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Modern Life's Pressures May Be Hastening Human Evolution
WASHINGTON - We're not finished yet. Even today, scientists say that human beings are continuing to evolve as our genes respond to rapid changes in the world around us.
In fact, the pressures of modern life may be speeding up the pace of
human evolution, some anthropologists think.
Their view contradicts the widespread 20th-century assumption that modern medical practice, antibiotics, better diet and other advances would protect people from the perils and stresses that drive evolutionary change.
Nowadays, the idea that "human evolution is a continuing process is widely accepted among anthropologists,'' said Robert Wald Sussman, the editor of the Yearbook of Physical Anthropology at Washington University in St. Louis.
It's even conceivable, he said, that our genes eventually will change enough to create an entirely new human species, one no longer able to breed with our own species, Homo sapiens.
"Someday in the far distant future, enough genetic changes might have occurred so that future populations could not interbreed with the current one,'' Sussman said in an e-mail message.
The still-controversial concept of "ongoing evolution'' was much discussed last week at the annual meeting of the American Association of Physical Anthropologists in Chicago.
It's also the topic of a new book, "The 10,000 Year Explosion,'' by anthropologists Henry Harpending and Gregory Cochran of the University of Utah, Salt Lake City.
"For most of the last century, the received wisdom in the social sciences has been that human evolution stopped a long time ago,'' Harpending said. "Clearly, received wisdom is wrong, and human evolution has continued.''
In their book, the Utah anthropologists contend that "human evolution has accelerated in the past 10,000 years, rather than slowing or stopping. . . . The pace has been so rapid that humans have changed significantly in body and mind over recorded history.''
Evolutionary changes result when random mutations or damage to DNA from such factors as radiation, smoking or toxic chemicals create new varieties of genes. Some gene changes are harmful, most have no effect and a few provide advantages that are passed on to future generations. If they're particularly beneficial, they spread throughout the population.
"Any gene variant that increases your chance of having children early and often should be favored,'' Cochran said in an e-mail message.
This is the process of "natural selection,'' which Charles Darwin proposed 150 years ago and is still the heart of modern evolutionary theory.
For example, a tiny change in a gene for skin color played a major role in the evolution of pale skin in humans who migrated from Africa to northern Europe, while people who remained in Africa kept their dark skin. That dark skin protected Africans from the tropical sun's dangerous ultraviolet rays; northerners' lighter skin allowed sunlight to produce more vitamin D, important for bone growth.
Another set of gene variants produced a different shade of light skin in Asia.
"Asians and Europeans are both bleached Africans, but they evolved different bleaches,'' Harpending said.
Despite modern medical and technological advances, the pressures that lead to evolution by natural selection have continued.
The massive AIDS epidemic that's raging in southern Africa, for example, is "almost certainly'' causing gene variants that protect against HIV, the virus that causes AIDS, to accumulate in the African population, Harpending said.
When he was asked how many genes currently are evolving, Harpending replied: "A lot. Several hundred at least, maybe over a thousand.''
Another anthropologist, John Hawks of the University of Wisconsin-Madison, said, "Our evolution has recently accelerated by around 100-fold.''
A key reason, Hawks said, is the enormous growth of the world's population, which multiplies the size of the gene pool available to launch new varieties.
"Today, beneficial mutation must be happening far more than ever before, since there are more than 6 billion of us,'' Cochran said.
The changes are so rapid that "we could, in the very near future, compare the genes of old people and young people'' to detect newly evolving genes, Cochran said. Skeletons from a few thousand or even a few hundred years ago also might provide evidence of genetic change.
"Human evolution didn't stop when anatomically modern humans appeared or when they expanded out of Africa,'' Harpending said. "It never stopped.''
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The American Association of Physical Anthropologists
40 Comments so far
Show AllI don't in the least doubt what these scientists are observing, i.e., that the genetic pool is undergoing changes. I just feel a reluctance in calling these changes 'evolution'.
'Devolution' strikes me as a better word to describe what I am seeing around me.
Touche!
There is no such thing as devolution. Life just is. If there's no fitness check, there's no pressure, and biological diversity will win out in the long run.
I read a lot. I've never heard of any scientist saying human evolution had stopped.
Yes, I concur with that observation. For instance, Darwin nowhere says anything to that effect. Nor does Simpson, or Mayr, or Dawkins, or the French biologist Monod.
