Future Evolution Possible?

[LeCynthia]

I was just thinking about this. Let's say, for example, you take a particular animal and split the population into three groups and put each group in another part of the world. In one area the trees are high and after thousands of years they evolve longer necks. The second group is in shrub country and evolve low-lying bodies and the third is in a more barren place and evolve tusks for digging. Okay, so one common anscestor but three paths of evolution.

But now go back to the beginning, split the groups, but this time every few years you scramble the populations. This would slow down evolution greatly, no one true advantage would surface, and all three groups would evolve into something that can dig, reach high, and reach low, however, it would seem like it would take a much longer time to do so.

Isn't this kind of where the human race is today? We scramble ourselves constantly so no one advantage is likely to emerge and people will start to become the same everywhere. Are we stopping our own evolution? Not that we need to evolve, what with all the tools we have to do everything for us, but did we create a biological dead-end for ourselves? If you look at all the diverse races in the world it's clear that a little tiny bit of seperation was starting, but are we nipping it in the bud?

I know there are other considerations, like will we evolve to fit our tools or this was the path we were meant to take anyway but I'm just offering it up for food for thought. I've seen pictures of the "averaged" human face of all races but I'm thinking beyond that. Will there be no branches on this tree?

 

[Marker]

You've been reading this weeks New Scientist...

 

[NeilC]

I was just thinking about this. Let's say, for example, you take a particular animal and split the population into three groups and put each group in another part of the world. In one area the trees are high and after thousands of years they evolve longer necks. The second group is in shrub country and evolve low-lying bodies and the third is in a more barren place and evolve tusks for digging. Okay, so one common anscestor but three paths of evolution.

But now go back to the beginning, split the groups, but this time every few years you scramble the populations. This would slow down evolution greatly, no one true advantage would surface, and all three groups would evolve into something that can dig, reach high, and reach low, however, it would seem like it would take a much longer time to do so.

Isn't this kind of where the human race is today? We scramble ourselves constantly so no one advantage is likely to emerge and people will start to become the same everywhere. Are we stopping our own evolution? Not that we need to evolve, what with all the tools we have to do everything for us, but did we create a biological dead-end for ourselves? If you look at all the diverse races in the world it's clear that a little tiny bit of seperation was starting, but are we nipping it in the bud?

I know there are other considerations, like will we evolve to fit our tools or this was the path we were meant to take anyway but I'm just offering it up for food for thought. I've seen pictures of the "averaged" human face of all races but I'm thinking beyond that. Will there be no branches on this tree?

If you believe in evolution then the idea that there is a path we are meant to follow - no plan is in operation.

But yes, it's an interesting topic. It can be hard to spot the environmental pressures on mankind that would actually translate into biological evolution. Sure we might be building computers but does that affect the number of babies we have and their deathrate? I would say that in general poorer people are having more children. I've heard that in the West, relatively low intelligence is over-represented in people of low income (relative to people in the same country) so it's possible that mankind is getting less intelligent?

 

[Matabiri]

If you believe in evolution then the idea that there is a path we are meant to follow - no plan is in operation.

No no no no no. What is this "meant"?

Evolution is an interaction between a population and its environment. There is no "path".

 

[Mojo]

There's a great quotation about this from Steve Jones:

Natural selection has superb tactics, but no strategy.

There is no long term goal: the only thing that drives evolution is the ability of an organism to pass on traits to its descendents, relative to the ability of its competitors.

 

[JamesM]

But now go back to the beginning, split the groups, but this time every few years you scramble the populations. This would slow down evolution greatly, no one true advantage would surface, and all three groups would evolve into something that can dig, reach high, and reach low, however, it would seem like it would take a much longer time to do so.

I'm not sure I agree with this. To take the first environment as an example, a long neck would only spread through the first population if there was a competition for resources.

If that's the case, then the other subpopulations are out of luck, they're going to die off in that environment. Long necks will outbreed the others.

So we'll see the same results as if the populations weren't mixed up, wouldn't we?

 

[NeilC]

No no no no no. What is this "meant"?

Evolution is an interaction between a population and its environment. There is no "path".

Yes. That is what I was saying....except for the typos! It meant to read "If you believe in evolution then the idea that there is a path we are meant to follow doesn't make sense - no plan is in operation.

 

[Asolepius]

Speciation occurs when populations get separated, commonly by geography. Half of Americans don't have passports, so don't travel outside the US. Europeans travel much more. Are Americans likely to become a new species? Or at least some Americans?

 

[Soapy Sam]

You don't know about the third buttock?


Yes, in a population which allows free movement, a degree of homogenisation is to be expected.

