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11 Cards in this Set
- Front
- Back
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Sexual Selection
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The process by which individuals that possess certain heritable traits are more sucessful at obtaining mates, and thus reproduce at a higher rate, relative to other individuals within a population
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pattern of competition
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Males compete more intensely for mates than do females and females are choosier of their mates rather than males.
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Bateman and Trivers' principle
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1. male fitness will be limited by the number of offspring whereas female fitness will not
2. Because females invest more within one gamete they should invest more in parental care of an offspring 3. Given greater investment in gametes and in care of offspring, females should be choosier about who they mate with, and males should compete more for mates than should females |
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Sexual Dimorphism
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Differences between the sexes in traits related to securing mates
can be formed by intra and inter sexual selection |
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Intrasexual selection
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1.male-male competition for male reproductive traits
2.ritualized displays-males used displays to gauge the strength of opponent-reduces risk of injury 3. sperm competition- mates to do not compete but sperm do! |
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Sperm Competition
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Sperm Scoops in damselflies
Female places her genitalia over the new penis. Male then scrubss the old sperm from female's sperm storage organ and deposits his |
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Intersexual selection
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Overt obvious female choice
1. Females choose males based on their phenotypes 2. Females often select the most "attractive" males 3. Females are not picky about mating 4. Females are promiscous 5. after mating female controls which sperm fertilizes their egg 6. females may remove or reject unwanted sperm |
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Direct Effects
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1.where males offer resources in addition to sperm, such access to food and nest sites, gifts, and parental care.
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Indirect Effects
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where males offer only sperm. The sperm presumably carries good genes that code for strong offspring (and sexy sons)
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Sexy Sons Theory
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females would mate with the most attractive males so that their offspring would have no problem mating
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Anisogamy
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Anisogamy- is defined by the occurence of gametes of different sizes
Eggs are expensive while sperm are relatively cheap |
