acquire each of those nutrients? What organs/tissues/cells are involved?

Adaptions that id in the acquisition of resources: Water, minerals, CO2, oxygen, and light. Stems are conduits for water and nutrients and supporting structures for leaves. Trade off between growing tall and branching Phyllotaxy is arrangement of leaves. The depth of the capably, the leafy portion of all the plants in a community affects the productivity of each plants (self pruning) Leaf orientation Soil contains resources mined by root system. can adjust to local conditions. Less competitive with roots from same plant than others. Roots and hyphae soil fungi form mutualistic associations called mycorrhizae. Helped plants colonize land and increase surface area for absorbing minerals and waters especially phosphate

Secondary growth

Adds thickness and is a result of lateral meristem activity. This occurs in the roots and stems of woody plants. Can occur simultaneously with primary growth. Vascular cambium a cylinder of meristematic cell one cell layer thick is responsible for the production of secondary vascular tissue. The cork cambium and the tissues it produces compose a layer of periderm. Bark consists of all the tissues external to the vascular cambium including secondary phloem and periderm

What is water potential? Why is it important?

Affected by solute potential: of a solution is directionally proportional to its molarity Pressure protenital: The physical pressure of a solution Turgor pressure: Exerted by the plasma membrane against the cell wall and the cell wall against the protoplast (living part of the cell which also includes the plasma membrane) Water potential is most negative in outside air least negative in the soil

What is primary ? How do they differ from one another? What tissues are involved in each type of growth?

All 3 tissue types are produced during the primary growth. IN eudictors the xylem is starlike with phloem between the arms. In many monocots, a core of parenchyma cells is surrounded by rings of xylem then phloem. Primary growth occurs in the roots. Root tips have protective root caps. Root growth occurs behind the root cap. Zone of cell division (apical meristem) Zone of elongation and zone of differentiation. Inner most of the cortex called the endodermis Primary growth in the shoots: A shoot apical meristem is a dome shaped mass of dividing cells at the shoot tip. Axillary buds develop from meristematic cells left at the bases of leaf primordial. The vascular tissue consists of vascular bundles in a ring (eudicots) IN monocots they are scattered Primary growth in the leaves: Stomata. Guard cells

What are the apoplast and symplast? Why are they important in plants?

Apoplast: consists of everyting external to the plasma membrane (cell walls, extracellular spaces, and interior of vessel elements and tracheids. Symplast: consists of the cytosol of all living cells in a plant as well as the plasmodesmata

Know the phylogenetic relationships among the three domains of life (and of course know what those three domains are).

Archaea is most closely related to eukaryotes but still shares traits with bacteria.

What are the defining features of the major groups of invertebrates? Consider how sponges differ from eumetazoans, and how the three major groups (Deuterostomia, Ecdysozoa, and Lophotrochozoa) differ.

Bilaterians divided into three clades: Deuterostomia, ecdysozoa, and lophotrochozoa Deuterostomia: Includes hemichordates (acorn worms) and echinoderms (sea stars) and chordates. Includes both vertebrates and invertebrates Ecdysozoa: Clade of invertebrates that shed their exoskeleton through a process called ecdysis. Most species rich. Have tough coat called cuticle and composed of chitin Lophotrochozoa: Another clade of bilateral invertebrates with triploblastic development. Some have feeding structure called lophophore. Others go through distinct developmental stage called a trochophore larva

What key characters unite the fungi?

Break down organic material and recycle vital nutrients . Are heterotrophs and absorb nutrients form outside their bodies. Use enzymes to break down a large variety of complex molecules into smaller organic compounds.

How do nonvascular, seedless vascular, and seed plants differ from one another? What key characteristics allow you to differentiate between the groups?

