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Mon 9 Aug, 2004 01:53 pm
I wasn't sure whether to put this in the philosophy section or here, but I thought I would let the people who are into hard science get the first crack:
Evolution has shown that we started out as small primates, then grew, learned to walk upright, expanded our brain pan, began communicating with language, and now here we are.
Barring any unforseen comet, war, ecological disaster or other tragedy that might send us back to food gathering nomads (and maybe back to the trees), does anyone want to speculate on how we will look and act in say, 24,400 AD?
20 or thirty thousand years from now, or longer, are we still as tall? Do we still speak to communicate?
I'm trying to stay away from any science fiction fantasy of how we may look. I'm trying to figure out a logical evoluntionary path.
For example:
For the last couple of hundred of years, our weak, sick, and diseased people have lived and procreated. Where a few thousand years ago the 'survival of the fittest', if you will, still was the rule of the day.
Currently, many people who would not have either been born or survived infantcy are now living to old age (good for them! I'm trying to stay strictly scientific here) and their offspring often carry some of the same illnesses. It seems like this will become even more dramtic as medical science improves.
I know gentic research and designer babies might be a factor here, but how will we evolve? Will we shrink? Will we lose our appendix and hair?
What does everyone think?
I doubt there has been much change in our genome in the past 20K years whatsoever. The change in stature is most likely simply due to improved nutrition and freedom from disease. (The adoption of agriculture actually appears initially to have made people smaller because of exposure to disease.) It's hard to imagine any sort of noncataclysmic selective pressure that would significantly influence our body plan.
At least, that's how I sees it...
First of all, i would like to point out that Spencer's chestnut about "survival of the fittest" begs the question of natural selection. Suvival is the means by which it is determined whether or not an individual is fit--those which survive are therefore fit by definition. The important question in natural selection is breeding opportunity. Simply surviving does not assure that one's genetic make-up gets passed along; producing viable offspring does.
To the extent that humans have more and more relied upon their brains as opposed to their brawn to survive in the world, whether or not the "weak, sick, and diseased people have lived and procreated" is not germaine. Stephen Hawking would not have survived even a century ago--but no one can doubt his intellectual stature.
In the animated motion picture Ice Age, Manfred the Mammouth is holding forth to the human infant he has rescued. He says: "So you're going to grow up to be a great predator, huh? I don't think so . . . whaddaya got here, a little patch of fur, no fangs, no claws, you're skin and bones surrounded by . . . by mush." Obviously, the passage is intended to be ironic. Humans could hunt the wooly mammouth and succeed many millenia ago because their brains enabled them to make spears and to hunt cooperatively in a manner that even the most effective pack of wild cannids would envy.
Whatever our future evolutionary path will be, i rather doubt that brawn will triumph over brains in the process.
Quote:even the most effective pack of wild cannids would envy.
And apparently did -- and enough to stick with us, too...
We could not have made a better bargain.
Re: Evoloution and Humans: Does it stop?
A Lone Voice wrote:I'm trying to stay away from any science fiction fantasy of how we may look. I'm trying to figure out a logical evoluntionary path.
Are we assuming an evolutionary path which is not affected by growing genetic and mechanical technology?
It's my guess that the human race will begin modifying itself artificially, and to ever more radical levels within the next few generations. The effects of this modification will far exceed natural evolutionary processes, and there probably won't be much left in 24k years which we would recognize.
What happens if we succeed in isolating human consciousness such that it can be stored in a synthetic matrix, like replicating the neurology of the brain in some type of super-computer-chip. Stored in such a way, a person's consciousness might live forever.
I know all this sounds fanciful, but I don't think it's sci-fi, I think it's probably our real future.
Quote:First of all, i would like to point out that Spencer's chestnut about "survival of the fittest" begs the question of natural selection. Suvival is the means by which it is determined whether or not an individual is fit--those which survive are therefore fit by definition. The important question in natural selection is breeding opportunity. Simply surviving does not assure that one's genetic make-up gets passed along; producing viable offspring does.
I guess I'm applying standard evolutionary thought in that the child/pup/cub/kid/calf/colt born with short legs will be slower then his brothers and sisters with long legs, meaning the short-legged one will be more likely to get caught and eaten. Hence, those with long legs tend to survive to breeding age. But as human culture continues to advance, this will be less important, which leads me to:
Quote:Whatever our future evolutionary path will be, i rather doubt that brawn will triumph over brains in the process.
I agree, but could you elaborate? I have seen some of your other posts, and you seem to have a pretty firm knowledge of many subjects, Setana. How do you think this process will make us look? As we evolve, we will need less and less "brawn". Do you think our species might start to shrink? What will this dependence on brain-power signify?
Quote:Are we assuming an evolutionary path which is not affected by growing genetic and mechanical technology?
It's my guess that the human race will begin modifying itself artificially, and to ever more radical levels within the next few generations. The effects of this modification will far exceed natural evolutionary processes, and there probably won't be much left in 24k years which we would recognize.
What happens if we succeed in isolating human consciousness such that it can be stored in a synthetic matrix, like replicating the neurology of the brain in some type of super-computer-chip. Stored in such a way, a person's consciousness might live forever.
