demo of evolution

[blaise]

Yes, there is change in living organisms over time. A fascinating study shows that today's organisms are not necessarily the same as their ancestors.

abcnews.go.com/Technology/DyeHard/story?id=666435&page=1

[IamCanadiens]

"About 80 years ago, when the predators were all over the place, the Daphnia retrocurva extended the size of its helmet and spines to make itself less appetizing. Later, when the number of predators shrank, the animal reduced the size of those features, thus conserving its energy for other uses".


That paragraph is so poorly written that the journalist should be drawn and quartered. He makes it sound as if the water flea voluntarily changed its morphology to prevent predation. Somebody needs to explain the concept of natural selection to him.

[blaise]

IamCanadiens said:

"About 80 years ago, when the predators were all over the place, the Daphnia retrocurva extended the size of its helmet and spines to make itself less appetizing. Later, when the number of predators shrank, the animal reduced the size of those features, thus conserving its energy for other uses".


That paragraph is so poorly written that the journalist should be drawn and quartered. He makes it sound as if the water flea voluntarily changed its morphology to prevent predation. Somebody needs to explain the concept of natural selection to him.

Think about it some more. While the statement lacks precision it doesn't lack logic. Natural selection implies the elimination of individuals and species with undesirable traits. It does NOT imply a volitional and sudden shape-changing. Instead, it implies the survival of organisms that had traits the others lacked. Initially, the selection of water fleas with better defenses may have been a plus. However, whatever mutation conferred the helmet and spines may have proved to be disadvantageous later on in the absence of predators. Why? Presumably because maintaining these protective features required greater expenditure of energy and requirement for nutrients in a newly unfavorable environment. The evolutionary advantage then shifted to the less-armored fleas. At this point there was selection toward a more compact form.

Perhaps you read about the diminutive elephants indigenous to island of Indonesia. This suggests selection of a mutation that permitted lower caloric consumption at a time of food shortages. Thus the isolated elephants diverged from the larger elephants on the Asian continent. The recent finding of remnants of a subgroup of diminutive tool-making Homo sapiens-like anthropoids (unrelated to African pygmies) that perished thousands (not millions) of years ago is consistent with this hypothesis.

[IamCanadiens]

I'm well aware of the concept of natural selection, whether it's from the angle of adaptive heritable traits being selected for or undesirable traits being selected against. The article is what it is; the writing of an individual that either does not fully understand what he is writing or does not realize that by dumbing it down has oversimplified the issue. The way he has explained this makes it appear as if the water flea is cognizant of its actions, or the changes occur within an individual. Does the water flea truly make itself less appetizing or reduce the size of its features? Only over generations due to selective pressures. I'm well aware that I'm preaching to the converted but I find this to be yet another perfect example of how the media can misslead the masses.

Maybe tomorrow I'll track down down the article and read it for myself.

[BadCompany]

To throw the topic into a separate, yet related area, who here thinks human beings are still evolving?

Natural selection implies that certain traits promote the survival of the species. Since the human species has no natural predators, and current procreation is largely dependant on social factors, I will say no. Human evolution has stalled. There are no uniquely human traits/mutations that are MORE likely to be passed on than others. Birth control, advances in medicine, and guns (to ward off those sabre tooth tigers, wouldn't you know), have killed human evolution.

In my opinion.

[M. Beaux-Eaux]

B-b-b-ut human beings must overcome themselves if they are to survive as a species...isn't that the lesson we should take from examples such as genocide and the willingness to build and use nuclear weapons...evolution isn't nearly done yet...

[Habs_fan_in_LA]

Blaise said:

Yes, there is change in living organisms over time. A fascinating study shows that today's organisms are not necessarily the same as their ancestors.

abcnews.go.com/Technology/DyeHard/story?id=666435&page=1

Natural selection always keep improving the species and the best survive and replace their forerunners. The best become alpha males and lead the pack.

















eg. Bush replacing Clinton.

[blaise]

Habs_fan_in_LA said:

Natural selection always keep improving the species and the best survive and replace their forerunners. The best become alpha males and lead the pack. eg. Bush replacing Clinton.