Bryophytes (non vascular plants): NOT a monophyletic group they are paraphyletic. Nonwoody plants. Liverworts, mosses, and hornworts. They are thought to represent the earliest lineages the diverge from the common ancestor of plants. The gametophyte dominates being larger and longer lived. Their height is constrained by lack of vascular tissue. Rhizoids not roots anchor gametophytes (do little water and mineral uptake) Mature gametophytes produce flagellated sperm Mosses have diverse environments and help retain nitrogen from soil Seedless Vascular plants: Flagellated sperm and are restricted to moist environments. Sporophytes is the larger generation. The gametophytes are tiny plants that grow on or below the soil surface. Have two types of vascular tissue xylem (conducts most of water and minerals strengthened by lignin) Phloem has cells arranged into tubes that distribute sugars, amino acids, and other organic products. Vascular tissue allow for increased height, which provide evolutionary advantage. Roots are organs that anchor them. Early ones lacked roots. Spoorophylls are modified spore bearing leaves. Homosporous (produce one type that develops into bisexual gametophyte). All seeds and some seedless are heterosporous but most seedless are homosporous Seed plants: Two clades: Gymnosperms (naked seeds are exposed on sporophylls that form cones. conifers) and angiosperms(Seeds plats with reproductive structures called flowers or fruits Seeds changed the course of plant evolution enabling their bearers to become the dominant producers in most terrestrial ecosystems. Seed consists of embryo and nutrients surrounded by a protective coat. Reduced gametophytes. Heterospory. Ovules (has megasporangium, megaspore, and one or more protective integuments) pollen. Sporophyte stage dominant Study fig 30.2

Long distance transport

Bulk flow is the movement of fluid driven by pressure. Made possible by lack of cytoplasm in xylem and lack of organelles in phloem. Pressure is created in the xylem by the movement of water from roots to shoots Most water and mineral absorption occurs near root tips where root hairs are located and the epidermis is permeable to water Root hairs account for much of the surface area of roots

What is evolution?

Change in populations over time (i.e. generations) Leads to a change in species over time Responsible for organic diversity on earth (Descent with modification: All organisms are related through descent from ancestor that lived in remote past)

What is a reproductive isolating mechanism? What are the various ways by which such mechanisms can prevent gene flow both before and after zygote formation?

Characteristics that prevent gene exchange Prezygotic: Prevent mating or fertilization (efficient) Postzygotic: Prevent hybrid from reproducing (Inefficient)

How do plants differ from their algal ancestors?

Charophytes and plant similarities: Rings of cellulose synthesizing proteins Morphologically similar flagellated sperm Formation of phragmoplast during cell division Similarity of some genes, including chloroplasts genes. Differences that are in plants but absent in charophytes: Alternation of generations Multicellular dependent embryos Walled spores produced in sporangia Multicellular gametangia Apical meristems Cuticle (waxy outer layer that prevents water loss) Stomata

How did John Endler test the hypothesis that color patterns in guppies represent a tradeoff between selection to avoid predation and selection to attract a mate?

Color patterns have evolved through natural selection. Trade off between mate attraction and predator avoidance. Manipulated the intensity of predation, bottom of substrate

What features unite the animals? Consider early development as well as nutrition

Consumers, heterotrophs that ingest their food, multicellular eukaryotes lack cell walls, bodies held together by collagen. Nervous tissue and muscle tissues. Most reproduce sexually, diploid stage being dominant. Fertilization->Zygote->Cleavage->Blastula->Gastrulation Have at least one larval stage

What are the various modes of selection and how do they alter the frequency distribution of a trait assuming that variation in the trait is genetically based?

Directional selection: Favors individuals at one end of the phenotypic range Disruptive selection: Favors individuals at both extremes of the phenotypic range Stabilizing selection: Favors intermediate variants and acts against extreme phenotypes

How do changes observed in the beak of morphology of medium ground finches over the last 20 years conform to the criteria for evolution by natural selection?

During the drought, seeds were larger and tougher. Therefor individuals with deeper beaks had higher survival rates. After drought chicks hatched had deeper beaks than before. So selection acts on phenotypes but evolution occurs through changes in gene frequencies. Natural selection does no adapt organisms to future changes only past.

What are the defining features of the prokaryotes?

Earths first organisms were likely prokaryotes because they thrive almost everywhere. Most are microscopic but very abundant. Most are unicellular although some form colonies.

What kinds of testable predictions can be derived from the theory of evolution as they apply to homogies at all levels of biological organizations: Structure, embryonic, cellular and molecular?

