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Bio 20C
Evolution
| Question | Answer |
|---|---|
| Science before Darwin: definition of evolution.. | transformed life on earth from earliest forms to diversity of the past and present |
| Eidos | species are FIXED and ETERNAL. variation seen as fail. ESSENTIALISM-all species had perfect essence. (dogs always dogs) |
| Scala Naturae | -the great chain of being -essentialism lead to this -species seen as rungs on ladder |
| James Hutton | -found earth was a lot older -UNIFORMITARIANISM-consist. in change -change happening since day 1 |
| Charles Lyell | -principles of geology -GRADUAL geo changes -change happens so slowly that we cant see it |
| Thomas Malthus | -principles of population -population growth/resource limitation -demography/econ - |
| Adam Smith | -econ/capitalism/competition -whoever has advantage will succeed |
| Jean Baptiste Lamarck | -developed 1st theory of organic evolution -mechanism of ACQUIRED CHARACTERISTICS -evo= force driving animals from simple to complex -animals change thru time -LADDER OF LIFE |
| Carl Linneus | -taxonomy -classification (separate animals into diff groups, mammals, fish, etc) |
| Charles Darwin voyaged on the: | Beagle |
| During Darwins voyage, he did observed/documented 3 things.. | 1. observed variety of GEO features, fossils, and living organisms 2. documented GEO phenomenon which supported lyells view 3. docum. BIOGEO patterns that suggest common ancestry of species (finches, tortoises, birds) |
| Darwin was a supporter of ____'s theory saying that "species change thru TIME" | Lamarck |
| Darwin/Wallaces theory of evolution: | evolution of new species occurs via DESCENT with modification of existing species |
| the MECHANISM for darwin/russels theory of evolution: | NATURAL SELECTION |
| 2 components of natural selection (2 S's) | 1. struggle for existance 2. survival of the fittest |
| natural selection: struggle for existance | -populations can reproduce beyond recources needed to sustain them -resources become LIMITED -becomes competition for them -not everyone will survive/reproduce |
| natural selection: survival of the fittest | -members of population show variety for heritable traits -some give indivs an advantage -these tend to lead to more offspring -over time character of pop changes |
| ____ is the smallest unit capable of evultion | population |
| Natural selection; fitness vs. adaptation | 1. fitness- ability of indiv. to reproduce 2. adaptation- trait that increases fitness |
| 2 points about species that show evidence for evolution | 1. species have CHANGED THRU TIME 2. species share COMMON ANCESTOR |
| 4 points that support that species change thru time (favorite pc) | 1. F-fossil record has transitional forms 2. V-vestigial traits( non functional traits taht once had a purpose, ex: human tail bone and goosebumps) 3. P-population- observed to have changed over time 4. C- color preference(moths) |
| species are related via ___ _____, & closely related species live in the same _____ _______ | related via COMMON ANCESTRY, & live in the same GEO AREA |
| species related via ancestry: homologous traits exist at 3 levels | 1. anatomical- common parts 2. embryological- single cell becomes functional adult 3. molecular- similar molecules in diff organisms |
| homologous vs. analogous traits | 1. homo- traits shared due to common ancestry 2. ana- similar traits w/ indep origins( ex dolphins and ichtysaurs look similar but dont have common ancestor) |
| lamarckian vs. darwinian evolution | lamarck- LADDER of life darwin- TREE of life |
| genotype vs. phenotype | 1. geno- determined by genes 2. phe- determined by genotype |
| gene ancestry: ortholog vs. paralog | 1. ortho- gene in 2 DIFF species share common ancestry 2. para- gene copies in SAME species |
| orthologs & paralogs exxamples of ____ evolution, which means: | VERTICAL EVOLUTION: evolution within a lineage thru time |