{And ruining the economy}

This is a misconception. Species can evolve to become dominant "alphas" and then some unexpected shift in the environment or ecology dooms them. Witness the predatory dinosaurs that ruled the earth for millions of years without natural enemies. The mammalian ancestors of humans were obliged to live an arboreal or subterranean or nocturnal existence for a long, long time in order to survive because it was too dangerous for them to venture into the open. Then they got lucky. The dinosaurs and large mammalian carnivores were wiped out either by several widely separated cataclysms or because after millions of years of flourishing there was no longer enough food for giants.

Agriculture can be ruined by such quirks as the introduction of foxes, which wipe out the bird population. The lack of bird guano depletes the soil of its natural fertilizers and crops can no longer be sustained. A similar thing happened in the Galapagos Islands when expeditions brought swine (on purpose to serve as food) and rats (inadvertently). Whole species became extinct.

In short, the history of the planet (and the solar system) depends on fortuitous events that could easily be termed luck, good or bad.

Did you ever wonder where deadly viruses come from? They appear to so primitive, with just a few nucleotides in their DNA (and some viruses don't even have DNA), that upon superficial glance it would appear that some of them might have given rise to primitive bacteria. That isn't at all what happened. Viruses are totally dependent upon their hosts not only for sustenance but also for replication--they usurp the DNA or RNA of their hosts. So without hosts, there would be no viruses. Logically, then, viruses must be DNA or RNA that in the past escaped from their hosts and became incomplete but semiautonomous. In other words, the hosts came first. Interestingly, even bacteria can be infected with viruses. There are bacteriophages (bacteria-eating viruses) that cause E. coli to explode and die, spewing forth viral particles that invade other bacteria.

Life is awfully complicated and messy. It's too difficult for mere humans, who are latecomers on the planet, to comprehend. However, it is theoretically possible for scientists to construct primitive organisms from scratch by decoding their genomes and assembling the nucleotides. If they can reconstruct one species of bacteria they might also be able to create species that never existed before. The successful scientists would thereby gain a reputation as Godlets.

[blaise]

BadCompany said:

To throw the topic into a separate, yet related area, who here thinks human beings are still evolving?

Natural selection implies that certain traits promote the survival of the species. Since the human species has no natural predators, and current procreation is largely dependant on social factors, I will say no. Human evolution has stalled. There are no uniquely human traits/mutations that are MORE likely to be passed on than others. Birth control, advances in medicine, and guns (to ward off those sabre tooth tigers, wouldn't you know), have killed human evolution.

In my opinion.

I disagree. Medical advances can go just so far. At one time we thought we were relatively safe from lethal bacterial infection. Penicillin was a miracle drug that could mop up Staphylococcus aureus but now the doctors are running out of antibiotic options. Hundreds of thousands if not millions of patients die each year of hospital-acquired infections. You would probably be safer having minor surgery in a rented hotel room than in an surgical suite because the pathogens are less virulent. Think about that!

In the event of nuclear war (or plague), there might be selection of those humans who have mutations that make them better able to survive radiation (or infection). Metabolism might have te reset to accommodate warmer or colder climates or less abundant food or flooding. Some people with specific mutations can live for decades despite HIV infection while others succumb. But even without these or other catastrophes there would probably be further evolution. Head and facial hair would be vestiges. The human spine would evolve to adapt better to weight bearing (a flaw that results from an imperfect transition to walking upright--other higher primates are still more poorly suited to an erect posture). The cranium might have to expand to accommodate a larger brain. (Wouldn't it be lovely to be more intelligent?) Indeed, there are quite a few anomalies in human anatomy and physiology that could be improved upon.

[HabbaDasher]

Aren't we losing our little outside toes?

[M. Beaux-Eaux]

I've still got my appendix and tonsils.

*

Will Satanists eventually grow tails and horns?

Will saintly people gradually become non-corporeal?

[BadCompany]

Blaise said:

I disagree. Medical advances can go just so far. At one time we thought we were relatively safe from lethal bacterial infection. Penicillin was a miracle drug that could mop up Staphylococcus aureus but now the doctors are running out of antibiotic options. Hundreds of thousands if not millions of patients die each year of hospital-acquired infections. You would probably be safer having minor surgery in a rented hotel room than in an surgical suite because the pathogens are less virulent. Think about that!