Embryonic homology: Chordata. Gill slits, notochord, hollow nerve chord, and tail Cell Structure: All eukaryotic cells have same structural elements (nucleus, cell membrane, membrane bound organelles) All prokaryotic cells have same structural elements (Naked DNA, RNA containing ribosomes) Molecular: All cells consists of same organic compounds (Proteins lipids nucleotides carbohydrates). Cellular reactions controlled by enzymes. DNA is inheritance. DNA.RNA have same chemical structure (Sugar, bases, phosphates) SAME GENETIC CODE

Be familiar with some of the key events in the history of life, including the origin of unicellular and multicellular organisms, and the colonization of land.

Endosymbiont theory: Proposes that mitochondria and plastids (chloroplasts and related organelles) wre formerly small prokaryotes living within larger host cells. (Endosymbiont is a cell that lives within a host cell)

What characteristics allow you to differentiate between them? What is an extremeophile?

Extreme envirnments Halophiles live in highly saline environemtns Thermophiles live in very hot environments . Methanogens live in swamps and produce marshes as a waste proctor are strict anaerobes and are poisoned by O2)

What is the ABC hypothesis of flower formation? How is flower formation affected by the loss of any of the ABC genes?

Flower formation involved a phase change from vegetative growth to reproductive growth. It is triggered by a combo of environmental cues and internal signals. associated with switching on of floral meristem identity genes. Seapl, petal, stamen, or carpel. The ABC identifies how floral organ identity genes direct the formation of the four types of floral organs.

How would you calculate the age of a fossil using radiometric dating?

Fossil record is biased in favor of species that existed for a long time, were abundant and widespread, had hard parts. Relative age: Revealed by sedimentary strata Absolute age: Determined by radiometric dating. A radioactive parent isotope decays to a daughter isotope at a constant rate. Each isotope has a known half life, C14 half-life = 5,730 years decays to N14 what is age of fossil with 25% of its original C14 remaining? 50% is gone after 5,703 years, so 75% is gone after 2 x 5,730 = 11,460 years Radiocarbon dating

Tetrapods

Four limbs and feet with digest Neck which allows separate movement of head fusion of pelvic girdle to backbone Absence of gills Ears

What are the various avenues of sympatric speciation? What process of sympatric speciation is especially applicable to plants?

Gene pool isolated in the midst of parent population. Reproductive barrier without geographic isolation 3 avenues polyploidy: Chromosomal mutatinos Sexual selection: Can drive sympatric speciation. Mates for different colors Habitat differentiation: Mutations leading to utilization of different hosts. Flies meat near host plant is habitat isolation. Apples mature more quickly is temporal isolation. Autopolyploidy: More than 2 sets of chromosomes from the same species Allopolyploidy: Multiple sets of chromosomes from the different species (wheat, oats, cotton, and potatoes)

Can genetic drift lead to adaptation? What effect does population size have on genetic drift?

Genetic drift is significant in small populations Can cause allele frequencies to change at random Lead to loss of genetic variation in populations Cause harmful alleles to become fixed. Cannot lead to adaption because this happens by chance

How is a pattern of gradual evolution different from a pattern of punctuated equilibria?

Gradual evolution: species change gradually over time Punctuated equilibria: Species appear suddenly in fossil record, persist unchanged for long periods of time and then suddenly disappear.

What are the pre zygotic barriers?

Habitat isolation (water and land), temporal isolation, behavioral isolation (mating attempts), mechanical isolation, and gametic isolation

What are the four major eons?

Hadean, Archaen, Proterzoic and phanerozoic.

Internal organization and DNA of prokaryotes

Has less DNA than eukaryotes Circular chromosome not surrounded by a membrane and located in the nucleoid region. Some of smaller rings of DNA called plasmids

What are the defining features of eukaryotes?

Have organelles and are more complex than prokaroytic cells mitochondria and well developed cytoskeleton that aids in support and allows shape change Eukarya have: Nuclear envelope Membrane bound organelles Unbranches hydrodrocarbons Methionine Introns No growth inhibition

What is the Linnean classification scheme? How do we currently organize (or classify) organisms using this method?

