Dr. Niles Eldredge addresses the question of how evolutionary change takes place over time. Is it dependent on a new species splitting from an ancestral one, or can species evolve as single lineages?  How long does this process take?  Comparing the fossil record with the geologic record, Dr. Eldredge explains his ground-breaking theory of punctuated equilibria, where he surmises that evolution is not a slow gradual change but instead long periods of stasis, or biologic stability, interrupted by periods of intense, rapid evolutionary change.

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Cladograms, or tree-of-life diagrams, show the evolutionary relationships among species.  This video shows the different ways scientists have represented cladograms visually, from traditional line diagrams to circular diagrams to 3-D representations that can show the evolutionary relationships between thousands of species at one time.

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Learn how humans are like—and unlike—Neanderthals (our closest extinct cousin) and chimpanzees (our closest living relative on the tree of life).  This simulation allows you to view three key biological features—the skull, pelvis, and foot—side by side and from any angle, as well as individually.  The Neanderthal skull used here is from the Museum’s 3-D digital scan of a complete skull specimen, the first available for viewing on the web.

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