In the event of nuclear war (or plague), there might be selection of those humans who have mutations that make them better able to survive radiation (or infection). Metabolism might have te reset to accommodate warmer or colder climates or less abundant food or flooding. Some people with specific mutations can live for decades despite HIV infection while others succumb. But even without these or other catastrophes there would probably be further evolution. Head and facial hair would be vestiges. The human spine would evolve to adapt better to weight bearing (a flaw that results from an imperfect transition to walking upright--other higher primates are still more poorly suited to an erect posture). The cranium might have to expand to accommodate a larger brain. (Wouldn't it be lovely to be more intelligent?) Indeed, there are quite a few anomalies in human anatomy and physiology that could be improved upon.

All of which ignores (the theory of) natural selection. In order for head and facial hair to disappear, there would have to be some sort of biological reason for people with less head and facial hair to produce more children with the mutated baldness gene, than people with regular, full-bodied locks. As it stands now, people (in the Western world at least) have their 2.3 children regardless of the mutants they pass on. Thus, bald-gene people do not outnumber hair-gene people. The trend in Asian countries is to have fewer and fewer children, either through social changes or outright laws (i.e China). Africa and South America still tend to have larger families, and an argument could be made that evolution still continues in those regions, but the current zeitgeist is to change opinions there, and reduce the willy-nilly procreation they currently engage in. Could a new Pope kill evolution completely, simply by accepting birth control?

As for viruses and anti-biotics, you still have the problem of natural selection. Your analogy *might* apply to sub-Saharan Africa, where the HIV rates are through the roof, but if a cure/vaccine is found in the next decade or two, those with a stronger, HIV-resistant system will have no natural selection advantage over those who don't. Both groups will still have their 2.3 children, and neither will gain any significant evolutionary lead on the other.

The nuclear war scenario is an interesting one, but highly speculative. Yes, assuming there are indeed radiation-resistance people out there already (who just don't know it for obvious reasons), then they will have an evolutionary advantage. Couples with radiation-resistant genes will produce more off-spring who reach the age of maturity thant non-radiation-resistant couples. But whether that is, or will be the case, is unknown, and will not be a factor until such time as the bombs start falling. In the meantime, radiation-resistant people have just as many children as non-radiation resistance people. Evolution has stalled.

[blaise]

BadCompany said:

All of which ignores (the theory of) natural selection. In order for head and facial hair to disappear, there would have to be some sort of biological reason for people with less head and facial hair to produce more children with the mutated baldness gene, than people with regular, full-bodied locks. As it stands now, people (in the Western world at least) have their 2.3 children regardless of the mutants they pass on. Thus, bald-gene people do not outnumber hair-gene people. The trend in Asian countries is to have fewer and fewer children, either through social changes or outright laws (i.e China). Africa and South America still tend to have larger families, and an argument could be made that evolution still continues in those regions, but the current zeitgeist is to change opinions there, and reduce the willy-nilly procreation they currently engage in. Could a new Pope kill evolution completely, simply by accepting birth control?

As for viruses and anti-biotics, you still have the problem of natural selection. Your analogy *might* apply to sub-Saharan Africa, where the HIV rates are through the roof, but if a cure/vaccine is found in the next decade or two, those with a stronger, HIV-resistant system will have no natural selection advantage over those who don't. Both groups will still have their 2.3 children, and neither will gain any significant evolutionary lead on the other.

The nuclear war scenario is an interesting one, but highly speculative. Yes, assuming there are indeed radiation-resistance people out there already (who just don't know it for obvious reasons), then they will have an evolutionary advantage. Couples with radiation-resistant genes will produce more off-spring who reach the age of maturity thant non-radiation-resistant couples. But whether that is, or will be the case, is unknown, and will not be a factor until such time as the bombs start falling. In the meantime, radiation-resistant people have just as many children as non-radiation resistance people. Evolution has stalled.