Hierarchial classification. Species genus family order class phylum and domain

Morpohlogical and molecular data that help form phylogenies

Homoglous characters: Are phenotypic and genetic similarities based upon shared ancestry. Most important. The more similar two complex structures are the more likely they are homologous Analogous characters: Are similarities between organisms due to convergent evolution. Similar environmental and selective pressures Homoplastic characters: Are analogous structures that arose independently. Not useful in constructing phlyogenies

Differences in cell surface structures

Important feature of all prokaryotic cells is cell wall which maintains shape, protects and prevents from bursting in hypotonic environment Eukaryotic cell walls made of cellulose or chitin Bacterial made of peptidoglycan Archaea have glycoproteins

Motility

In a heterogeneous environment, ayn bacteria exhibit taxis which is the ability to move toward or away from a stimulus Chemotaxis is the movement toward or away from chemical Most bacteria have flagella which is a homoplastic character

Shared ancestral character vs shared derived character

Is a character that orginated in an ancestor of the taxon vs an evolutionary novelty UNIQUE to a particular clade It can be both depending on the context

What is the biological species concept? What are the disadvantages associated with this definitions of species?

Main criteria: Reproductive isolation. If populations do not hybridize or only produce infertile offspring then they must be different species. Groups of populations whose members can exchange genes are are reproductively isolated from other groups Benefit: This concept confirms the absence of gene flow Disadvantage: Does not apply to asexual species, extinct species, and populations that are geographically separated.

prokaryotes can obtain energy, undergo cellular respiration (metabolism)

Metabolism: Obligate aerobes: Require O2 for cellular respiration Obligate anaerobes: Poisoned by O2 and use fermentation or anaerobic respiration Facultative anaerobes: Can survive with or without O2

What are monophyletic, paraphyletic, and polyphyletic groupings? More important than knowing the definition - be able to recognize each when you see them in a phylogenetic tree.

Monophyletic: Valid clade that consists of ancestor species and ALL its descendants Paraphyletic: Consists of ancestral species and some but not all descendants Polyphyletic: Grouping includes distantly related species but not not include most recent common ancestor

What is horizontal and vertical gene transfer? How do they affect our understanding of phylogenetic relationships? BE ABLE TO GIVE SPECIFIC EXAMPLES

Movement of genes among individuals from different species is called horizontal gene transfer

How is genetic variation created? What are the major kinds of mutations, and how do they alter DNA sequences?

Mutation is a mistake made during DNA copying. Origin of variation AND mechanisms of change. Point: Source of new alleles. Change in one of nucleotide bases. Three kinds, substitution, insertion, and deletion. Can lead to silent mutations Chromosomal: Source of new genes, species. 3 characteristics: Chromosomal breakage, order of base pairs remain unchanged, order of genes is altered. Common chromosomal mutation is misalignment which leads to a gene duplication (duplication is typically less harmful)

Do mutations arise by chance or nonrandomly? Are most mutations harmful or beneficial?

Mutations arise randomly and ones that result in a change of protein are often harmful. Harmful mutations can be hidden from selection in recessive alleles. Can sometimes be beneficial

What are mycorrhizae? Why are they important?

Mutually beneficial relationships between fungi and plant roots. Mycorrhizal fungi deliver phosphate ion and minerals to plants most vascular plants have mycorrhizal Mycorrhizal fungi colonize soils by the dispersal of haploid cells called spores

Why is natural selection not simply a matter of chance?

Natural selection results in adaptive evolution, an improvement in the math between organisms and their environment. This tends to REDUCE genetic variation

What are the three primary evolutionary forces factors that can take a population out of Hardy-Weinberg equilibrium?

Natural selection, Genetic drift, and gene flow Gene flow: Consists of movement of alleles among populations. Alleles can be transferred through the movement of fertile individuals or gametes. Tends to reduce variation over time Natural selection: Involves both chance and sorting. New genetic variations arise by chance (mutation) Beneficial alleles are sorted and favored by natural selection (non random). ONLY natural selection consistently increase the frequencies of alleles that provide reproductive advantage

What characteristics indicate that bacteria and archaea are distinctly different domains?

