Chapter 9: Genetic Variation and Inbreeding Flashcards

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1
Q

founder effect

A

the original population could give rise to different founder populations

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2
Q

genetic variation

A

the difference in the genetic makeup (DNA) of individuals or populations among the same species

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3
Q

genetic variation is important for….

A

survival & adaptation

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4
Q

what does genetic variation help with?

A

helps in terms of natural selection and evolution

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5
Q

genetic variation

A

measure of the genetic differences within individuals or population

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6
Q

genetic diversity

A

the genetic variation of an entire species

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7
Q

Tasmanian devils

A
  • loss of genetic variation near ext.
  • devil facial tumor disease
  • contagious cancer
  • cancer cells do not recognize as foreign and proliferate
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8
Q

effective population size variable

A

Ne

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9
Q

effective population size

A

the number of individuals that effectively participates in producing the next generation

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10
Q

which is smaller - effective population size or census size?

A

effective population size

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11
Q

small Ne

A

bigger increase in genetic drift

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12
Q

Ne and sex ratio

A

Ne is highest at equal breeding sex ratio

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13
Q

types of genetic variation

A
  • intrapopulation
  • interpopulation
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14
Q

intrapopulation

A
  • within population
  • amount of variation within the members of a species in the same area
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15
Q

interpopulations

A
  • between populations
  • comparing two or more populations of a species
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16
Q

what determines levels of genetic variation in populations?

A
  • mutation
  • genetic drift
  • gene flow
  • sexual selection
  • natural selection
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17
Q

levels of genetic variation that cause rapid and powerful phenotypic changes on management-relevant time scales

A
  • genetic drift
  • gene flow
  • natural selections
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18
Q

mutation definition

A

random change in the DNA of a gene

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19
Q

mutation functions

A
  • can form new allele
  • can be passed on to offspring if in reproductive cells
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20
Q

genetic drift

A
  • change in allele frequencies by chance
  • genetic drift causes a loss of genetic diversity
  • it is most common in small populations
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21
Q

what can lead to genetic drift

A

a population bottleneck

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22
Q

when does a bottle neck occur?

A

when an event drastically reduces population size

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23
Q

is Ne greater or smaller than N

A

Ne < N

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24
Q

how to measure genetic drift?

A
  • depends on the effective population size
  • essentially the number of individuals in a population who contribute offspring to the next generation
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25
Q

gene flow definition

A

the movement of alleles between population

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26
Q

when does gene flow occur

A

when individuals join new populations and reproduce

27
Q

gene flow keeps neighboring populations ____

A

similar

28
Q

low gene flow

A

increases the chance that two populations will evolve into different species

29
Q

sexual selection occurs when:

A
  • certain traits increase mating success
  • there is higher cost of reproduction for females
  • males produce many sperm continuously
  • females are more limited in clutch size
29
Q

sexual selection

A

non-random mating

30
Q

intrasexual selection

A

competition among males

31
Q

intersexual selection

A

males display certain traits to females

32
Q

what does natural selection act on?

A

distributions of traits

33
Q

natural selection acts on distribution of traits

A
  • highest frequency near mean value
  • frequencies decrease toward each extreme value
34
Q

natural selection can take one of three paths

A
  • directional selection
  • stabilizing selection
  • disruptive selection
35
Q

interbreeding

A

loss of heterozygosity and increased expression of recessive homozygotes

36
Q

F IS

A

inbreeding due to preferential mating with relatives

37
Q

F ST

A

inbreeding due to genetic drift in a small population mating randomly

38
Q

inbreeding coefficient

A

a measure of loss of heterozygosity = increase of homozygosity

39
Q

what is one form of inbreeding?

A

genetic drift

40
Q

symbol for inbreeding due to genetic drift

A

F ST

41
Q

F ST range

A

0 - 1

42
Q

F ST range: 0

A
  • no loss of heterozygosity
  • all populations have the same allele frequencies
43
Q

F ST range: 1

A
  • complete loss of heterozygosity
  • fixation of one or another allele in each population
44
Q

F ST increases _________ when Ne is small

A

rapidly

45
Q

F ST = 1 - [1 - (1/2 Ne)] ^t

A

expression showing increase in F ST among completely isolated populations of different size

46
Q

inbreeding depression

A

the loss of heterozygosity and expression of deleterious recessive alleles due to inbreeding disturbs vital rates

47
Q

examples of inbreeding depression

A

births & deaths

48
Q

inbreeding due to genetic drift is ________ by ____________

A

reduced by gene flow

49
Q

what gets washed out if there is too much gene flow?

A

local selection

50
Q

calculating allele frequencies

A

allele frequencies measure genetic variation

51
Q

allele frequencies measure genetic variation

A
  • measure how common an allele is in a population
  • can be calculated for each allele in a gene pool
52
Q

population

A

a freely interbreeding group of individuals

53
Q

gene pool

A

the sum total of genetic information present in a population at any given point in time

54
Q

phenotype

A

a morphological, physiological, biochemical, or behavioral characteristic of an individual organism

55
Q

genotype

A

the genetic constitution of an individual organism

56
Q

locus

A

a site on a chromosome, or the gene that occupies the site

57
Q

gene

A

a nucleic acid sequence that encodes a product with a distinct function in the organism

58
Q

allele

A

a particular form of a gene

59
Q

gene (allele) frequencies

A

the relative proportion of a particular allele at a single locus in a population

60
Q

genotype frequency

A

the relative proportion of a particular genotype in a population

61
Q

natural selection paths - directional selection

A

favors phenotypes at one extreme

62
Q

natural selection paths - stabilizing selection

A

favors the intermediate phenotype

63
Q

natural selection paths - disruptive selection

A

favors both extreme phenotypes