PSYC315 Ch. 7 (Pts. 1 & 2): Sexual Selection

sexual selection

process by which mating members of a species selectively favor mates possessig specific variants of a trait, thus providing selective pressure that creates a fitness measure

Bateman’s Principle

Principle that explains how the female chooses the male & thus shapes male traits

intrasexual selection

competition within a sex for access to members of the opposite sex

intersexual selection

choice of mates across sexes, whereupon the fitness of the mate being selection depends on the choosing mate’s preference for certain trait variants

secondary sexual traits/epigametic traits

physical & behavioral traits that are used to attract/choose a mate

epigametic traits

secondary sexual traits are also called…

courtship displays

behavior of showing off secondary sexual traits/epigametic traits

1) Direct benefits

2) Good genes

3) Sensory exploitation

4) Runaway selection

4 models of mate choice by females

genetic control

Female mate choice is belived to be influenced by what?

direct benefits

Model where females who choose mates that provide tangible resources will have more viable offspring (better fitness)

good genes

Model where females choose based off the “"indirect benefits” of adaptive genes for their offspring

Sexy son hypothesis

Hypothesis that says females choose based off the “"indirect benefits” of adaptive genes for their offspring

good genes

A male’s ability to provide tangible resources likely correlates with what?

Hamilton-Zuk hypothesis

proposes that sexual selection drives the evolution of costly ornaments because they are honest indications of a male's health & good genes

Major histocompatibility complex (MHC) peptides

These affect female choice in a male because they correlate with immune health & disease resistance

one that is different from her own

What kind of MHC profile do females usually prefer?

Carotenoids

Causes the bright red color in house finch males

1) Feed young more often

2) Less bacteria on their feathers

3) Better foraging skills

3 reasons a female prefers a brighter red house finch as a mate

sensory exploitation (sensory bias/preexisting bias)

phenomenom where mate traits elicit activation in already existing neural circuits

runaway selection

phenomenom where a secondary sexual trait expressed in one sex becomes genetically correlated with a preference for the trait in the other sexl

gene for the traits & gene for the preference of the trait must be on the same chromosome (linked genes)

genetic condition that must exist for runaway selection to happen

sexual imprinting

learned mate preference where animals come to prefer a secondary sex characteristic that their opposite sex parent had