Behavioral Ecology ch 11

Primary sexual characteristics

genitalia and organs of reproduction

secondary sexual characteristics

morphological differences between the sexes that are not directly involved in reproduction (ex. stag beetle horns, widowbird tails)

sexual selection

a form of natural selection that acts on heritable traits that affect reproduction via mate competition and choice

mate choice

selection by one sex for members of the other sex for reproduction

mate competition

selection in which one sex competes with other members of the same sex for access to the other sex for reproduction

anisogamy

different size gametes

isogamy

same size gametes

parental investment theory

the sex that has the greater investment in offspring production should be choosier when it comes to mates. Other sex will experience more intense sexual selection (why males exhibit exaggerated traits

weapons

exaggerated morphological traits used in male-male competition

ornaments

exaggerated morphological traits used to attract females

runaway process

an evolutionary process in which a male trait co-evolves with a female preference for it and becomes increasingly exaggerated (will exaggerate until costs outweigh benefits)

handicap principle

well-developed secondary sexual characteristics are costly to survive but reliable signals of fitness

good genes

the alleles of high-quality individuals

Bateman’s Hypothesis

female reproduction limited by egg number and success. Male limited by number of mates. males have higher repro success variation and higher sexual selection upon them.

red deer study

firefly study

sensory bias hypothesis

mating preference could be linked to pre-existing preferences in the population

direct material benefits

material resources obtained by a female from mating with a particular male

nuptial gift

a physical resource such as a food item that a male provides to a female to enhance his mating success