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Are humans still evolving?
Posted: 30 March 2007 05:52 AM   [ Ignore ]
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[size=18:36700b3452][color=green:36700b3452]As I think most of us were taught - I believed that homo sapiens stopped evolving with the onset of the agricultural revolution. Apparently that is NOT the case! An article in the NY Times:
Still Evolving Human Genes Tell New Story
is very interesting. Does this work open the old racist biology for reexamination? Will it create classes of citizens based on genetic makeup?
Jim[/color:36700b3452][/size:36700b3452]

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Jimmie Keyes
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Posted: 30 March 2007 02:46 PM   [ Ignore ]   [ # 1 ]
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Interesting articles, but as usual in the poular press not nearly enough detail nor opinions from other scientists in the field to evaluate the legitimacy of the work, much less it’s broader imlications. It makes sense that humans are continually evolving, though I suspect many of the selection pressures are created by features of social living rather than changes in the environment, which we largely compensae for with technology. There was some recent discussion of genetics and race in the
“right of center” thread under Humanism, if you didn’t see that previously. I take the position that race is pretty questionable as a biological concept, and not especialy useful except possibly in some areas of medeicine, but as you can see there are plenty of folks who disagree with me on that.

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Posted: 30 March 2007 03:05 PM   [ Ignore ]   [ # 2 ]
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I see that my first post didn’t make my views of race and class clear. I am one of those who has no use for any racist theorizing, my fear is this will allow those who want to use to to begin again with their hateful posturing.
Jim

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Jimmie Keyes
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Our lives begin to end the day we become silent about things that matter. (MLK Jr.)

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Posted: 30 March 2007 04:10 PM   [ Ignore ]   [ # 3 ]
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I did actually get the gist of your position from the original post, and I agree with you. I was just refering you to the other thread since it went into the topic in more detail. I am conflicted in that I think it is dangerous to resist scientific research simply because it has potentially harmful social implications, but I was strongly affected by reading Gould’s Mismeasure of Man as a youngster, and I am highly skeptical of the validity or utility of any research on the topic of racial differences.

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Posted: 31 March 2007 10:39 AM   [ Ignore ]   [ # 4 ]
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I suppose isolated groups who remain in one environment will gradually move toward those genetic characteristics which adapt best.  So, the studies may be of historical interest, however, the whole human population is so mobile now, that people are quite frequently not in the environment for which their genes best suit them.  In addition, there is so much continued cross-breeding, that those genes that were specific to one group will soon be spread among just about all populations. 

As a chemist I once worked with said, “My only problem is that I was born a thousand years too soon.”  His father was Chinese his maternal grandfather was German, and his maternal grandmother was black from South Africa.  His ratio matched the approximate world ratio of Asian, Caucasian and Negro -  2:1:1. 

Personally, I wish my Northern European ancestors had picked up a bit of deeper pigmentation people so I wouldn’t have to have had a number of Southern California skin cancers removed.  smile

Occam

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Posted: 31 March 2007 04:03 PM   [ Ignore ]   [ # 5 ]
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I’d like to read the study in full. The story seemed to say that there were genes they tested for that had mental application. I would like to see what they mean by small brain genes etc.
Jim

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Jimmie Keyes
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Our lives begin to end the day we become silent about things that matter. (MLK Jr.)

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Posted: 31 March 2007 06:10 PM   [ Ignore ]   [ # 6 ]
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First, I ever doubted our species continuing evolution (both in genetics and memetics), though I can’t say if I learned that or just grasped it as what should follow.

But the interesting thing is that we now have the ability to guide our species evolution, both biologically and technologically. So I have little doubt that the beings that inhabit the future earth will not be H.S.S. but something else.

There are some very interesting sci-fi pieces on the questions you bring up Jimmy. I suggest Gattaca as one example.

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Posted: 14 April 2007 12:31 PM   [ Ignore ]   [ # 7 ]
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Not sure if this fits in here or not… ( do read all the way please, as it starts out provocately) but two weeks ago at a small gathering i asked some of my friends non-challantly if they believed in evolution…they all began to tell me “of course” and they were talking away trying to prove to me why they did, citing examples of mutations and the like , probably because they thought i was going to challenge them ( hehe) but then i said: “Ok ladies, well let us just assume we hadn’t evolved this far yet, that is, there would be no homo sapiens or homo erectus yet for that matter, would god still exist?”
oh my.. you should have heard some of the comments i got there! eventually the consensus among the others was that it was a mute question, because, as one woman said adamantly, ” god made us evolve to what we are now so we could believe in him”

sighhhh….

then they went on to talk about the latest gossip… arghhh(’:x’)

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Posted: 15 April 2007 06:17 AM   [ Ignore ]   [ # 8 ]
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[quote author=“fragen”] ” god made us evolve to what we are now so we could believe in him”

That’s a delightful example of completely circular “logic”.  LOL

However, taking the role of Devil’s Advocate, had I been there and on their side, I could have asked, “Doesn’t your question imply that at earlier points of evolution before homo erectus, there may have been no god?  If that was so, then it would seem that god suddenly appeared at the advent of the homo genus.”  And, as a god-fearing-Christian, she probably couldn’t accept that.

Occam

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Posted: 26 April 2007 03:17 AM   [ Ignore ]   [ # 9 ]
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Evolution will never stop as long as there are selective pressures. In the past those pressures involved evading predators and finding food. Today you have to look a little harder to determine what selective pressures are working on our species to cause us to evolve. Generally any trait that allows an individual to gain an advanatage in producing offsrping and then allowing a greater number of those offspring to live to reproductive age will give that individual’s genes a survival advantage.