Neither have Nuclear envelope Membrane enclosed organelles Both have Circular chromosomes Bacteria have fimbriae allow to stick to substrate Peptiogylcan in cell walls unbranced hydrocarbons formylmethionine Inhibited growth to antiobiotics and no growth above 100C Ahchae have Some branched halocarbons Methionine No growth inhibition to antibiotics Some histones with DNA and growth over 100

How do prokaryotes metabolize nitrogen?

Nitrogen fixation: Convert N2 to ammonia NH3

What are the 5 conditions for non evolving populations? (Conditions for the Hardy-Weinberg equilibrium

No mutation Random mating No natural selection Extremely large population size No gene flow

What is heterozygote superiority? How does heterozygote superiority lead to the maintenance of the sickle-cell hemoglobin gene in natural populations?

Occurs when heterozygotes have a higher fitness than either homozygote. Natural selection will tend to maintain two or more alleles at that locus. Sickle if homozygous leads to anemia but heterozygotes are resistant to malaria

What characters suggest that Fungi and Animals are closely related taxa?

Origin was a single celled protists. Multicellularity arose separately in animals and fungi

What is the Cambrian Explosion, and why is it thought to be important for the evolution of animals?

Paleozoic era 535 to 525 million years ago was the earliest fossil appearance of many major groups of living animals. Most fossils are bilaterians (have bilaterally symmetric form, complete digestive tract, one way digestive system. Animals to land and then plants. Mammals increased in size and exploited vacated ecological niches. the global climate cooled

Cell Types

Parenchyma: Least specialized, carry out most metabolic functions Collenchyma: Provide flexible support to growing parts of shoot Sclerenchyma: Provide rigid support, highly lignified, dead at maturity. Sclerids (thick lignified walls) Fibers (long slender thread like Water conducting cells of the xylem: Dead at maturity. Highly lignified walls, 2 types: tracheids which are found in all vascular plants and vessel elements which are larger Sugar conducting cells of the phloem: Alive at maturity Sieve-tube elements lack organelles but have companion cells whose nucleus and ribosomes serve both cells. Sieve plates allow fluid to move between cells

What are the five major extinctions that have dramatically influenced the diversity of life on Earth?

Permian extinction: Defines the boundary between the palezoic and mesozoic 251 million years ago. Caused extinction of 96% of marine animal species. Intense volcanism, global warning and ocean acidification from CO2, anoxic conditions resulting from nutrient enrichment of ecosystem 70% of terrestrial vertebrates. Only known mass extinction of insects Cretaceous extinction: 65.5 million years ago. Half of all marine species and many terrestrial plants and animals including most dinosaurs. Meteorite impact. Dust blocked sunlight. Chicsulub crater off coast of mexico.

What are meristems? Where are they located? What is their function?

Perpetually embryonic tissue and allow for indeterminate growth. Organs that stop growing at a certain size are determinate growth Apical meristems are located at the tips of the roots and shoots they elongate shoots and roots a process called primary growth Lateral meristems add thickness to woody plants a process called secondary growth. Two types of lateral meristems. The vascular cambium (Adds layers of vascular tissue called secondary xylem wood and secondary phloem) and the cork cambium. (replaces the epidermis with periderm which is thicker and tougher)

How prokaryotes obtain energy and carbon

Phototrophs: Obtain energy from light Chemotrophs: Obtain energy from chemicals Autotrophs: Require CO2 as a carbon source Heterotrophs: Require an organic nutrient to make organic compounds

What are phylogenies? How are they constructed? Which types of characters are used in constructing phylogenies and why?

Phylogenetic trees are pictorial representations of evolutionary relationships. They also represent hypotheses about these relationships. Provide info about relatedness, testable, revisable but not tell when a species evolved. Basal taxon: Single Sister taxa: Multiple Polytomy: An unresolved pattern of divergence Caldogram: Pictoral representation

What is alternation of generations? Explain this in detail. How does it the relative importance of the two generations differ among the major groups of plants? Beyond knowing definitions, be able to recognize alternation of generations in a life cycle.

Plants alternate between two multicellular stages, a reproductive cycle called alternation of generations. The gametophyte is haploid and produced haploid gametes by mitosis. Fusion of the gametes gives rise to the diploid sporophyte which produces haploid spores by meiosis.

