The evolution of a species can branch off in many different directions. Over thousands of generations, one species can split into several new ones. Some of these new species may die off, but others can split into yet more new species. By tracing this history, biologists are able to see the branches of an incredibly complex family tree—what they call the phylogenetic tree.

By studying just a handful of species, one biologist can contribute to our picture of the history of life as a whole.

Even the finest structural details hold clues to a species' evolutionary history. For entomologist Andrew Polaszek , the veins on the wings of a wasp speak volumes about its relationship to other insects.

Watch Andrew study the wasp.
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DNA analysis can help trace the relationships between species because closely related species share much of the same genetic material. The technique can challenge previously accepted classifications, showing just how complex evolution actually is.

Hear how DNA analysis has changed Andrew's view of evolutionary biology.
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When biologists establish a species' place on the phylogenetic tree, they are making a scientific hypothesis about the evolutionary path it has taken. By saying that something is a distinct species, they are saying that the path that organism has taken is unique, and has led it to have properties that no other species on earth has.

Zoologist Mark Wilkinson explains the importance of naming.