Have humans weakened natural selection's potency?

[GDG]

I'm thinking more along the lines of direct combat...or even guerilla tactics. The "Aliens" are superior in that they are stronger than us, faster than us, their blood is acid, and they could rip us to shreds in a matter of seconds.

 

But now, I see that humans would have many "superior" adaptations over aliens, such as our hands and tools and weapons that the aliens do not have, and could not even control.

 

But I would think that being stronger and smarter than your competitors would be a universally valued trait. Aside from the microbial world, could you give me an example of where being stronger and smarter ISN'T an advantage?

 

For one-on-one combat, unarmed, I don't think you can beat a grizzly bear.

 

"Stronger and smarter" is not an advantage if your ecological niche has only low-quality food. If you don't need strength and intelligence to survive, the energy to maintain those traits is wasted -- and critters that don't waste their energy will out-reproduce you. Look at rabbits, for example.

 

The real long-term trait that wins is adaptability -- the ability to survive changes in your environment.

[dttom]

Sorry if this question has been asked. I did a search for it and nothing came up.

 

Anyways, what I mean is that what with the advent of medicine and technology, we keep people alive that wouldn't have lived (or reproduced) a few decades ago, let alone a few centuries ago.

 

I have a very limited understanding of biology, so I was wondering if we were "controlling" natural selection to an extent. People with genes that are "unfit" for survival usually survive in the developed countries. Some even have children and pass on their bad genes.

 

Is this sort of thing happening, or do I have a misunderstanding of the fundamentals of natural selection?

 

Also, taking the concept of evolution to the extreme, will humans progressively get smarter or gain more physical advantages? Is there a "terminal velocity", as it were, for evolution? A life form that is perfect in every way for its evironment?

 

If you consider even the human activities, actually without any difference with any other behaviours in other organism, are under the selecting force of natural selection, human the species definitely is not controlling or limiting natural selection as well as evolution at all. This is my view point but I do think different people would get different thinking, this depends to an extent how one view the state of human in a spectrum of species on earth.

 

As for the medical technology that the unfavourable genes are preseved, it is true, and is supported by the fact that the occurance of red-green color blindness is more frequent in cities than in rural areas. The gene pool of human might become less fit to the environment. But, as long as the medical technologies are in act, such 'unfit' would not be exposed to natural selection and there could in no way be saying that human the species is becoming less fit, if you adopt this new view in considering that physical fitness is not as important as before anymore, but of course this would vary from time to time as the environment changes.

 

For the issue of if there would be any instant a species would become 'perfect', I should doubt about that. The environment keeps changing and there could not emerge a so called 'perfect' form. And also, there does not exist the wording 'perfect' at all, the possiblility of a form that performs superior to the 'perfect' form could by no means be eliminated afterall.

[Ophiolite]

As for the medical technology that the unfavourable genes are preseved, it is true, .

Sorry, but you are misunderstanding. It is not true that unfavourable genes are being preserved. Unfavourable genes will generally be 'weeded out'. The rate at which this happens will depend upon how unfavourable they are. Their 'favourability' will in turn depend upon the specific environment. If genes that were previously unfavoured are now 'preserved' that is because the environment has changed and they are no longer unfavourable (or certainly less unfavourable).

The gene pool of human might become less fit to the environment.

Very unlikely and certainly not the case in the example you have cited.

The But, as long as the medical technologies are in act, such 'unfit' would not be exposed to natural selection .

Absolutely false. All that medical technologies have done is to change the environment in which natural selection works and therefore changed the genes which are favourable and unfavourable, fit and unfit. Natural selection is still fully engaged in controlling the gene pool.

[Baby Astronaut]

As for the medical technology that the unfavourable genes are preseved, it is true, and is supported by the fact that the occurance of red-green color blindness is more frequent in cities than in rural areas.

You have that part backwards. It's usually in rural areas that generally are isolated where higher occurrences occur.

 

 

Isolated communities with a restricted gene pool sometimes produce high proportions of color blindness, including the less usual types.Examples include rural Finland, Hungary, and some of the Scottish islands.

Also, color blindness frequency would be no indicator of favorable or unfavorable genes, as it helps little in survival either way.

[A Tripolation]

Instead of better adapted, could it be more accurate to say they're better equipped? As it'd have little dependence on environment then, and more in (relative) fighting or invasive abilities.