You would think that intelligence would give one a survival advantage, but in theory it could be a disadvantage. Intelligent individuals tend to seek out more challenging careers and may delay having children thus reducing the number of offspring they have. On the other hand, intelligent people may have better acces to healthcare and more of their offspring may survive to reproductive age.

Figuring out exactly what selective pressures are working on our species is complicated, but there are ALWAYS selective pressures of some sort and therfore a species never truly stops evolving.

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Posted: 26 April 2007 04:31 AM   [ Ignore ]   [ # 10 ]
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Posted: 26 April 2007 04:40 AM   [ Ignore ]   [ # 11 ]
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My view of Sapiens evolution is it has stopped! I’ve read or am reading most of the books written by Dawkins on the subject and Dennett’s too. The theory (wrong word but you know what I mean) posits the need for competition. Without it there is no force that requires an evolutionary response. I know that there is some sort of idea that our genes are competing at the level of dna for a reproductive advantage but I’m sorry I believe the whole body is the thing that evolves. We no longer gain any advantage except within the species for short periods, perhaps a few generations and then that strain dies out. Look back at the time of the US founders, Washington, Jefferson, Franklin, Adams, Hamilton, Madison, and we could write a lot more of those sort of family names. Would we not agree that there is in those lines serious stuff for reproductive advantage? Have any survived to become leaders of the world?
Actually I’m joking that is not evolution in action, Just reproductive luck of the draw at the time.
I agree that we can force modification of the species and it will in all likelihood happen but that is not evolution.
Jim
rolleyes

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Posted: 26 April 2007 04:59 AM   [ Ignore ]   [ # 12 ]
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[quote author=“jimmiekeyes”]
I agree that we can force modification of the species and it will in all likelihood happen but that is not evolution.
Jim
rolleyes

Well, it would be evolution by artificial selection rather than by natural selection.

FWIW, I agree that the human race is basically at evolutionary stasis at this point, at least as regards natural selection. The fossil record gives ample reason to believe that once species become widely established they can remain unchanged for millions—even hundreds of millions—of years.

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Posted: 26 April 2007 05:03 AM   [ Ignore ]   [ # 13 ]
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The variety of life on this planet is limited only by the variety and combination of proteins that life can produce. There is a theoretical limit to the number of proteins that can be coded for if you assume some upper limit to the length of amino acids that can be practically used to make a protein, but its a huge number ( There are proteins that are made up of over 1000 amino acids. If you only use the 20 amino acids found in humans, that would give you 20 to the 1000 power - 2 with 1001 zeros after it- possible proteins that can be created). If you look at the billions of species that have existed on this planet and the individual mechanisms they have developed to adapt to this ever changing world there does not seem to be a true limit to evolution.

Evolution is not the process of continued “improvement”, its a process of adaptation to the changing environment and then refining those adaptations by natural selection. The idea that this process results in the formation of “more improved” species over time is simply a homocentric tendency we have to view ourselves as the latest and greatest product of evolution.

I guess it would be more accurate to refine my original statement that “as long as there are selective pressures there will always be evolution” While this may be true it is more acurate to say that “as long as there are selective pressure and those pressures continue to change there will always be evolution”. Since every ecosystem is a dynamic system, selective pressures will always be in flux. Also given what we know about our planet, its past, present, and its most likely future, we can assume that change will always be a part of our world, and so will evolution.

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Posted: 26 April 2007 05:09 AM   [ Ignore ]   [ # 14 ]
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[quote author=“jimmiekeyes”]My view of Sapiens evolution is it has stopped! I’ve read or am reading most of the books written by Dawkins on the subject and Dennett’s too. The theory (wrong word but you know what I mean) posits the need for competition. Without it there is no force that requires an evolutionary response. I know that there is some sort of idea that our genes are competing at the level of dna for a reproductive advantage but I’m sorry I believe the whole body is the thing that evolves. We no longer gain any advantage except within the species for short periods, perhaps a few generations and then that strain dies out. Look back at the time of the US founders, Washington, Jefferson, Franklin, Adams, Hamilton, Madison, and we could write a lot more of those sort of family names. Would we not agree that there is in those lines serious stuff for reproductive advantage? Have any survived to become leaders of the world?
Actually I’m joking that is not evolution in action, Just reproductive luck of the draw at the time.
I agree that we can force modification of the species and it will in all likelihood happen but that is not evolution.
Jim
rolleyes

Thats just not true. Just because we don’t have to climb a tree to get away from a lion does not mean there aren’t selective pressures. The example I gave above is a clear case of that.  Natural selection is occuring all the time and to all species, even humans, but it takes thousands of generation to see the result.

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Posted: 26 April 2007 05:11 AM   [ Ignore ]   [ # 15 ]
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While I don’t see any strong evidence human phenotypes are changing, I’m not sure that over the time scales evolution works we would, so I don’t know that we can say we are not evolving. Remember, selection pressure can produce modifications in invisible characteristics; MHC haplotypes in our immune systems, resistence of susceptibility to toxins, infectious agents, dietary tolerances. Why are many people of European descent lactose tolerant and most othe rpeople aren’t? Because there was a sufficient selection pressure (or founder effect, or whatever) to change the relative frequencies of the genes involved. I think it is difficult to see contemporary selection since we are generally looking a small statistical differences in reproductive success based on characteristics that do not dramatically distinguish one person from another.

I would agree that many of the selective forces are induced by our own behavior, and in that sense are somewhat artificial. And we do influence reproductive success by artificially compensating for disabilities and disease effects through healthcare. But I think there is insuficient evidence to declare us at a standstill.

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