In Evolutionary Biology , describes the process whereby organisms not closely related independently acquire similar characteristics while evolving in separate and sometimes varying ecosystems.
In Cultural Evolution , ''convergent evolution'' is the development of similar cultural adaptations to similar environmental conditions by different peoples with different ancestral cultures.
An example of convergent evolution is the similar nature of the flight/ Wing s of Insect s, Bird s, Pterosaurs , and Bat s. All four serve the same function and are similar in structure, but each evolved independently. Some aspects of the lens of Eye s also evolved independently in various animals.
Convergent evolution is similar to, but distinguishable from, the phenomena of Evolutionary Relay and Parallel Evolution . ''Evolutionary relay'' refers to independent species acquiring similar characteristics through their evolution in similar ecosystems, ''but not at the same time'' (e.g. Dorsal Fin s of extinct Ichthyosaur s and Shark s). ''Parallel evolution'' occurs when two independent species evolve together ''at the same time in the same ecospace'' and acquire similar characteristics ( Extinct Browsing-horse s and extinct Paleothere s).
Structures that are the result of convergent evolution are called or '''homoplasies'''; they should be contrasted with Homologous structures, which have a common origin.
- Spines have evolved in several mammal groups independently - Echidna s ( Monotremes ), Hedgehog s ( Insectivores ), Old World Porcupine s ( Rodents ) and New World Porcupine s (a separate group of rodents). In this case, because the two groups of Porcupines are relatively closely related, they would be considered to be an example of Parallel Evolution ; neither Echidnas nor Hedgehogs, however, are closely related to Rodents at all. In fact the last common ancestor of all four groups was a contemporary of the Dinosaurs.
- The Monotreme Platypus is remarkably similar in appearance and life-style to semi-acquatic placental mammals such as the Beaver .
- are in the eagle and hawk family and use ''eyesight'' for food discovery; the New World Vultures are related to storks and use the sense of smell (as well as sight) to hunt. Both kinds of vulture eat carrion and typically have featherless necks. In both cases they search for food by soaring, circle over carrion, and group in trees.
- the Flightless Cormorant of the Galapagos Islands , unlike other Cormorants , now has non-flight wings, equal in proportion to the swimming penguins. It feeds in close proximity to the shoreline.
- The Neotropic al Poison Dart Frog and the Mantella of Madagascar have independently developed similar mechanisms for obtaining Alkaloid s from a diet of Ant s and storing the toxic chemicals in skin glands. They have also independently evolved similar bright skin colors that warn predators of their toxicity.
- Assassin Spider s are a group comprised of two genetic lines which apparently evolved separately. They have very long necks, fangs larger in proportion than any other spider, and hunt other spiders by snagging them from a distance.
- The smelling organs of the terrestrial Coconut Crab are similar to those of insects.
- The aerial rootlets found in English Ivy (''Hedera helix'') are similar to those of the Wintercreeper (''Euonymus fortunei'') (and other Vine s). These rootlets are not derived from a common ancestor but have the same function of clinging to whatever support was available.
- The existence of distinct families of Carbonic Anhydrase is believed to illustrate convergent evolution.
- Bats are classified into two distinct morphological groups: the megabats ( of all living bat species.
|
