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Tuesday, October 19, 2010

Stasis: Things don’t change nearly as much as we think ...

Nope. The liverwort (sort of) was around 471 million years ago.

On this, British physicist David Tyler writes,
On ecological grounds, the plants that grew in the Ordovician were ideally suited to initiating the colonisation process. They were not there because they were primitive (because there are plenty of complexities if we look for them) but because they were pioneers in the colonisation process. Furthermore, although there is evidence of diversification, the message we need to take home is one of stasis. Having established diversity, the authors of the research paper are constrained to comment that this same diversity is apparent at higher stratigraphical levels. It would appear that diversification was accompanied by stasis. This is not a story of macroevolutionary transformation, but of variations within a basic type. Today there are over 6,000 liverwort species: there is plenty of evidence for diversification, but all of it is within the Liverwort group.
Go here for more.

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