Sexual Selection Flashcards
Sexual Reproduction (2)
Combination of Gametes
eukaryotes only
sexual selection is a subset of
natural selection
Single sex type
individuals have 1 one reproductive function
Hermodaphrodite
species which contain individuals that can perform male and female reproductive functions
instantanneous hermaphrodite
performs male or female functions at same time
ie. earthworm
Sequential hermaphrodite
changes sex over time
ie clownfish, indo pasific cleanser wrasse
Protandrous hermaphrodite (C)
subsection of sequential
-live in groups of male(sexually immature) and female breeding pair
-once female removed from population the next biggest male becomes breeding male and the prior breeding male turns female
-clownfish
protogynous hermaphrodite
-live in groups with one male and smaller females
-if male dies largest female changes sex in 2 weeks
what is the common sex type in plant, where are the reproductive organs situated in angiosperms?
hermaphroditic
stamens and pistils organized together
Conifer sex type
Monoecious
malke and female cones on this bitch
female top, male bottom
Monogamy
-one male and one female in exclusive relationship for some time
-may be sired by another male
Genetic Monogamy
-parents raise offspring
-full fidelity
Social Monogamy
-parents raise offspring but
-not full fidelity
-90% of songbirds experience social monogamy
fairywrens
social monogomy, hella of these mfs gettin cucked
why did monogamy evolve? (4)
anisogamy
-Anisogamy:females more selective since gametes larger and cost more energy-female got bigger gamete
-both parents required to maintain
-partners rare
-reduction in STD
Promiscuity
several sexual partners
polygyny
1 male multiple females
polyandry
1 female multiple males
polygyandry
multiple everyone
secondary sexual characteristics
-traits found that not directly involved in reproduction-cannot be described by natural selection –> sexual selections
intersexual selection
individuals consistantly choose mates among members of opposite sex based on particular trait
often bright coloration, dance, singing
intrasexual selection
individuals of one sex compete among themselves for mates
sometimes have mechanisms that settle conflicts w/o physical aggression
handicap principle
somtimes secondary sexual characteristics so there is a maximum they can go to before they start to fuck bro over
why are female signals underappreciated
darwin says there is a struggle between MALES for possession of the females
Armaments and onaments limits of sexual selection
Armaments: risk of injury during combat
inhibits animal from using some resources
ornament: predation, physiologically expensive
Sexual Conflict
-Behavioural or physical traits that enhance the fitness of one sex that comes to the cost of the other
-mating inexpensive for males, but is for females
sexual arms race
leads to coevolution of armaments within species