| horizonatal evolution | -much rarer - involves gene transfer btwn species - most common in BACTERIA -prob how eukaryotes evolved from prokaryote ancestors - instant change laterally |
| genetic concepts: gene vs. locus vs. allele | 1. gene- REGION of DNA coded for specific molecule 2. locus- LOCATION of gene on chromosome 3. allele- VERSION of specific gene |
| 4 causes of change in allele frequencies (NgMg) | 1. natural selection 2. gene flow 3. mutation 4. genetic drift |
| hardy weinberg equation used to measure if ____ _____'s change. how does it do that? | measure if ALLELE FREQUENCIES change. if you know allele freq of all alleles in CURRENT generation, can predict allele freq. of NEXT generation |
| frequencies of all alleles in a POPULATION add up to #___ | 1 |
| hardy weinberg assumptions | NO NgMg...RANDOM MATING |
| -if freq. of allele=1, allele is ___ -if freq. of allele=0, allele is___ | =1 FIXED =0 LOST |
| genetic diversity in populations (in terms of allele frequency) | # & relative frequency of alleles in a poluation |
| natural selection occurs based on ____type | PHENO |
| 2 times when natural selection occurs | -when 1 phenotype has HIGHER FITNESS -when alleles associated with phenotype will increase in frequency |
| 4 types of natural selection (DSDS)..what each favors & an example | 1. DIRECTIONAL- favors 1 extreme of trait distribution(giraffe necks). 2. STABILIZING- favors mean(birthweight). 3. DISRUPTIVE- favors BOTH extremes (can make 2 separate species) 4. SEXUAL- favors indivs(usually male) w/ higher fitness(repro success) |
| DSDS reduce/increase trail & genetic diversity/variability(1st 3)..but last results when... | 1. directional- REDUCE genetic diversity 2. stabilizing- REDUCE both trait & genetic variability 3. disruptive- INSCREASE genetic diversity 4. sexual- results when indivs in a population differ in their ABILITY to attract mates |
| 2 types of sexual selection(think about sexes) | 1. FEMALE CHOICE- remales respond to some aspect of male PHENOtype 2. MALE-MALE COMPETITION- males compete for females |
| sexual selection leads to sexual _____. definiton(bird) & example | DIMORPHISM. -males look diff than females ex: male zebra finches, orange beaks=healthier ex: widowbirds- sexual selection favors long tails for males |
| balancing polymorphism(definiton). maintains (less/more) fit alleles in population? | def: when 2 or more clearly diff phenotypes exist in same species ex: diff colored jaguars ...maintains LESS fit alleles in pop |
| 2 mechanisms to balance polymorphism (HA NF DS) (HA! not fit d's) | 1. heterozygote advantage 2. (negative)frequency dependent selection |
| balancing polymorphism: heterozygote advantage + example | - hetero have HIGHER fitness in some cases - maintains less fit alleles in population ex: mating success |
| balancing polymorphism: negative frequency dependent selection | -RARE indivs have HIGHER fitness ex: scale eating fish & non rewarding orchids(flowers w/o nectar) |
| balancing polymorphism: positive vs. negative frequency dependent selection (in terms of increase in fitness) | 1. positive- fitness of PHENOtype increases as it becomes MORE COMMON 2. negative- fitness increases as it becomes RARER |
| heterozygotes vs. homozygotes (similar to ortholog/paralog) | 1. hetero- 2 diff alleles @ genetic locus (Bb) 2. homo- 2 copies of same allele on locus (BB/bb) |
| definition of GENETIC DRIFT & 3 key aspects | def: natural selection driven by ENVIRONMENT. undirected & random. 1. random with respect to FITNESS 2. most pronounced in SMALL pops 3. over time can lead to fix/lost alleles |
| 2 causes of genetic drift (FE & GB)..dealing with population | 1. FOUNDER EFFECT- small # of indivs FOUND new pop -may NOT reflect allele freq of source pop 2. GENETIC BOTTLENECK- results from drastic & random reduction in pop SIZE |
| GENE FLOW: definition & does WHAT to allele frequencies btwn populations? | def: movement of ALLELES from 1 pop to another -EQUALIZES allele frequency btwn pops |