I don't get it. How can evolution happen in rich countries where it's easy for people to live long enough to reproduce? For any trait to evolve in any species, I mean for any trait to appear and then become characteristic of that species, doesn't there need to be something that kills off the individuals who haven't got that trait? Otherwise there's a mutation, which is passed on to the descendants of the mutant, but everyone else continues without having that mutation. If everyone survives, the species does not evolve. Which is great because it's ethically bad when people die. But then how can there be evolution? There's something I'm not understanding here.
Extinctions can and do take place over a period of time, but that isn't the driving force of evolution. As the article says, there may come a time when there is enough genetic changes within a section of the population to actually create a new species of human that will not be able to breed with the old species. Whether the older species will become extinct or not doesn't prevent the newer species from evolving and continuing. Circumstances may arise where the new species is better adapted to survive these new conditions than the old one which could lead to the ultimate extinction of the latter, but again, it's not necessary for evolution to proceed.
Look at skin color. By your reasoning, because not every human in the world has white skin, skin color must have nothing to do with the evolutionary process.
But that's silly. In reality, white skin evolved in parts of the human population that didn't need extra UV protection, but did need to produce as much vitamin D as possible during the limited exposure to sunlight available where they lived.
Killing off individuals doesn't even enter into it. It's just that in northern climes with no modern technology, people with white skin tended to be healthier than people with black skin, and healthier people have more babies.
An adaptation does not have to spread to the entire population, or kill off even a single member of the population, to be part of the evolutionary process.
Consider this: as you may be aware, people in rich countries with a high standard of living are exposed to quite a lot of plastic. In recent years, we've found that certain kinds of plastic, when used for drinks, can leach harmful chemicals into the liquids we drink. The ocean is full of plastic trash, fish are eating little bits of it, and we eat the fish.
Suppose that someone in a rich country develops a mutation that protects them from getting cancer from the chemicals in plastic. That's adaptation to the environment - the essence of evolution. Over time, for as long as plastic is ubiquitous in the environment, people with the anti-plastic-cancer mutation are going to tend to have more and healthier children than people without it. It may never spread to the entire human population, because this mutation is not an advantage in plastic-free regions, but it's still evolution.
Ever wonder why orientals are small people? They don't need as much food to survive, and food has been scarce in parts of Asia for thousands of years.
Japanese learned thousands of years ago that boiling water could make it safer to drink. Europeans, meanwhile were drinking water mixed with alcohol to help make water safer. The result? Europeans have an enzyme in their guts that allows them to drink much more alcohol without being drunk.
You are ignoring the small differences that happen over very long periods of time. Humans from fifty thousand years ago would fit right in the with the present population.
this is fascinating. if stress is a positive in human development, and strain is caused by an ineffective response to stress, this makes perfect sense. once again, the human race masters its environment!
Sorry, but...duh? The day a species stop evolving is the day after it has become extinct. Especially for shorter-lived species (compared to trees, maybe whales, humans don't live too long).
"Asians and Europeans are both bleached Africans..."
LOL. What a great comeback for a racist tool.
"Shaddap. Yer a bleached African. Live with it."
One of the reasons that Darwinism and evolution sparked Social Darwinism and it's counterpart eugenics, is concern over devolution of the species as a result of the Industrial Age making life too easy and defective folks who otherwise would die off without breeding would be able to breed. Also, survival of the fittest justified the exploitation of rich over the poor and middle classes, so was an attractive social philosophy for the well to do.
One of the benefits to the various crisis that are created for us is that it theoretically should increase mans rate of evolution. They call it doing evil to do good, or the end justified the means.
Still, in the developed world, especially in America, we actually see first hand some devolution, people seem to have lost the ability to think and reason for themselves, are not in very good physical condition and so do not make very good physical workers. But having a white collar class who just follows orders and is subservient to the ruling class might be what they want, since the blue collar jobs have all went to China, and the Chinese are very good workers.
In the developing world and even the 3rd world, those who succeed tend to migrate and a certain number immigrate to the developed world, thus refreshing the gene pool for the working class, since as David Rockefeller once said, we don't need anymore thinkers, and these groups do jobs many Americans are no longer fit to do, or inclined to do.
It is interesting that the fertility rates in the poorer countries which are under continuous stress are much higher than in the developed countries with their devolving populations and increasing, yet not continuous stress.
One wonders if mans evolution is being engineered to create various class of workers who will be obedient and not question their rulers.
