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AP BIO > the micro evolution of population > Flashcards

the micro evolution of population Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

what did biologists of darwin’s accept and reject?

A

accepted the idea of evolution, but not the mechanism of natural selection

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2
Q

since mendel and darwin were contemporaries, what could’ve happened?

A

they lived at the same time but mendel’s work were unappreciated at the time, so if darwin had an understanding of inheritance that could explain how variations arise in a population and get passed onto offspring, then his ideas would have gained more acceptance

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3
Q

what was a turning point for evolutionary theory?

A

population genetics - emphasizes genetic variation within a population and the importance of quantitative traits like polygenic inheritance traits

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4
Q

modern synthesis

A

integrates Darwin, Mendel, and different field ideas
1) population evolve, not individuals
2) natural selection is the most important mechanism for evolution
3) gradualism explains how lots of small changes over long periods of time bring about big changes

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5
Q

what is a population?

A

localized group of individuals of the same species

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6
Q

species

A

population that can interbreed and produce fertile offspring

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7
Q

how often is genetic material exchanged in 2 isolated populations? does this happen?

A

rarely
populations are not usually isolated and do not have such sharp boundaries

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8
Q

the closer two populations are, what happens to relatedness?

A

the more closely related they are

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9
Q

gene pool

A

the total of all genes in a population

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10
Q

what does a gene pool consist of?

A

all alleles at all gene loci in all members of a population

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11
Q

what is a fixed gene pool?

A

when all members of a population are homozygous for the same allele, but usually there are 2+ alleles for a gene

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12
Q

what doeS the Hardy-Weinburg theorem state?

A

the frequencies of alleles and genotype in a population’s gene pool remain constant across generations unless acted upon agents other than sexual recombination
A GENE POOL THAT IS NOT EVOLVING IS AT H-W EQUILIBIRUM

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13
Q

what does the HW equilibrium provide?

A

a baseline for tracking genetic structure of population across generations

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14
Q

HW equilibrium equation

A

p^2+2pq+q^2=1

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15
Q

p^2

A

probability of getting an AA phenotype

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16
Q

q^2

A

probability of getting an aa phenotype

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17
Q

p

A

frequency of the dominant allele A

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18
Q

q

A

frequency of the recessive allele A

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19
Q

2pq

A

frequency of heterozygous/carriers

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20
Q

rules of HW equation

A

solve for q first
1-q=p

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21
Q

mircoeveloution

A

generation to generation change in a population’s frequencies of alleles or genotypes

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22
Q

what is the scale of change of gene pools?

A

microscopic–therefore why it is called microevolution

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23
Q

when is micro evolution occuring?

A

even if just one genetic locus is changing allele frequencies amongst the entire gene pool

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24
Q

5 conditions that H-W can remain true

A

1) large population size
2) no immigrations or emigrations
3) no mutations
4) random mating
5) no natural selection

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25
Q

what causes a population to microevolve?

A

5 things opposing HW equilibrium
small population
immigration
mutations
selected mating
natural selection

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26
Q

genetic drift

A

results due to small population size
smaller the sample size, greater the deviation from the expected results

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27
Q

2 situations that lead to genetic drift

A

population bottleneck and founder effect by a small number of individuals

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28
Q

population bottleneck

A

occurs due to disasters like tornadoes, hurricane, and earthquake which reduce the size of a population drastically, killing victims randomly
representation of alleles will be underrepresented, overrepresented or even eliminated reducing genetic variability in a population

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29
Q

where else can genetic drift happen? how so?

A

when just a few individuals colonize an isolated island, lake, or new habitat
the smaller the sample size, the less genetic makeup of the colonist swill represent the gene pool of the larger population they left

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30
Q

founder effect

A

genetic drift in a new colony

31
Q

why does gene flow occur?

A

because most populations are not completely isolated

32
Q

how do populations gain/lose alleles

A

due to im/emigration

33
Q

what does im/emigration do?

A

reduced differences between populations and can eventually turn 2 separate populations into one with common genetic structure

34
Q

what happens if a mutation occurs in gametes?

A

can cause immediate change in the gene pool of a population
in the long run, they are important to evolution as they bring about genetic variability that serves as raw material for natural selection

35
Q

how does non-random mating occur?

A

individuals mate with close neighbors versus those far away, promoting inbreeding

36
Q

what happens as a result of inbreeding?

