Just a cautionary note there, Iain, Jonah, on how nature adapts.
When a sudden, major environmental change takes place (the super-volcanos Jonah was informing us about last week come to mind–likewise asteroid collisions, ice ages, massive solar flares, and the like), the first thing that happens is a big die-off.
An entire speies might be wiped out in a big die-off. Assuming this doesn’t happen in the case of some particular species, the tiny number of survivors form a “founder group” for their subsequent genetic descendants. Likely they have, on average, some qualities of toughness or resourcefulness that helped them survive. Even when that is not so, you get accelerated effects from increased inbreeding and genetic drift.
On this account, these big die-offs–there have been LOTS of them, the evidence there in the fossil record, and now also visible in comparative genomic studies (where they are known as “population bottlenecks“)–have been described as “natural selection in a hurry,” though in strict logic you could equally well call them “genetic drift in a hurry,” or “inbreeding effects in a hurry.”
If you’re a paleontologist or a genomicist, this is all very fascinating.
What has happened, though, is still… a big die-off. Lots, lots, lots of dead tissue.
And that’s how nature adapts.
Mother Nature can be an awfully stern parent.