Evidence for evolution comes from several sources.
Fossils provide evidence of evolution - fossils in older layers are more primitive than newer layers
Geography can provide evidence - island species most closely resemble the nearest mainland species, and populations can show variation on different islands
Embryology provides evidence - crabs and barnacles have identical larvae - but different adult bodies
Anatomy can provide evidence - different species can have homologous structures - that have different functions, sometimes different species can have analogous structures - that have similar functions, vestigial structures also are evidence of evolution - structures that had a function in an early ancestor
