Lesson Summary

Sexual selection theories allow us to predict and understand some important differences in sexual behavior between males and females throughout the animal kingdom. In this lesson, we looked at two common mechanisms of sexual selection—competition among males and mate choice by females—that resulted early in our evolution and continue to influence the differences in our mating strategies today. We also examined two key theories—parental investment and the relative reproductive rate—to discuss how fundamental differences in our biology—fast sex versus slow sex—can have a major impact on issues such as child care, commitment, promiscuity, interest in casual sex, choosiness, and so on.

Over the next few weeks, we will be exploring many different facets of human sexual behavior. Having a good understanding of evolutionary theory will help us make accurate predictions about where and how the sexes differ when it comes to a variety of behaviors. We will continue with this biologically oriented theme for the next few weeks by learning more about men’s and women’s bodies—specifically the external genitalia and the internal reproductive tracts, as well as the influence of sex hormones on the body. We’ll also look at sexual differentiation and development of male and female anatomy. These key biological differences in the sexes can also shed light on some sex differences in our mating psychology.