Human Evolution site

[Badger]

I just stumbled across this site. It doesn't look well travelled. It deals mostly with Neanderthals and Anatomically Modern Humans.

So, if anyone's interested, here's the link:

http://www.modernhumanorigins.com/phpBB2/index.php

 

[athon]

I'd still be interested to know what we'll involve into one day. Given another million years of evolution, and ignoring the 'we'll make ourselves extinct' nonsense, what traits will dominate the human race?

I think that without any form of eugenics, conditions such as myopia will be a mainstay. With different stresses on our selection processes, I often think that our future holds grim prospects.

Socially-bound stresses, such as socio-economic situations, will see more offspring born to lower SE groups, as it is within social groups that populations tend to reproduce. With a bias of intelligence and health (unsupported by evidence -- I'm just rambling here) towards higher SE groups, this means that we'll have more sick stupid people in the future.

Please note, whilst I'm being somewhat facetious, this isn't without some small merit.

Any thoughts?

Athon

 

[Dragonrock]

I believe that The Marching Morons will be prophetic. People who are intelligent and driven have a better chance to be financially comfortable. Financially comfortable people tend to reproduce less. Rich but stupid people tend to lose their money. Intelligence will still be selected for, just due to slightly different pressures than what initially caused us to become the tool using apes we have become.

This is all my opinion and as such don't mean nothin' to nobody.

 

[drkitten]

I'd still be interested to know what we'll involve into one day. Given another million years of evolution, and ignoring the 'we'll make ourselves extinct' nonsense, what traits will dominate the human race?

I think that without any form of eugenics, conditions such as myopia will be a mainstay. With different stresses on our selection processes, I often think that our future holds grim prospects.

Right now you're only looking at half the problem. For all intents and purposes, there is no selection pressure on humans right now other than the self-applied. You can have as many children as you like and they will all survive to adulthood (at least in the "first world"). Even in the third world, the population is exploding exactly because there is little selection pressure. Under such conditions, it's rather unlikely that there will be any evolution at all.

Of course, this condition can't last; we'll eventually hit a spot where the population stabilizes or even drops sharply. The real question is : what will cause that (alternatively, what will start killing people and applying selection pressure)? If what kills us is a disease, we'll evolve better immune systems. If what kills us is war, we'll evolve better fighting (and survival) abilities.

But the "marching morons" scenario (a good short story, by the way, which I recommend) I find unlikely, simply because I don't really think that the stupid and sickly will have a comparative advantage when the midden really does hit the windmill. If we really do get a killer disease that cuts world population by 2/3 (sort of like the Black Death did to Europe), then, almost certainly, the infants that get killed off will be disproportionately the sickly ones. Offhand, I can't imagine what would disproportionately kill off only the higher-SE classes. Even a revolution would simply replace one group of higher-SE people with another group (the Outer Party replaces the Inner Party; the proles go on....)

 

[Johnny Pneumatic]

I'd still be interested to know what we'll involve into one day. Given another million years of evolution, and ignoring the 'we'll make ourselves extinct' nonsense, what traits will dominate the human race?

Any thoughts?

Athon

If natural selection worked on us again for 1 million more years I have no idea. Maybe we'd look like morlocks. Humans have really seperated ourselves from natural seletion though. Humans are rarely eaten, we engineer our environments to suit us. Think AC, heaters, lights, fire, toilets, beds, towns, farms, clothing. Really the only thing that I can think of that still is selected against is disease. Mentally retarded people don't usually have kids. A better question is what will humans do to themselves. Take a look at my avatar. We'll be able to do anything we want with GE, nanotech and robotics etc. Should they even be called "humans"?

 

[BillHoyt]

Right now you're only looking at half the problem. For all intents and purposes, there is no selection pressure on humans right now other than the self-applied. You can have as many children as you like and they will all survive to adulthood (at least in the "first world"). Even in the third world, the population is exploding exactly because there is little selection pressure. Under such conditions, it's rather unlikely that there will be any evolution at all.

Of course, this condition can't last; we'll eventually hit a spot where the population stabilizes or even drops sharply. The real question is : what will cause that (alternatively, what will start killing people and applying selection pressure)? If what kills us is a disease, we'll evolve better immune systems. If what kills us is war, we'll evolve better fighting (and survival) abilities.

Where do you get the idea there's no selection pressure because the population is exploding? Where the idea that it has to do with survival to adulthood? It has to do simply with differential production of offspring.

 

[Dymanic]

Originally posted by new drkitten

Even in the third world, the population is exploding exactly because there is little selection pressure.

I also can't agree with that. Infant mortality rates in some third world countries are probably not much lower than they ever were.

Under such conditions, it's rather unlikely that there will be any evolution at all.

You're only looking at half of what constitutes evolution.

 

[roger]

Humans have really seperated ourselves from natural seletion though. Humans are rarely eaten, we engineer our environments to suit us. Think AC, heaters, lights, fire, toilets, beds, towns, farms, clothing. Really the only thing that I can think of that still is selected against is disease. Mentally retarded people don't usually have kids. A better question is what will humans do to themselves. Take a look at my avatar. We'll be able to do anything we want with GE, nanotech and robotics etc. Should they even be called "humans"?

