LEGALIZE IT

[AlexM]

Marijuana vs. cancer = old news

http://www.webmd.com/news/20000228/m...y-brain-cancer

[Subfallen]

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Doesn't work that way. Darwinian evolution no longer happens in humans nowadays.

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Baldwin effect for the win!

[vhawk01]

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Doesn't work that way. Darwinian evolution no longer happens in humans nowadays.

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Baldwin effect for the win!

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Dawkins talks about a concept of the 'evolution of evolutionability.' This reminded me of that.

[soon2bepro]

it doesn't work that way at all because nowadays being a better learner doesn't mean you'll survive longer and it especially doesn't mean that you'll have the greatest number of offspring [img]/images/graemlins/wink.gif[/img]

[vhawk01]

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it doesn't work that way at all because nowadays being a better learner doesn't mean you'll survive longer and it especially doesn't mean that you'll have the greatest number of offspring [img]/images/graemlins/wink.gif[/img]

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I'm not sure how you can say that no traits will be consistently selected over enough generations to cause any change in frequency. I don't know if there are or not, but I don't see how you can just dismiss it. A possible candidate: the desire to have as many children as possible. In many populations, this would be selected against, because you are less likely to have grandchildren if your birth your way to starvation. But human populations haven't been like this for a while, and there is no reason to think they will be in the future. I'd also think that the qualities that allow people to successfully attract fit mates are pretty homogenous over time, its just the more superficial ones that change with the trends. Bear in mind that nice cars, a good job, nice clothes, are all really representations of the same skill and attribute.

[soon2bepro]

Do you really think people with nice cars, good jobs and nice clothes are the ones who have the largest number of offspring? Think again...

Anyway. In some general senses maybe there can be progress (though much slower that it'd be in the wild), but it's clearly not going to be like this for most specific, unique traits. So no major changes will happen naturally. Even if they do, they'd take so long by that time humans will have probably altered themselves enough to make that change irrelevant.

[vhawk01]

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Do you really think people with nice cars, good jobs and nice clothes are the ones who have the largest number of offspring? Think again...

Anyway. In some general senses maybe there can be progress (though much slower that it'd be in the wild), but it's clearly not going to be like this for most specific, unique traits. So no major changes will happen naturally. Even if they do, they'd take so long by that time humans will have probably altered themselves enough to make that change irrelevant.

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The speed of the change is usually proportional to the strength of the selection pressure. I would probably agree, intuitively at least, that humans are subject to far fewer and far weaker selection pressures than most animals.

Also, yes, I do think those are the people having the most kids. I don't mean the Fortune 500 CEO's, I mean the 23 year old with the Trans-Am and the boss tats.

[CallMeIshmael]

Soon,

Evolution != natural selection

Evolution = changes in gene frequencies = natural seletion + genetic drift + mutation + sexual selection + recombination + probably a few other things not on the top of my head


Now, even if we assume that natural selection is 100% gone for humans, that doesnt preclude evolution from happening


However, I believe the assumtion that natural selection is 100% gone for humans stands on very shaky ground. It is most certainly NOT true is certain parts of the world where resources are still limited.

However, even in our society there are still many possible ways that NS could be acting. Random examples off the top of my head:

- Aversion to fatty foods...fatty foods once presented a great benefit to our ancestors leading them to enjoy thier taste, however their abundance in our culture now renders this trait unfavourable; are people who dislike fatty foods more likely to live to procreation? Are they more likely to be able to find mates? Perhaps, perhaps not.

- What about intelligence? Intelligent people today often choose to remain in an adolescent type phase until their mid-20s (college grads, perhaps beyond), while the less intelligent often procreate at a much younger age.
(http://www.jstor.org/view/00223808/di950958/95p0009z/0) shows a negative correlation between education and fertility. Intelligence itself correlates with the decision to pursue more education. Does this mean intelligence is at a relative fitness disadvantage? Perhaps, perhaps not. There could be many outside factors.


These are just two examples off the top of my head, and I dont claim that either are all that great. But there is certainly much room for natural selection, even in our environment.

[latefordinner]

I love it when people clim that evolution isnt working because traits they don't like aren't being selected against as if they could know in advance what traits are useful or not

[Rduke55]

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I'd definitely like to know more about that. Can you cite any sources?

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Gregory Cochran has something coming out about it. Bruce Lahn talks about it in the brain a lot, especially relevant here is the ASPM gene 6000 years ago. Also there are some indicators that brain size is changing as well (getting smaller surprisingly) but that's pretty new.



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But As long as they're not strongly being selected for, they won't survice and reproduce more than the other genes, which is what makes large evolutionary changes possible.

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Depending on population size neutral variants can hang around a long time.

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but it seems to me like maybe you making a mistake along the line.

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I'm pretty sure I'm not. Someone asked me about why I don't like the preponderance of Dawkins in the popular evolution literature and this thread gives a pretty good example why. soon2bepro seems pretty intelligent and clearly has thought about these things but it seems like Dawkins is essentially his only source on evolution so he has a biased and very narrow view about how evolution works.

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A major evolutionary change only happens after many, many generations of small steps towards it.

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But it can happen a lot faster than you think it does. Mayr's work on speciation, Eldridge and Gould's punctuated equilibrium kind of introduced this idea (although even in Darwin's writings there was some discussion of something like it), Dawkins talks about things like this (he referred to "variable speedism" - PE being one type) in The Blind Watchmaker (someone correct me if I'm citing the wrong book - it's been a while).

Why do you think that it needs to take so long for changes?

Also, I'm having trouble reconcinling some of your views. Ignoring "quick" evolutionary change for a moment, you said that evolutionary change, specifically with natural selection, takes tens of thousands, hundreds of thousands, or millions of years, (and I agree with you for a lot of stuff) however, then you state that humans are not being acted on by natural selection - but this view is is based on what? Forty (or less, depending on who you are talking to) thousand years? How would you know that based on such a small snip of evolutionary time.

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If completely different traits are selected for in every consecutive generation

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I'm not sure what you mean here or how it's related to my views. I'm not talking about one generation (although some sunflowers are thoguht to have speciated in a few dozen generations).

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So if any major evolutionary change is to naturally take place in such an scenario, it'll be on based on random chance alone, not natural selection.

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What are you referring to when you talk about "random chance"?

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None of these happen often enough on a large scale, nor make for a major change to be selected for.

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Whaaa?!?!? Populations of people don't move around that much? (there have been several major migrations to the US in the past 500 years or so that have drastically changed allele frequencies in the population)

There haven't been disease epi- and pandemics over the past fivehundred years that have removed large portions of the population and drastically changed allele frequencies?


Also, look at this for some ideas:
http://www.berkeley.edu/news/media/r...5/30_aids.html
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I guess a major event like an extremely contagious, world wide, short-term mortal disease or a severe change in all of earth's natural enviroment could change the way things are going, but that's not the point.

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Isn't it?