 

Well, wouldn't it benefit humans today to be equipped as the aliens are?

 

Or is it because that our environment doesn't DIRECTLY require this adaptation, that we will never have the strenghts of the "Aliens".

And if that is so, does that mean were the environment to change to where great strength was needed, humans would adapt and become more powerful versions than what they are today?

---

Merged post follows:

Consecutive posts merged

For one-on-one combat, unarmed, I don't think you can beat a grizzly bear.

 

"Stronger and smarter" is not an advantage if your ecological niche has only low-quality food. If you don't need strength and intelligence to survive, the energy to maintain those traits is wasted -- and critters that don't waste their energy will out-reproduce you. Look at rabbits, for example.

 

The real long-term trait that wins is adaptability -- the ability to survive changes in your environment.

 

Well, see, that's my point. Look at rabbits! If we were so compelled, humans (even without our armaments) could easily wipe them off from the face of the earth. They would be our food. If humans were more destructive than they are today, what species could oppose us except one that was even more intelligent and strong?

 

That was my point with the Aliens. I was saying that they seem to be more well evolved due to the fact that they would be the dominant species on Earth.

 

Sorry if I'm bringing up issues that have been resolved. This is a very new topic for me.

[Mr Skeptic]

Which aliens are we talking about? If they require humans as hosts, then after they kill off most of the humans (some hiding in bunkers might escape) they all die out... If they can't use technology, we can pick them off from helicopters (and how in the world did they get to earth?). Of course we'd probably catch one, study it's physiology, and make a pesticide/sickness to kill them all off if there were lots of them. You see, technology makes us very adaptable very quickly.

[Sisyphus]

Well, wouldn't it benefit humans today to be equipped as the aliens are?

 

How? And keep in mind that "benefit" in the context of evolution just means having more surviving offspring.

 

Well, see, that's my point. Look at rabbits! If we were so compelled, humans (even without our armaments) could easily wipe them off from the face of the earth. They would be our food. If humans were more destructive than they are today, what species could oppose us except one that was even more intelligent and strong?

 

Well, again, a virus could wipe us out, but there's nothing less "intelligent and strong" than a virus. They aren't even technically alive! Or a natural disaster. Or, for that matter, ourselves. No other animal is capable of wiping itself out like we could with, say, a nuclear war. And yes, we've made lots of species extinct. In fact, we're the impetus of a mass extinction, that may yet include ourselves. How is that superior?

[Ophiolite]

That was my point with the Aliens. I was saying that they seem to be more well evolved due to the fact that they would be the dominant species on Earth.

I think I see where the root of your misunderstanding lies. You are under the mistaken impression that humans are currently the dominant species on the planet. I understand that many of the globergerina feel the same way.

[JillSwift]

I think I see where the root of your misunderstanding lies. You are under the mistaken impression that humans are currently the dominant species on the planet. I understand that many of the globergerina feel the same way.

Coleoptera, too.

 

The root of this kind of misunderstanding of evolution is not being able to understand that evolution by natural selection does not make value judgments. Intelligence and strength are things we value, and for good reasons. But that value requires our conscious intellect to exist.

 

Evolution is just a name given to a self interacting process. It has no sense of value, no judgment on what works and does not work. Species survive well enough to continue, or they don't, purely as a matter of random mutation over time.

[Baby Astronaut]

Well, wouldn't it benefit humans today to be equipped as the aliens are?

It's possible we'd lose something as a trade-off in the process.

 

Or is it because that our environment doesn't DIRECTLY require this adaptation, that we will never have the strenghts of the "Aliens".

And if that is so, does that mean were the environment to change to where great strength was needed, humans would adapt and become more powerful versions than what they are today?

Seems it. But even if we didn't have mutations that left behind physically strong humans, we'd build machines that have the required strength.

 

Also, it's have to be a survival requirement, not just a convenience. Even so, this is more complex than at first appears. As one example: humans tend to aid others in need, so only a few (or just enough) humans would need to adapt to the new environment in order for the rest to survive. Thus it's no longer a survival requirement for that environment.

[GDG]

Well, wouldn't it benefit humans today to be equipped as the aliens are?

 

Nope. If it were that easy for us to slay each other, the world would be a very different place right now...

