Tuesday, November 18, 2008

The end of New-darwinism?

According to Neo-darwinism:
''Neo-Darwinism postulates that natural selection acts on the heritable (genetic) variations within individuals in populations and that mutations (especially random copying errors in DNA) provide the main source of these genetic variations. Because positive mutations seem to be rare, Neo-Darwinism contends that evolution will be a slow, gradual process. '' [source]

But perhaps genes are not that information-filled:
''Now it turns out that genes, per se, are simply too feeble to accept responsibility for much of anything. By the traditional definition, genes are those lineups of DNA letters that serve as instructions for piecing together the body’s proteins, and, I’m sorry, but the closer we look, the less instructive they seem, less a “blueprint for life” than one of those disappointing two-page Basic Setup booklets that comes with your computer, tells you where to plug it in and then directs you to a Web site for more information.'' [source]

There are actually some very nice theories considering other driving forces behind evolution, like symbiosis:
''Primary endosymbiosis involves the engulfment of a bacterium by another free living organism. Secondary endosymbiosis occurs when the product of primary endosymbiosis is itself engulfed and retained by another free living eukaryote. Secondary endosymbiosis has occurred several times and has given rise to extremely diverse groups of algae and other eukaryotes. Some organisms can take opportunistic advantage of a similar process, where they engulf an alga and use the products of its photosynthesis, but once the prey item dies (or is lost) the host returns to a free living state.
...
One possible secondary endosymbiosis in process has been observed by Okamoto & Inouye (2005). The heterotrophic protist Hatena behaves like a predator until it ingests a green alga, which loses its flagella and cytoskeleton, while Hatena, now a host, switches to photosynthetic nutrition, gains the ability to move towards light and loses its feeding apparatus.
'' [source, and source] [Book]

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