A

the genotype frequencies in a population express more recessive phenotypes

37
Q

assortive mating

A

a type of non random mating when individuals select partners that are like themselves phenotypically, which increases the number of gene loci in the population that are homozygous

38
Q

what does natural selection provide?

A

differential success in reproduction

39
Q

what do populations consist of?

A

varied individuals and some leave more offspring

40
Q

how is natural selection different than the other 4 ways HW cannot be maintained?

A

only one that adapts a population to its environment so it is able to maintain favorable genotypes in a population

41
Q

morphs

A

when 2 or more forms of a character are present in a population, and the contrasting forms are morphs

42
Q

when is a population polymorphic?

A

if the 2 or more morphs are in high frequency and very noticeable in a population

43
Q

example of polymorphism

A

many morphs/coloring patterns with cats

44
Q

examples of polymorphism with the human population

A

physical (appearance) and biochemical (blood group) characters

45
Q

to what does polymorphism apply?

A

to only discrete characters that are “either-or” and not to traits that vary along a continuum

46
Q

what do most species exhibit?

A

geographical variation - differences in genetic structure between populations

47
Q

how does geographical variation come about?

A

due in part to differences in environmental factors from one place to another like elevations

48
Q

cline

A

type of geographical variation
graded change in some trait along a geographic axis

49
Q

when are mutations beneficial?

A

in changing environments

50
Q

two ways to generate genetic variation

A

mutations and sexual recombination

51
Q

with sexual recombination, how do members of a population differ?

A

due to the shuffling of alleles during meiosis to produce a wide variety of gametes

52
Q

how does the fact that organisms are diploids preserve variation?

A

maintains and sometimes preserves a huge pool of alleles

53
Q

how does natural selection preserve variation?

A

balanced polymorphism - as in the case of heterozygous advantage

54
Q

heterozygous advantage with sickle cell anemia

A

heterozygous for sickle cells anemia helps fight against malaria while not being severely affected by the disease

55
Q

heterozygous advantage with crops like corn

A

when plants are highly inbreed homozygous loci increases and this can stunt corn growth and decrease the ability of the plant to fight disease

56
Q

what happens with crossbreeding between 2 inbred varieties?

A

brings about more variety and produced hybrids

57
Q

neutral variations

A

variations that have no impact on reproductive success
ex. human fingerprints have no advantage even tho they are all different

58
Q

what is it impossible to do with neutral variations?

A

to prove that an allele brings no benefits at all to the organism and what may be neutral may not be in another environment

59
Q

what is the critical contribution an individual makes to the gene pool of the next generation?

A

traits that best fit the environment, enable natural selection, and have reproductive success that can be measured by Darwinian fitness

60
Q

does survival guarantee reproductive success?

A

no- sterile animals leave no offspring

61
Q

what is survival a prerequisite for?

A

reproducing

62
Q

correlation between life length and offspring number?

A

longer one lives, the higher the chances of leaving more offspring

63
Q

what does an organism expose to the environment?

A

its phenotype not genotype

64
Q

what does natural selection act on?

A

phenotypes adapting to a population to its environment by increasing favorable genotypes in the gene pool

65
Q

what three ways can natural selection affect the frequency of a trait in the population?

A

1) stabilizing selection
2) directional selection
3) diversifying/disruptive selection

66
Q

stabilizing selection

A

acts against extreme phenotypes and favors the more common intermediate variants

67
Q

directional selection

A

most common during periods of environmental change or when members of a population migrate to a new habitat with different environmental conditions

68
Q

diversifying/disruptive selection

A

occurs when environmental conditions are varied in a way that favors individuals on both extremes of a phenotypic range over the intermediate phenotype

69
Q

what can disruptive selection result in?

A

balanced morphism such as birds with 2 different beak sizes

70
Q

sexual dimorphism

A

males and females of many animals species have distinct secondary sex characteristics

71
Q

how is sexual dimophism expressed?

A

difference in size with males larger than females
colorful plumage in male birds
manes on male lions
antler on male deers

72
Q

which is the more showier sex?

A

males as they attract females or compete with other males

73
Q

how can showier secondary sex characteristic lead to problems?

A

showy plumage can attract predators

74
Q

what does sexual dimorphism do to reproductive success?

A

enhances it, which perpetuates the alleles generation to generation

AP BIO (30 decks)

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