Gene Selection

Different types selection have different effects of Important for population to have • • ↳ adapt to ↳ environmental • • • change . genetic variation no . Heterozygote advantage homozygose traits allele maintained Not evolving - but not allele ↳ no Selection on what if selector favored . never Both variation go in in extinct population heterozygose ? . . HWE frequency changing . quantitative traits stabbing directorial, disruptive : . , stabling • . most ex) selection common individuals body size shaded = . environment Inbreeding ↳ genetic variation genetic on , dominant form of selection vilhsmorrye survive body . dies and only intermediate . genotype • Directional selection phenotype populuton willsnrviue.li population becomes less variable in - , individuals with ext males with extreme tail length Directorial selectors would - Disruptive selection • • - less one extreme have better chance to mate . eventually become stubliziny common opposite of Hubli zing selection Select on pushes populates in two separate peaks . - * Situation There : is a drought in galapuyok island . selection . Directional selection • why ↳ recessive ex) are Frequency Black hare in only force for search It there more i. eat Frequency dependent image selection predator have bad eH In population of frogs living things changes adaptation least at is Limited Limited - Plays ' by by catch available , after Selection • - is not the other forces recall → non - - - - - No mutation No gene How Random mutiny No selection . not be in period on of time others . summer . fitness relative . . being for bearers rare . . form search image for grey sarnies . forms (rare phenotype has . advantage ) . . selection one ) one individual → avoid eating throes individual yellow ( minority ) frogs and is more cannot common , more . chance preditor with hang prior . environment ? pridit the future and direct the evolution toward that . generation behind . perfection variation . . . between changes . competing dominance? only forces that drives evolution but only force that adapted evolution hurdy weinberg assumption very large population size - specific . - would direction . environment Trade offs ( compromise • same increases forms ( balancing selection) not genetic in in - Squires hawks because that trail dominance relationship up preys red ( majority natural . advantage advantage perfectly adapt to their Selection → adaptation - Environment experience with simply - . environment ↳ ↳ common rare ↳ urn't traits for ' . frequency dependence red selection that ↳ → . . spunks hunt warning colouration Why vs for fitness . white hare adaptation grey to advantage Positive e) winter grey more preferentially ' directional population with one predator form • , experiences in are alleles on on dependent selection frequency dependence - Negative ex ) left ' population phenotype ex ) Selection be could so Not all ↳ - all genetic variation for traits related havent directorial selection removed . drives adaptive evolution . bad experience of eating Genetic drift : whenever population - - strongest drift ex changes ounpredictible random , ) Tossing in . population suddenly becommiy and , error small ( bottleneck, founder events) . coin ↳ 2 times ↳ 100 times likely less . bottle through gone been ex) A heads all could give cheek 's had ⇒ population small . sampling due to frequencies alleles in than infinite less size . neck event low genetic diversity → . founded with small number of founding individual populaton had is always happening because all populations are less than infinite ↳ but happens much faster in populations that are small Drift often opposes selection cheetahs in . . * Genetic drift . . . . - Mutation creates Mutation - - most - - depends Outcome mutations Mutation often opposes can , moves introduce nearly or that affect fitness Like mutation - neutral Of those Gene flow (migration) size . directed toward the need of the not , are population , . random but not is allele new of selection and strength on , - neutral effects most , (but all) not selection but also provides , alleles between population new alleles on harmful are . . . materials for adaptive evolution raw → fitness organism prevent . perfectly adapted . . Like mutation often opposes selection ext mice with dark fur have advantage when mice from mountain migrate it ' selection migration balance . - , in opposes , while mountain . selection with mice light fur have advantage . - . How do these evolutionary force Selection - ] Genetic drift • Mutation • Gene How - HWE also But mating • is - inbreeding - assortative - population might assumes or inbreeding or not be in opposes one another ? HIWE with respect to mutiny random often non-random or reinforce yenanotype . . avoidance disassortative . . mutiny . while geese preferentially mute with white blue male with blue geese ex) white stripes mute with dull stripe → disassortative assorting ex) . . → assortative . in desert . mutiny and evolution population begins mating Non-random ' It a happen what will - 2alleles , 3. certain a trail , but all genotype have the same fitness , ? , aa , dominance ) . assortituvely mates - assortative, for genotype ( AA Aa intermediate - . . 