1/31/17 lecture: evolution III - ways of studying evolution Flashcards Preview

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Flashcards in 1/31/17 lecture: evolution III - ways of studying evolution Deck (28):
1

natural selection

differential reproductive success - fitness differences, given start you can predict results

2

fitness differences are also known as

differential reproductive success

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mutation

new allele- change in gene, weak evolutionary force

4

why is mutation critical

bc it creates heritable variation (new versions of genes) which can mean differential reproductive success

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what does selection depend on

mutations creating heritable variation

6

genetic drfit

small population size sampling phenomenon by chance, one allele randomly chosen; population evoles just by chance- one allel sampled more than another, can be a stronger force, causes differences, smaller population loses alleles, unable to predict results compared to selection results

7

more habitat on graph

more genetic diversity, greater genetic diversity in larger habitats

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larger habitats lead to on the graph

specialization - selection for different aleles

9

mutation on the graph

larger population, more individuals, more chances of mutation to occur

10

genetic drift on graph

larger population size, more gametes chosen - less evolutionary change

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genetic drift can occur at what levelse

individual, population levels

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bottleneck effect

large population, random things, not heritable features - loss of genetic variation ie. cheetahs, prarie dogs

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gene flow

migration - introduce gene pool into new population - increase genetic diversity in population reciving

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gene flow works against

genetic drift

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gene flow ___ variation

increases

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genetic drift ____ variation

decreases

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ways of studying evolution

fossil record, comparative anatomy

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fossil record

longest timescale, record of evolutionary history on planet, oldest fossils simplest organisms, more complex types appear later, older fossils = greater difference between it and living species, fossiles more similar in consectuive geological formations, more similar than those from remote areas

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cambrian explosion

increase in diversity, but extinction events, increase in number of species

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cretaceous

dinos extinct

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archaeopteryx

transtition between birds and reptiles

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comparative anatomy

homogolous structure, analgous structure, vestigial strucutres, imperfect structures

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homologous structure

inherit by two sepcies from common ancestor - vertebrae forelimb, bats, humans, whales

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analagous strucutre

evolve independely [convergent evolution] - not found in common ancestor ie. wings - bats, mammals, insects, birds

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vestigial structures

identifiable structures that have no apparent contemporary use = had function but no longer in use ie. snakes and their legs

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"imperfect" structures

panda's thumb - not usefful, maybe evolution still working on pandas

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sexual dymorphism

body, size, color

28

team activity chimps, gorrilas penis and testicle size

chimp - large testes, large penis, gorrilas - small testes, small penis

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