This entry presents an analysis of human sexual reproduction at two different time scales, one nested within the other, respectively, addressing the ultimate and proximate levels of causation: (a) the adaptive functions of sexual reproduction over the time scale of human evolution and (b) the physiology of human sexual reproduction over the time scale of individual human development.

The Adaptive Functions of Sexual Reproduction Over Evolutionary Time

The essence of sexual reproduction is the recombination of genes. In humans, this is accomplished by the fusing of two haploid gametes, a sperm cell from the diploid father and an egg cell from the diploid mother, into a diploid offspring zygote. Sexual conjugation in certain microorganisms (e.g., bacteria, ciliates, dinoflagellates, and diatoms), which involves a direct exchange of genetic ...

  • Loading...
locked icon

Sign in to access this content

Get a 30 day FREE TRIAL

  • Watch videos from a variety of sources bringing classroom topics to life
  • Read modern, diverse business cases
  • Explore hundreds of books and reference titles