A Brief History of Sex

1. A Brief History of Sex • From Primordial Ooze to Evolutionary Psychologists

2. Males produce sperm. Females produce eggs. Sex by Definition

3. Why have sex? • Asexual reproduction allows genes to reproduce themselves exactly. • Sexual reproduction seems to serve the species at expense to the individual, which is contrary to Darwin’s premise. • The prevalence of sexual reproduction cannot be explained through genetics alone.

4. Sexually Avoiding Diseases • Parasites are simple and evolve faster than we do. • Sexual reproduction is insurance for surviving future diseases.

5. Sex is all about compromise • Individual genes have an incentive to cheat instead of playing nice during reproduction. • To avoid conflict and sabotage, the two different kinds of sex cells evolved as a compromise. • Male sex cells sacrifice the possibility of passing on their organelle’s genes in order to keep reproduction moving smoothly. They specialize in being small and swift.

6. Cellular Sexism • Female sex cells represent a larger investment than male sex cells. • Sexual practices have evolved that either reinforce or offset this asymmetrical investment.

7. The Sex Life of Peacocks • Males gather in a meat market called a “lek”. • Females peruse the males on display. The best-looking peacocks get nearly all the females. • Result: evolution of expensive beauty standards.

8. The Sex Life of Swallows • Males and females form ostensibly monogamous pairs. • Males try to keep their females faithful while pursuing discrete affairs themselves.

9. The Sex Life of the Preying Mantis • The female frequently consumes the male shortly after sex. • Presumably, she is more amply compensated by the additional nutrition for furnishing the larger sex cell.

10. The Sex Lives of Humans • Sexual selection clearly helped shape gender roles as we know them today. • Analogies with animals help us theorize about the process of sexual selection. • However, our understand is clearly far from complete.