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BIOEE 1780 > prelim 2 (adaptation/speciation 1 - pop genetics 4) > Flashcards

prelim 2 (adaptation/speciation 1 - pop genetics 4) Flashcards

1
Q

sexual selection

A

type of selection resulting from differences among individuals in their ability to mate or
fertilize eggs

  • gives rise to diversity in morphology + behavior

individuals possessing traits that help them reproduce will be favored by sex selection

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2
Q

two fold cost of sex

A

asexual organisms can multiply faster than sexual organisms.

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3
Q

costs of sex

A
  • finding an appropriate mate
  • parents are less related to their offspring (r = 1 in asex but here r = 0.5)
  • risk of contracting STDs
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4
Q

why is sex common

A
  • gene recombination for genetic exchange; allows for the weeding out of deleterious mutations
  • combining favorable mutations more quickly
  • allows for faster adaptation again thru
    reshuffling of genetic diversity
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5
Q

cost of asexual reproduction

A
  • entire genome passed down generations
  • deleterious mutations accumulate
  • accumulation results in genetic load
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6
Q

sexual dimorphism

A

phenotypic difference between the male/female in population

  • size, color, behavior, physiology
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7
Q

sex selection trade offs

A

investment strategies differ between species and the sexes

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8
Q

anisogamy

A

gametes are different sizes

  • egg tends to be larger; female might need to have diff life history strategy to account for energy
  • fruit fly exception w the v long sperm
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9
Q

internal fertilization

A

in females usually; evolved multiple times

  • sets up different level of investment
  • females have large energetic investment; specialized adaptations for offspring care in females
  • internal fertilization means those carrying are certain of their offspring
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10
Q

operational sex ratio

A

ratio of males to females available for reproducing at given time
- how strong sexual selection is

male biased OSR and stronger sexual selection on males (bc females get pregnant) - when there is larger male population and females are not reproductive due to pregnancy and other

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11
Q

variance in reproductive succes

A

higher male variance in a more male-biased OSR
- stronger sex selection in males

  • lower variance in female reproductive success
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12
Q

male-biased OSR

A

males are most likely to maximize fitness by fertilizing eggs

females invest in choosing good mates, producing good eggs, provisioning offspring

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13
Q

females-biased OSR

A

females control territories: invest in attracting mates bc there are more female than male

males: invest in high quality mates and offspring care

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14
Q

strength of sexual selection

A

higher in mating system where variance in reproductive success is higher
-* stronger in species that mate w multiple during fertile period

  • members under stronger selection = mating competition; weaker selection = mate choice
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15
Q

cryptic females choice

A

females can store sperm and decide later which to use more of

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16
Q

geographical barriers= extrinsic

A

mountains, rivers, oceans, physical separation

  • allopatric and peripatric
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17
Q

intrinsic = reproductive barriers

A

difference in attraction and stuff
or infertile children

  • parapatric and sympatric speciation
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18
Q

allopatric speciation

A

ancestral pop divided by extrinsic barrier

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19
Q

peripatric

A

small number of individuals cross a barrier and are separated geographically
- founder affect?

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20
Q

vicariance

A

formation of geographic barriers that separate a population

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21
Q

dispersal and colonization

A

populations become separate by dispersal to new areas

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22
Q

parapatric speciation

A

occurs when species is spread out over large geographic area that causes differences; mate with ones closer to them until they diverge more and more

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23
Q

sympatric speciation

A

some individuals begin to exploit a new niche and mate with other occupying the same niche

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24
Q

behavioral isolation

A

utilize different mate recognition system

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25
Q

prezygotic barrier

A

occur prior to the fertilization of the egg

  • ecological isolation: habitat isolation, temporal isolation, pollinator isolation
  • behavioral isolation, copulatory behavior isolation, mechanical isolation, gametic isolation
  • mechanical isolation
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26
Q

copulatory behavioral isolation

A

behaviors mate may need to perform during copulation to entice the partner

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27
Q

habitat isolation

A

breeds in different locations or prefer different microhabitat

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28
Q

mechanical isolation

A

the species genitalia compatibility

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29
Q

temporal isolation

A

species breed in different seasons and/or time of day

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30
Q

pollinator isolation

A

species pollinated by different organism

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31
Q

post zygotic isolation

A

hybrid infertility or inviability, ecological hybrid inviability, behavioral sterility

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32
Q

hybrid inviability

ecological hybrid inviability

behavioral sterility

A

hybrids are not able to reproduce

hybrids are not able to survive as well in either of the parent habitats

hybrids can’t obtain mates

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33
Q

hybrid zones

A

areas where two populations meet, interbreed, create hybrid offspring

  • primary and secondary zone
34
Q

primary zone =

A
35
Q

secondary zone

A

when two populations that have been physically separated come back together

36
Q

phonetic species concept

A

define species using morphological traits

disadvantages:
- same species can be morphologically distinct
- cryptic species=morphologically similar but genetically distinct

37
Q

phylogenetic species concept

A

species as ‘tips’ on the phylogenetic tree

limitation = relies on accurate phylogeny

38
Q

biological species concept

A

species = groups of potentially or actually interbreeding populations

advantage = no problems w different morphological problems
disadvantage = unclear potential interbreeding definition

39
Q

heterozygote advantage

A

a1a2 allele result in diff phenotype then homozygous and give it a fitness advantage

40
Q

additive inheritance system

A

makes heterozygotes intermediate phenotype and intermediate fitness

can be a1 or a2 additive & advantageous depending which allele is advantageous

41
Q

selection differential

A

The difference between the mean of the initial population and the mean of the reproducing individuals of the population/the mean of the population after selection

42
Q

response to selection

A

difference between the mean of the initial population/before selection and the mean of the offspring of the population/mean of the next generation

