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Evolution > Exam 2 (16, 17, and 18-ish) > Flashcards

Exam 2 (16, 17, and 18-ish) Flashcards

1
Q

define sexual dimorphism

A

when males and females of the same species look morphologically different

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2
Q

what is the solution to extreme morphologies that appear to be maladaptive in one sex often resulting in exaggerated traits?

A

sexual selection

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3
Q

define sexual selection

A
  • differential reproduction due to the variation in the ability to obtain mates and/or fertilize offspring
    OR
  • unequal distribution of sexes with differential levels of mating
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4
Q

the sex of a species subjected to ____ (strong to weak) selection will be competitive

A

strong

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5
Q

the sex of a species subjected to ____ (strong or weak) selection will be choosy

A

weak

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6
Q

what does it mean to be the sex subjected to strong selection?

A

more variation in success than the other sex in your species

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7
Q

sexual selection in pipefish (what happens? who is choosy? who is competitive?)

A
  • males raise the young
  • males have less variation (choosy)
  • females can mate with a male and leave to mate again (competitive)
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8
Q

sexual selection in rough-skinned newts (what happens? who is choosy? who is competitive?)

A
  • males compete for mates (competitive)
  • females get mated by winner of competition (choosy)
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9
Q

when does sexual selection occur?

A

when there are differences in reproductive opportunity, reproductive variance, or costs of reproduction between sexes

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10
Q

where do the differences that cause sexual selection to occur come from? (3)

A
  • metabolic/nutritional cost of sperm vs. eggs
  • potential rates of reproduction
  • parental care
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11
Q

causes of sexual selection: metabolic/nutritional cost of sperm vs. eggs

A

cheap to produce sperm so males can fertilize many females but females may be more choosy

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12
Q

causes of sexual selection: potential rates of reproduction

A

One individual can be more sexually successful than others (social systems affect this)

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13
Q

causes of sexual selection: parental care

A
  • investment in offspring
  • different in parental care between sexes
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14
Q

what are the overarching modes of sexual selection?

A
  • intersexual selection
  • intrasexual selection
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15
Q

what are the four types of intrasexual selection?

A
  • direct combat
  • sperm competition
  • infanticide
  • alternative mating strategies
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16
Q

define intrasexual selection

A

competition between individuals in the same sex (males vs. males)

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17
Q

intrasexual selection examples: direct combat (2)

A
  • Galapagos iguanas
  • bighorn sheep
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18
Q

direct combat: Galapagos iguanas

A
  • males butt heads to find stronger individual
  • stronger one controls territory and therefore has control of the offspring production
  • if you’re too big you have bad survival but great sexual selection
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19
Q

intrasexual selection examples: sperm competition (2)

A
  • damselflies
  • primate testes
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20
Q

sperm competition: damselflies

A
  • female fly is fertilized by a male (sperm sac inside female)
  • another male comes and rips out the sperm sac and puts his own in
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21
Q

sperm competition: primate testes

A

female primates prefer larger testes for more sperm per ejaculation

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22
Q

intrasexual selection examples: infanticide (1)

A

Male lions taking over a pride

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23
Q

infanticide: lion prides

A
  • new male takes over pride and kills all offspring of the old male
  • makes females more receptive to mating with him
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24
Q

intrasexual selection examples: alternative mating strategies (1)

A

coho salmon

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25
Q

alternative mating strategies: coho salmon

A
  • males choose to come back after either 18 months or 6 months
  • if after 6 months they look more like females (sneakers)
  • males after 18 months come back and battle to release sperm killing each other
  • sneakers hide and release their sperm and hope it fertilizes
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26
Q

what determines whether a male coho salmon is a sneaker or becomes fully grown?

A

genetic and environmental components so if too common it is not advantageous

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27
Q

define intersexual selection

A

when one or both sexes are choosy (interactions between sexes)

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28
Q

types of intersexual selection (3)

A
  • direct benefits
  • indirect benefits
  • preexisting bias
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29
Q

give an example of when females preferred a male trait that possibly reduces male survival

A

female choice in frogs where females prefer to mate with males with longer songs than shorter ones

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30
Q

define direct benefits

A

by mating with males with preferred characteristics females get some direct benefit and thus increase their offspring’s chances of survival (nonheritable)

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31
Q

intersexual selection examples: direct benefits (2)

A
  • house finches
  • dragonflies
32
Q

direct benefits: house finches

A
  • red pigment in males is sequestered by the food they eat
  • males with brighter colors are more likely to mate cause it shows they have a good food source
33
Q

direct benefits: dragonflies

A
  • males bring female prey and mate with her while she eats
  • the bigger the prey, the longer he will get to mate with the female so the more sperm he can deposit
34
Q

what is the key difference between direct and indirect benefits?

A

indirect benefits has a genetic correlation and direct has an environmental

35
Q

what are the two kinds of indirect benefits?