Post zygotic barriers

Prevent hybrid zygote from developing into viable, fertile adult Reduced hybrid Viability: Reduced hybrid fertility: Hybrid breakdown

Review the general life cycle of fungi. What are plasmogamy and karyogamy? What is the heterokaryotic stage? Why are these processes important?

Produce vast number of spores either sexually or asexually. Normally haploid. Use pheromones plasmogamy is the union of cytoplasm from two parent mycelia. In most fungi, the haploid do not fuse right away they exist in mycelium called a heterokaryon for hours days or centuries. Karyogamy is after and is nuclear fusion. The haploid nuclei fuse producing two diploid cells. Short lived and undergoes meiosis producing haploid cells. Important because karyogamy and meisos produce genetic variation

What does heritability measure? Can natural selection alter the evolution of a trait that has a heritability of zero?

Proportion of phenotypic variation that is due to genetic differences between individuals. h2 ranges from 0-1 Selection results in evolutionary change only when h2>0 Measured via resemblance between relatives

Why is it likely that the first genetic material was RNA, and that early life existed in an "RNA world"?

RNA molecules called ribozymes have been found to catalyze many different reactions. Ribozymes can make complementary copies of short stretches of RNA. Vesicles containing RNA capable of replication may have been the first protocols

What is adaptive radiation and how does it lead to an increase in species diversity?

Rapid evolution of diversily adapted species from a common ancestor. May follow: Mass extinctions, the evolution of novel characteristics, and the colonizatino of new regions.

What is endosymbiosis as it pertains to the Eukaryotic cell? What groups have participated in this process/been formed as a result of this process? Distinguish between primary and secondary endosymbiosis. Be able to give examples.

Relationship between two species in which one organism lives inside the cell or cells of the other organism (the host) Protist diversity has its origins in endosymbiosis. Mitochondria and plastids are derived from prokaryotes that were unglued by the ancestors of early eukaryotic cells. Mitochondria evolved once by endosymbiosis of an alpha proteobacterium Plastids evolved later by endosymbiosis of a photosynthetic cyanobacterium. The ancestral host cell may have been an archaean or an protoeukaryote from a lineage related to but diverged from archaea ancestors Mitochondria first arose through descent from a bacterium that was engulfed by a cell from an archaea lineage. The plastid lineage evolved later fro m a photosynthetic cyanobacterium that was engulfed by a heterotrophic eukaryote. The plastid bearing lineage of protists evolved into photosynthetic protisist, red and green algae

What is sexual selection? What are the two mechanisms by which adaptations that promote mating success can evolve?

Sexual selection: Sexual dimorphism (Size, strength, coloration.) Intrasexual (Enhance male competition) Intersexual Traits that enhance attractiveness female mate choice. Balancing selection: Occurs when natural selection maintains stable frequencies of two or more phenotypic forms in a population. Two types are Heterozygote advantage and frequency dependent selection

How are short- and long-distance transport of nutrients accomplished?

Short distance: Plasma membrane permeability controls short distance movement of substances both active and passive. Membrane potential pumping H+ protons. Balance water uptake and loss by osmosis (diffusion of water into our out of a cell that is affected by solute concentration and pressure) Water potential Measurement that combines the effects of solute concentration and pressure. Water flows from regions of higher water potential to lower water potential.

What is homology?

Similarity in underlying structural elements. Even if function and appearance differ. Morphology Embryology Cell Structure Molecular Structure/biochemical processes

What are the major trends in vertebrate evolution?

Skeletal system and complex nervous system have allowed vertebrates efficiency at moving and feeding. Capturing food, evading predators, large size. have vertebrae enclosing spinal cord, an elaborate skull, and fin rays in the aquatic forms. earliest lacked jaws. Mineralization originated in mouth parts

Prokaryote reproduction

Small, reproduce by binary fission, have short generation times Not primitive but highly evolved Have considerable genetic variation 3 factors contribute to genetic diversity: 1. Rapid reproduction 2. Mutation 3. Genetic recombination

What is the 3 step process to speciation? What are the two major mechanisms of speciation and how do they operate? What is micro and macroevolution?

