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Reversing Undesirable Fish Evolution
TaeKwonDood writes "Your granddad's approach to fishing — throw the little 'uns back — may have hurt their evolution, but we can reverse that, says a group of researchers, with a change of policy.
Fish have been 'reprogramming' themselves to be smaller and live longer. Welcome to evolutionary dynamics, Lamarck. But, no, they are serious. And it can be fixed within 12 generations. What do the smart people out there think about this? Are they using the term 'evolution' the wrong way?"
Are they using the term 'evolution' the wrong way?
Nope. It seems correct to this biology teacher. This is a clear case of directional selection. Keep eliminating the larger fish and the median size of fish in the population will be smaller. So, by taking the large ones, we are selecting against them and for smaller fish and juveniles. If, over time the frequencies of the alleles for large and small change in the population, then we have, by definition, evolution.
What makes you think this wouldn't be an example of evolution?
"Empathise with stupidity, and you're halfway to thinking like an idiot." - Iain M. Banks
What does Lamarck have to do with it? These fish haven't been passing down traits they've developed during their lifetimes - we've been killing all the big fish, so smaller fish are selectively left to breed. That's Darwinian evolution.
In normal situations, I'd imagine that bigger fish tend to reproduce more often. But when some external force (e.g., thousands of fishers in boats with GPS and big nets) changes things, you get a different outcome.
If we preferred to eat fish that were darker in colour, they'd be getting lighter instead.
Either TaeKwonDood misunderstands evolution, or rushed to post his article a little too quickly...
---sheath
No, but you're being rather careless with your language.
It hasn't "hurt" their evolution. Their evolution has been helpful, based on the selection pressures they face.
Nor are the fish "reprogramming themselves". The species' genetic make up may be shifting (in a loose sense "reprogrammed") but they aren't doing it to themselves.
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Animal Husbandry has been doing it for years in one form or another.
See Wikipedia
Of course, if you leave the runts of the litter only, you end up with smaller critters. Its how many lap dogs were bred in the first place.
And like any breeder can tell you, of course it can be fixed in 12 animal generations!
For years, the elephants in southern India have been hunted for their tusks. Fifteen years ago, you could very well run into a lone tusker in the wild with metre long tusks.
But now of late, there are baby elephants being born who grow up to be fertile males without the large tusks. With tiny foot long points out of their mouths, instead of something resembling the original giants that I used to love.
It's almost as if the poachers are even more of a significant selection force than nature and female preference put together.
Quidquid latine dictum sit, altum videtur
just because those fish didn't evolve the way we would have liked that it somehow means that it "hurt their evolution."
I'd in fact go further and say it has helped their evolution. If they become small enough that us humans cannot be bothered with them then they have managed to eliminate the most dangerous predator on the planet as a concern. Seems like a smart move to me.