A
  • good genes
  • Fisherian runaway selection
36
Q

indirect benefits: good genes

A

male traits are indicators of the quality of other genes

37
Q

intersexual selection examples: good genes (1)

A

barn swallows

38
Q

good genes: barn swallows

A
  • experimentally tested to see what length of tail females preferred (short, normal, or long)
  • females preferred long tails because the individuals with this trait are less likely to contract parasites than the shorter tailed individuals
39
Q

indirect benefits: fisherian runaway slection

A
  • genetic correlation forms between male trait and preference
  • if there is variation and females have a gene that prefer that variation the two genes will become linked after they mate
40
Q

intersexual selection examples: fisherian runaway selection (1)

A

stalk eyed flies

41
Q

intersexual selection examples: preexisting bias (1)

A

swordtail fish

42
Q

intersexual selection: preexisting bias

A
  • female preference is a pleiotropic effect of selection on the sensory system for another function
  • predicts that the preference evolved before the male trait
43
Q

Give the statement that answers the question “what is a unit on which selection can act?”

A

Selection acts upon unit X while group Y, the larger population of Xs, is what actually evolves

44
Q

When you get higher up in the levels of organization of individuals what happens to the relationship between traits and evolution?

A
  • The traits of the units below what evolution is working on do nto change but the traits of the actual unit do
  • ex. clades change for species selection
45
Q

What makes an organizational level a unit of selection? (4)

A
  • variability
  • heritability
  • differential replication
  • individuality
46
Q

Define differential replication

A

More offspring are produced than can survive

47
Q

Define individuality

A

Individuals are separate organisms with their own unique identity

48
Q

Define selfish genes

A

Idea that organisms are just a vessel for genes to replicate and get passed on to the next generation

49
Q

What are examples of selfish genes

A

Retrotransposons (SINES, LINES, and LTRs)

50
Q

Retrotransposons

A

Genes that have no benefit to the organisms and exist not to help the organism but themselves

51
Q

Define altruism

A

Individual instigates action that pays a fitness cost (actor) and the individual on the receiving end benefits (recipient)

52
Q

What allows for altruism to evolve? (2)

A
  • kin selection
  • inclusive fitness
53
Q

Define kin selection

A

Selection favoring genes that promote the fitness of relatives

54
Q

Define inclusive fitness

A

Fitness as measured by the reproductive success of the individual who carries an allele (direct fitness) plus that of the relatives also likely to carry it (indirect fitness)

55
Q

What are good examples of altruism? (2)

A
  • meerkats forgoing feeding to stand gaurd for the colony
  • turkeys helping other individuals mate and forgoing mating themselves
56
Q

Hamilton’s Rule equation

A

Br > C

57
Q

Define “r” in Hamilton’s equation

A
  • The coefficient of relatedness and is analogous to F
  • how closely related the actor is to the recipient
58
Q

Define Hamilton’s rule

A

The benefit of the action performed by the actor must be greater than the cost to the actor based on the likelihood of the genes carried by the actor being passed on

59
Q

Explain the test done on Beld ing’s ground squirrels and what was tested

A
  • tested Hamilton’s Rule
  • have the same behavior of prairie dogs and meerkats
  • guards are more likely to call when they see a threat when it will harm a close relative rather than a far relative/random individual
60
Q

White fronted bee eaters and Hamilton’s Rule

A
  • Some individuals forgo their own reproduction to assist another in raising their offspring
  • more likely to help close relative than a far relative/random individual (more likely to help sibling than cousin)
61
Q

Carnivorous spade foot toad tadpoles and Hamilton’s Rule

A
  • two different tadpole morphs: carnivorous and herbivorous
  • becomes one morph or other dependent on environment
  • carnivorous is cannibalistic and is less likely to eat sibling than a non-sibling
62
Q

_____ is the best supported level of selection outside of the indiviual

A

Kin selection

63
Q

Define eusociality (3)

A
  • overlapping generations between parents and adult offspring
  • cooperative brood care (helping raise offspring whether related or not)
  • specialized, non-reproductive castes (physiologically can not reproduce)
64
Q

What metazoa show eusociality?

A
  • ants
  • termites
  • bees
  • naked mole rats
65
Q

How many evolutionary events of eusociality occurred in Hymenoptera?

A

3-4

66
Q

What is the only animal to undergo eusociality as a haploid organism?

A

Naked mole rats

67
Q

Eusociality in hymenoptera is facilitated by ______

A

Haplodiploidy

68
Q

Define haplodiploidy

A

Females are diploid and males are haploid

69
Q

How related are sisters in haplodiploidy?

A

3/4

70
Q

Why does Hamilton’s rule stand in eusociality?

A

Since sisters are so closely related (3/4) and a mother and her offspring are less related than this (1/2) it is more likely you will have your genes passed on to the next generation if you help your mother raise more sisters than if you have your own offspring

71
Q

Explain eusociality in naked mole rats

A
  • have a queen that is morphologically different than the rest of the colony
  • interact in the tunnels underground by shoving based on relatedness
  • less like to shove a close relative out of the way and just let them pass than a far relative/random indidivual
72
Q

define species selection

A

selection on species where species are analogous to individuals and speciation is analogous to reproduction

73
Q

what kind of traits will be favored in species selection? (2)

A
  • increases the rate of speciation
  • decreases the likelihood of extinction
74
Q

what evolves in species selection?

A

clades

75
Q

give an example of species selection we talked about in class

A
  • planktotrophic larvae species
  • feed on plankton as larvae rather than their yolk sac
  • ones that feed on plankton are less likely to go extinct than those that don’t because they can stay in the water column for longer
76
Q

give a couple of reasons as to why planktotrophic larvae are less likely to go extinct than those that use a yolk sac (2)

A
  • geographic diversity is greater
  • population is larger

Evolution (3 decks)

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