Speciation is the origin of a new species. Process by which one species splits into two or more species. Microevolution is change in allele frequency over time Macroevolution is speciation evens that lead to new groups of organisms. 3 stage process: Separation Divergance of traits Reproduction isolation upon secondary contact 2 major mechanisms: Allopatric: VICARIANCE EVENTS (geologcal events that lead to division of populations) Sympatric Seperation of gene pools is critical to both mechanisms

What is the importance of symmetry, tissues, and body cavities in animal development? What features define protostomes and deuterostomes?

Symmetry: Radially symmetric: Animals are often sessile or planktonic (drifting or weakly swimming). No front back left or right Bilaterally symmetric: Moving actively and have a central nervous system. Tissues: Collections of specialized cells isolated from other tissues by membranous layers. True tissues are eumetazoa. Sponges and others lack true tissues. Germ layers give to tissues and organs. Ectoderm: Germ layer covering the embryos surface. Endoderm: Innermost germ layer and lines the developing digestive tube called archenteron Diploblastic: Animals ave ectoderm and endoderm Triploblastic: Animals als o have an intervening mesoderm layer (all bilaterians which are flatworms arthropods, and vertebrates) Body cavities: Most triploblastic have body cavity. True body cavity is coelom and is derived from mesoderm only. Coelomates (small white) are animals that have a true coelom. A psuedocoelom (large gap of white)is a body cavity derived from th emesoderm and endoderm. Called pseudocoelomates. Aceolomates (no white) lack a body cavity Protostomes: Cleavage is spiral and determinate (cell fate is determined early in development) Splitting of solid masses from the coelom Blastopore becomes MOUTH Deuterostomes: Radial and indeterminate Mesoderm buds from the wall of the archenteron The blastopore becomes the anus

Amniotes

Tetrapods whose living members are the reptiles including birds and mammals. Amniotic eggs key adaption to life on land Reptiles are ectothermic Birds are endothermic and maintain body temp through metabolism

If you were given allele frequencies, how would you determine expected genotype frequencies at Hardy-Weinberg equilibrium?

The frequency of genotypes can be calculated CRCR =p2= (0.8)2 0.64 CRCW =2pq= 2(0.8)(0.2) 0.32 CWCW =q2= (0.2)2 0.04 The frequency of genotypes can be confirmed using a Punnett square p2+2pq+q2=1 p2=homozygous genotype q2= Homozygous genotype pq=both

Review the Hardy-Weinberg theorem. If you were given a set of genotype frequencies, how would you determine the relative allele frequencies?

The hardy weinberg equation describes the genetic makeup we expect for a population that is NOT evolving at a particular locus Gene pool: Consists of all the alleles for all loci in a population Locus is fixed if all individuals are homozygous for same allele For diploid organisms, the total # of alleles at a locus is the total times For example, consider a population of 500 wildflowers showing incomplete dominance for color 320 red flowers (CRCR) = 64% (freq. = .64) 320/500 = .64 160 pink flowers (CRCW) = 32% (freq. = .32) 160/500 = .32 20 white flowers (CWCW) = 4% (freq. = .04) 20/500 = .04 Calculate the number of copies of each allele CR (320 2) 160 800 CW (20 2) 160 200 To calculate the frequency of each allele p freq CR 800 / (800 200) 0.8 q freq CW 200 / (800 200) 0.2 The sum of alleles is always 1 0.8 0.2 1

What benefits and problems did plants experience when they moved onto land? What characteristics of plants that are adaptations to the challenges of to success on land?

The origin of land plants began with green algae in the group charophytes. Land plants are not descended from modern charophytes but share a common ancestor with modern charophytes. Charophytes were already located near the edges of water and likely experienced periodic drying. Have a layer of durable polymer called sporopollenin that prevents zygotes from drying out. The movement provided unfiltered sun, more plentiful CO2, and nutrient rich soil. However they had unpredictable water sources and lack of structural support

Evolution of eukaryotes

The prokaryotic ancestors of mitochondria and plastids probably gained entry to the host cell as undigested prey or internal parasites. The process of becomeing more interdependent the host and endosymbionts would have becom a single organisms. Anaerobic host gained aerobic capacity. endosymbiont gained secure environmental and fuel. Serial endosymbiosis: Mitochrondira evolved BEFORE plastics because all eukaryotes have mitochondria but not all have plastics

What is the importance of cell division in establishing polarity in plants? What is asymmetrical cell division and why is it important?

