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chapter 20 Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

mutations in skin cells that are non-heritable are [blank] mutations, whereas mutations that can be passed on from parent to offspring are referred to as [blank] mutations.

A

somatic, germline

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2
Q
  • shifts the population mean
  • one extreme trait is favored
    what type of selection is this?
A

directional

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3
Q

when calculating the allele frequency of allele A in a population, why do we multiply the frequency of individuals who are homozygous for A by 2?

A

because each individual who is homozygous for A has two copies of the allele.

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4
Q

in a population of mendel’s garden peas, the frequency of green-flowered plants (genotype aa) is 49%. The population is in Hardy Weinberg equilibrium. What are the frequencies of the AA and Aa genotypes?

A

9% AA, 42% Aa

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5
Q

which type of selection decreases overall phenotypic variation in a specific trait?

A

stabilizing selection

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6
Q

what does the term 2pq represent in the Hardy-Weinberg equilibrium?

A

the frequency of heterozygotes

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7
Q

what does variation promote?

A

survivorship and/or reproduction

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8
Q

what is one major mechanism of evolution?

A

natural selection

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9
Q

define gene pool

A

consists of all the alleles that are present in all individuals in a species or population

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10
Q

what causes variation?

A

it can be caused by genetic differences p, or due to environmental effects

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11
Q

what’s the ultimate source of genetic variation?

A

mutation

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12
Q

what type of mutation cannot be passed on to the next generation?

A

somatic cells

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13
Q

what are germ cells?

A

sperm and egg

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14
Q

which cell mutation is the only type that can impact evolution?

A

germ cells

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15
Q

what is a deleterious mutation?

A

a negative impact on survival or reproduction

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16
Q

what is an advantageous mutation?

A

they have a positive benefit on survival and reproduction or they might be neutral

17
Q

what is the other way of producing genetic variation?

A

recombination

18
Q

how do we get the allele frequency?

A

the number of copies of an allele divided by the total number of alleles

19
Q

what is the fixation of an allele?

A

all individuals in a population possess the same allele; it’s frequency is 1.0

20
Q

how do we calculate allele frequencies?

A

number of copies of an allele / total number of alleles in a population?

21
Q

the hardy-weinburg equilibrium is also known as a…?

A

null model (meaning a model of no change)

22
Q

what is the frequency of homozygous individuals?

A

p^2 and q^2

23
Q

what is the frequency of heterozygous individuals?

A

2pq

24
Q

what five key conditions need to be met in order for a population to be in Hardy-Weinburg equilibrium?

A
  1. there can be no natural selection happening
  2. no migration
  3. no mutation
  4. no genetic drift
  5. individuals must mate at random
25
Q

no genetic variation means…

A

no natural selection

26
Q

an individual that is best adapted to survive due to advantageous alleles can do what?

A
  • leave more offspring
  • can be passed on to the next generation
27
Q

when it asks you a question about an organism being the most fit, remember to choose the answer focused on reproduction.

A

!

28
Q

what are the three types of selection?

A

(1) positive (2) negative (3) balancing

29
Q

directional selection occurs when environmental pressures favor one phenotype more than another.

A

!

30
Q

which selection maintains the status quo and acts against extremes?

A

stabilizing (think of the black and white animal that can’t survive in said environment, in a stabilizing environment the grey animal is likely to survive. another example is if a baby is too heavy or too light there may be complications, therefore the optimal birth weight would be in between these two extremes)

31
Q

which selections selects against the mean?

A

disruptive (it’s basically a preference to the extremes over the intermediate traits)

32
Q

what is artificial selection?

A

it’s man made / manipulated

33
Q

sexual selection influences what and does not improve what?

A

it influences your ability to get a mate and does not improve survival or reproductive success

34
Q

whats the difference between intersexual and intrasexual?

A

intersexual is one sex has a preference for the opposite sex trait while intrasexual the same sex creates a competition to have access and win over the other sex

35
Q

the correlation between the time two species have been evolutionary separated and the amount of genetic divergence between them is known as…

A

the molecular clock

36
Q

distinct populations of an ancestral species separate and diverge through time, again and again, giving rise to multiple descendant species, this is the definition of…

A

phylogeny

37
Q

competition among members of one sex for access to the other sex results in (blank) selection
A. disruptive
B. sexual
C. directional
D. stabilizing

A

the answer is B. sexual

38
Q

in genetics, two individuals are part of the same population if :
select al that apply
A. they are the same species
B. they are in the same geographic area
C. they have the same phenotype
D. they are from different gene pools

A

the answer is A and B

39
Q

if a populations is not in hardy-weinberg equilibrium, we can conclude that:
A. nonrandom mating has occurred
B. natural selection has occurred
C. one of the assumptions of the hardy-weinberg equilibrium has been violated.
D. evolution has occured because one or more of the assumptions of the hardy-weinberg equilibrium has been violated.
E. all of these choices are correct

A

the answer is D

biology (10 decks)

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