Hmm, I still feel selective pressure in breeding. I have a decent IQ, am reasonably motivated, live in a rich country (US), and have a plethora of cultural interests. As such, I look to mate with somebody like me - I'm unlikely to date somebody with a low IQ, somebody in another country (due to logistical concerns), somebody whose greatest intellectual endevoer is reading People magazine each week, etc. Now, to the extent that there are genetic differences between the mentioned populations, there will be differential production of offspring. Plus, cultural norms affect # of births in a family. I'm just an armchair reader of Dawkins, Gould, etc., but I think (guess) it is too early to say we have finished evolving.

Of course in my case I have no desire to procreate, so I'm an evolutionary dead end anyway!

 

[BillHoyt]

I also can't agree with that. Infant mortality rates in some third world countries are probably not much lower than they ever were.
You're only looking at half of what constitutes evolution.

"Half's" being generous here. It all comes down to allele percentages in the population, and changes in those percentages over time. The "death" thing is a popular misconception dating back to the 19th century.

 

[SGT]

Humans are working against natural selection! The advances of Medicine make sickly persons, who would normally die in their childhood and leave no offspring, reach maturity and procreate, thus keeping their bad genes.
If there areno environmental pressures, the offspring of those sick people will reproduce too. Only if there is some heavy change in the environment (or a shortage of resources to maintain those people) will the bad genes be ruled out.
In the other way, think of Stephen Hawking. He has probably bad genes to survive outside of a rich country, but he has a marvelous set of genes for inteligence.

 

[BillHoyt]

Humans are working against natural selection! The advances of Medicine make sickly persons, who would normally die in their childhood and leave no offspring, reach maturity and procreate, thus keeping their bad genes.
If there areno environmental pressures, the offspring of those sick people will reproduce too. Only if there is some heavy change in the environment (or a shortage of resources to maintain those people) will the bad genes be ruled out.
In the other way, think of Stephen Hawking. He has probably bad genes to survive outside of a rich country, but he has a marvelous set of genes for inteligence.

We can't work against selection, SGT. It is an impossibility. Selection is defined as a response to various pressures, amongst them, the environment. What you are really saying is we are changing that environmental context and, therefore, changing the course of our selection. That is a totally different matter.

 

[drkitten]

Where do you get the idea there's no selection pressure because the population is exploding? Where the idea that it has to do with survival to adulthood? It has to do simply with differential production of offspring.

Because "differential production of offspring" is not, by itself, selection pressure. As I said, differential birthrate is only half the problem. The other half of the problem is differential death rate, which has temporarily been rendered a non-issue.

Re-read Gould and Dawkins. Evolution doesn't occur as a gradual uniform process; it usually happens in fits and spurts when there's competition for resources and niches. We're almost certainly in one of the in-between times, exactly because competition for resources has dropped so far. We're therefore almost certainly not experiencing much evolution at the moment. This will remain the case until we have a shock to the system and nature gets a chance to sort the wheat from the chaff, as it were.

 

[Dymanic]

Originally posted by new drkitten

The other half of the problem is differential death rate, which has temporarily been rendered a non-issue.

Unless you happen to be one of the millions who die each year from diseases of the heart, lungs, liver, kidneys, etc.

Re-read Gould and Dawkins. Evolution doesn't occur as a gradual uniform process; it usually happens in fits and spurts when there's competition for resources and niches. We're almost certainly in one of the in-between times, exactly because competition for resources has dropped so far. We're therefore almost certainly not experiencing much evolution at the moment. This will remain the case until we have a shock to the system and nature gets a chance to sort the wheat from the chaff, as it were.

I just re-read this quote by Dawkins:

". . . strong 'selection pressure', we could be forgiven for thinking, might be expected to lead to rapid evolution. Instead, what we find is that natural selection exerts a braking effect on evoluion. The baseline rate of evolution, in the absence of natural selection, is the maximum possible rate. That is synonymous with the mutation rate."

 

[BillHoyt]

Because "differential production of offspring" is not, by itself, selection pressure.

I didn't say the differential production is selection pressure. It is not at all selection pressure; it is the result of selection pressure.

As I said, differential birthrate is only half the problem. The other half of the problem is differential death rate, which has temporarily been rendered a non-issue.

Actually, you wrote nothing about "differential." You wrote strictly of population growth, which is absolutely irrelevant, as proven with the Hardy-Weinberg Equilibrium introduced in the early 20^TH century.

Re-read Gould and Dawkins. Evolution doesn't occur as a gradual uniform process; it usually happens in fits and spurts when there's competition for resources and niches. We're almost certainly in one of the in-between times, exactly because competition for resources has dropped so far. We're therefore almost certainly not experiencing much evolution at the moment. This will remain the case until we have a shock to the system and nature gets a chance to sort the wheat from the chaff, as it were.

You misunderstood those authors. They were speaking of speciation, a distinct result of evolution. "Evolution" is the change in any population's allelic frequency over time. Period. There is no gradualism/cataclysm debate about that.

We are, today, undergoing evolution. We may or may not be speciating.

