Mating_Systems - Mating Systems The classical way of...

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Mating Systems The classical way of looking at mating systems : 1. Monogamy One male + one female (exclusive mating) Shared parental care Most commonly for one breeding season 92% of bird species 2. Polygyny One male + two or more females Female parental care 2% of bird species Northern Mockingbird Red-winged Blackbird
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Types of mating systems (continued) 1. Polyandry One female + two or more males Male parental care 0.4% of bird species 2. Promiscuity Multiple males and females Who does parental care is variable Often there is little social interaction There is mate selection A “catch-all” group (6% of species) Red-necked Phalarope Ostrich
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Why such variation? Keep in mind: 1. The mating system must be advantageous to individuals 2. Investment in gametes is different for males and females Female gametes are large; a female’s reproduction is limited by number of eggs she can produce. (Finch example) Male gametes are small; a male’s reproduction is limited by number of mates he can acquire 3. Therefore, males have more to gain by multiple matings and females have more to gain by being highly selective in who they mate with. 4. Mating systems are best viewed as “conflicts”, with one sex controlling the outcome.
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A closer look at Monogamy It’s a balance of cooperation and selfishness Old views are wrong : “Almost certainly the main advantage of monogamy is that two parents can feed the young and hence can raise more offspring than if the female does so alone” (David Lack) Your textbook: “…ornithologists have viewed monogamy as the mating system of choice; a pair can raise more young than can a female without a mate” (Frank Gill) David Lack
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How does monogamy evolve? 1.
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Mating_Systems - Mating Systems The classical way of...

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