The Evolution of Sex

Based on our understanding of natural selection, at first glance sexual reproduction doesn't appear to be advantageous from the female perspective (due to the two-fold cost of sex). However, the fact that sexual reproduction is so common in all groups of organisms suggests that there must be some major benefits of sex that outweight the costs.

Expected Learning Outcomes

By the end of this course a fully engaged student should be able to

- explain "the two-fold costs of sex"
- discuss possible benefits of sexual reproduction including adaptation to environmental uncertainty and fighting disease
- be able to discuss the problem of the evolution of antiobiotic resistant microbes
- be able to discuss what the medical field may be able to learn from observing how nature fights disease.

Past Exam Question (answer at the bottom of the post)

1. What is the “two fold cost of sex”?
(a) female gametes are twice as expensive to produce as male gametes
(b) the genetic variation produced by sexually reproducing females provides a benefit if there is environmental uncertainty
(c) individuals reproducing asexually pass on twice as many of their genes
(d) a and b
(e) b and c

2. Which of the following hypotheses can explain a benefit of sex?
(a) males pass on more genes in sexual reproduction than in asexual reproduction
(b) the genetic variation produced by sexual reproductions provides a benefit in uncertain environments
(c) females reproducing asexually pass on twice as many of their genes
(d) a and b
(e) b and c


Further Readings

Although I am usually a little skeptical of articles form Wikipedia, this one is pretty good. It goes into more detail than you need to know, but provides some useful information

Evolution of Sexual Reproduction http://en.wikipedia.org/wiki/Evolution_of_sex

Interesting Article by Evolutionary Biologist David Barash

The Good News About Sex http://chronicle.com/blogs/brainstorm/the-good-news-about-sex/43292

Life in Local Playa Lakes

If you would like to learn a little more about local playa lakes-

Playa Lakes http://www.eoearth.org/article/Playa_lake

Drawings of cladocerans similar to those inhabiting playa lakes.

This is what they don't look like.

answer- 1. c 2. b