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Biology 2 Lecture > Chapter 23 > Flashcards

Chapter 23 Flashcards

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1
Q

what 4 processes drive evolution

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

how does natural selection drive evolution

A

increases frequency of certain alleles

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3
Q

how does genetic drift drive evolution

A

allele frequencies change randomly

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4
Q

how does gene flow drive evolution

A

individuals leave one population, join another, and breed; introduce different alleles

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5
Q

how does mutation drive evolution

A

modifies allele frequencies by continually introducing new alleles

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6
Q

what did Hardy and Weinberg calculate

A

what would happen if pairs of gametes are plucked at random out of a gene pool and then form offspring

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7
Q

do allele frequencies change over time

A

NO

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8
Q

what does a null hypothesis specify

A

what should be observed if hypothesis being tested is NOT correct

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9
Q

what does nonrandom mating cause

A

only genotype frequencies to change, not allele frequencies unless it occurs with other processes

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10
Q

what does inbreeding lead to

A
  • increase in homozygosity of population
  • leads to decrease in average fitness via selection
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11
Q

what is the most extreme form of inbreeding

A

self fertilization

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12
Q

does inbreeding cause evolution

A

no because allele frequencies do not change in population as a whole

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13
Q

how does inbreeding influence evolution

A

increases the rate at which natural selection eliminates recessive deleterious alleles from a population
- speed up rate of evolutionary change

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14
Q

when does nonrandom mating occur due to sexual selection

A

occurs sometimes because an organism actively choses a certain mate based on it’s physical and/or behavioral traits

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15
Q

what does natural selection violate

A

assumptions of Hardy-Weinberg

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16
Q

what combines to cause natural selection

A

ecological selection + sexual selection

17
Q

what are the 4 main patterns of natural selection

A
  1. directional
  2. stabilizing
  3. disruptive
  4. balancing
18
Q

when is genetic drift random

A

in respect to fitness- changes in allele frequency that it produces are not adaptive

19
Q

when is genetic drift most pronounced

A

in small populations

20
Q

over time, what can genetic drift lead to

A

random loss or fixation of alleles
- genetic variation then decreases

21
Q

what causes genetic drift in natural populations

A

founder effect and bottleneck effect

22
Q

what outcomes can genetic drift cause on fitness

A

increase, decrease, or same

23
Q

what causes gene flow

A

when individual leaves one population, joins another, and breeds

24
Q

is gene flow random

A

with respect to fitness, yes

25
Q

what ways can mutation occur

A
  • point mutation
  • chromosome level mutation
  • lateral gene transfer
26
Q

is mutation fast or slow

A

slow

27
Q

when can mutation have a large effect on evolution

A

when combined with genetic drift, gene flow, and selection

28
Q

mutation in evolution

A
  1. mutation is ultimate source of genetic variation
  2. mutations are random with respect to fitness
  3. if mutation did not occur, evolution would eventually stop
  4. mutation alone is usually inconsequential in changing allele frequencies at a particular genre
29
Q

what reduces differences between populations

A

gene flow

30
Q

what causes populations to diverge

A
  • natural selection
  • genetic drift
  • mutation
31
Q

what is genetic drift caused by

A

sampling error

32
Q

what are the causes of a bottleneck effect

A
  • disease outbreak
  • natural catastrophes
  • human catastrophes
33
Q

what occurs in disruptive selection

A
  • competition
  • abiotic or biotic
  • eventually lead to different species
  • increase variation in trait
34
Q

what occurs in balancing selection

A

maintains “status quo”

35
Q

inter sexual selection involves who in a species

A

between different sex’s
- male showing off for female
- make and female usually look different

36
Q

intra sexual selection involves who

A

within a sex
- competition for mate
- shift in features that allow for better chance to win competiton

37
Q

directional

A

favors one extreme, shifting the population traits

38
Q

stabilizing

A

favors average traits, reducing variability

Biology 2 Lecture (18 decks)

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