One of the points made in the book is how certain groups of people can evolve more rapidly than others. He points out the Ashkenazi Jews and explains why they are smarter than any other ethnic group for which there is data, mainly due to them being forced into white collar jobs (merchants, banking) due to anti-semitism and not assimilating into the general population . He stays away discussing those groups who might be dumber, other than to point out that non-Ashkenazi Jews do not have high IQ's.
Of course, the overlap between group,s as pointed out in a book called The Bell Curve, is so great, that one can not say that just because an individual belongs to a smarter group that he is smarter than one who belongs to the dumber group.
I was going to question the science, but then I realized that news articles always change what scientists say and make up the conclusions. There is a lot of stuff here that is implied or the reader might think without thinking about it. The idea that evolution is accelerating would make the average person think they'll be mutants walking around during the next generation. I think the purpose of much of the media's discussion of science is to have the biological trump the social. If we are evolving faster, then everything can be biological, and we can ignore the fact that most of our lives are socially created, and can therefore be changed.
As for skin color changing during the "short" time of 10,000 years, that says more about how small a difference skin color is than it says about how quickly we evolve.
It's not at all surprising that evolution is continuing in modern humans. However, what's happening today is very different from what happened in the past.
Much of our physiology has evolved for a very different lifestyle, more nomadic and pastoral. Today we are faced with all kinds of new stresses: tremendous amounts of information, less social support for many people, less support from religious and other belief systems, and so on. In many parts of the world, there is tremendous stress from constant aggression and warfare (though this is not necessarily new).
It's fairly easy to imagine that people who can better cope with these stresses will have a selective advantage in the future. I don't want to be too speculative here, but two possibilities are (1) We know that stress impairs immune function. Thus, those with the stress-adaptive genes will have better immune function, be more healthy, and thus better able to reproduce and support their offspring. (2) We know that stress can interfere with reproduction itself (by depressing libido and performance). So again, it would make sense that those with stress-adaptive genes could gradually become more numerous.
But this picture breaks down for me when it comes to spreading these individuals throughout the population. Given the six billion people alive today, it seems like it would take an extremely long time, a time during which the environment would be ever-changing and providing new stresses. In addition, one of the main approaches to evolutionary change and speciation is based on the localization of a relatively small group of individuals within which the adaptations can spread relatively fast. But the world is moving in the opposite direction, toward more interconnectivity and less isolation.
So I suspect my speculations are stuff for science fiction. It seems that advances in genetic engineering (the use of stem cells, etc) will be much faster and more important.
"Someday in the far distant future, enough genetic changes might have occurred...." - that's all i hear out of evolution. well have fun waiting for that someday in the far distant future.
i have a question - why are we talking about asian, african, and european skin colors? isn't it just a difference in melanin(sp?)...and that's not all that makes africans and asians and europeans different.... our bone structures are a tad bit "customized" as well.
i have a thought....since all these scientists agree that either evolution sped up really fast over the past 10,000 years, or it has been what it is today since 10,000 years ago - doesn't that give alot'a credit to the Creationism theory that states man was created about 8,000 - 10,000 years ago??? pretty similar. to me evolution seems like it knows it needs more evidence to support it's whole theory, and that's why its so avid about discovering anything that they can smash into their list of theories and make it "fit" :discarding anything that straight up supports Creationism. it seems like evolution has to manufacture all their "evidence" while Creationists look at the earth and everything in it and it supports their theory that someone created all this wonderfully complex stuff.
what do ya think?
we'll definately never see evolution "in motion" in our lifetime. and i think the one thing that keeps people coming back for more, just like with tv shows, is the "to be continued...". When the show ends people always complain about how it should have ended differently, or better; but they stuck with it throughout those 15 long seasons because it was different, and it promised to go somewhere - to entertain.
If you don't see evolutionary changes you are not looking. Of course you can't see it in one generation, but bacteria can go through millions of generations in a human lifetime, and they have definitely evolved. There are many strains that are resistant to antibiotics to which they were sensitive only fifty years ago.
Dogs can evolve into vastly different species over only a few hundred years through artificial selection. Turn all dogs loose to breed freely at random and in 200 years all dogs will be like the common mutt.
i have another thought....bare with me.
if evolution were true.... and all of life on earth has evolved from single celled organisms to multiple celled organisms, to like goo stuff which became simple little creatures and became more and more complex until it got to where it is today.....wouldn't we still have every species/transformation/ "middle-stage" that therehas ever been, alive today?
this is the most simple diagram i could make:
1 ....... splits to two 1's
1-1 ....... which split to two more; one 1 morphs to a 2.