| gene flow: genetic diversity- increase/decrease in donor/recipient population | -DECREASE in DONOR population (DD) -INCREASE in recipient population |
| Mutation: definition & what its due to | def: production of a NEW ALLELE -due to damage or replication errors to DNA |
| mutation increase/decrease genetic diversity? | INCREASE. allele mutation rates extremely low |
| mutation: effects on FITNESS variation | -most LOWER fitness -some INCREASE fitness |
| mutation: 2 ways in which natural selection increase/decrease freq. of ALLELES that increase/decrease FITNESS | -INCREASE allele freq. that INCREASE fitness -DECREASE allele freq that DECREASE fitness |
| inbreeding: definition. example of what kind of mating? | mating btwn relatives. example of NON-RANDOM MATING |
| inbreeding: increase/decrease 1. homozygosity in genotype alter/doesnt alter 2. allele freq. in gene pool 3. genotype frequency | 1. INCREASES homozygosity in genotype 2. DOES NOT ALTER allele freq. in gene pool 3. DOES ALTER genotype frequencies |
| inbreeding: homozygous recessive (bb) genotypes are often lower/higher in fitness? | LOWER |
| inbreeding depression: definiton & example | def: reduced FITNESS in pop due to mating relatives. often result of bottleneck(less variety=less options=mating relatives) EX: many more deaths in children of 1st cousins |
| speciation: definition & 2 components (genetic ID) | def: formation of new species from ancestral species 1. GENETIC ISOLATION: prevents gene flow btwn groups 2. GENETIC DIVERGENCE: natural selection, drift, mutation |
| 4 types of species (BEMP) | 1. BIOlogical 2. ECOlogical 3. MORPHOlogical 4. phylogenetic |
| BIOlogical species: based on what? advantages & disadvantages | -based on reproductive isolation(cant breed outside of their kind). ADV: strong theor. found. w/ respect to darwins theory DIS: -CANT apply to fossils & asexual organisms -CANT apply to geograph. isolated pops |
| ECOlogical species:based on what? advantages & disadvantages | -based on environmental context ADV: -each species occupies unique niche - avoids problems associated with: >morpho similar species >asexually reproducing species DIS:-difficult to characterize in sufficient detail |
| MORPHOlogical species: based on what? advantages & disadvantages | -based on differences in morphology(shape, structure, color) ADV: -widely applicable to fossils, sexual, & asexual orgs DIS: -criteria subjective -intra-species morpho variation often greater then inter-species variation (males vs females) |
| PHYLOgenetic species: based on what? advantages & disadvantages | -based on ancestral analysis -SMALLEST group assnd species status ADV: -widely applicable -strong theor. foundation DIS: few thorough phylogenies available (ex: phylogeny of jellyfish not as common bc lack of bones) |
| speciation adds a new ____ to the ____ of life | new BRANCH to TREE of life (darwinian) |
| 2 types of reproductive isolaton (PI)..most common with biological species | 1. PREzygotic isolation: zygote is NEVER formed 2. POSTzygotic isolation: zygote formed is not viable *sexual repro forms zygote |
| 3 causes of PREzygotic isolation(DGM) | 1. disruptions (diff time, area,behavior) 2. gametic barriers 3. mechanical incompatibility (chihuahua & great dane, flowers facing diff ways) |
| 2 causes of POST zygotic isolation...hyrbid ___ity | 1. hybrid VIABILITY- zygote fails to survive 2. hybrid STERILITY- offspring cant reproduce |
| mechanisms of speciation: 2 basic types (AS) & where do they occur | 1. ALLOpatric- occur btwn geo isolated populations 2. SYMpatric- occurs w.o physical isolation |
| 3 points on ALLOpatric speciation:(what happens to them genetically & their gene flow) | 1. pops become geographically isolated 2.gene flow CEASES btwn them 3. diverge genetically by: -natural selection -genetic drift -mutation |
| 2 types of ALLOpatric speciation (derivatives) | 1. dispersal/colonization 2. vicariance |
