Recently, a reader wrote to me concerning Stasis: Life goes on but evolution does not happen. Reader asked,
Concerning horseshoe crabs and coelecanths, could it be possible that marine-environment organisms are under less pressure to change/evolve than terrestrial organisms?
Thank you very much for your thoughts!
You could of course be correct. And then we face several conceptual tasks prior to research:
1. Specifying testable hypotheses as to why the longest-conserved marine life forms were under less pressure to change/evolve. We must not fall into the trap of assuming that they must be under less pressure because they didn’t evolve.
We don’t know for sure that pressure has much to do with it. That is, we assume so. But there is no known law of physics or chemistry that requires change/evolution, as opposed to stasis/extinction. There may be other factors in why life forms do or don’t change/evolve. How can we weight the ones we find?
Conversely, why are terrestrial life forms under MORE pressure to change/evolve?
2. Many marine life forms survived tens of millions of years, then went extinct. One thinks of the Cambrian biota. We need a hypothesis that can account for why life forms that have shown long-term stasis later disappear, one that correlates to our hypothesis as to why some just persist.
3. Some life forms strut the stage a short while and then disappear – one problem is that in our present state of research, we are much less likely to find enough of them to establish that that is so, but research does continue after all, and recent finds have been promising.
4. Some extinctions are so complete – all dinosaurs, for example – that they constitute either a special case (that currently relies almost entirely on storytelling, as opposed to biological principles), or they could shed much light on both extinction and stasis.
It is early days yet. But this seems clear to me: We will not understand evolution if we do not understand stasis and extinction. If there are any general principles that would turn the history of life from history into science, they must incorporate all three outcomes. – Denyse O’;Leary, for Uncommon Descent News
Anyone wish to weigh in?
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