 

[Mercutio]

With the availability of birth control, there could be selection against caring about overpopulation...(to the extent that there is a genetic component, of course), leaving us with people who don't care....

Ok, cynicism aside...things that are directly related to reproductive success tend to be selected much more rapidly...with birth control, we now have the availability to separate "sex for pleasure" from "sex for reproduction" (again, if this distinction has a genetic component). We could conceivably (pun intended) see, eventually, an increase in the desire to have kids, and perhaps a decrease in the actual physical pleasure of sex. (BTW, this is not my original idea, although I no longer remember the source I first heard it from. Myself, I am opposed to the idea.)

 

[Johnny Pneumatic]

Hmm, I still feel selective pressure in breeding.

That's Sexual Seletion. They don't talk about Sexual Seletion much in Biology Class. I don't know why. Peacock feathers, frog neck sacks(not the technical term) and hundreds of thousands of other biological things don't make sense without it.

 

[Eos of the Eons]

As a result of our accomplishments we are seeing some evolution. A lot of people need their wisdom teeth pulled because our lower jaws are getting smalller. We normally would die of infections and such, but our intelligence allows this "mutation" to flourish.

Aren't we also getting taller as a species? Women generally (not me) prefer tall men, and seem more likely to have children with them. At least we still have short people around in case this trait is selected for some day from some environmental stressor.

As a whole, humanity may still evolve very very slowly, but I can't see any other species branching off for any reason. There aren't really any populations in isolation, etc. I can't see us evolving so much that we could become a different species. What we have now "works".

Thing is, the most succesful species survive because they are in a good form already. We still have sharks and crocodiles, etc. They have remained very unchanged for a loooong time, and anything that may have been closely related, but a different species may have died off because of survival of the fittest. The present form won out.

So, even if we saw a different species of human evolve, would that new form be better able to survive than the model we are now? They may die out in some kind of test on their survival. Or maybe we would, and they would live on. Thing is, I can't see another humanoid species developing, we just don't have the conditions available on this planet for that to happen right now.

Maybe if we colonize another planet? Then we might see some changes that would make another species of humans?

 

[Johnny Pneumatic]

Maybe if we colonize another planet? Then we might see some changes that would make another species of humans?

Yes, but we'd do it to ourselves. Why waste millions of years when species level or much greater level of changes could be made in a matter of days(maybe even hours) when our biotechnology and nanotechnology is sufficiently advanced?
It would certainly be at that level if we had off Earth colonies.
Think four armed astronauts. Have you ever watched video of them in zero-g? human legs are worse than worthless. They're so big. All you can really use them for is pushing off walls. That's nothing a good extra set of arms couldn't do.

 

[Eos of the Eons]

True, but are 4 armed humans another species? The 4 armed humans would also only be good for non-gravity situations. It would be alright, but we need 2 legged ones around to colonize planets, it would be better right?

It's also more interesting to see what makes something evolve as well. It takes longer, but I think we'd learn more from it? I'm not sure the human rights activists would put up with us messing with the current model much. They can't argue if things happen "naturally" though.

Very interesting though. What else could we bake up in a lab situation that would be beneficial?

 

[Badger]

It seems to me that people are looking too "short term" here. It is still unclear if Homo Sapien Sapien, Homo Sapien Neanderthalensis, and Homo Erectus are different species.

There's a big debate that rages between proponets of the "Out Of Africa" theory (OOA) and the "Multi Regional Evolution" (MRE) theory. OOA proposes that modern humans are a separate species originating in Africa around 150 000 years ago, and expanding throughout the world. MRE propontents submit that from the time of Homo Erectus leaving Africa and spreding across Europe and Asia, regional characteristics have developed and been affected by various "waves" of adaptive mutations. This debate is by no means settled, in spite of the mtDNA data.

From my perspective, looking for species changes amongst Homo Sapiens in the last 40 thousand years is a bit myopic. We are still in too much of a transition period....from hunter gatherers to farmers to information managers.... for any clear environmental pressure to have obviously raised its head. But this is just my opinion.

Generally, though, I feel that the more we can be jacks of all trades, as a species....highly adaptable to any environment (currently, our strength is adapting environments to suit our needs such as space, undersea, arctic, desert through use of clothing housing, etc) the greater our success. So, perhaps the 3rd world is the place to look for the "new human" in that they have the harshest conditions to exist in, and so have had to become the most robust and innovative to survive in the cusp between low tech and high tech.

The success of our species on earth, in my opinion, is guaranteed in that we have expanded across the globe in all climates using only natural products (eskimos, bedouin, pygmies and the vast range of environments between). We have survived the Toba explosion (volcano, about 70 000 yrs ago, worldwide climate effect, reduced human population to less than 100 000 people, is estimated) so I feel there will always be humans around. Perhaps not in the populations that we have at the current time, but we will always be able to find or make a niche to survive in.

Our challenge is to evolve a species that can become interplanetary and/or interstellar. This pressure, obviously, tends towards resource conservation and intelligence. If our species is to survive until the death of the universe, this is the challenge faced.....to get to places that can support our life form, as places we leave behind can no longer support our needs.