Hypermedia Glossary Of Genetic Terms
|Homoplasy||Appearance of similar structures in organisms not inherited from a common ancestor or developed from a common anlage. Indication for the universal mechanisms of evolution
The term includes convergence, parallelism, and reversal.
|Anlage||Embryonic primordium from which a specific part of the organism develops. The rudimentary basis of an organ in an embryo.|
|Evolution||In Darwinian terms a gradual change in phenotypic frequencies in a population that results in individuals with improved reproductive success.|
|Convergence||The evolutionary development of similar external morphological traits in organisms which are unrelated (except through distant ancestors) as each adapts to a similar way of life and/or environment.
Sharks (fish), dolphins (mammals), and ichthyosaurs (extinct reptiles) provide good examples of convergent adaptation to the aquatic habitat.
|Parallelism||Occurence of the same of similar structures independently evolved in two or more lineages, that may be but must not be related to another.|
|Reversal||Resemblance between two taxa because one of them has evolved a new character, then lost it again, and the other taxon has never evolved it.|
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