Re:The Global Fertility Crash
by journalctl on Thursday October 31, 2019 @03:46PM
(#21412872)
That’s not evolution, that’s just... nobody having non-blue eyes anymore because you killed them. It’s contrived. People would still have babies with non-blue eyes, though. Getting rid of all members of a species with a specific trait doesn’t make that trait go away.
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It's a purposely extreme example of evolution. Because blue eyes are a recessive trait, there would not be any babies with non-blue eyes until a fresh new mutation occurred. The trait really does go away when there is no DNA in the population that could express it.
The point of my example is to crush the mistaken notion that evolution is inherently slow.
It happens in the real world too. The cold and flu viruses mutate constantly, which is why last year's flu shot isn't going to help you much with avoiding this season's flu, and you getting a cold in the past doesn't make you immune to catching it again.