The Evolutionary Biology of Sex

Note: This 12-credit program will meet from 6 to 9:50 p.m. on Mondays and Wednesdays and from 9 a.m. to 4:50 p.m. on five Saturdays (Oct. 4, 18, Nov. 1, 15, and Dec. 6). First class will meet in Sem2 E1107.

Why reproduce sexually? In sexual species only half of the individuals produce offspring, so they should be at a competitive disadvantage relative to asexual species. By definition, evolutionary fitness is one’s relative success at passing on one’s genetic information to future generations; but in sexually reproducing organisms, the offspring only carry half of the genetic information from each parent. Despite the numerical and genetic costs of sexual reproduction, few strictly asexual organisms exist, and sexual reproduction is virtually ubiquitous in biology. Why?

In addition to inquiring about the advantages of sexual reproduction, we will explore the astonishingly diverse means of sexual reproduction. Male green spoonworms are tiny; they live in the female’s reproductive tract and fertilize her eggs as they pass by. In wattled jacanas, a tropical bird, males sit on the nest, and females defend territories containing several mates. Depending on the species, the sex of each individual may be determined by genetics, by environmental factors, or even by social status.

We will read works on the natural history of reproduction in animals and plants and study evolutionary theory, genetics, and ecology. Students will be expected to approach the topics with rigor from a scientific perspective. Some upper division credit may be awarded for upper division work by arrangement with the faculty at the beginning of the quarter.