In this Evolution Web feature, test your skills at judging who's who on the tree of life while you learn about the tools and methods of cladistics.

This video segment explores the benefits and pitfalls of cloning as a means of reproduction. From Evolution: "Why Sex?"

This video segment describes how the Australopithecus afarensis skeleton known as Lucy could have been fossilized. Footage courtesy of NOVA: "In Search of Human Origins."

This video segment from Evolution: "Extinction!" shows the impact of invasive species on native ecosystems.

This video segment from Evolution: "Darwin's Dangerous Idea," together with interviews with Daniel Dennett and James Moore, depicts Darwin struggling with publicizing his revolutionary theory.

Dr. Stephen O'Brien of the National Cancer Institute discovers a 700-year-old mutation that makes a person resistant to HIV infection. From Evolution: "Evolutionary Arms Race."

This video segment from Evolution: "Darwin's Dangerous Idea" illustrates the remarkable camouflage of a praying mantis against its leafy backdrop.

This video from Evolution explores the evolution of humans from a common ancestor of humans, chimpanzees, and other apes.

This video from Evolution highlights Charles Darwin's personal struggle to bring to light his theory of evolution through natural selection.

In this video from Evolution, an exploration of multi-drug resistant tuberculosis in the Russian prison system highlights one reason it is important to understand evolution.

This Evolution video segment depicts the landmark hominid fossil finds by Don Johanson and his team in Ethiopia.

In this video segment from Evolution: "Great Transformations," paleontologist Jenny Clack explains that vertebrates evolved fingers before they invaded land.

The shared set of genes for body segments, possessed by all animals, are discussed in this video segment from Evolution: "Great Transformations."

This Evolution video segment describes how the famous track fossils known as the Laetoli footprints might have been formed and what they can reveal about the creatures who left them.

In this video segment from Evolution: "Extinction!", geologist Peter Ward discusses evidence for a Permian-Triassic mass extinction.

The peacock provides a classic example of sexual selection, the force behind nature's extravagances. From Evolution: "Why Sex?"

Bonnie Chen builds on students' prior knowledge of mutations to lead her class through a simulation of wading birds feeding.

Marilyn Havlik leads students through a simulation of the Hardy-Weinberg Principle to develop their understanding of population genetics.

In this transcript of an interview filmed for Evolution: "Great Transformations," Ted Daeschler and Neil Shubin describe the discovery and significance of some of their key fossil finds.