The symmetry of cell division, the distribution of cytoplasm between daughter cells determines cell fate. Asymetrical cell division signals a key event in development. (guard cells) Polarity: Condition of having structural or chemical differences at opposite ends of an organism. Asymmetrical cell division play a role in establishing polarity. The first division of a plant zygote is normally asymmetrical and initiates polarization into the shoot and root

What is genetic drift? What consequences does genetic drift have for genetic variation?

The three major factors that alter allele frequency and bring about the most evolutionary change are natural selection, genetic drift, and gene flow. Genetic drift describes how allele frequency change from one generation to the next do to CHANCE events. The smaller the sample the greater change of random derivation from predicted result. REDUCE genetic variation from loss of alleles

What are the key characteristics that define the chordates? The vertebrates? What features allow you to differentiate between the major vertebrate groups?

They are bilateral deuterostomes. Comprise all vertebrates and two groups of invertebrates. Notochord (Rod bw digestieve tube and nerve chord) Dorsal, hollow nerve cord (develops into central nervous system), pharyngeal slits or clefts (gas exchange), muscular post anal tail

Be able to give some reasons why are protists thought to be important ecologically? In what environments are they particularly important?

They are eukaryotes that are not plants, animals, or fungi. Polyphyletic group. Most eukaryotes are protists.Most are unicellular but some are colonial and multicellular. Protists are found in diverse aquatic and moist terrestrial environments. Play KEY ROLES as symbiont and producer. Some protists symbionts benefit from their hosts Some are parasitic Some are producers that obtain energy from the sun In AQUATIC environments, photosynthetic protists and prokaryotes are main producers

Tissue types

Tissue system is continuous throughout the plant Dermal: In Non woody plants the dermal tissue is epidermis. Cuticle helps prevent water loss In woody plants periderm replace the epidermis in older regions of the stems and roots Vascular: Functions to transport resources and provide mechanical support. Xylem (goes up) and phloem (both ways) Ground: Tissues that are neither dermal nor vascular are the ground tissue system Internal to vascular tissue is the pith External is the cortex Specialized for storage, photosynthesis, support, short distance transport

What are the processes of transformation, transduction, conjugation? How can they lead to genetic variation? Are there other processes that can lead to variation in prokaryotes?

Transformation: A prokaryotic cell can take up and incorporate foreign DAN from the surrounding environment Transduction: Movement of genes between bacteria by bacteriophages Conjuction: Is the process where genetic material is transferred between prokaryotic cells. In bacteria this transfer is one way. Donor cell attaches to a recipient by a PILUS pulls it closer and transfers DNA

What are the four principal requirements of evolution by natural selection?

Variation Fitness Differences Inheritance More offspring produced than can survive

Is xylem sap pushed or pulled? Why? How is this accomplished? What is the importance of adhesion and cohesion in this process?

Xylem sap, water and dissolved minerals is transported from roots to leaves by bulk flow. Involves transpiration, the evaporation of water from a plants surface. Transpired water is replaced as water is replaced as water travels up from the roots

How do xylem and phloem differ in structure and function?

Xylem transports water and minerals from roots to shoots. Phloem transports photosynthetic products from sources to sinks

What is frequency dependent selection? How does frequency dependent selection help maintain genetic variation in a population?

in frequency dependent selection, the fitness of a phenotype declines if it becomes too common in the population (negative). Selection favors which is LESS common (ex scale eating fish that have two morphs, dextral and sinistral which is the right side)

What is reinforcement, and how does it promote reproductive isolation between incipient species?

strengthening reproductive barriers to gene flow Hybrids should be poorly adapted to habitat of either parental population. FAVORS POSITIVE ASSORTIVE MATING (mating with members of the same parent species). When hybrids are less fit, selection should favor barriers to reproduction. Barriers should be stronger for sympatric than allopatric species