exam 3 ppt 9 Flashcards

1
Q

which of the HWE assumptions does not happen in sexual selection?

A

individuals mating at random

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2
Q

how many processes is evolution driven by?

A

evolution is driven by four processes that change allele frequencies

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3
Q

what are the four processes that change allele frequencies that drive evolution?

A

1) natural selection, 2) genetic drift, 3) gene flow, 4) mutation

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4
Q

what is the only adaptive mechanism of evolution?

A

natural selection

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5
Q

only ______ results in adaptations

A

natural selection

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6
Q

definition of adaptation

A

a feature that has become common in a population by natural selection, because it provides some improved function, leading to increased fitness

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7
Q

exps of adaptations

A

a behavior or anatomical feature that allows escaping predators, a protein or other compound with special physical/chemical properties, an anatomical feature that allows an organism to access resources (bats using echolocation, etc)

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8
Q

non-adaptive evolutionary mechanisms (listed)

A

genetic drift, gene flow, mutation

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9
Q

what do genetic drift, gene flow, and mutations cause?

A

they cause allele frequencies to change, but do not lead to adaptation

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10
Q

definition of genetic drift

A

a change in the frequency of an allele due to the random effects of small population size

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11
Q

what is genetic drift with respect to fitness?

A

it is random with respect to fitness

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12
Q

is genetic drift more pronounced in big or small populations?

A

small

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13
Q

what can genetic drift lead to?

A

it can lead to random loss or fixation of alleles

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14
Q

two things that cause genetic drift

A

founder effect, bottleneck

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15
Q

definition of founder effect

A

when a few individuals leave a population to establish a new population; reproductively isolated (ex: amish populations in US)

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16
Q

what alleles will the new population likely have regarding founder effect?

A

new population is likely to have different allele frequencies than the source population, by chance

17
Q

definition of bottleneck

A

an extreme example where the population falls to a few surviving individuals; survivors have random traits, no specific reason they survived (ex: cheetahs)

18
Q

what will the alleles be like in a bottleneck population from genetic drift?

A

bottlenecked population is likely to have different allele frequencies than original population, by chance

19
Q

exp of founder effect in amish populations

A

amish people had higher frequency of the trait for polydactyly -> resulted in extra fingers/toes being more prevalent in kids now because of reproduction with themselves

20
Q

why is population size important when it comes to genetic drift?

A

a smaller population= more likely to lose genetic variation more quickly/easier

21
Q

definition of migration

A

the movement of individuals from one population to another; results in gene flow

22
Q

if individuals that are migrating are producing, what does this lead to?

A

gene flow (alleles can come and go from populations)

23
Q

exps of migration and gene flow

A

butterflies

24
Q

consequence of migration/gene flow

A

populations become more similar -> gene flow “homogenizes” allele frequencies between populations

25
gene flow is ______ alleles
exchanging
26
genetic drift and gene flow measure…
change in allele frequencies
27
where do new alleles come from?
mutation
28
types of mutations
neutral (silent), beneficial or harmful (missense, nonsense, frameshift, etc)
29
types of beneficial or harmful mutations
missense, nonsense, frameshift
30
what is the ultimate source of genetic variation?
mutation
31
no mutation ->
no evolution of any kind
32
mutation alone is usually ____
inconsequential
33
mutation alone is usually inconsequential, but how can it become an important evolutionary process?
combined with natural selection, genetic drift, and gene flow, it becomes an important evolutionary process