1-1-1-2 ....... these then split to two more; one 2 becomes a 3
1-1-1-1-1-1-2-3
.....and eventually if you did this until single celled organisms (1) became humans (5,908,419,758,39....and so on) wouldn't you still have every number (animal or life form) still existing today?
and say their environment changed and they died off....wouldn't there be an endless supply of new evolutionary trees being started every so often, and those extinct life forms would be re-evolved?
i'm curious...i just thought of that.
Well, mutations can be beneficial, detrimental, or neutral in a given environment. What matters is selective pressure in an environment affecting successful reproduction. Given that there is a finite environment and species compete for their ecological niches, they either have to adapt or die. In your scenario, if something happens that makes variant 2 unable to reproduce effectively - let's say that drought strikes and 1's and 3's are better resistant, they're gone. Any of these could disappear as the environment changes and their advantages are surpassed, or made irrelevant.
It's an interesting scenario you propose, but over 95% of all living species we know to ever have existed are gone. It's not that they were inferior in all ways, but at some point they were either outcompeted or subjected to circumstances they could not survive.
It's interesting to posit how pterosaurs or trilobites would fare if they reappeared. Trilobites, for example, apparently had incredibly sharp vision. It doesn't matter. They were wiped out, and the survivors are on their own path with the adaptations they had in hand. Example: some species of dinosaur might thrive today, in some environments. It doesn't matter. There was an intermediate time period that made them extinct, and mammals moved into their niches. It is minutely possible that specific selection could have favored some bird species to backtrack, and actually there have been some intriguing species of large flightless birds that look rather reminiscent of the old theropods. Another case in point: reptiles and mammals have both re-entered the oceans, but they didn't become fish even if they came to resemble fish a great deal. Why would they need to? But all the complexities of the old species are lost.
Sadly, some species don't make it that might have done interesting things later on if they had, and evolution plays out with the genomes that remain.
"if evolution were true...."
Be careful here: you don't want to tip your ideological hand too blatently when posing an otherwise innocent question, or you might get disdain and derision instead of education and enlightenment. Hold to your convictions, but be prudent in revealing them.
In the meantime, I'm happy to bear with you.
"wouldn't we still have every species/transformation/ "middle-stage" that there has ever been, alive today?"
If the branching of evolutionary trees never ever concluded with the loss of one of the branchings, then yes, we would. But clearly, that has not happened. Competition between two closely related species sometimes extinguishes one of them. Environmental conditions always change, and those species who are not better-fitted to flourish in the new paradigm will lose their reproductive advantage over those (mutants) who have acquired adaptations better-fitted for the new environment. They lose territory, resources, and physical space in which to reproduce to the individuals (and entire new species, on a larger scale) who have new mutations conferring advantage.
"wouldn't there be an endless supply of new evolutionary trees being started every so often, and those extinct life forms would be re-evolved?"
If the conditions under which an extinct "life form" (may I use "species" instead of that term?) do not re-appear, then an extinct species would have little chance in increasing its population to viable numbers, even if its exact genetic makeup were to re-appear (improbable but not impossible) in the form of a mutation. You can even see this happen in real-time: when an island population of a species differentiates into two distinct (non-reproductively compatible) species, one might be better-fitted for the island, while the other might migrate towards another landmass and continue to differentiate. Years later, one of the "other landmass" species might return to the point of origin and out-compete the original ("mother") species for resources and space. Then you would have the new species (from the "other landmass") taking the role of "best-fitted" on the original landmass, and thus becoming the scion from which further mutations occur.
I'm truly sorry if my explanation is difficult to comprehend: I'm an English teacher, not an Evolutionary Biology teacher, and the time I have to explain this (without knowing your competency level in this area) is limited. But I'd like to assure you and ask for your trust that as one who has taken his share (I majored in Botany) of biological science classes, this is indeed how it works, and the process is well documented and supported.
Evolution is true. There...I've tipped my hand. But I hope I've also enlightened and educated.
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If you don't ask yourself why, you know nothing.
This is the most absurd thing I have read in a long time. It completely misunderstands the most basic concepts of evolution. It's very scary that a anthropologists,theoretically educated people could be so profoundly ignorant.
Evolution occurs when genetic differences provide a superior opportunity for survival, and a particularly adaptive mutation might confer an advantage over a relatively few generations. Resistance to the AIDS virus would certainly convey some superior adaptive value if, over several generations, AIDS were untreated, and AIDS sufferers died without reproducing.