| type of ALLOpatric speciation: DISPERSAL/COLONIZATION (small) | -small # of indivs DISPERSE to diff habitat - founder effect INCREASES likelyhood of genetic drift -if environment is diff, selective pressure will ALSO be diff -especially prevalent on ISLANDS (ex: darwins finches) |
| type of ALLOpatric speciation: VICARIANCE (large) | - LARGE population splits into 2 or more sub-populations -usually due to emerging geographic barriers -new pops now isolated genetically -NO GENE FLOW (bc alleles cant move from 1 pop to another) -CAN diverge genetically (selection, drift, mutation) |
| SYMPATRIC speciation: definition. ___ _____ overwhelms gene flow | def: speciation WITHOUT geo isolation. NATURAL SELECTION overwhelms gene flow |
| 4 sympatric population mechanisms that REDUCE gene flow (PBST) *B,S,& T same as those for causes of PREzygotic isolation | 1. POLYPLOIDY-more chromosomes, harder to reproduce 2. BEHAVIORAL ISOLATION- diff ppl 3. SPACIAL ISOLATION- diff areas 4. TEMPORAL ISOLATION- diff time |
| type of sympatric speciation: polyploidy | - more than 2 homo chromosomes - usually caused by mutation that creates extra chromosome copy |
| types of sympatric speciation: polyploidy...2 TYPES | 1. AUTOploidy- mutation doubles chrom # -resulting indiv can ONLY self fertilize to make viable offspring 2.ALLOploidy: -2 diff species mate -mutation in offspring doubles chrom # -allows self fertilization |
| types of sympatric speciation: polyploidy...main difference between autoploidy & alloploidy | -AUTO= chromosome doubling WITHIN a species -ALLO= HYBRIDIZATION, followed by doubling chromosomes |
| hybrids: definition. 1. if recently separated 2. if suffic. genetic diverg. occured (_____ isolation) 3. if viable hybrids form | def:formed when isolated pops reconnect 1.recent sep: lack of genetic divergence should allow GENE FLOW 2. genet. div. occured: PREZYGOTIC ISOLATION (zygote NEVER formed) 3. hybrids form: -may have lower OR higher fitness then 1 or both parent spp. - |
| hybrid zones: definition | def: areas of overlap where interbreeding of SEPARATE species occur. -creation of new species, separate from either parent spp. |
| hybrid zones: if hybrid fitness LOWER than either parent species...& example | -predict NARROW hybrid zone -reinforcement (selection favors each pops separate traits) ex: european fire vs. yellow bellied frogs |
| hybrid zones: if hybrid fitness HIGHER than either parent species...& example | - can lead to EXTINCTION of spp with LOWER fitness ex: townsend vs. hermit warbler |
| For a hybrid zone to be stable, the offspring produced by the cross (the hybrids) have to be MORE/LESS fit than members of the parent species? | LESS fit |
| Macroevolution: 2 views of how evolution proceeds through time (GPE) | 1. GRADUALISM:-genetic change continues & accumul. thru time -leads to change in phenotype & new species -predicts transitional forms 2. PUNCTUATED EQUILIBRIUM:-change occurs in short bursts -long periods of little change -predicts spp to appear rapi |
| main difference btwn gradualism & punctuated equilibrium | -GRAD: change constantly accumulates thru time -PUNC. EQUIL: new species show up SUDDENLY |
| Evolutionary-Developmental Bio (evo-devo) ..the point? | - incorporates both feilds of study - paleontology(fossils), anatomy, developmental bio, molec bio, genetics - attempts to explain RAPID DEVELOPMENT of new body plans |
| Homoeotic genes (HOX GENES), what they do? | - REGULATE DEVELOPMENT along an axis - responsible for growth in specific areas - can be specific to regions of body - turned on/off by own regulatory genes |
| HOX genes & body complexity: more hox= (more/less) complexity? - gene ____ produce MORE hox genes! | -more hox = MORE complexity! (bc more hox allows for more axes of development which leads to more complex body plans!) - gene DUPLICATION/MUTATION produce more hox genes (PARALOGS- GENE COPIES) |
| Mutations affecting hox gene expression | - vary when partic hox gene is turned on - can cause changes in STRUCTURE - can cause structures to FORM IN NEW PLACES |