Where do you get your 2.3 children in Western Europe? Certainly not among caucasoid stock. It has been predicted that at the present birth rates the original ethnic populations of the W. European countries would age and decline were it not for not for the immigration from Africa and Asia.

As for your statement about vestigial hair, you might find this reference from a reputable medical journal informative. It tends to affirm what I said and negate what you said.
Arch Dermatol. 1998;134:867-869.

You're also being optimistic about HIV infection. Even if we assume that drugs or vaccines are 100% effective in holding the virus in check (which is a big assumption), I suggest you look up the many ways in which present antiretroviral drugs are harmful to human health and shorten life before you begin to equate virus-free individuals and treated patients.

Finally, I have no idea what you mean when you say a more liberal pope who condones artificial conception could kill evolution.

[BadCompany]

2.3 was a number I pulled out of mid-air. In and of itself, it is neither relevant to the actual question, nor does changing it alter in any way the strength/weakness of my argument. It could be 1.3, or 0.3, it doesn't matter. As long as the ratio between a have gene offspring and and a have not gene offspring remains the same, no evolution is taking place.

[blaise]

BadCompany said:

2.3 was a number I pulled out of mid-air. In and of itself, it is neither relevant to the actual question, nor does changing it alter in any way the strength/weakness of my argument. It could be 1.3, or 0.3, it doesn't matter. As long as the ratio between a have gene offspring and and a have not gene offspring remains the same, no evolution is taking place.

It's good you admitted that 2.3 was a made-up figure, because if you had persisted it would have been hard for me to believe anything you said.

The original purpose of hair was to serve as protection against a frigid environment. Humans are able to control both personal and room environment, so hairiness confers no survival advantage, and the trend in Homo sapiens has been toward less of it. So why should anyone be confident that it will persist? If anything, body hair (as distinct from head hair) in a woman has been regarded as a cosmetic disadvantage since clam shells were state of the art implements in beauty salons and may in some cases turn off potential mates. If you don't think so, why are there so many ads for hair removal creams, lotions, mechanical depilatators, and laser removal?

I'll tell you one thing that could make a big difference in demographics. If the demand for electrical power (particularly for air conditioning) drastically exceeds the supply, you'll see reverse immigration in Florida.

[BadCompany]

I'm beginning to think you either have a poor understanding of the theory of natural selection and evolution, or you are deliberately engaging in the fine art of sophistry.

Frequent trips to the hair salon do not result in off-spring genetically programmed to have less hair. No more so than wearing tinted contact lenses to influence your child's eye color. In order for evolution to continue, a mutated gene has to afford one, and one's offspring, a greater chance of producing still more offspring with that mutated gene.

If anything, hair removal creams, lotions, mechanical depilatators, and laser removal will further stall evolution, as they successfully (the ads say so) hide the undesirable "very hairy" gene, leaving said poorly afflicted women just as much chance to produce their 2.3 ( ) children as their more "naturally" beautiful and bald competition.

[blaise]

You suggest that I have a poor understanding of evolution and natural suggestion when your posts on this thread sound as they are spillovers from the Art of Gibberish thread? The death of evolution? What the devil are you talking about? Was the 2.3 children figure you posited pulled out of your left nostril or your right, or perhaps a somewhat larger aperture? You have no idea how a gross error like that can discredit what you are saying. The negative population growth in Europe has been a hot topic for years. It makes me suspect that you're not focusing on much in the world news nowadays besides the CBA. I cited an article on vestigial hair in a medical journal. Not only do you seem to unaware of this phenomenon but you don't seem to be motivated to do any research on the subject. On what are you basing your blunt proclamation that this is not happening? My dig about depilatories and unsightly body hair was a momentary intentional lowering to the level of your posts. It's not sophistry, it's sarcasm in case you don't know the difference.

[BadCompany]

Still sounds like sophistry to me. I tried to get an interesting debate going, but alas, you are trying to stick to a position you either don't understand, or don't really support.

