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To: FreedomCalls

Times UK are suggesting this might be a newly evolved species! (rather than an old one newly discovered).


49 posted on 12/06/2005 7:02:36 AM PST by vimto (Life isn't a dry run)
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To: vimto

>> Times UK are suggesting this might be a newly evolved species! (rather than an old one newly discovered). <<

Now that's just plain silly. Speciaition is the inability to interbreed. Newly acquired phylogenic traits (i.e., a genetic change resulting in an altered appearance) are said to LEAD to speciation, but if an organism is so profoundly unique that speciation occurs immediately, by definition, it cannot reproduce. When that happens, it's simply called a "birth defect."

People do misunderstand that evolution can be sudden in the sense that a mutation takes a single generation to occur. But the propigation of that gene takes a long time from the perspective of human history... even though it appears instantaneous from the perspective of billions of years of geological history.

If speciation does occur due to a sudden new phylogenic trait, first enough inter-breeding has to occur to establish a fair-sized population of organisms with that trait. Eventually, offspring of two parents with that trait may cease to recognize that those without the trait are potential mates. Or those with the trait and those without it may become seperated. (For instance, superior vision in dim light may make one species choose hunting grounds deeper in a forest.) Then, when additional genetic mutations occur, they aren't shared among the two groups, and the organisms become more and more dissimilar.

This may make the term "speciation" seem surprisingly relative. It is. It's always a judgment call as to when two races or subspecies of organisms should be said to have speciated. For instance, two dissimilar subspecies may still be perfectly capable of interbreeding, but geographically isolated. But with land bridges and the like, that can change rapidly. And what constitutes geographic isolation? For small creatures, being in a different forest may be more of an isolation than bears being on seperate continents.

In any event, the notion that a species "just evolved" is ridiculous.


55 posted on 12/06/2005 8:18:13 AM PST by dangus
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