Chapter 7 Primate Mating Systems

Chapter 7 Primate Mating Systems - Chapter 7: Primate...

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Chapter 7: Primate Mating Systems - Mating systems (the way animals find mates and care for offspring) can play a crucial role in our understanding of primate society - Understanding the diverse reproductive strategies of nonhuman primates illuminates human evolution because we share many elements of our reproductive physiology with other species of primates o Reproductive strategies of living primates are influenced by their phylogenetic heritage as mammals The Language of Adaptive Explanations - In evolutionary biology, the term strategy is used to refer to behavioral mechanisms that lead to particular courses of behavior in particular functional contexts, such as foraging or reproduction o Strategy describes certain characteristics of behavior of animals; it is not conscious o Strategies are the product of natural selection - The terms cost and benefit refer to the effect of particular behavioral strategies on reproductive success The Evolution of Reproductive Strategies - Primate females always provide extensive care for their young, but males do so in only a few species - Males do not care for their offspring when they can easily use their resources to acquire mayn additional matings, or when caring for their offspring would not appreciably increase the offspring’s fitness o Unequal parental investment will be favored when one or both of the following are true Acquiring additional mates is relatively easy, so considerable gains are achieved by allocating additional effort to attracting mates The fitness of offspring raised by only one parent is high, so the payoff for additional parental investment is relatively low - The mammalian reproductive system commits primate females to investing in their offspring o In primates and other mammals, the bias toward female investment evolves because females lactate and males do not Males cannot lactate because the developmetal changes that would enable males to lactate would also make them sterile This is a developmental constraint Reproductive Strategies of Females - Female primat es invest h e avily in their offspring o Primates h ave a n extend ed pregn ancy bec aus e it takes a long time for our brains to gro o There is also an extend ed time of dep end ence after birth o Because it takes so m uch time to produce an infant, e ach fem ale can rear a relatively s m surviving offspring during her lifetime - A fem ale’s reproductive success dep ends largely on h er ability to obtain enough resources t h erself a nd h er offspring Sources of variation in female reproductive performance - High-ranking fem ales tend to reproduce more successfully than do lower-ranking fem ales o Reproductive activity of subordinate fem ales is suppressed in the presence of do minant b ecause subordinate fem ales do not cycle norm ally When subordinate fem ales do bre ed, their infants m ay b e killed by do minant fem ales infants of their own o When there is intense comp etition within groups, only the d aughters of the do minant fem
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Chapter 7 Primate Mating Systems - Chapter 7: Primate...

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