Of course I am aware of the population trends in Western Europe. Just as I am aware of the declining birth rate of pure laine Quebecois. So? Not only is the time frame we are talking about miniscule in terms of evolution, but its not even relevant to the (original) discussion of natural selection. Unless you want to argue that French Canadians are genetically inferior to other population groups, of course. In that case, you are on your own.

You speak of sarcasm, yet seem unable to move past a random number that has little bearing on my position. Pity. I thought we could have had a nice intellectual debate. Next time, instead of using "2.3 children" to denote middle class banality, I'll say "two cats in the yard." Unless, of course, you'd like to post some different pet number statistics that clearly prove human evolution is still ongoing.

Whether human evolution has stalled or not has been discussed in scientific journals, and by scientists specialized in the field. It may be gibberish to you, but I thought it would be fun. Guess not. Lets just go back to your "George Bush ruined my life" non-gibberish and call it a day.

[M. Beaux-Eaux]

BadCompany said:

Frequent trips to the hair salon do not result in off-spring genetically programmed to have less hair. No more so than wearing tinted contact lenses to influence your child's eye color. In order for evolution to continue, a mutated gene has to afford one, and one's offspring, a greater chance of producing still more offspring with that mutated gene.

If I were less sensitive I'd say that you are mocking my question regarding the probability of Satanists eventually evolving into tailed and hornèd specimens.

*

This thread seems to have devolved to definitions 3 and 4 below.

evolution

• noun 1 the process by which different kinds of living organism are believed to have developed, especially by natural selection. 2 gradual development. 3 Chemistry the giving off of a gaseous product 4 a pattern of movements or manoeuvres.

And here I was hoping that possibly the discussion would get around to whether we are talking about evolution or, rather,

adaptation

(also adaption)

• noun 1 the action or process of adapting or being adapted. 2 a film or play adapted from a written work. 3 Biology a change by which an organism becomes better suited to its environment.

And eventually to discussion of non-physical evolution.

Maybe next time.

*

BTW, Blaise, care to recommend some books on the art, craft and business of evolution?

[Cranky]

M. said:

If I were less sensitive I'd say that you are mocking my question regarding the probability of Satanists eventually evolving into tailed and hornèd specimens.

I have a tail and horns but I ain't no Satanist. Oh wait, I was once a card carrying Liberal, does that count?

Guys, where's the love? Remember, we're here to have some fun, bake a few lies, toss out a few cents, chase the woman (where ARE the woman? Did BC try to date them AGAIN?).

Stay cool......

[M. Beaux-Eaux]

Mr. said:

I have a tail and horns but I ain't no Satanist. Oh wait, I was once a card carrying Liberal, does that count?

Guys, where's the love? Remember, we're here to have some fun, bake a few lies, toss out a few cents, chase the woman (where ARE the woman? Did BC try to date them AGAIN?).

Stay cool......

Relax, man! There is nothing happening here except that some theoretical ex-apes of evolution are rattling their cages. Nothing more serious than that.

Care for a banana?

[blaise]

M. said:

Relax, man! There is nothing happening here except that some theoretical ex-apes of evolution are rattling their cages. Nothing more serious than that.

Care for a banana?

Humans are NOT descended from apes, although creationists use that canard to mock evolutionists. The hominidae branched off from earlier forebears and not from apes, although apes and humans may have had a common ancestor. Of course, I'm tempted to say that George W. Bush is a throwback, but since he has some normal ancestors it would be presumptuous to go that far.

[blaise]

BadCompany said:

Still sounds like sophistry to me. I tried to get an interesting debate going, but alas, you are trying to stick to a position you either don't understand, or don't really support.

Of course I am aware of the population trends in Western Europe. Just as I am aware of the declining birth rate of pure laine Quebecois. So? Not only is the time frame we are talking about miniscule in terms of evolution, but its not even relevant to the (original) discussion of natural selection. Unless you want to argue that French Canadians are genetically inferior to other population groups, of course. In that case, you are on your own.

You speak of sarcasm, yet seem unable to move past a random number that has little bearing on my position. Pity. I thought we could have had a nice intellectual debate. Next time, instead of using "2.3 children" to denote middle class banality, I'll say "two cats in the yard." Unless, of course, you'd like to post some different pet number statistics that clearly prove human evolution is still ongoing.

