(evolutionary biology) The evolutionary process in which the organisms evolve bodily parts that are analogous in terms of structure and function despite their ancestors that are very dissimilar or unrelated
(ophthalmology) The coordinated focusing of the eyes, particularly at short range
(general) The act of converging; coming together of two or more things
In evolutionary biology, convergence pertains to an evolutionary process wherein organisms evolve structures that have similar (analogous) structures or functions in spite of their evolutionary ancestors being very dissimilar or unrelated. It is also called convergent evolution. Examples of convergent evolution are the wings of bats, birds, and insects that evolved independently from each other but all are used for flying. Another example is the complex eyes of vertebrates, cephalopods, cubozoan jellyfish and arthropods that evolved separately but are associated with vision. The smelling organs of the terrestrial coconut crab similar to those of insects are also a display of convergent evolution. This evolutionary process is in contrast to the other evolutionary process called divergence (or divergent evolution), which is a process by which an interbreeding population or species diverges into two or more descendant species, resulting in once similar or related species to become more and more dissimilar.