I know all this sounds fanciful, but I don't think it's sci-fi, I think it's probably our real future.
Excellent point, Rosbor.
Do you (or anyone else) think this could lead to a sub-species? Affluence is what will lead to genetic modification. Might this lead to a so-called 'super species that evolves into it's own sub-species?
I suspect that we are still selecting for various traits, e.g. intelligence, the ability to live in close proximity to other people, and many others, just not quite the same set of traits as in prehistory.
ALV, my point about "survival of the fittest" is that it is a distraction from the true point of natural selection. That cub born with shorter legs is likely an expression of a randomly recurring mutation. At any such time as there would be an opportunity to exploit a food source and avoid danger by scuttling through dense undergrowth, the short-legged cub has a survival advantage which could potentially enhance breeding opportunity. Mutation is the understudy waiting in the wings of natural selection.
The notion that we would "shrink" has always been laughable to me. Human women continue to need wide hips to facilitate the birth of large-headed offspring through a large birth canal. We still need bodies large enough and strong enough to allow us to walk around on two legs against the gravitational influence of the planet, while carrying that large brain case upright. Perhaps we might "evolve" into leaner creatures, but affluence and gluttony mitigate against that, it seems to me. I really don't see that there is any advantage which would accrue to the species from altering our present physical profile.
I should add that we have moved our agents of "natural selection" out of our bodies and into our libraries, public facilities and research institutions. Evolutionary pressures on the physical make-up of human beings ceased to important for most of the speices many centuries ago. Now, even warfare does not implicitly demand athleticism. I see no reason to believe that future evolutionary paths would be concerned with our physiognomy.
1. A third breast in the back for slow dancing
2. Super hard but non growing toenails
3.Elimination of male pattern baldness
4.No space between teeth to eliminate the need for flossing
5.Lemon scented ear wax.
6. Elimination of pubic hair
7. Vagina running horizontally
A few of my evolutionary suggestions
A few things here.
First, it would appear that most people are able to pass on their genes. Thus, most people are fit (in the evolutionary sense), and selective pressures are very low. It would be interesting to see some sort of study to see how people who don't pass on their genes compare to those who do. I suspect that in the vast majority of caes, the folks who don't pass them are phenotypically very similar to the folks who do pass them on -- especially in the first world, where the decision not to reproduce is often a conscious one.
Second, the only way any sort of generalized physical reduction would confer an advantage is if it was concomitant with some other change which conferred a significant advantage in the face of a selective pressure. I'd argue that the sedentary lives that most of us live today is less demanding in physical and intellectual terms than our distant ancestors, so I don't think that there is any pressure that favors a bigger brain right now.
There is the temptation to think that our unused faculties -- our physical brawn, for instance -- could atrophy, but this would generally be an effect of genetic drift and our gene pool is so large that it's hard to imagine this happening at any significant rate. The only other way to account for our butts permanently taking the shapes of our computer chairs would be to invoke a Lamarckian model of evolution, and unfortunately it doesn't work like that.
I would suggest that evolutionary pressures associated with physical structure disappeared thousands of years ago. After the domestication of animals and plants for agronomic purposes, physical attributes of size and strength only mattered in warfare, by and large. As long ago as the Sumerian civilization of 5,000 years ago, the military became a line of men bearing shields and spears. The only effect of an extraordinarily large or strong individual in such circumstances would have been a morale effect on his opponents--they might get scared.
Although life continued to be hard for most people in the human race for that last few thousand years, and remains that way for many today, we basically stepped aside from size and strength being evolutionarily significant factors quite a long time ago. About the only thing which now matters in this regard is carrying around this large brain case, and the necessity of a large birth canal to accomodate it. With the pressures removed, as PPD points out, nothing will act to alter human physiognomy from now on, apart from living on other planets with lower or greater gravity for many, many generations.
I won't be around for that party, most likely.
So you're not going to be taking the cryonics route, then?
Nah, eat drink and do Mary, i always say . . .
Or... eat drink and be Mary depending on your predeliction.
An interesting side-subject here might be the evolutionary effect of medicine and global mobility on immunity to disease. In wild animal populations, disease and parasitism have a sort of cyclical effects on the immune strains that predominate in a population. As disease becomes more global and as medicine continues to mitigate the selective pressures of disease, I wonder what the effects on the diversity of immune types within the human species might be (if any)...
Setanta wrote:I should add that we have moved our agents of "natural selection" out of our bodies and into our libraries, public facilities and research institutions.
Culture is now the environment to which we adapt. In terms of natural history, we are "the damndest thing to come down the pike".
Yo, I'm new here, names ray. I am doing an essay on human evolution. One thing I'm dicussing is the possible weakening of the human race due to the lack of natural selction. I would just like your guys imput on weather you think thats true.
I agree not much natural selection is occurring in first world countries, but some unnatural selection is occurring. In recent centuries women have preferred tall men, so the tall men were more successful in passing along tall genes. As human men got taller they started rejecting the women that were 6 inches or more shorter than themselves. As a result both sexes are rather rarely under 5 feet while it was 1/2 in some countries just a few centuries ago. If better nutrition contributed significantely to our height, we should be getting shorter as nutrition has been poorer since the 1940s in most 1st world countries as well as some other countries. Neil
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