- Colby, C. The TalkOrigins Archive: Introduction to evolutionary biology www.tinyurl.com/60qt
- Lively, C. M. Evolution of sex and recombination www.tinyurl.com/kyzdmbv
- Newman, L. Flatworms penis fencing (video) www.tinyurl.com/ybxsvxwy
- PBS: Evolution—Show #5: Why sex? www.tinyurl.com/587f2
- UC Museum of Paleontology and the National Center for Science Education: Welcome to evolution 101 www.tinyurl.com/yblqkpv9