Of course, we have barely had a full generation since the onset of AIDS, we have done everything possible to treat it and protect the victims against the consequence of their illness, to equalize them with those who are naturally resistant. And, of course, AIDS viruses, with millions of generations to our 1, can out mutate us with ease.
The rest of this article sounds like the completely discredited theory that conditioning in one generation results in changed genetics in the next--- Lamarck, out of favor among scientists except in Stalinist Russia where for ideological reasons his theory was praised is rejoicing in his grave.
I agree that this article is a little too rosy to stomach, but I took it as an announcement of possible trends for the future. Evolution occurs in starts and jumps, after all! Lamarck was a sophomore: a wise idiot. I didn't get the impression that this article promoted his thought process, but I will admit it came close. The devil is--as always--in the details: your point about mutation rates of HIV vis-a-vis humans is very poignant.
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If you don't ask yourself why, you know nothing.
I agree. Mr Boyd does not understand even the most basic principles behind evolution, and is spreading a number of common misconceptions.
For instance, the article states: "Some gene changes are harmful, most have no effect and a few provide advantages that are passed on to future generations. If they're particularly beneficial, they spread throughout the population."
Genetic change does not "spread throughout the population" as if it were a contagion. As Jerry says, adaptive changes become more prevalent in certain populations over generations because those who possess them are more likely to survive and reproduce. The process is a value-neutral numbers game, pure and simple.
And how Mr Hawks can conclude that a larger population can lead, within a generation, to evolutionary changes in basic human biology, escapes me. If he means to take the population explosion as evidence of genetic adaptation, I would say he's deluded. Earth's ballooning population is strictly a matter of the mathematics of exponential growth, that is, until the air and water run out. THAT is the process that's accelerating, comin' at us faster than we'll be able to adapt, genetically or otherwise.
I'm also in the camp that Mr. Boyd went to a meeting of anthropologists and misunderstood much of what he heard.
For starters his opening idea of little or no biological evolution must derive from the scientific consensus that cultural evolution far surpasses biological evolution. Trivially put we now routinely fly across oceans without having evolved wings. Our cultural heritage evolves orders of magnitude faster than do our genes.
Of course our genes continue to change at the same rate as always, or perhaps slightly quicker due to nuclear radiation. Our large population allows many more variants to occur than would be found in a primitive tribal population of a few hundred individuals.
The idea of a new species arising within the current, existing huge interbreeding human population is bizarre. Speciation is rarely driven by single gene change (and assortative mating) and is more often driven by chromosome change. Individuals with different chromosome structures who mate will have a high frequency of abortion due to chromosome imbalance. In small isolated populations a novel different stable chromosome type can become established leading to a new species. For example horses and donkeys produce only sterile hybrid offspring as either mules or hinnys while humans differ from chimpanzees by having one fewer chromosome pair due to an ancient chromosome fusion event.
CQ from Maine:
Evolve or Die -- Who or what might we become?
"Devolution' strikes me as a better word to describe what I am seeing around me." This is the true observation of a participant. Our currant social structures are a mirror of our brains, i.e. conceptual thought.
The social structures are a mess. It doesn't look good for the future.
Perhaps, but the past was worse so as bad as things are; they are improving.
"Evolutionary changes result when random mutations or damage to DNA from such factors as radiation, smoking or toxic chemicals create new varieties of genes."
In that case humans will become a Kafka nightmare. Only cockroaches and other insects are immune to these pollutants.
While survival-of-the-fittest may still apply to most sub-human species, it applies less and less to humans. With our advancement of sciences and our dependence on each other, it is quite easy for the weaker members of our species to survive quite well and to reproduce and even select partners from their own development level, thus insuring the survival of even the weaker portion of our society.
Therefore, our evolution includes a declining ability to survive on one’s own and a greater and greater dependence on society and science for survival. A very successful physician benefiting from generations of good breeding may be very well suited to survive in our societal environment, but in a less hospitable environment such as we find in parts of the Orient and Africa survival might be very difficult, handicapped further by the lack of will to survive in that environment. Nevertheless, we still evolve and it should not be called devolution even though we are less able to exist outside our societal dependence. Evolution is merely adaptation to changing environmental conditions including the changing environment we create. It includes both stronger physical and mental attributes as well as weaker.
