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Evolution > midterm 1 > Flashcards

midterm 1 Flashcards

1
Q

what are the 4 horsemen

A

selection, migration, mutation, drift

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2
Q

what are Darwins 4 postulates

A
  • there is variation
  • variation is heritable
  • more offspring are there than can survive/reproduce
  • survival and reproduction isn’t random and is effected by what traits an individual has
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3
Q

what are the classes of selection

A

fecundity: differences in reproduction success
viability: differences in survival success

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4
Q

what is the term for when the fitness of a phenotype becomes less common as genotype becomes more common

A

negative frequency dependent selection

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5
Q

what are the 2 types of mating

A

assortative: more likely to mate with similar looking individual
dissassortative: more likely to mate with someone less similar

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6
Q

does natural selection act directly on traits

A

no

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7
Q

what is genetic drift

A

change in allele frequency due to chance

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8
Q

what are the causes of drift

A

continuous drift
population bottleneck
founder effect

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9
Q

what is a population bottleneck

A

sudden decrease in population size

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10
Q

are the effects of drift bigger in bigger/smaller populations

A

smaller

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11
Q

what is fixation

A

change in gene pool to multiple alleles to just one

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12
Q

where is fixation fastest

A

smaller populations

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13
Q

what is heterozygosity

A

possession of 2 different alleles

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14
Q

where is heterozygosity maximized

A

when allele frequencies are similar

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15
Q

what is Ne

A

effective population size

the population of individuals that contribute alleles to next generation

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16
Q

what is ne effected by

A

number of adults, sex ratio, fluctuations over time

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17
Q

what do things that suppress Ne make the population be

A

genetically smaller than it looks

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18
Q

what are the types of variation

A 
genetic variations (vg)
environmental variation (ve)
genotype by environment variation (vge)
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19
Q

how many mutations come from male germ line mutations

A

2/3

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20
Q

what are the types of mutation

A

point mutation, insertion, deletion, inversion, chromosome fusion, aneuploidy, polyploidy

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21
Q

what is a nonsense mutation

A

mutation that introduces a premature stop codon

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22
Q

what is a non-synonymous substitution

A

mutation that changes amino acid coded for

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23
Q

what is a synonymous substitution

A

mutation that keeps amino acid coded for the same

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24
Q

how many is the average germ-line mutation rate

A

1.0x10^-8

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25
Q

what is a indictable defence

A

response activated only when needed

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26
Q

what is an intron/ exon

A

intron is area before coding region (exon)

27
Q

what is cnv

A

where sections are repeated and number of repeats varies between individuals

28
Q

are more mutations a result of cnv or point mutations

A

cnv

29
Q

what is dn/ds > 1

A

advantageous

30
Q

what is dn/ds < 1

A

deleterious

31
Q

what is dn/ds=1

A

neutral

32
Q

how to neutral mutations fluctuate

A

via drift

33
Q

what is a substitution

A

replacement of one allele for another as predominant allele

34
Q

what does neutral theory state

A

neutral mutations that rise due to fixation by drift outnumber benefical mutations that get selected for and substitute so drift if predominant evolutionary mechanism

so rate of evolution = neutral rate

35
Q

what is issue with neutral theory

A

neutral mutation rate should vary among species and go off generation time not clock time

36
Q

what is nearly neutral theory

A

species with large populations tend to have small populations and vice versa

  • so as generation time goes up, population and therefore 2NeS goes down
  • this makes it so they balance out as in large populations mutations are selected against
  • and in small populations more mutations are subjected to drift
37
Q

what is neutral theory a null hypothesis for

A

if natural selection caused the evolution

38
Q

what is neutral mutation rate = neutral substitution rate captured by

A

synonymous mutation rate

39
Q

what is codon bias biased towards

A

for codons associated with abundant species of tRNA making it more efficient

40
Q

what is a monophyletic group

A

a clade

node and all its descendants

41
Q

what is a polytomy

A

node on phylogeny with more than 2 descendant lineages

42
Q

what is a paraphyletic group

A

contains node but not all descendants

43
Q

what is a polyphyletic group

A

when 2 lineages convergently evolve similar traits

44
Q

what is an apomorphy

A

trait unique to a species/group

45
Q

what is a pleisiomorphy

A

ancestral trait

46
Q

what is analogy

A

similarities due to convergent evolution

47
Q

what is homology

A

similarities due to common ancestor

48
Q

what is Homoplasy

A

similarities due to convergent evolution

49
Q

what are synapomorphies

A

similarities from common ancestor, but only in a subset of the species

50
Q

what are symplesiomorphies

A

plesiomorphies shared by two or more taxa

51
Q

is an out group or any species on the tree ancestral?

A

nope

52
Q

what are the different ways alleles affect phenotypes

A

dominance, epistsasis, pleiotropy, and plasticity

53
Q

what is epistasis

A

effect of mutation dependent on on the presence/absence of another mutation

54
Q

what is pleiotropy

A

when one gene influences multiple seemingly unrelated traits

55
Q

what is codominance

A

when both alleles in genotypes are in phenotype

56
Q

what is incomplete dominance

A

both parents genotypes blend into a new phenotype

57
Q

what is mosaic evolution

A

evolution of different parts of organism at different rates

58
Q

what is mutation selection balance

A

new copies of allele keeps mutating allowing it to persist at low frequencies

59
Q

what is the speed of fixation/increase in frequency for new dominant alleles

A

increase in frequency fast

fixate slowly

60
Q

what is the speed of fixation/increase in frequency for new recessive alleles

A

increase in frequency slow

once common fixate fast

61
Q

what are the hardy Weinberg equilibrium assumptions about a population

A 
allele frequencies in a population are constant when there's:
no mutation
no migration
random mating
large population 
no selection
62
Q

what is migration

A

movement of alleles between populations

63
Q

what is the effect of migration

A

immediate change in allele frequency of recipient population

64
Q

what happens with migration in absence of selection

A

migration homogenizes allele frequencies across populations

Evolution (8 decks)

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