| Variation in SPATIAL expression of developmental genes..what happens? | - changes in WHEN AND WHERE (spatial & temporal) regulatory genes are expressed - can lead to big changes in structure |
| Examples of regulatory gene mutations that cause morphological change:GREMLIN IN (CHICKEN VS. DUCK) FEET | -both chicken & duck feet WEBBED as embryos - BMP4: gene causing tissues to degenerte - GREMLIN gene- produces protein to INHIBIT BMP4 -presence of GREMLIN= WEBBED FEET |
| Examples of regulatory gene mutations that cause morphological change:Ubx in arthropod appendages (insects vs others) | - MUTATION in ubx gene INHIBITS d11 gene which causes legs to grow - DELETION of ubx gene causes wings to grow on 3rd thoraic segment |
| Examples of regulatory gene mutations that cause morphological change:Hox d11 expression in fish vs limb buds | - both mouse limbs & fish fins form from LIMB BUDS in embryos - hox d11 & 5hh regulate DIRECTION of limb bud growth - FISH: only express hoxd11 & 5hh in REAR of limb bud - MOUSE: 1st similar but later in devel. ADDITIONAL EXPRESSION in head-tail axis |
| Paedomorphosis, definition: | def: a phenotypic and/or genotypic change in which the adults of a species retain traits previously seen only in juveniles. - CAN lead to new body plans! |
| Using orthologs to infer evolutionary relationships of structures | - many structures in orgs are similar bc genes that direct their devel. are evolutionarily related (ORTHOLOGS!!) |
| example that orthologs are cause of relationship: eyes in animals (Pax6 in mice vs eyeless in flies) | 1. eyeless gene in flies: -switch to turn on genes that form eyes in flies - normal gene= normal eye -MUTATION causes eyeless flies 2. pax-6 in mice:- switch to turn on gene - normal gene=normal eye - MUTATION forms SMALL eyes in mice |
| phylogenies. definition phylogeny | def: evolutionary history for a group of organisms. typically depicted as a TREE |
| phylogenetic tree contains 8 things: 3 basic components & 5 others | BASIC: 1. branches 2. nodes 3. tips OTHER: 4. polytomy 5. sister taxa 6. root 7. ingroup 8. outgroup |
| phylogenetic tree: 3 basic described (BNT) | 1. BRANCHES- populations thru time 2. NODES- forks where ancestors split into 2 or more descendents 3. TIPS- extinct or extant species |
| phylo tree: 5 other components (SIROP) | 1. SISTER TAXA: node, connected 2. INGROUP: 3. ROOT: bottom=most ancient 4. OUTGROUP: taxon diverged prior to most ancient node of tree 5. POLYTOMY: more than 2 groups emerging from a node |
| 3 types of phylogenetic groups (MPP): ___phyletic | 1. MONOphyletic: ancestor & all descdendents 2. POLYphyletic: group of species with diff common ancestors (ppl that dont belong) 3. PARAphyletic: group with common ancestor but only some of its descendents(incomplete mono group) |
| Adaptive radiations: causes of, effects on phylogenetic trees | appear in phylogenies as polytomies & represent period of RAPID SPECIATION |
| fossil & fossil record definitions | 1. fossil= PHYSICAL TRACE of organism that lived in the past 2. fossil record= TOTAL COLLECTION of fossils that have been discovered |
| 4 fossil formation (COP-C) | 1. compressed carbon rich films (pressure compresses rock, imprint) 2. organically preserved (insects in amber) 3. perminieralized (petrified wood) 4. cast 3D representation- a mold |
| 4 fossil limitations (biases) (THAT) | 1. TAXONOMIC BIAS- orgs with hard parts more likely to leave fossils 2. HABITAT BIAS- more fossils in sedimented area..burrowing orgs 3. ABUNDANCE BIAS- more numerous orgs more likely 4. TEMPORTAL BIAS- older orgs less likely to have fossils(hard2find) |
| molecular clock: definition, uses & limitations | def:tool used to create phylogenies USES: can use neutral mutations to estimate time of divergence for lineages LIMITS: relationships should be linear |
Created by:
jprepeli
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