Whether human evolution has stalled or not has been discussed in scientific journals, and by scientists specialized in the field. It may be gibberish to you, but I thought it would be fun. Guess not. Lets just go back to your "George Bush ruined my life" non-gibberish and call it a day.

As I write this I have beside me my personal copy of TThe Origin of Species by Means of Natural Selection or The Preservation of Favoured Races in the Struggle for Life. I recommend that you read (or reread) it.

I would also recommend that you hunt up the recently published articles about diminutive hominids with small crania who nevertheless constructed tools and coexisted with Homo sapiens until comparatively recently on the island of Flores. Try The National Geographic Explorer, March 7.

[M. Beaux-Eaux]

Blaise said:

Humans are NOT descended from apes, although creationists use that canard to mock evolutionists.

Like, "Duck, here comes one of those chimps from the lab"?

The hominidae branched off from earlier forebears and not from apes, although apes and humans may have had a common ancestor. Of course, I'm tempted to say that George W. Bush is a throwback, but since he has some normal ancestors it would be presumptuous to go that far.

Interesting theories.

[franko]

Fact, Fable, and Darwin
By Rodney Stark

I write as neither a creationist nor a Darwinist, but as one who knows what is probably the most disreputable scientific secret of the past century: There is no plausible scientific theory of the origin of species! Darwin himself was not sure he had produced one, and for many decades every competent evolutionary biologist has known that he did not. Although the experts have kept quiet when true believers have sworn in court and before legislative bodies that Darwin's theory is proven beyond any possible doubt, that's not what reputable biologists, including committed Darwinians, have been saying to one another.

Without question, Charles Darwin would be among the most prominent biologists in history even if he hadn't written The Origin of Species in 1859. But he would not have been deified in the campaign to "enlighten" humanity. The battle over evolution is not an example of how heroic scientists have withstood the relentless persecution of religious fanatics. Rather, from the very start it primarily has been an attack on religion by militant atheists who wrap themselves in the mantle of science.

awaiting the rebuttal

[blaise]

I have a problem with the refutation. I need an explanation of how new species appear fully formed--the chicken without the egg. Assuming that new species appear fully formed--which I have every right to doubt--why is the DNA map of these "new" species so amazingly similar to those of closely related "old" species? Why have bird species become more birdlike over a span of millions of years? Certainly on a time scale most of today's bird species are better fliers than their predecessors. That alone suggests a direction rather than randomness. There are exceptions in the case of the ostriches, for example, but ostriches have developed compensatory traits for the inability to fly, such as running speed, great bulk, and a powerful kick that enables them to stand up to some predators. Why has there been a directional change from the early hominids to Homo sapiens and not the reverse? If humans are supposed to be entirely different from all other creatures on the planet and the recipient of God's benefaction, why do they have such a high degree of genetic homology with other primates? Why do humans and rats have similar brain receptors for endogenous neurotransmitters, including opiates?

[M. Beaux-Eaux]

Blaise said:

I have a problem with the refutation. I need an explanation of how new species appear fully formed--the chicken without the egg. Assuming that new species appear fully formed--which I have every right to doubt--why is the DNA map of these "new" species so amazingly similar to those of closely related "old" species? Why have bird species become more birdlike over a span of millions of years? Certainly on a time scale most of today's bird species are better fliers than their predecessors. That alone suggests a direction rather than randomness. There are exceptions in the case of the ostriches, for example, but ostriches have developed compensatory traits for the inability to fly, such as running speed, great bulk, and a powerful kick that enables them to stand up to some predators. Why has there been a directional change from the early hominids to Homo sapiens and not the reverse? If humans are supposed to be entirely different from all other creatures on the planet and the recipient of God's benefaction, why do they have such a high degree of genetic homology with other primates? Why do humans and rats have similar brain receptors for endogenous neurotransmitters, including opiates?

God only knows. It's a mystery.

[BadCompany]

Blaise said:

As I write this I have beside me my personal copy of TThe Origin of Species by Means of Natural Selection or The Preservation of Favoured Races in the Struggle for Life. I recommend that you read (or reread) it.

