test 1 review
U of L
Popular in Evolutionary Biology
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This 4 page Study Guide was uploaded by Mary-elizabeth Notetaker on Thursday September 8, 2016. The Study Guide belongs to Bio 409 at University of Louisville taught by Jeffery Bara in Fall 2016. Since its upload, it has received 23 views. For similar materials see Evolutionary Biology in Biology at University of Louisville.
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Date Created: 09/08/16
Test review 1 Thursday, September 8, 2016 2:23 PM • Darwiniasm theory of descent: ○ Microev-specieschange thru time Artificial selection by humans Nat selection by nature □ Seed collection.. Rainy vs dry seeds. Dry seeds flower early in drought so survive better ○ Speciation-split and diverge Fruit flies on diff food sources kept separate then combined □ Didn’t interbreed at same rate each species bred with itself Bacteriophage- full speciation->specialist □ Mutation prevented it from using original host bacteria Gilraker- feed at top or bottom…eventually don’t breed with each other □ Subpops develop, could lead to new species ○ Macroev- life derives from earlier forms Transitional forms □ Bleny- fish w diff forms(terrestrial/amphibious/aquatic) Fossil evidence ○ Commonancestors Homology- nested shared traits Vestigial stxs Pseudogene- nongenic dna segment.. Nonfunctional/noncoding □ Researcher found defective genes(75) in humans □ Mutations accumulate at certain rate bc no stx and can show commonancestor ○ Life on earth is old COMPARE CONTRAST…CONCEPT • Nat selection- only process that leads to adaptation ○ Enhances survival/reproductionof orgs w beneficial trait ○ 4 postulates of NS: 1. Variation in phenotype- pop indivs differ 2. Heritable variation- diff among indiv passed in part from parent to offspring Variation has to be due to genetics 3. Differential survival- more born than can survive 4. Differential success is attributable to certain alleles/allele combos- nonrandom survival/reproductionw respect to phenotypic variation Diff mean in phenotype that survive than whole pop R is diff in trait mean for offspring, S is for parents ..if all 4 are true tehre is logical consequence, which is that over time pop will change phenotypically • Darwinian fitness- relative measure of indiv ability to survive and reproduce ○ Selection acts on indiv but affects pops ○ Restated postulates w genetics: 1. Variation among indiv from mutations creating alleles 2. Indiv pass alleles to offspring 3. Some indiv more successful at survive/reprodthan others Bio 409 Page 1 3. Some indiv more successful at survive/reprodthan others 4. Indiv best at reproducing are those w alleles that best adapted them to envir …over time alleles w best traits will inc in freq over time • Selection on existing traits ○ New traits can emerge ○ Exaptation- trait used in novel way ○ Ex) butterwort producing sticky sub to catch insects • Modes of selection: ○ Directional- selection acts on extreme trait value Ex) euk pop in incubator, slowly inc heat over time, pop evolvs to have higher thermal tolerance Mean of phenotype shifts Later could not go back and tolerate lower temps ○ Stabilizing- mean doesn’t change, variance around does…very common Most mutations are deleterious/lethalso purged from pop Movementbetween hosts causes loss in variation Viruses/diseases Ex) org created gall in plant □ Selection against large and small, moderate size survived and not parasitized ○ Disruptive- against most commontype HIV □ Antibodies etc, target most commontype, causes those able to survive against the disruptive selectionto inc in number Birds… beak width/length, long/short survive, medium don’t • Qualitative- discrete, easily identifiable traits ○ Phenotype diff can be explained by small # loci: CF? y/n Smooth vs wrinkly peas Blood type • Quantitative- most ecologically relevant…complex Continuous distributions, not discrete class Affected by many genes(polygenic) Affected by environmental factors ○ …most traits(shape weight morphology lifespan fecundity) ○ As # loci inc, phenotypes blend and discrete categories difficult to identify ○ QTL- map genes- what dna stretch contributes to quantitative trait and how many genes involved Q- DNA region that affects trait of interest M- DNA regions whose chromosomalpositions are known • Vp= Vg + Ve • Vg=Va+Vd ○ a- additive genetic variability- contribution of alleles across gen is understood ○ d- recessive/dom- effect depends on what other loci is • Broad sense heritability- degree of genetic determination ○ Btwn 0 & 1 ○ H^2= Vg/Vp • Narrow sense heritability Bio 409 Page 2 ○ d- recessive/dom- effect depends on what other loci is • Broad sense heritability- degree of genetic determination ○ Btwn 0 & 1 ○ H^2= Vg/Vp • Narrow sense heritability ○ h^2= Va/Vp ○ Btwn 0 & 1 ○ Ex) cuttings of same plant in diff greenhouses, diff btwn pops still diff due to envir ○ Each allele has known contribution, allow prediction of how pop will respond to selection Birds: beak heritable from parents, no envir effect High narrow sense heritability bc resemble parents • Selection differential- diff in trait mean after or before selection R always less R- response to selection O- trait mean of offspring gen O- mean pre selection = P- trait mean in parents • Phylogenic trees: ○ Branches show divergence ○ Ex) inject gf w HIV, strain from patient? Victim shares most recent commonstrain w patient not whole pop • Defining taxon traits: Bio 409 Page 3 ○ ○ Ex) inject gf w HIV, strain from patient? Victim shares most recent commonstrain w patient not whole pop • Defining taxon traits: • Monophyletic- contains commonancestor & all descendants ○ Multiple • Paraphyletic- some but not all descendent from commonancestor • Polyphyletic- no most recent commonancestor • Homoplasy- shares traits w/out commonancestor ○ Convergent evol Body shape: dolphin/shark More Commonin quantitative phenotypic traits ○ Reversions- can be due to mutation(virus/bac) • Trait matrix- 0- Same trait as outgroup(ancestral) 1- Diff trait than outgroup(derived) • Parsimony- simplest explanation most likely • Phylogenetic apps: ○ Forensic evol- track source of infection ○ Conservationbio ○ Track spread of infection ○ Sequence data to map emergence of traits into pop Bio 409 Page 4
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