What we have to look at more closely is the instinct of survival in humans. While it still exists in poorer regions of the planet, it is declining where societies thrive. I believe our once strong instinctual drive for survival has been replaced somewhat with similar characteristics, but more difficult to associate with survival. Our need to compete, to win, to be superior are driving forces that contribute more appropriately to our technological advancements rather than survival alone.
Unfortunately, the very characteristics that have served us so well in developing technologically is now standing in our way toward survival as a species.
"While survival-of-the-fittest may still apply to most sub-human species, it applies less and less to humans. With our advancement of sciences and our dependence on each other, it is quite easy for the weaker members of our species to survive quite well and to reproduce and even select partners from their own development level, thus insuring the survival of even the weaker portion of our society."
Excellent point. Modern weaponry doesn't discriminate between the weak and the strong. And inheriting money gives the weak a leg up.
These comments are all very interesting. But we need to keep in mind that many of these behavioral traits are the product of an interaction between genes (evolution) and the current environment (learning). Something like a genetic "will to survive" is so fundamental that it's hard to believe it has become less strong as a result of evolution. Evolutionary processes are extremely unlikely to select against it because it so critical to reproduction. It may be weaker in some people today, but this is surely the result environment factors (e.g., learned religious beliefs regarding an afterlife). Such weakening would not be the result of biological evolution - only a result of the interaction between genes and environment. A similar case could be made for the even more fundamental sexual motivation.
As for our societal dependence, it's important to note that our species (as a primate) has been extremely social for many millions of years. Social traits such as cooperation and competition have been evolving along with our other important motives for a long time. So it's hard to say whether we are any more socially dependent today than we were 1 million or 5 million years ago. The case could be made that we are actually less socially dependent today, because we are exposed to many more people and cultures which serve to dilute the social dependence. In any event, a decreased ability to survive in more hostile environments would most likely be the result of "environmental" (we simply didn't learn the survival skills) rather than evolutionary (genetic) processes.
The idea that the "weaker portion" of our society is now surviving has some truth to it but can also be misleading. This is because people often misinterpret "suvival of the fittest" in the sense of being physically fit and strong. I think Darwin actually meant the survival of those who best "fit" into the environment's niches. So it could easily turn out that some of these physically weaker individuals will actually fit better in future environments, and thus end up with a selective advantage (it depends on the environment, which today is very different from the one we evolved to fit).
I agree with most of what you say, but you're talking here about CULTURAL, not biological, evolution.
Allergies, scoliosis, fertility/pregnancy problems, heart defects, diabetes, MS, severe learning disabilities, genetic defects of all sorts,... Many people who once wouldn't have survived early childhood are now surviving to reproduce. Not exactly evolution. (Even I did!)
Then there is that socially promoted pinnacle of our species: Dubya!
I think it's the Chimpanzees turn to run the planet. The homo sapiens have loused it up big time.
It is not homo sapiens, it is homo civilised. Pick up a copy of Daniel Quinn's Story of B and educate yourself.
I still stand behind the chimpanzees. You should educate yourself about non-human primates. Homo sapiens have lost their way.
i agree with you there one hundred percent............
Actually we are very similar. We now know that chimpanzees may kill and eat more than 150 small and medium sized animals such as monkeys, wild pigs and small antelopes each year.
We know a great deal about their predatory patterns. Chimpanzees have been recorded to eat more than 35 types of vertebrate animals , the most important vertebrate prey species in their diet is the red colobus monkey. At Gombe, red colobus account for more than 80% of the prey items eaten. But Gombe chimpanzees do not select the colobus they will kill randomly; infant and juvenile colobus are caught in greater proportion than their availability; 75% of all colobus killed are immature.
I guess immature monkeys are kind of like their veal.
http://www-rcf.usc.edu/~stanford/chimphunt.html
When I look at pond scum and think that I may have evolved from that stuff, I tear up and begin apologizing to the scum.
A mere 150 years ago, we lived in a largely agrarian society on small family farms where we were indeed very independent and capable of survival with little assistance from society outside the family. Communities would develop with time making life easier and mostly welcome, but the means of survival were passed on from generation to generation. Now, even the small farmer would have a difficult time without the utility company, the grocery store, the gas station, the farm supply store, the doctor, etc.
What affect this is having on our evolution as a species is very complex and opinions vary widely. It is far too complex to discuss here, but it is good to see so much interest in the subject. I do believe that cultural and biological evolution are interrelated and should never be separated in scientific studies. We will always evolve, but predicting the outcome of evolution in the future is highly speculative.