I would also recommend that you hunt up the recently published articles about diminutive hominids with small crania who nevertheless constructed tools and coexisted with Homo sapiens until comparatively recently on the island of Flores. Try The National Geographic Explorer, March 7.

I too, have a copy of The Origin of the Species. I'm also very curious to what further research will reveal on "the Hobbit" men recently discovered in Indonesia, though admittedly I am more interested in their social and cultural lives, than their biology. Still not sure what you are trying to say.

My original assertion was that human evolution has stalled. Most specifically evolution through natural selection. I had originally thought that some clever individual would bring up gene therapy as proof of further possible evolution, from which a whole new branch of discussion could have, ahem, evolved, but alas, no such clever individual has emerged.

I never said that human evolution - or evolution in general - never took place. Merely that our advances in science and technology, most specifically medicine, and have made it such that natural selection no longer plays a role in human evolution. That various incarnations of humanoid species have existed throughout the millennia is not in question for me, nor is it inconceivable to me that some versions of humanoids co-existed, even inter-mingled. We are fairly certain this happened with the Neaderthals and early Homo Sapiens Sapiens. Its not even inconceivable to me that "Hobbit-men" exist to this day, on some dark corners of unexplored Asian islands. Though I hope we aren't once again treated to the sad spectacle of National Geographic Photographers fawning over Philipino villagers dressed up as cave men.

But I digress.

From Darwin himself:

...it follows that any being, if it vary however slightly in any manner profitable to itself, under the complex and sometimes varying conditions of life, will have a better chance of surviving, and thus be naturally selected. From the strong principle of inheritance, any selected variety will tend to propagate its new and modified form.

I proposed that the advancement of technology, particularily medicine, reduces, it not eliminates completely, the species' need for a genetic variation to ensure "a better chance of surviving" and furthermore, that the prevalence, and gaining prevalence of birth control, would severely limit the ability of that genetic variation to be passed on in sufficient numbers so as to ensure an "evolution" of the current human species into something different. If even slightly.

Any takers on this proposal?

[blaise]

I do not believe that the human genome is set in stone. Given the total number of genes in the human genome, the chances of mutations are quite high, although obviously it would take many generations for any mutation to affect a large number of people. With 6.2 billion people now alive, the process would be much slower than in the past. I mentioned greater resistance to harmful irradiation. The consequences of a nuclear holocaust that didn't wipe out all human life would therefore spare only a small subset of survivors, and the world would have to repopulate itself from that small breeding stock.

Some mutations are immediately lethal and cannot be passed along (e.g., there are no female hemophiliacs). Some are neutral with respect to survival. Some are beneficial, such as the reduction in melanin that enables fair people living in the northern lands to make maximal utilization of the sun's rays. Some are defective, but the severe survival disadvantage they impose may in some instances be compensated for by technology. Thus, an extremely hostile environment (i.e., a catastrophe) would not only wipe out any individual indiscriminately but could deprive many survivors of the life support measures made possible by advances in medicine, such as insulin for insulin-dependent diabetics, gene therapy or periodic infusions of recombinant coagulation factors VIII and VII for type A and type B hemophiliacs, respectively; asthma drugs for asthmatics, antiretroviral drugs for AIDS victims, etc. It would also wipe out genetic screening for Tay-Sachs disease and numerous other metabolic, hematologic, neural, etc., disorders.

If there really were intelligent design, how can we explain hemophilia? Hemophilia A (the main type) is a lifelong bleeding disorder transmitted by a faulty gene located on the X chromosome. Hence the disorder is limited to males, all of whose sons will be normal and all of whose daughters will be obligatory carriers of the trait.

[PTH]

BadCompany said:

Any takers on this proposal?

Not really; evolution is still going on - if anything though, less desirable traits are becoming more and more common. A stupidity gene that would just appear now probably wouldn't be weeded out by natural selection, but would be perpetuated, since the less fortunate in society are often those who have more kids.

Evolution is still going on, but it's more of a keep-all-genes-in-small-quantities thing than true natural selection.

So IMO evolution is very much going on, only we're regressing.