[charles brough]

Originally Posted by CraigD

Before this claim can be accepted, it’s necessary to show that it actually is the consensus of evolutionary biologists that H.Sapiens.S. has not evolved since becoming a species.

Aside from the difficulty of defining a distinct event of “becoming a species”, I don’t think this is the conseusus. For example, as described in this World Science article, and discussed in this hypography thread, scientists such as controversial but well-respected anthropologists Gregory Cochran have proposed that not only has human evolution in the past 200,000 years not slowed or stopped, but that it has dramatically accelerated.

Charles, what support can you present for your claim? Might your impression of the consensus among evolutionary biologists be based on out-of-date data?

My soucre was: In March 2007, Cochran/Hawks in World Science reported that the main genetic changes have merely been a slight shrinking of body and brain size and changes in metabolism! Don't you think that is unlikely to explain the growth of the human cultural heritage? If it is, then it assumes the different societies located on and in certain races are superior to others and that they evolve superior and then devolve in line with the rise and fall of civilizations!

"Experts" will not explain natural selection as working on religion-bonded societies because that would give religion an evolutionary natural cause explanation and lead to a lot of bitter religion-science controversy. Do you really think social science theory is OBJECTIVE?

[CraigD]

Originally Posted by charles brough

My soucre was: In March 2007, Cochran/Hawks in World Science reported that the main genetic changes have merely been a slight shrinking of body and brain size and changes in metabolism!

The article in question states

Human evolution has been speeding up tremendously, a new study contends—so much, that the latest evolutionary changes seem to largely eclipse earlier ones that accompanied modern man’s “origin.”

and

The traditional picture of humans as a finished product began to erode in recent years, scientists said, with a crop of studies suggesting our evolution indeed goes on. But the newest investigation goes further. It claims the process has actually accelerated.

Although it does state

Hawks and Cochran said some of the most notable physical changes in humans have been ones affecting the size of the brain case.

it continues immediately

A “thing that should probably worry people is that brains have been getting smaller for 20,000 to 30,000 years,” said Cochran. But brain size and intelligence aren’t tightly linked, he added. Also, growth in more advanced brain areas might have made up for the shrinkage, Cochran said

and

“A constellation of features” changed across the board, Hawks and Cochran wrote in their presentation.

In short, I don’t find that the research and speculation presented in this article supports the OP’s claim

… there has been no actual biological evolution since we became a species (which is the concensus now) ...

that is, that there is a scientific consensus that there has been no biological evolution of humans in the past 200,000 years. Rather, is suggest the opposite, that biological evolution of humans has been greater in the past 10,000 years than it was in the hundreds of thousands of years prior to 200,000 years ago.

[orbsycli]

theres the crescendo!

[charles brough]

Sorry to disappoint you both but you did not read the article to the bitter end. I did. I kept reading it because it kept on blabbing about their great findings without saying what they did find. I had to wade through all of that to reach the final dull end and there it finally was: slightly smaller skeletal and brain case with slight changes in metabolism.This goes not all the time. Everyone wants to see evidence we are still evolving biologically and the Science magazines are eager to supply it.* So, this explains the sorry way that article was written.

I would have warned you had I thought you were going to go to all that trouble to discredit me!* What gives us the illusion of biological evolution is the epigenetic changes that occur like in our society when we eat to much, keep the misfits alive, don't get enough exercise, etc.* All that epigenetic damage is eventually errassed by the down cycle of hardship societies eventually undergo.

[Rade]

I do not see the possibility that humans (Homo sapiens) will "evolve" physically into a new species of Homo in the future, not on earth. At one time in the past, there were different species of Homo coexisting, but our species won the game--we are the only ones standing. Thus, we know that in the past, there was an evolution into different species within our genus Homo, that is, we know that Homo sapiens evolved. However, with modern breakdown of racial isolation and commingling of racial gene pools over the next few thousand years, the possibility that Homo sapiens will itself evolve into a new species (on earth) is close to 0.0 %. But this is not unusual, many, many species, once evolved undergo stasis--they become evolutionary dead ends. Homo sapiens is such a species, we are a dead end, a branch on the evolution tree now branched challenged. Not a good thing or a bad thing, just a fact of reality.

I do, however, see one possibility of physical evolution for humans dealing with future space colonization. It is possible that a breeding and isolated colony of Homo sapiens on another planet or space-station society could become isolated genetically such that physical evolution (perhaps via genetic drift or/and mutation) could occur, and result in speciation into a new species of Homo.

There are two additional types of human evolution possible in the future other than physical--intellectual and social. It has been said that intellectual evolution results in the fittest being the most rational, and that social evolution results in the fittest being the most ethical. I see a future possibility that humans will learn how to produce genetic "good mutations" that will result in increased use of reason in offspring in such a way as to maximize the most ethical behavior toward other humans (that is, I hold to hope that Homo sapiens will, in the future, find a genetic engineered method to break the obnoxious social evil coined--man's inhumanity to man), for I hold such behavior to have genetic basis evolved from our primate origins. So, sorry John, love is not all we need, it just will not do, all we need is reason, and love will follow.

