Sexual Selection Flashcards Preview

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Flashcards in Sexual Selection Deck (31):
1

Differential Reproduction

Critical to natural selection

2

Sexual Selection

selection arising from differences in mating success

Selection arising from competition between or within sexes in a single population

3

Adaptations

Features which enhance relative fitness and thus lead to greater reproductive success

4

Materials For Selection

Differences in phenotype that have consequences for survival and reproductive success

5

Copulation (reproductive model)

Individuals recognize and encounter conspecifics of the appropriate sex

Means of transmitting gametes

requires time and energy searching for mates

number of potential encounters may be limited so each copulation potentially limits future choices or opportunities

6

Spawning (reproductive model)

Coordination of members of population with respect to timing of spawning

typically prevents extensive parental care

concentration and density of gametes appropriate to environment

gamete recognition mechanisms

7

Polyandry

oldest and largest individual is a female, males compete for access

- better guarantee of successful reproduction
- promote competition among males and among their sperm --> more variation possible
- multiple males can procure more resources for the female

8

Polygyny

Oldest and largest individual is a male, maintains group of females

males maximize mating opportunities

9

intrasexual

sexual selection between members of one sex for access or opportunity

10

intersexual

preference by one sec for certain phenotypes in mates

11

what is assortative mating? what two types are there?

contrast to random mating

positive assortative mating and negative assortative mating

12

Positive assortative mating

preference for similar phenotype (possible inbreeding)

13

Negative assortative breeding

preference for different phenotype

may make it hard to maintain species boundaries

14

what are the components of reproductive fitness?

Viability
Mating Success
Fecundity
segregation advantage
gamete viability
fertilization success

15

Who typically picks for mating

Females

16

Sneaking

pretending to be females

17

Cheating

Having multiple mates

18

Zahavi Handicap hypothesis

extravagant male morphologies means the male has passed the "test" and males without haven't

"honest advertisement"

female preference for extreme morphology is therefore a preference for higher fitness males! WOW

19

Tail Length

Test done showing females prefer the longest tail

20

Runaway Sexual Selection

female choosiness and male elaboration form a positive feedback loop --> the females like long tales so males keep making their tails longer and longer

male appearance and fitness become de-coupled; extreme morphology NOT correlated with higher fitness

female's choice NOT a guarantee of better genes for her offspring

21

what are two basic kinds of reproductive modes?

copulation and spawning

22

what HW requirement does sexual selection violate?

random mating!

demonstration of mate preference violates the random mating tenet of HW

AND that all offspring have an equal chance of survival and reproduction because if mate choice is based on heritable phenotype then some offspring will have a greater/lesser chance of reproducing

23

what is viability?

probability that individual bearing genotype will survive

24

what is mating success?

number and quality of mates

25

what is fecundity?

number of gametes per individual

26

what is segregation advantage?

alleles wind up in the games more/less frequently

27

what is gamete viability?

alleles impact the longevity or quality of the egg or sperm

28

what is fertilization success?

alles impact the probability that fertilization will take place

29

why do females typically do the picking?

females produce the expensive gametes --> may also have post-mating responsibilities


female strategy is typically focused on obtaining the best mate so that HER investment in eggs pays the greatest genetic dividend --> higher proportion of offspring survive and reproduce

30

what kinds of things typically act as cues in female choice?

features that suggest health and capability in feeding

features that emphasize distinction between males and females

novelties that suggest that males are from another population

31

what are costs associated with extreme morphologies?

plumage or antlers or complex songs require energy to make

males bearing extreme trait are more conspicuous to predators so face a greater threat of being eaten but those males that survive despite this handicap have demonstrated their superior fitness