43
Q

heritability (h^2?)*

A

how heritable a trait is? LOL
R = h2*S

proportion of population variation in a trait that comes from genetic factors

graph of midparent against midoffspring: slope = heritability; more heritable when slope is positive and points are close to the line

44
Q

directional selection

A

when selection favors phenotypes at one end of a distribution
- mean changes but the variation may stay the same

45
Q

stabilizing selection

A

selection favors values toward the middle of the distribution

  • the mean stays the same but there is less variation in the population
46
Q

disruptive selection

A

favors phenotypes at both ends of the distribution = bimodal

the mean may stay the same if equal distribution on both sides, variance increases

47
Q

darwin logic: critical ingredients to natural selection

A

fact 1= species have great potential fertility that their population size would increase exponentially if all born reproduced successfully
fact 2 = populations normally display stability in size
fact 3 = natural resources are limited and remain ~constant in a stable environment

fact 1+2+3 = inference `; more individuals are produced than can be supported meaning there’s a struggle for survival and only a small survival and progeny of each generation

fact 4: no two are the same; variability
fact 5: variation is heritable

4+5 = inference 2; survival is not random but depends on heritability constitution of the surviving
- unequal survival = natural selection

Inference 3 = over generations process of natural selection leads to gradual change of populations

48
Q

darwins postulates (3)

A
  • individuals are variable in some traits
  • some of this variation is heritable
  • there’s a struggle for survival or reproduction in which some fare better than others
49
Q

traits selection may operate on

A

morphological
behavioral
physiological

50
Q

causes for phenotypic variation

A

genetics
environment
interactions between the two

*measurement error
*developmental stages = ontogenetic

51
Q

mechanisms of evolution

A

natural selection
gene flow
genetic drift
mutation

52
Q

frequency dependent selection

A

when fitness of a genotype depends on its frequency

  • negative and positive
53
Q

negative frequency dependent

A

phenotype has greatest selective advantage if it is rare
- ex: viruses against antibodies

54
Q

positive freq dependent

A

phenotype is more advantageous if common; higher commonness = higher fitness

55
Q

truths about natural selection

A
  • is not forward looking, does not act “for the good of the species”
  • actos on individuals of certain phenotypes
  • depends on environmental conditions of the moment
56
Q

life history traits*

A

timing and duration of key events during a lifetime that can influence an organism’s fitness
- age, time of reproduction, number and size of offspring, lifespan

57
Q

inclusive fitness

A

sum of indirect and direct fitness

58
Q

direct fitness

A

contribution individual makes to gene pool through own offspring

59
Q

indirect fitness

A

genes being represented in gene pool from their relatives but not own offspring

60
Q

antagonistic pleiotropy

A

when a genetic variant w beneficial effect on one trait also has a detrimental effect on another
ex: selection for trait early in life causes shortened overall lifespan (senescence)

61
Q

senescence

A

a decline with age in per capita reproductive performance, physiological function, or prob of survival

  • selection is weaker on traits that favor later life survival; absent or very weak on post-reproductive traits
62
Q

kin selection

A

can favor behaviors that reduce direct fitness if indirect fitness is greater or increased

63
Q

Hamilton’s rule

A

R - relatedness coefficient
B - benefit to recipient
C - cost to donor

rB > C

64
Q

life history tradeoffs

A

based on - current reproductive success, future “ “, and likelihood of surviving

65
Q

eusociality

A

highest level of organization of a society - insect colonies

66
Q

post-copulatory mating competition

A

sperm competition
- produce a lot
- remove sperm already present
- prevent the next

more competition where females were polyamorous

67
Q

mates under stronger sexual selection will

A

compete: mating competition

68
Q

members under weaker sexual selection will

A

be choosier: mate choice

69
Q

sexual conflict

A

interests of mating partners are opposed
- example w the ducks

  • antagonistic coevolution
  • cannibalism
70
Q

“antagonistic coevolution”

A

aka evolutionary arms race
- ex of the female vagina evolving to decreased forced copulations and the male penis also evolving
- antagonistic coevolution b/w parasite and host

71
Q

muller’s ratchet

A

when asexual beings may accumulate deleterious mutations

72
Q

red queen effect

A

proposes that organisms must constantly adapt, evolve, and proliferate not just for continuous reproduction but to merely survive within their competitive habitats

73
Q

runaway selection

A

a mechanism whereby a secondary sexual trait expressed in one sex becomes genetically correlated with a preference for the trait in the other sex

74
Q

fusion

A

if divergence in allopatry results in no prezygotic or post zygotic isolation and the barrier is removed fusion occurs

75
Q

heterozygote advantage

A

heterozygous has the highest fitness compared to both homozygous

76
Q

additive fitness pattern

A

heterozygous has an intermediate fitness level between the two different homozygous

  • advantageous genotype reaches fixation faster than recessive and advantageous
77
Q

dominant and advantageous

A

homozygous dom and heterozygous have the same and higher fitness than homozygous recessive

  • population will never go to fixation in dominant allele
  • frequency increases quickly
78
Q

recessive and advantageous

A

homozygous recessive has highest fitness; hetero and homozygous dom are lower

  • may reach fixation but it would take a much longer time
  • frequency doesnt increase for a whole and then inc sharply
79
Q

polygenic traits

A

traits determined by the contribution of many independent genes

80
Q

microevolution

A

A change in the relative frequencies of alleles in the gene pool of a population

81
Q

founder effect

A

founder events involve mvt to a new uncolonized area

  • is a type of bottle-neck
  • population that experiences higher effects of genetic drift
  • population w diff allele frequencies from original
82
Q

mutation role in evolution

A

introduce new source of variation

BIOEE 1780 (2 decks)

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