ANTH 331 Lecture Notes - Lecture 3: Robert Trivers, Parental Investment, Anisogamy
12 Jan 2017
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Robert trivers - extended the theory of sexual selection. 95% females provide most or all of the parental investment. Carnivora and primates, paternal investment in 30-40% Human males invest heavily in offspring compared to virtually all other mammals. In general, females are the higher investing sex. Anisogamy: reproduction by the union of two different gametes (the ova and the sperm) couple hundred eggs vs. millions of sperm. Females have a higher minimum obligatory investment than males. On average, number of offspring females can produce is relatively low (compared to males) Internal gestation (and postpartum care, where it happens) create an important sex difference, favouring males in terms of the rate in which males and females can reproduce. Biological bias: of how many offsprings females produces compared to males. The differential initial and subsequent levels of parental investment leads to very different reproductive strategies for males and females (trivers 1972) Factors limiting reproductive success are different for females and males:
