I think that, so long as genes continue to randomly mutate, evolution won’t end. And since genes will always continue to randomly mutate, evolution will continue.
The question that arises is what kind of evolution? IOW, is “survival of the fittest” still relevant to humanity?
IMHO, it is not. My argument is not based on (essentially) first world advances in medicine (though, if it spreads, it will take on more importance), but on man as a social animal. So long as humans protect the “weaker” in their tribes, those genetic traits will not be weeded out. Dude mentioned vision problems. I submit, however, that near- and farsightedness were not eliminated as barriers to survival by the invention of glasses, but instead by the protection afforded to the impaired person by the tribe.
Two questions arise concerning the validity of my views, which hopefully someone here can answer:
Some “negative” traits, such as vision issues, are actually beneficial to the tribe as a whole. For example, farsighted people would make excellent lookouts, while nearsighted people are very good at detail work. Do tribes/societies equally protect people with “negative” traits that don’t contribute to the whole?
Are humans unique among social animals in protecting the weak? Do nearsighted wolves get tossed out of the pack?
Assuming that my theory is valid, I see evolution as spreading genetic diversity in humanity in the future. Genetic mutations that would have once been considered bad are no longer weeded out. It should be interesting to see the result. One thing I don’t see happening is new speciation in the Homo genus.
Because the human race seems to largely support itself, aid persons who need aiding, and so on, all that is left to evolve is really intelligence.
Genetic traits don’t disappear through evolution unless all people with that genetic trait die off before passing it along. Because this, largely, ain’t gonna happen anymore we’re not going to evolve in quite the same way. We will keep all the bad stuff, and gain all the new stuff which happens through random copying errors.
But since genetics has not found a correlation with intelligence, apart from disfunctions and retardation, it isn’t that likely that we will evolve into a new intelligence.
However, that depends on if we want to limit evolution to genetics. It is possible that we are causing evolution of a new lifeform; ie-computers, as was already mentioned. We may have to revise what we mean by “evolution” in a good fifty years or so.
“Dude” the problems with your understanding of evolution and genetics are legion. I frankly do not have the time to correct them, however for others benefit let me make some notes:
Simplistic use of pseudo-darwinian language to describe short term social arrangements is both intellectually dishonest as well as unsupportable scientifically. Social darwinism has a bad name in science for very good reasons.
No, it is not, it is a simplistic distortion. Access to resources may limit births, depending to what extent the family/community expects in terms of resources per child. Money per se may or may not play a decisive role in the decision to have children, depending on what extent children are viewed as generating resources versus consuming them. In the developed world, requirements for education may lead to a view of children as resource consumers, but this is not a necessary one. Further, depending on the subjective weight a family or society places on child bearing versus individual consumption and standard of living, the limits on child bearing may not be any more or less for a middle class --income wise-- family than a family on public assistance.
All this of course abstracts away from any number of detials but should be sufficient to show that your analysis of welfare and child bearing is hopeless simplistic and hardly worthwhile in terms of evolutionary impact.
Your grasp of what heriditary means is weak and your evident assumption that it is genetically over-determined is unsupported by any evidence. Intelligence itself is a hopelessly, at this stage of the game, subjective and poorly defined. There have been several interesting and well-informed discussions of the problems of defining, measuring and attributing intelligence here on this board in the last several months. I invite everyone to search on intelligence and genetic in both GQ and GD (without date restriction) for some well-argued discussions.
Sadly, in America, the poor are so well taken care of that those with little education and low incomes usually have far more children than those with more money and education. This is probably partially due to a lack of education on birth control for the uneducated and the inability to afford birth control and non-sexual methods of entertainment when you are poor. (After all, when you have no luxuries, there is nothing to do but have sex or talk, and with little education, the talk dies out faster).
That is only if a farsighted person has better vision than a normal person when looking at far away objects. This could be the case, but I never thought it was.
My dear fellow, I hardly need a web search to get a grasp of this. As I said, this subject has been recently discussed, do a search here in this board on intelligence and genetics.
Humans have not stopped evolving no. We are forever evolving.
People from centuries ago would very likely not be able to inhale the toxins that we do with every breath. Or eat foods that have been sprayed with pesticides and laden with preservatives. Or drink water that has been contaminated by acid rain. Etc.
As we affect and change our environment, we are forced to adapt to those changes, or die out as a species.
However, we are no longer evolving according to the law of natural selection. We as humans control too much of our environment to be ruled by it. Yes natural disasters can destroy entire cities and certain modern day diseases can be construed as plagues, but humans are doing better now than ever, mostly due to medical science.
We have found ways to keep premature and defective babies alive and well. We have no natural enemies that we have any need to fear. We promote and help those that would normally not be able to support themselves.
If natural selection were at work still, the physically and mentally incapable or handicapped would be weeded out by the process. Nature is unthinking and seemingly cruel, but it is only a force of balance. The fact that we have taken it upon ourselves to care for those that cannot care for themselves, on a massive level, is a prime example of how we have averted natural selection.
Unlesds we’ve made some massive medical advance I’m not aware of, there are still plenty of genetic diseases and diseases with genetic predispositions that kill long before reproductive age.
Therefore, we still are undergoing natural selection. So we’re evolving (gratuitously simplified answer).
There is no such thing as “devolving”. This idea is based on the mistaken presumption that there is a preferred outcome in evolution, which of course there isn’t.
And why do people constantly try to make some distinction between “natural” selection and our current environment? Just because we affect our surroundings does not make our evolutionary path “artificial”. Other species protect their own, we simply do it far more successfully.
Granted it’s a fairly vague difference Hardcore, but I think what they’re trying to get at with the ‘artificial’ vs. ‘natural’ evolution line is that humans might now be capable of existing for their entire lives free of ‘natural’ stimuli like weather, predators, disease, solar radiation etc. This theoretically makes it possible for evolution based on ‘natural’ selection to stall. Evolution based on genetic drift and ‘artificial’ selectors like synthetic chemicals then take over. Thus we have ‘artificial’ selection and, I assume, ‘artificial’ evolution. The last 50,000 years of evolutionary selection then potentially becomes worthless.
I can’t think of any animals where the reproductive individuals could ever be protected from all the selectors listed above.
like all animals we adapt to our environment, we also change our environment… you could say someone in new york is adapted to that environment as much as a someone living on the plains in africa.
this probably explains the wide diversity of people in africa i.e. very tall near pygmies etc, where city dwellers are similiar.
‘almost like a whale’ - update of origin of the species makes some good points about this.
for example, a lot of the diseases around to day actually offer protection against past diseases i.e. you get this when 70+ but stops you getting the pox etc… its the same with malarie, there are diseases which are bad for you if you get both genes BUT they protect you therefore people in high malarie areas often get it.
In the new Discover magazine, an article asserts that humans may have attained better brainpower by accepting slower genetic change.
The evidence came from an analysis of noncoding DNA in more than three dozen primate species. The researchers found a dramatic decrease in mutation rates in humans and those species closly related to humans. “The speed of mutation is systematically lower in species with more brainpower. Primates with the biggest brains and longest life spans, including chimps and humans, exhibited the lowest rates of all.”
The proposed explanation is that slowing the rate of mutation means fewer deleterious mutations and therefore a longer time before a cascade of cell deaths due to the mutations. “In other words, putting the brakes on mutations may be the key to having a big brain and a sufficiently long life span to make good use of that intelligence.”
The one thing missing from the article was an explanation of how mutation rates are slowed in higher primates. I thought they were, by definition, random.
I don’t think there’s any evidence that humans have evolved to become more tolerant of synthetic toxins in our environment, or at least not significantly so. For one thing, we do a pretty good job of avoiding consuming actual toxic chemicals - some people belive that many chemical additives and byproducts of industry are hazardous to our health with nothing but anecdotal evidence. Secondly, people in the past oten had to deal with far worse pollution and everyday poisoning than we do now. Up until the 20th century miners had basically no protection from inhaling fumes and dust, and people have been mining for thousands of years. Industrial pollution was far worse a hundred years ago than now, at least in the big population centers like New York, London, etc. Primitive food preservation techinques often led to natural or artifical food poisoning. We probably have a healthier environment now than we’ve had for hundreds of years, and before then we had other causes of death that would kill people off before various forms of pollution would.
A book I once read said that the size of the brain does not really change as one is introduced to a intellectually rich enviroment but that it gains more “wrinkles” and gets heavier. Or at least it did in mice. Couldn’t give you a cite right now, I don’t remember the name of the book. But I will give it a zing in the old Google engine.