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Flashcards in Sexual Selection Deck (14):

What is intersexual selection

Individuals of the same sex choose a mate


What is Bateman’s principle

Women are the choosier sex because eggs are more costly to produce than sperm and their reproductive success is limited


What are 2 learning models of intersexual selection

1. Classical conditioning - Japanese quail learn to stay in areas where there are lots of females

2. Imprinting - learn mating preferences from adult interactions. Humans chose a mate similar to their opposite sex parent


What are 2 cultural transmission models of intersexual selection

1. Mate choice copying - female mate choice is affected by other females. Grouse males are more likely to mate if they have recently mates

2. Song learning - birds learn songs from others. Cowbirds prefer songs of the birds they were raised with


What are the 4 evolutionary models of intersexual selection

1. Direct benefits
2. Good genes
3. Sensory bias
4. Runaway selection


Give an example of direct benefits

Nuptial gifts
E.g Scorpionfly - chose the male that brings the largest prey. Copulate longer the larger the prey. Direct benefits of food. Dangerous for males and time consuming to catch prey


Give 2 examples of good genes as an evolutionary model of intersexual selection

1. MHC - prefer mates with dissimilar MHC genes e.g humans prefer the smell of mates with dissimilar MHC

2. Pronghorn antelope - harem defence is a sign of good genes. Better they defend the harem, more likely to mate


Give an example of sensory bias as an evolutionary model of intersexual selection

Primates - as a male trait emerges it may be preferred if it elicits a neurobiological response. Primate males have red faces and they eat red fruit. More attracted to red things


Give an example of runaway selection as an evolutionary model of intersexual selection

E.g stalk eyed flies - prefer males with eyes on long stalks. In their genes


What is intrasexual selection

Members of one sex compete with each other for access to mates


Give 2 factors of male male competition

1. Interference

2. Cuckoldry


Give an example of male male competition

Red deer
Roar is an indicator of strength
If roar is stronger than the other they are less likely to fight


Give an example of interference

Elephant seals
Females protest at mating attempts with subordinate males
Larger the harem, bigger the males and more male male competition


Give an example of cuckoldry

Blue gill sunfish
1. Parental morphs - build nests and look after babies. Less but higher quality sperm

2. Sneaker morphs - hide and shed sperm in to parental male territory. More but lower quality sperm

3. Satellite morphs - look like females and position themselves between a mating couple