Reversing Undesirable Fish Evolution 216
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?"
Clear example of directional selection... (Score:5, Informative)
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 [wikipedia.org]. 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?
Sounds like evolution (Score:5, Informative)
Are they using the term 'evolution' the wrong way?"
If being smaller enables the fish to survive long enough to breed, then no. Big fish die off, small fish breed.
Darwin, not Lamarck (Score:5, Informative)
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...
Its called Breeding (Score:5, Informative)
Animal Husbandry has been doing it for years in one form or another.
See Wikipedia [wikipedia.org]
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!
Re:Clear example of directional selection... (Score:3, Informative)
well yeah, the summeries on slashdot can be pretty bad but there's two redeeming features about all of this: the article [when it is relevant] and the discussion about said article and potentially about said summery. And the mod points...
Who ever asked that silly question... (Score:4, Informative)
Re:Clear example of directional selection... (Score:3, Informative)
I see you are new here, the zen of slashdot is never read TFS/TFA, if you must you can glance at the headline before going straight to the comments. Personally I don't know of any other site where geeks regularly gather in such numbers and diversity to hurl abuse at each other.
Re:Clear example of directional selection... (Score:4, Informative)
"If, over time the frequencies of the alleles for large and small change in the population, then we have, by definition, evolution."
No, we haven't. We just have frequency variation. But we haven't change the gene pool a dime. Without new characteristics we have no evolution, by definition.
I have to agree with GP, we indeed have evolution, by definition. Evolution is not defined by "new characteristics", whatever that is. Could you please provide a reference that defines evolution as "new characteristics"?
Evolution is (as I have learned during my biology studies) defined as a change in allele frequency. If the genetic make-up of the population changes from one generation to another (and frequency variation constitutes such a change), then we have evolution.
Furthermore, you assume that only frequencies change. That need not be the case. A phenotypical change in size (as in this case) might also very well be caused by mutation, what might be a "new characteristic". Superficially you have no way if distinguishing the two processes.
Re:Helped their evolution (Score:3, Informative)
I don't know - once one of the selection pressures is an intelligent force that can predict the eventual path of evolution, I'd say words like, 'hurt' can start to apply.
What if the fish evolving to be smaller to avoid human mouths eventually leaves them set to be eliminated by some other force? In other words, what if we're forcing a short term evolutionary advantage that is long term fatal to the species?
The Amerindians knew (Score:2, Informative)
Re:Helped their evolution (Score:3, Informative)
Natural selection works to increase the fitness of the average individual in a population sure, but Evolution also includes cases where the average fitness level can go down. Consider, for instance, the founder effect [wikipedia.org].
Re:Helped their evolution (Score:3, Informative)
Bananas are a bad example. They might be a lot easier to eat these days, but they can't reproduce on their own anymore. They're also so limited genetically, because they don't reproduce like plantains do, that a banana-specific bacteria or mold or something could totally decimate a very large supply of the fruit.