Essay On Oceanic Dispersal

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The resurrection of oceanic dispersal in historical biodiversity. by Alan de Queiroz.

The distribution of many taxa that are separated by oceans can be explained by either vicariance or oceanic dispersal. At first oceanic dispersal was the explanation used for the distribution of taxa separated by oceans. Since the 1930s till the 1960s time oceanic dispersal was the most common explanation because there were many plausible dispersal mechanisms that would make oceanic dispersal possible. Support for the plausibility of oceanic dispersal was provided by experiments performed by Darwin and his supporters that showed that organisms (mostly plants seeds) could survive in oceans for extensive time periods. More importantly it was argued that organisms
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The fragmentation of Gondwanaland could explain the distribution of southern beeches, cichlid fish, pleurodiran turtles and ratite birds. Falsifiability was used by many cladistic biogeographers, since they argued that vicariance is falsifiable (testable), whereas oceanic dispersal was not. Since the support for vicariance was so great, vicariance became the most probable explanation for most biogeographers and dominated historical biogeography. However, in more recent years there has been increased support for oceanic dispersal. Even in cases that were previously thought to have occurred due to vicariance, not oceanic…show more content…
The radiation of the chameleons originated in Madagascar via oceanic dispersal, not vicariance. This corresponds with the fact that the oldest found fossil came from Kenya 18 million years ago. This is long after Madagascar fragmented from Africa 120 million years ago (Raxworthy et al.). It is more challenging for animals to move across ocean barriers, but it is possible that these chameleons were swept up by the Mozambique current moving southwards and “rafted” from the Mozambique current into the Madagascar current, moving northwards, and then ended up in

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