Geographical isolation of a small group may permit a particular gene complex to dominate the group rapidly. Not all isolation is geographical though. Among humans, it may be cultural - (which is why geneticists love the Ashkenasim as well as the Icelanders).
And then there's technological isolation, my own favourite:- If a significant subset of births are premature and a significant set are by Caesarean, and that permits survival of babies with - (to pick just one possible distinction) higher foetal brain growth rates- will we eventually see a degree of speciation into people who can be born by unassisted birth process and people who cannot?

 

[LeCynthia]

You've been reading this weeks New Scientist...

Don't read that. I was thinking about this after watching an old episode of Cosmos with Carl Sagen.

I'm not sure I agree with this. To take the first environment as an example, a long neck would only spread through the first population if there was a competition for resources.

If that's the case, then the other subpopulations are out of luck, they're going to die off in that environment. Long necks will outbreed the others.

So we'll see the same results as if the populations weren't mixed up, wouldn't we?

But if no population stays in one place long enough to develop long necks, and interbreeds with all the other populations then how would a long neck even evolve in the first place? My point is, the surviving animals would have to be able to compete for resources in all three environments so no one feature would dominate any group.

Speciation occurs when populations get separated, commonly by geography. Half of Americans don't have passports, so don't travel outside the US. Europeans travel much more. Are Americans likely to become a new species? Or at least some Americans?

Even though half of all Americans don't leave, the other half does, mixing in with other races, and other races come here mixing in with the half that doesn't leave. Heck, here where I work we have an asian, african-american, mexican, and I'm from the middle east not to mention the caucasions. I've seen spouses and girl/boyfriends and no attempt is made at sticking to their own race.* I'm sure this becoming more the norm. If these races had stayed geographically seperate then I can see each race evolving to be more and more diverse, but the boundries have dropped so we are all intermixing.

Look at this way, supposedly we all came from a common anscester and somehow the different races were starting to evolve, so different races (species?) were developing, but as we become a global society it's like all that diversness will stop and we are all going to average out. I don't know if this is good or bad, it just is, if you get my meaning. Will there be a day, in the distant eons when all humans will look the same?

(*Please take this from a biological point of view. I'm not comparing cultures, or being racist, and hopefully this isn't coming across as anything bad, I was just thinking about evolution and what happens to evolution when groups are no longer isolated and humans are the best example of this.)

 

[Serenity]

If you believe in evolution then the idea that there is a path we are meant to follow - no plan is in operation.

But yes, it's an interesting topic. It can be hard to spot the environmental pressures on mankind that would actually translate into biological evolution. Sure we might be building computers but does that affect the number of babies we have and their deathrate? I would say that in general poorer people are having more children. I've heard that in the West, relatively low intelligence is over-represented in people of low income (relative to people in the same country) so it's possible that mankind is getting less intelligent?

I think you're right about no plan in operation. It's up to us now to take over the evolutionary reigns.

It is third-world countries that are leading in birth-rates. First-world countries tend to break even or decline relying on immigration to augment the populace. Maybe someone can locate a source if they have one handy... I recall reading somewhere that IQ scores are continuing to go up, not down. I hope the test isn't being dumbed down.

 

[LeCynthia]

You don't know about the third buttock?


Yes, in a population which allows free movement, a degree of homogenisation is to be expected.

Geographical isolation of a small group may permit a particular gene complex to dominate the group rapidly. Not all isolation is geographical though. Among humans, it may be cultural - (which is why geneticists love the Ashkenasim as well as the Icelanders).
And then there's technological isolation, my own favourite:- If a significant subset of births are premature and a significant set are by Caesarean, and that permits survival of babies with - (to pick just one possible distinction) higher foetal brain growth rates- will we eventually see a degree of speciation into people who can be born by unassisted birth process and people who cannot?

I'm hoping cultural differences don't isolate us too much, but that's a whole 'nother discussion.

You did bring my thoughts to another direction, if evolution occurs because the fittest survive, and with modern technology the weakest are also surviving and presumedly breeding, then I can see it taking longer and longer for any one trait to survive, hence slowing evolution. Did that make sense? It did when I thought it.

 

[blutoski]

I was just thinking about this. Let's say, for example, you take a particular animal and split the population into three groups and put each group in another part of the world. In one area the trees are high and after thousands of years they evolve longer necks. The second group is in shrub country and evolve low-lying bodies and the third is in a more barren place and evolve tusks for digging. Okay, so one common anscestor but three paths of evolution.

But now go back to the beginning, split the groups, but this time every few years you scramble the populations. This would slow down evolution greatly, no one true advantage would surface, and all three groups would evolve into something that can dig, reach high, and reach low, however, it would seem like it would take a much longer time to do so.