500A 250A A 250 aa a . 1 ¥4 €*zsoAa I v v 250 AA 250 3175A A ace 375 au . changes • type frequency does not change allele frequency mutiny preturbs HWE but does not cause evolution gene Non random - . . Evolution is only a theory conjecture an assumption based on limited knowledge a coherent set of testable hypothesis that attempt to explain facts about a atomic theory of matter • . . . . . • - theory Germ - theory Devolution changes happens ③ Speciation is ↳ happens species Speiaton . bottleneck ↳ Does not . allele frequency in ② most evolution ↳ all theory . evolution ? of ext Cheetos disease of infectious Gravitational is ' population a from phenotype from one evolved event all life have - single lineage split / brunches by common . into species . . ancestor of LUCA evolutionary changes ⑥ Evolution occurs in populations ↳ Population change to selection ↳ . from LUCA Much of ( Does generation other . ↳ Darwin between . It speiaton not occurred only one type of ④ All life is related through common ancestry ↳ trace back and find common ancestor ↳ all He is related common ancestor ⑤ , . gradual leap in ↳ ↳ . . - What the natural world not but act on caused by selection not within individuals is , . individual) individuals do . not adjust . Darwin 's model Disent . of modification) . in response . two or in Earth more . branches which are reproductively isolated . Descent (from ' ' Homologies Intermediate Homologies - in ancestor) with modification common . fossils (transit.nu/ forms ) show common structural, developmental, ancestry Similarity between molecular . two explainable by shared function that reflects shared ansesctry p fferent function but have same structure structural Different select but same structure Inherited from common ancestor species not , , . . ] , - - on • . homologies Developmental homologies . • Molecular Early dolphin development hind limb develop Dolphin desended from four legged organism in • . homologs ' human bacteria horses have the . Not the best ↳ Inherited supports everything had evolved from same , , homologies , genetic from common Connon code . ancestor ancestor . . genetic mechanic . . . Descents : . transitional form ' link related ' groups . - Intermediate form before Modification : fossil evidence of change . modern day Vestigial vestigial traits ( and ) gene only make sense in the context of evolution cave - ↳ - sake mender lives without light Des ended from ancestor who vestigial traits longer tunctonal ↳ no ↳ may ↳ hot Sex ' as - Sex =/ → genetic diversity crossover, offspring - - ( new combination independent assortment distinct from parent of allele ) . and each other (exception . Binary fission genetically sex psudo - . identical to mom . . reproducing sexually (flower) or asexually * tacultively sexual / asexual option to be expressed on identical twin ) Reproduction Reproduction without . desended recombination Recombination - have , - sex without sex reproduction . independent exchange of gene . on . reproduce recently * asexually evolved from sexual ancestor obligate asexual . . light lived with often smaller . from ancestor . . sexually reproducing - organisms be may . dioecious . or monoecious . human dioecious female / male ↳ ( Tandon on different individual ) • dioecious Some trees . ↳ . mule creates pollen but can't make both • . - ever . have male / female futon ( one individual Could hold female/mule individual Monoecious Male and ↳ flower female tree creates fertilized female and . in being same individual fertilized . function) monoecylsex change ) Sequential female to mule all born female < - model of advantage size → change to male ( large fish) change sex so e- mhe female ¥ ÷:* Size Different selection * all individual Distribution of First . male/ female on with start off . female but if larger becomes male , sex life forms almost certainly reproduced ↳ most . organism , except plants and animals , Disadvantage of sexual cost of mutiny asexually . reproduces mostly asexually . reproduct on - ( only half of Cost of meiosis Cost of male - - genome passed from individual ) . Mutational explanation for • Sexual recombination - - • combining . benefits the species discard harmful mutation benefitiul sex by speeding up evolution . , mutation . This decreases the likelihood of extinction . Muller's ratchet asexual lineages accumulate harmful evolution : • - reform Sex genotype continually so creates descendents could have fewer