Adaptations & Traits 3 Flashcards
sexual cooperation (2)
- when males and females share a reproductive interest in combining gametes
- females need access to sperm; males need access to eggs
sexual conflict (2)
- describes the divergent interests males and females have for sex
- both sexes have adaptations that take control over reproduction
sexual conflict: what are males selected for (3)
- to mate with female regardless of whether she’s fully ready
- to fight off other males or their sperm
- to induce females to invest in their offspring
sexual conflict: what are females selected for (3)
- mate only when they have the resources to support eggs/babies, and only as often as she needs
- mate with multiple males to have more diverse babies or to have sperm to select from
- hold back some investment for a future brood
sexual antagonistic coevolution (2)
- describes the arms race between sexes for adaptations to have better control over reproduction
- balance of cooperation and conflict
sexual selection: mate selection -> mating
- when the female “chooses” whether she wants to participate in mating with a male
sexual selection: mate selection -> mating
- when the female “chooses” whether she wants to participate in mating with a male
sexual selection: mating -> zygote (2)
- whether the female allows the male sperm to fertilize her egg
- whether the male sperm is able to outcompete sperm from other males
sexual selection: zygote -> adult offspring
- whether the mother invests a lot of resource into the males offspring or not
cryptic female choice (2)
- sexual selection that occurs after mating and is not easily visible because it occurs within her body
- describes how the females decision is not complete just because she allows the male to copulate
how can a female choose to reject a male after copulation has occurred? (5)
- dump the sperm
- don’t transfer the sperm to the right pace in the body
- re-mate so the second male’s sperm competes
- doesn’t ovulate
- doesn’t mature the eggs
isogamy (2)
- same-size gametes
- 2 mating types, called plus and minus
anisogamy (2)
- some gametes are really big (eggs), some are really small (sperm)
- animal and land plants and anisogamous
what does the difference in gamete size mean? (2)
- eggs are costly, sperm are cheap
- females have a larger consequence for choosing the “wrong” male as this could lead to relatively long term and large investment in unfit offspring compared to males
male-biased operational sex ratio (2)
- describes a mating pool where there are more males than females
- leads to more males competing for fewer females
why are operational sex ratios male-biased (2)
- females are tied up growing eggs, tending babies, etc; they aren’t in the pool of available mates all the time
- males are always looking for another mating; they are in the pool of available mates all the time
why do females tend to be more choosy than males (2)
- females don’t compete as much: they can afford to reject males because there are plenty more males in the mating pool
- females suffer a higher cost of a mistake: her investment per mating is likely higher than his
variance in reproductive success: males (2)
- have a relatively greater variance
- some males mate a lot, whereas others don’t at all due to competition
variance in reproductive success: females (2)
- have a relatively smaller variance
- females are more or less assured of some offspring, as long as they are healthy, because there is little competition
intrasexual selection
- males compete amongst each other and females mate with the winner
intersexual selection
- females choose among males according to their qualities
types of intersexual selective forces (4)
- direct benefits
- good genes, honest signals
- sensory bias
- runaway
direct benefits hypothesis (2)
- females are selected to choose males that give them resources or protection
- these direct benefits ensure the females can survive and reproduce and means that her genes have a better chance of getting into the next generation
direct benefits hypothesis: prediction
- males that offer more resources/protection are given a better chance to mate