[InfiniteNow]

Originally Posted by Rade

I do not see the possibility that humans (Homo sapiens) will "evolve" physically into a new species of Homo in the future, not on earth.

Your lack of vision does not necessitate a lack of possibility.

[CraigD]

Originally Posted by charles brough

Sorry to disappoint you both but you did not read the article to the bitter end.

Yes, I did read the article to the end. Reading brief articles completely before commenting on them is a habit that was drilled into me in elementary school, though I do occasionally get hurried and fail to follow it. This article was discussed about 9 months ago, so I’m fairly familiar with it, and other work by and about Gregory Cochran.

Originally Posted by charles brough

Everyone wants to see evidence we are still evolving biologically and the Science magazines are eager to supply it.

From what evidence do you conclude, Charles, that “everybody wants to see evidence that we are still evolving biologically”?

One of the point of the World Science article appeared to me to be nearly the opposite – that for many years, scientists and laymen assumed that we were not evolving biologically, but, in light of increased understanding of molecular genetics and interpretation of it by anthropologists such as Cochran, this view is not longer widely held by people familiar with popular and professional biology and anthropology literature. The old status quo, which we could say people “want to believe”, is no longer accepted.

Originally Posted by charles brough

I would have warned you had I thought you were going to go to all that trouble to discredit me!

Please accept my apology if I gave the impression that I meant to personally discredit you. Rather, I sought to show that your statement that “there has been no actual biological evolution since we became a species … is the consensus now” is incorrect, and help dispel mistaken conclusions you may have drawn from this assumption. For example, this implied claim

Originally Posted by charles brough

What gives us the illusion of biological evolution …

(that biological evolution is not actually occuring, but rather is an illusion) appears to me to result from your belief that it’s the consensus of evolutionary biologist that there has been no biological evolution in humans in the last 200,000 years, which is not true.

This is the alternative theories forum, so perhaps you intend to present a theory radically opposed to the mainstream consensus of evolutionary biology. Supporting the extraordinary claims made by such a theory, however, requires extraordinary evidence – it can not simply proceed from the claim that mainstream science already accepts its claims, which has been amply shown, IMHO, to be false.

As some of the most rigorous methods available to evolutionary biology now involve bioinformatics, it’s necessary to present an alternative explaination of the diversity of genes known to exists in the human population, and the observed rate of genetic change.

Originally Posted by charles brough

I had to wade through all of that to reach the final dull end and there it finally was: slightly smaller skeletal and brain case with slight changes in metabolism

The argument that some of the visible consequences of genetic change, such as smaller size and changes in metabolism, are intuitively too minor to be considered true evolution, is, IMHO, unconvincing, and not shared by most evolutionary biologists.

I, too, was un-awed by the writing style of the World Science article. However, poor writing style does not discredit the theories presented in a science article.

[charles brough]

What the article says is that the braincase of modern humans has shrunk a little. That is what I said. The article does not mention any other changes that could explain how we acquired our modern cultural heritage. You say they found a lot of things and they claim they have, but they only mention the smaller size. They were just putting a good face on their failure to find what they were looking for.

I know your intense favoritism to scientific researches, science magazines, etc. and I share it, but I am also objective and look just at the facts, not the promoting, emotion, etc. Science is an ideal not "the Truth," and we need to be sharp to be accurate.

[Michaelangelica]

Well I have not read the article but what is challenging is the 'two speed' evolution we seem to have.
Why do some things like stomatolites in W.Aust. and crocodiles hardly seem to change at all. Why do minor changes happen, say in Galapagos birds, in a very short time frame?

Tracing the genetic ancestry of humans, as is now being done, seems to show that there have been genetic changes even in the last 10,000 years. Albeit very small ones.
I don't think they are epigenetic. But they certainly seem to be a response to our changing environment.

[Kayra]

Personally, I have a few issues with the concept that humans are considered to be still evolving.

As I understand it, in order to evolve an environmental stressor must be present. If you are perfectly (or nearly so) suited to your environment then evolution is drastically slowed, with only minor improvements over long periods of time, just as was pointed out with the crocodiles and sharks.

Changes due to epigenetics are not (as far as I can see) evolution. We are simply leveraging traits that we already possessed, not evolving new ones. Epigenetics itself however, was something that we evolved. The fact that some of these changes can be passed on to our offspring is a testament of the wonder of this particular evolved trait, but not proof we are still evolving.

We have, as a race, removed most environmental stressors in our lives. As a result, I would expect over the next 10-50 generations to see in increase in non-functional mutations creeping into our gene pool as we can medically deal with a considerably larger number of debilitating or crippling issues and still procreate, passing on these bad mutations.

The only place I expect to see evolution still in action is in third world countries, where those that are unfit for the harsh conditions do not live long enough to pass on those unfit traits.

If evolution in humans is still occurring, could someone enlighten me as to what the stressors are? What traits are evolving that allows a greater likelihood of genes possessing those traits to be passed on? The only stressors I see are social ones (local, national, or global) that may make someone appear to be a desirable mate or encourage more offspring.

What other stressors are out there?