mutation than parents genotype with fewer (and . harmful mutation than more) parental genotypes . helpful Sex and Could - - mutation - benefitiul mutation but to have all discarding harmful combing benefited in occur , Mutational explanation for sex sexual recombination benefits the - • speedup benefitiul Unlikely • mutation mutation mutation same in species individual . large population there are , by speeding up chance . evolution . . . Decreases likelihood of extinction * Selection does not favor, traits that . individual fitness Ecological - - in • benefits individuals environment, sex hypothesis ticket . is hypothesis . sex in is - constant stable unstable sex is - - versus unpredictable asexual environments . reproduction reproduction sexual favored when . environment is constantly evolving . costly an inefficient but phenomenally successful Long term advantage is removing harmful mutations and combining Short term advantage bet hedging in changing environment - • ' . Red Queen Sex persistence of . when environment when environment - long-term explanation changing Lottery benefit , helpful mutation . - - . - Which - is more reduced important extinction in risk maintaining sex ? may be just a consequences of set not a explanation . the group ' at the expense of immediate Sexual selection - • explains dimorphism sexual . explains traits that reduces survival ↳ louder the frog calls the more . Intrasexual selection /Intersexual selection Intra sexual females and preditor attracted to . . competition against same sex (males) to have access to the other ↳ horns body size Intersexual : female 's choice male compete indirectly to impress female : sex . . . , . . . ↳ bird The distinction songs can . be blurry male birds gather blue ↳ Intersexual feather to impress females . . other male birds savatage other's ↳ Intra sexual hangout place to active female . Both intersexual intrasexual and Direct benefits • Mormon cricket with female ↳ - mate spermatophore with cricket with . largest spermatophore . House finch ↳ red tethered male are better fathers . Indirect benefits It male doesn't have ↳ try to have genes to offer there have better offspring something to , . maybe genetic quality difference . could operate at same time . Females an than often choosier male isogamy lineal gamete size = - - Why ? . . large energetically egg : expensive , Sperm small, less : ↳ sperm energetically is cheap . expensive . Sex differences and potential fitness set . is ↳ female Selective forces invest females males and on choosy . fitness of male . ↳ - how fitness many of female female could he reproduce with . . have limited eggs ↳ Quality of the offspring ↳ reproduce ↳ males could Sex - reversal . have both female/male parents extreme low always extreme high role lifetime . offspring ↳ No over more male in always have sym average fitness Females and males ↳ ¥ always Potential fitness . or . . . male select female ↳ female compete for . ↳ male takes care What if both In human sexes of to male access . offspring . heavily invest in parental care , long term ↳ short-term ↳ : who to with marry . . Some traits important for How it looks some trails value both sexes ↳ more highly by one provide direct material benefits ↳ female, look for male's resources Some traits value more highly by one ↳ mules sex than another . . . ↳ ↳ fertility status of the mate . than the other . . certain features (shape of face) ↳ fertility set is associated with circulating estrogen in sex hormone , in and more parental investments determine which which in sex is offspring competes → . timely resource . Sexual selection type - of selecton to mates ) struggle between individuals ( bat to get Usually male compete female choose ↳ know by how much each Sey invest in offspring ↳ - access , . . . ↳ High investing sex = limiting resource . • Altruism ↳ decrease your fitness for own • may ↳ But increase also * parental Unrelated individuals body else penguin ↳ ' som risking • care life . the survivability increase is not parent 's fitness always can traits offspring . . altruism . Older individuals in - * How of their community protecting younger offspring independent but stay in parent 's for parent, to make more offspring territory go reducing fitness ( offspring reproduction / be selectively favored ? . . More to fitness than simply producing direct Descendents Personal reproduction / direct fitness → Additional reproduction by relatives . altruism inclusive fitness ↳ Direct 1- indirect fitness * kin selection = favours traits that → indirect fitness . . indirect fitness increases . rb> C - - ' • Hamilton 's Rule determine whether altruistic trait tavord Benefits by reared donors relatives , b weighted by degree of relationships Does it outweigh costs of donors Cooperation reciprocity , . . r . direct fitness CD . .