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BIO1130 > microevolution > Flashcards

microevolution Flashcards

1
Q

what is microevolution

A

change in allele frequency in population/species across generations
–> evolutionary change over shorter time periods

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2
Q

what is macroevolution

A

evolution above species level –> variation among species and questions related to diversification
–> over long periods of time

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3
Q

(T/F) macroevolution is the results of microevolution

A

T

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4
Q

what are the 4 processes that can cause microevolution

A
  • mutation
  • gene flow
  • genetic drift
  • natural selection
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5
Q

what does microevolution NEED

A

genetic variation

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6
Q

what is panmixia

A

random mating in a population

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7
Q

what is random mating

A

individuals mate randomly with respect to their genotype at locus of interest

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8
Q

what is non-random mating

A

mating system in which at least some individuals are more or less likely to mate with individuals of a particular genotype than with individuals of other genotypes
–> more common

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9
Q

why is mating often non-random

A
  • relatives may mate more often or less often than expected by chance
  • individuals may self-fertilize more or less often than expected by chance
  • individuals may mate more often with others more or less similar to them in phenotype than expected by chance
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10
Q

what is inbreeding

A

when mating takes place between related individuals
–> resulting offspring are inbred

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11
Q

what are the effects of inbreeding

A

can cause increase in frequency of homozygotes
–> 1+ generations of random mating may restore HW ratios

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12
Q

what is inbreeding depression

A

decrease in fitness as a consequence of inbreeding
–> can increase loss of gene variation that occur in small populations due to genetic drift

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13
Q

what are the 2 mendelian causes of inbreeding depression

A
  • dominance hypothesis: alleles that decrease fitness (deleterious alleles) tend to be partially-completely recessive –> homozygosity will increase expression of these alleles
  • heterozygote advantage: heterozygotes have higher fitness than either homozygotes –> increased homozygosity = lower fitness
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14
Q

what is outbreeding

A

mating between individuals that are less related

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15
Q

what are the effects of outbreeding

A

increases heterozygosity

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16
Q

what is heterosis

A

increase in fitness relative to non-outbred individuals

16
Q

how does heterosis occur

A
  • deleterious alleles more likely to be masked
  • heterozygotes have higher fitness
16
Q

what is a mutation

A

a change in genetic information of an organisms DNA

17
Q

what are the effects of mutation

A

can create new alleles –> ultimate source of genetic variation
–> RANDOM

18
Q

when are mutations heritable

A

if they are present in the germ line

19
Q

what are the types of mutation

A

small scale (point mutation):
- substitution: single nucleotide is replace with another –> silent or replacement
- insertion/deletion: 1+ nucleotide is added or removed

large scale: mutations in chromosomal structure
- translocation
- inversion
- duplication

20
Q

(T/F) most new mutations are beneficial

A

F

21
Q

what is gene flow (AKA migration)

A

movement of alleles between populations occuring via migration
–> introduces/removes alleles from populations

22
Q

what are the effects of gene flow

A

homogenizes populations –> reduced genetic variation

23
Q

what is local adaptation

A

population adapts to its local environment

24
Q

can gene flow impede local adaption

A

yes, by constantly introducing maladaptive alleles from other populations –> outbreeding depression

25
Q

what is genetic drift

A

random changes in allele frequencies across generations
–> occurs due to sampling variation: difference between value in finite sample compared to true population size

26
Q

effects of genetic drift

A

causes unpredictable changes in allele frequencies

typically reduces genetic variation –> alleles are lost

will cause populations to diverge from one other (without gene flow)

27
Q

what are population bottlenecks

A

severe decrease in population size which reduces genetic variation and enhances genetic drift

28
Q

what is a founder effect

A

small group of individuals colonize a new geographic area, isolated from other populations

29
Q

what does natural selection act on

A

phenotypes

30
Q

what is frequency-dependent selection

A

when fitness of a phenotype depends on its frequency in the population

31
Q

what is positive frequency-dependence

A

directional selection for a phenotype strengthens as phenotype becomes more common

32
Q

what is negative frequency-dependence

A

directional selection for phenotype is stronger when the phenotype is less common
–> form of balancing selection

33
Q

what is heterozygot advantage

A

when heterozygote at locus has a higher fitness than either homozygotes

BIO1130 (14 decks)

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