The independent evolution of similar features, structures or functions in unrelated species or other taxonomic groups due to living in the same kind of environment. It often occurs due to similarity of function such as the evolution of wings in the ancestors of bats, birds and flies and which serve an analogous function (viz., flight). Similarities in structure between the shark (a fish) and the dolphin (a mammal) are a result of convergent evolution in that they evolved independently as adaptations to aquatic life. A contrast is sometimes made with parallel evolution, a term put forward by George Gaylord Simpson (1902-1984), which involves similarities due to both analogy and homology. The distinction is sometimes difficult to make. One way of doing so is to treat convergent evolution as occurring when descendants resemble each other more than was the case for their ancestors with regard to some feature, structure or function. In contrast, parallel evolution means that two or more lineages have changed in similar ways so that descendants are similar to each other as were their ancestors. Thus, for example, Australian marsupials evolved in parallel with the evolution of placental mammals in other parts of the world.
See Analogy (biology), Adaptation, Biological evolution, Function, Homology, Incipient speciation, Lineage, Theory of natural selection