 

Well, see, that's my point. Look at rabbits! If we were so compelled, humans (even without our armaments) could easily wipe them off from the face of the earth. They would be our food. If humans were more destructive than they are today, what species could oppose us except one that was even more intelligent and strong?

 

Talk to the Australians: they've been trying to wipe out their rabbits for quite a while now, unsuccessfully.

 

That was my point with the Aliens. I was saying that they seem to be more well evolved due to the fact that they would be the dominant species on Earth.

 

Naw, they'd probably all die from fluorine deficiency...

[A Tripolation]

And yes, we've made lots of species extinct. In fact, we're the impetus of a mass extinction, that may yet include ourselves. How is that superior?

 

I just thought that since we are capable of making other species extinct, that means we are above them on the evolutionary ladder. They continue to exist because we allow it. And I'm sure we couldn't survive if we wiped out all other species except humans, I'm just saying that it seems to me that since we can destroy them, that makes us superior.

---

Merged post follows:

Consecutive posts merged

Evolution is just a name given to a self interacting process. It has no sense of value, no judgment on what works and does not work. Species survive well enough to continue, or they don't, purely as a matter of random mutation over time.

 

I completely understand that. I was just wondering if we have had some impact on these random mutations, which we can now ascribe a value to, due to our developed mental abilities. Seems to me that with us keeping people alive that wouldn't be alive without medicine is cheating---but now I understand that we are simply changing our environment...speeding up the process of evolution quite a bit.

---

Merged post follows:

Consecutive posts merged

I think I see where the root of your misunderstanding lies. You are under the mistaken impression that humans are currently the dominant species on the planet. I understand that many of the globergerina feel the same way.

 

...We aren't the dominant species? Well then, to whom does that honor go to?

---

Merged post follows:

Consecutive posts merged

Talk to the Australians: they've been trying to wipe out their rabbits for quite a while now, unsuccessfully.

 

I think if EVERY Australian was committed to the extermination of rabbits, like we would an opposing species, the rabbits would be dead.

[Baby Astronaut]

I just thought that since we are capable of making other species extinct, that means we are above them on the evolutionary ladder. They continue to exist because we allow it. And I'm sure we couldn't survive if we wiped out all other species except humans, I'm just saying that it seems to me that since we can destroy them, that makes us superior.

What measure are you using? If we go by how equipped we are to kill other animals in this environment, then we're only superior for killing in this environment.

 

But if you took all 5 billion humans and teleported everyone naked to a wilderness planet of 5 billion lions, no trees, and only shark-infested waters, then instantly...humans are no longer superior in killing -- even when nothing's changed about their physical body or mind. It's the environment.

 

...We aren't the dominant species? Well then, to whom does that honor go to?

Ophiolite gave us the answer: "I understand that many of the globergerina feel the same way."

 

And then JillSwift gave us another one.

 

 

I think if EVERY Australian was committed to the extermination of rabbits, like we would an opposing species, the rabbits would be dead.

They wouldn't all be committed to the extermination of rabbits though. And such is the environment that makes the rabbits fit to continue their existence (in Australia).

[Ophiolite]

I just thought that since we are capable of making other species extinct, that means we are above them on the evolutionary ladder.

1. There is no evolutionary ladder.

2. If there was, on this basis the KT impactor was much higher on the evolutionary ladder than anything since, ourselves included.

3. It certainly places us below other species on two ladders - the ethical ladder and the intelligence ladder. It isn't smart to mess up your environment since that will ultimately lead to your demise.

 

 

And I'm sure we couldn't survive if we wiped out all other species except humans, I'm just saying that it seems to me that since we can destroy them, that makes us superior.

See above.

[Whatnow]

I have to agree with your 1st post. Sad but true. Evolution cannot precede as long as we are reproducing with things that should have died off to develope a stronger and more evolved race. I know.. there is a chance that any of us would not be here now without medicine. The way we are as a people now....evolution does not have a chance. The world has been changing for billions of years and life has been changing to meet the needs of survival... We have stopped out nature process of staying in sync with the world, air and climate changes. One bad apple in the bunch ... is what they say. Instead of letting the host expire and mating with stronger genes for procreation... we allow the viruses to stay around and mutate into something it was never meant to become. It may sound heartless, but science is not for the timid.... we have fairytale and magic shows for them.

Im in no way saying we should stop medicines and allow the weak to die so we can become a strong race. If we do that.... we will lose alot of people to start of with but in time the strong will mate with the strong and strength will provail, but we will lose a lot in humanity.

