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| - Convergent evolution besides being a major mechanism of evolution itself, is one of the major methologies of speculative evolution. When we see that eyes or hair have evolved several times on Earth, it becomes very plausible that they would continue being independently discovered further on in Earth history or during evolution on an alien world. Better than that even, we can examine the similarities and differences amongst these semi-independent occurrences, and get a better idea of what the general space of possibilities looks like.
- Convergent evolution describes the acquisition of the same biological trait in unrelated lineages. The wing is a classic example of convergent evolution in action. Although their last common ancestor did not have wings, birds and bats do, and are capable of powered flight. The wings are similar in construction, due to the physical constraints imposed upon wing shape. Similarity can also be explained by shared ancestry, as evolution can only work with what is already there—thus wings were modified from limbs, as evidenced by their bone structure.
- In evolutionary biology, convergent evolution is the process by which two organisms or taxonomic groups have a character in common due to independently adapting to a similar environment or niche, not by homology.
- Convergent evolution (Japanese: 収斂進化) is a special circumstance within an evolution family in which a single Pokémon can evolve from more than one pre-evolved form. This is in contrast to the more common phenomena of linear evolution, in which a single Pokémon has only one possible evolutionary path, and divergent evolution (more commonly known as branched evolution), in which a single Pokémon may have multiple evolutionary paths.
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| abstract
| - Convergent evolution describes the acquisition of the same biological trait in unrelated lineages. The wing is a classic example of convergent evolution in action. Although their last common ancestor did not have wings, birds and bats do, and are capable of powered flight. The wings are similar in construction, due to the physical constraints imposed upon wing shape. Similarity can also be explained by shared ancestry, as evolution can only work with what is already there—thus wings were modified from limbs, as evidenced by their bone structure. Similarity can also result if organisms occupy similar ecological niches—that is, a distinctive way of life. A classic comparison is between the marsupial fauna of Australia and the placental mammals of the Old World. The two lineages are clades—that is, they each share a common ancestor that belongs to their own group, and are more closely related to one another than to any other clade—but very similar forms evolved in each isolated population. Many "body plans," for instance sabre-toothed cats and flying squirrels, evolved independently in both populations. Traits arising through convergent evolution are termed analogous structures, in contrast to homologous structures, which have a common origin. Bat and pterodactyl wings are an example of analogous structures, while the bat wing is homologous to human and other mammal forearms, sharing an ancestral state despite serving different functions. Similarity in species of different ancestry which is the result of convergent evolution, is called homoplasy. The opposite of convergent evolution is divergent evolution, whereby related species evolve different traits. On a molecular level, this can happen due to random mutation unrelated to adaptive changes; see long branch attraction. Convergent evolution is similar to, but distinguishable from, the phenomena of evolutionary relay and parallel evolution. Evolutionary relay describes how independent species acquire similar characteristics through their evolution in similar ecosystems, at different times: for example the dorsal fins of ichthyosaurs and sharks. Parallel evolution occurs when two independent species evolve together at the same time in the same ecospace and acquire similar characteristics—for instance extinct browsing-horses and paleotheres.
- In evolutionary biology, convergent evolution is the process by which two organisms or taxonomic groups have a character in common due to independently adapting to a similar environment or niche, not by homology. An example of this would be the similarities in behavior and morphology between bats and birds. Although superficially very similar, the two groups are considered by evolutionists to be only very distantly related (being grouped only within the clade Reptilia). Their similarities are therefore considered to be a result of evolution in response to nearly identical ecological niches and pressures. Convergent evolution is a theory and has not been observed in action. Also, it presents the following conceptual problems. First, it requires that random chance produce the same outcome in at least two independently occurring instances, which is substantially less likely even than doing so once. Such evolutionary coincidence is a less plausble explanation than one that evolutionists assume away, namely, a common Designer. Second, because convergent evolution would work by random chance rather than by being intelligently guided, simple probability indicates that even if it produced a good result in one organism, it might well produce a suboptimal result in another organism. No such result has been observed.
- Convergent evolution (Japanese: 収斂進化) is a special circumstance within an evolution family in which a single Pokémon can evolve from more than one pre-evolved form. This is in contrast to the more common phenomena of linear evolution, in which a single Pokémon has only one possible evolutionary path, and divergent evolution (more commonly known as branched evolution), in which a single Pokémon may have multiple evolutionary paths. The first known evolution family to observe this phenomenon is that of Feldspawn. Feldspawn's evolution is uniquely complicated; it can evolve into one of three Pokémon, each of which can go on to evolve into one of the same two Pokémon, as seen below: This makes Feldspawn's final evolution an example of both convergent and divergent evolution, and gives Feldspawn a total of six possible evolutionary paths, the most among Pokémon that evolve twice (only Eevee has more, evolving once into one of ten different Pokémon). The second evolution family to undergo convergent evolution is that of Elleielle. In spite of being able to bear 20 different Baby Pokemon as offspring, as shown below, any female offspring have unstable genes that cause them to evolve back into Elleielle.
- Convergent evolution besides being a major mechanism of evolution itself, is one of the major methologies of speculative evolution. When we see that eyes or hair have evolved several times on Earth, it becomes very plausible that they would continue being independently discovered further on in Earth history or during evolution on an alien world. Better than that even, we can examine the similarities and differences amongst these semi-independent occurrences, and get a better idea of what the general space of possibilities looks like.
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