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Originally Posted by Pedestrian
I don't agree with that. Humans have more or less stopped natural selection for themselves. When you can change your environment to suit you, there is no longer a need or drive to adapt to it.
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Quote:
Originally Posted by Pedestrian
I'm inclined to think it would take a more grievous and long term disaster than we've seen for any evolution to take place. Disasters like Katrina and the 04 tsunami just killed a shitload of people, seemingly without any rhyme or reason. I imagine that if there were an evolutionary effect of these incidents, it wouldn't be seen for hundreds of years, by which point I imagine we'll all have died out due to some other circumstance. The one thing I can see still forcing evolution of our species is global warming/pollution, which is widespread and ongoing enough for long term natural selection.
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Originally Posted by Ian E Coleman
You're right about this. Natural disasters kill on an instantaneous and random basis (the exception being geographical so there might be an argument there). But, I think that if over the next million years if humans stopped eating meat, there might be some small effects. Then again some studies say even our appendixes may not be totally inactive.
Perhaps human evolution has taken a different turn. Maybe the next step is genetic engineering (I hope so). And it might be a necessary one since flipping the bird to natural selection can have some funky genetic effects.
In any case I still think that the argument that humans aren't ethically subject to their own nature is a valid one.
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Natural selection is a consequence of life as we know it. You can't turn it off. What changes is stuff like the strength and direction of selection (is it better to have a smaller or larger beak? Better to birth females or males?). Random killings from natural disasters is part what's called
genetic drift and it generally does have an effect (it changes the overall genetic makeup (allelic frequencies) of the human population ever so slightly), but the effect is smaller the larger the population is.
As for what evolution favours, you should remember that fitness which is what is selected for is measured by how much one's able to perpetuate one's genes. If society is made up in a way that makes asocial people and criminals have overall less fitness (have fewer children) than their counter parts, then that could translate to a selection on a genetic level with important effect on our common genetic makeup over the course of our relatively recent history. You could arguably call that natural selection because it is the environment of the societies which dictates the consequence (making it a natural consequence in that environment), but it's not consciously selected for by a great manipulator. Environment is important, so for our example, let's say in pre-society, the traits which more often create asocials and criminals had a generally more positive effect on fitness.
Ecologists often say simply that evolution is simply a change in allele (varieties of genes) frequencies over the course of generations, for example that the relative frequency of the allele which codes for blue eyes is less in the new generation compared to the parent generation. Going by that definition, it would be hard to argue that mankind does not evolve .. or is f.ex the North American population pretty much similar to what it was like 100 years ago?
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In modern society, people can get by as vegetarians as they can get fruits and vegetables from all over the world, filling every nutritional dietary need. For us to evolve the ability to eat and digest more greens than we can now so that we can get by more efficiently on a plant diet, you'd need a pressure in that direction (generally speaking; vegetarians with plant eating behaviours would need to have a fitness benefit over meat eaters) and you'd need a helluva lot of time too .. making it a sort of irrelevant argument.