Isn't this kind of where the human race is today? We scramble ourselves constantly so no one advantage is likely to emerge and people will start to become the same everywhere. Are we stopping our own evolution? Not that we need to evolve, what with all the tools we have to do everything for us, but did we create a biological dead-end for ourselves? If you look at all the diverse races in the world it's clear that a little tiny bit of seperation was starting, but are we nipping it in the bud?

I know there are other considerations, like will we evolve to fit our tools or this was the path we were meant to take anyway but I'm just offering it up for food for thought. I've seen pictures of the "averaged" human face of all races but I'm thinking beyond that. Will there be no branches on this tree?

Incorrect assumption: that isolation is necessary for evolution. It isn't.

Consider: if suddenly trees grew tall, the population would respond by growing longer necks. If they shrank again, the necks may shorten. Splitting the population in this exercise is a red herring. Evolution is unaffected. All you need to do is *change* the environment.

In the case of humans, we will evolve or not, depending on whether there is an environmental challenge, not depending on whether we eliminate isolation.

Come to think of it, since many traits are the result of recombination rather than de novo mutations, the more we mix, the faster superior combinations will be revealed, so arguably admixture will accelerate human evolution, at least until novel gene combinations have been exhausted.

 

[blutoski]

I'm hoping cultural differences don't isolate us too much, but that's a whole 'nother discussion.

You did bring my thoughts to another direction, if evolution occurs because the fittest survive, and with modern technology the weakest are also surviving and presumedly breeding, then I can see it taking longer and longer for any one trait to survive, hence slowing evolution. Did that make sense? It did when I thought it.

The problem with this is that the definition of 'fittest' for humans (and even higher primates) is not the same thing as 'physically strongest/healthiest'.

Concievably, "fitness" in the human world may be a mix of social grace and technical competence.

 

[Soapy Sam]

I'm hoping cultural differences don't isolate us too much, but that's a whole 'nother discussion.

You did bring my thoughts to another direction, if evolution occurs because the fittest survive, and with modern technology the weakest are also surviving and presumedly breeding, then I can see it taking longer and longer for any one trait to survive, hence slowing evolution. Did that make sense? It did when I thought it.

"Survival of the fittest" was a phrase coined by Herbert Spencer, not by Darwin.

(See- http://en.wikipedia.org/wiki/Survival_of_the_fittest for history of the phrase).

It might be better rendered "Survival of the best fitted". (Those creatures which are better fitted to their environment than others have a reproductive advantage. ) However , much of the modern human environment consists, quite literally, of other humans, which is where it all gets very messy, cultural, political.
The confusion over the two definitions of "fit" has doomed the phrase to misunderstanding. There is always a danger of "fit" being interpreted politically- "fit to share MY society. Fit by MY definition of acceptability." , - which leads to the perversions of eugenics.

You ask a complex question. Probably it's too complex for a forum like this. If you have not read Richard Dawkins' book "The Selfish Gene", I strongly reccommend it.

 

[Roboramma]

I'm hoping cultural differences don't isolate us too much, but that's a whole 'nother discussion.

You did bring my thoughts to another direction, if evolution occurs because the fittest survive, and with modern technology the weakest are also surviving and presumedly breeding, then I can see it taking longer and longer for any one trait to survive, hence slowing evolution. Did that make sense? It did when I thought it.

If "the weakest" are also surviving, it's because the environment has changed, and so too has the definition of fitness. For instance, we might usually think of an ability to plan ahead as an attribute which would increase fitness, but in a world where we have to think about sexually transmitted diseases, planning ahead might tend to make one less likely to partake in sexual activity that has a high chance of producing offspring.
Meaning that genes for rash behavior (if such genes exist) would be selected for. Of course, there might be other factors that change the scales in favour of planning ahead, this is just a thought. The point being that in this example, the fittest individual is the one that doesn't think about the future.

But you're right, modern medicine is probably weaking the selective pressure that keeps genetic diseases and predispositions to health problems out of the population. I don't know how much of an effect this is likely to be having, nor can I think of any viable solution. We can't exactly require that everyone who goes to the hospital for antibiotics also get sterilised.

Anyway, what's really happening is that the environment is changing. Different traits are being selected for now than were in the distant past. But it's sure to change again before we really see much effect of that. It would be very hard to predict any trends in human evolution, because we just don't know what the enviroment is like - even now - let alone 100 years or 1 million years from now.

As to the point about speciation, well, I'd have to agree, I doubt that we're likely to see any divergence of populations any time soon. There's just too much interbreeding.
I think this is likely to limit the speed of evolution, small populations in isolated niches can go in very different dirrections from the main population that they split from. But if they aren't genetically isolated, the influence of the main population can often stall that adaptation.
On the other hand, that doesn't suggest that there is no evolution taking place. Speciation can certainly be a very important force, but it's not necessary to evolution.