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Life Science 1 > week 2(ch 26 &27) > Flashcards

week 2(ch 26 &27) Flashcards

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Biology 101 flashcards
1
Q

a group of individuals from the same species that live in the same area at the same time and can interbreed

A

population

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2
Q

a group of all the alleles from all the gametes produced in each generation

A

gene pool

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3
Q

equation for allele frequencies

A

p + q = 1

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4
Q

equation for genotype frequencies

A

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

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5
Q

Hardy-Wienberg’s assumptions

A
  1. random mating
  2. no natural selection
    3.no genetic drift
    4 no gene flow
    5 no mutation
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6
Q

inbreeding causes — to increase, but does not change—-

A

inbreeding causes homozygosity to increase, but does not change allele frequencies

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7
Q

alleles that lower fitness

A

deleterious alleles

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8
Q

inbreeding does not cause evolution, but it can…

A

increase the rate at which deleterious alleles are eliminated

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9
Q

what are two reasons why inbreeding depression occur?

A
  1. many recessive alleles represent loss of function mutations ( are bad)
  2. many genes that are involved in fighting disease need heterozygote
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10
Q

the number and relative frequency of alleles that are present in a particular population

A

genetic variation

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11
Q

changes the average value of a trait because individuals at one end of the distribution experience low reproductive success

A

directional selection

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12
Q

reduces the variation of a trait, but keeps the average value constant

eg. Weight of baby

A

stabilizing selection

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13
Q

extreme phenotypes are favored. increases the amount of genetic variation

A

disruptive selection

eg only birds with extremely short or extremely long necks survive

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14
Q

disruptive selection sometimes plays a role in…

A

speciation!

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15
Q

when no single phenotype is favored; genetic variation is maintained

A

balancing selection

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16
Q

when an individual of one gender selects for an individual of another gender

A

intersexual selection

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17
Q

when selection occurs within two organisms of the same gender

eg. giraffes fighting or seals fighting

A

intrasexual selection

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18
Q

any trait that differs between males and females

eg. Mallards

A

sexual dimorphism

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19
Q

any change in allele frequency due to chance

A

genetic drift aka sampling error

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20
Q

genetic drift occurs especially in

A

small populations

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21
Q

over time genetic drift can lead to…

A

the random loss or fixation of alleles

22
Q

a change in allele frequency that occurs when a new population is established

A

founder effect

23
Q

when a large population experiences a sudden reduction in size

A

genetic bottleneck

24
Q

occurs when an individual leaves one population, joins another, and breeds

A

gene flow

25
Q

gene flow is — with respect to fitness

A

gene flow is random with respect to fitness

26
Q

an evolutionary process that increases genetic diversity in populations

A

mutation

27
Q

mutation can have a very large effect when…

A

combined with genetic drift, gene flow, and selection

28
Q

the ultimate source of genetic variation

A

mutation

29
Q

a splitting event that creates two or more distinct species from a single ancestral species

A

speciation

30
Q

an evolutionarily independent population or group of populations

A

species

31
Q

the main criterion for identifying species is reproductive isolation

A

biological species concept

32
Q

isolation that prevents individuals from different species from mating ( before)

A

prezygotic isolation

33
Q

occurs when the offspring of matings between members if different species do not survive or reproduce

A

postzygotic isolation

34
Q

what is a disadvantage of using the biological species concept?

A

it doesn’t apply to asexual organisms, fossils, or populations that do not overlap geographically

35
Q

identifying different species based on their size, shape, or other features

A

morphospecies concept

36
Q

the naming of two or more species when there is only one

A

polymorphic species

37
Q

two species that differ in traits other than morphology

A

cryptic species

eg. eastern meadow larks and western meadow larks are almost identical in morphology, but their hybrid offspring are infertile

38
Q

what is disadvantage of using a morphospecies concept?

A

it is objective. It miss it misidentifies polymorphic species and misses cryptic species

39
Q

identifies species based on the evolutionary history of populations

A

phylogenetic species concept

40
Q

consists if a ancestral population, it’s descendants, and ONLY those descendants

A

monophyletic group ( also clade or lineage)

41
Q

what is a disadvantage of phylogenetic species?

A

relatively few well- estimated phylogenies are currently available

42
Q

populations that are geographically isolated are in

A

allopatry

43
Q

speciation that begins with geographic isolation

A

allopatric speciation

44
Q

the physical splitting of a habitat

A

vicariance

45
Q

when populations or species live close enough that interbreeding is possible

A

sympatry

46
Q

speciation that occurs even though species live in the same geographical area

A

sympatric speciation

47
Q

error that creates the doubling of chromosome number

A

polyploidy

48
Q

when two species that have diverged and there is selection against interbreeding

A

reinforcement

49
Q

a geographic area where interbreeding occurs and hybrid offspring are common

A

hybrid zone

50
Q

4 processes that can create evolution

A
  1. Natural selection
  2. genetic drift
    3 gene flow
    4 mutation

Life Science 1 (10 decks)

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