It is not a problem that will solved in our lifetime and I pray they do not even try in children's time.

I'm sure if the time comes that they need to do something....it will already be too late.

 

Sorry for all typos

[JillSwift]

I have to agree with your 1st post. Sad but true. Evolution cannot precede as long as we are reproducing with things that should have died off to develope a stronger and more evolved race. I know.. there is a chance that any of us would not be here now without medicine. The way we are as a people now....evolution does not have a chance. The world has been changing for billions of years and life has been changing to meet the needs of survival... We have stopped out nature process of staying in sync with the world, air and climate changes. One bad apple in the bunch ... is what they say. Instead of letting the host expire and mating with stronger genes for procreation... we allow the viruses to stay around and mutate into something it was never meant to become. It may sound heartless, but science is not for the timid.... we have fairytale and magic shows for them.

Im in no way saying we should stop medicines and allow the weak to die so we can become a strong race. If we do that.... we will lose alot of people to start of with but in time the strong will mate with the strong and strength will provail, but we will lose a lot in humanity.

It is not a problem that will solved in our lifetime and I pray they do not even try in children's time.

I'm sure if the time comes that they need to do something....it will already be too late.

 

Sorry for all typos

You are making a value judgment about "strength". Evolution makes no value judgments - what survives does so because it can, and for no other reason.

 

Humans have developed a set of phenotypes we label "intelligence" and "social behavior". This is a potent combination that has allowed our species to adapt to new environments without waiting on the right set of mutations to come along.

 

To claim that this somehow "impedes" evolution is to assume that evolution has some sort of purpose or direction to it. Unless someone can show evidence of this, the only conclusion that fits the observed facts is that is it impossible to impede evolution.

[PhDP]

Coleoptera, too..

 

"The creator, if he exists*, has an inordinate fondness for beetles".- attributed to Haldane.

 

As for the subject of the discussion... Many have pointed out the basic flaw in Tripolation's reasoning, but I think nobody mentioned this: one of the first discovery of population genetics was that natural selection is much, much more effective in large populations.

 

To put it another way; if a given allele decreases fitness, it is of course less likely to reach fixation than a beneficial allele... that's basically what selection is about. By the way; allele = the particular form a gene, and fixation = when only one allele is present in a population (frequency = 1.0). But still, if the population size is small, and the allele doesn't decrease fitness by an enormous amount, it has actually a decent chance to reach fixation at some point because random genetic drift is a very potent force in small populations.

 

Of course, the nature of fitness has changed a lot with modern technology, but it's also the case for other organisms when there is some variation in their environments. By allowing us to maintain such an unusually large population, technology has shielded us, at least in large part, from some of the most dangerous stochastic forces, making selection more effective.

 

* = ...and he doesn't

[A Tripolation]

By allowing us to maintain such an unusually large population, technology has shielded us, at least in large part, from some of the most dangerous stochastic forces, making selection more effective.

 

But you're basically saying that we have a viable control over natural selection, which is what I stated (and was told I was wrong ).

So...are you agreeing with me?

[dttom]

Sorry, but you are misunderstanding. It is not true that unfavourable genes are being preserved. Unfavourable genes will generally be 'weeded out'. The rate at which this happens will depend upon how unfavourable they are. Their 'favourability' will in turn depend upon the specific environment. If genes that were previously unfavoured are now 'preserved' that is because the environment has changed and they are no longer unfavourable (or certainly less unfavourable).

Very unlikely and certainly not the case in the example you have cited.

Absolutely false. All that medical technologies have done is to change the environment in which natural selection works and therefore changed the genes which are favourable and unfavourable, fit and unfit. Natural selection is still fully engaged in controlling the gene pool.

 

For your first quote, it is absolutely correct that, in a natural environment, unfavorable genes would definitely be wipped out, with exceptions like that gene gradually became not so unfavorable and later became favorable or neutral, but these exceptions are not considered here. In an artificial environment, it is also true that natural selection is always in work, but the targets of which it works on could be manipulated. My opinion should be put more clearly that, medical technologies, like prolonging the life of some patients with genetic diseases, that without the technoloy such patients probably could not live to reproductive age, would alter the targets of which natural selection works on. In my example in the previous sentence, the gene for the genetic disease is now not so visible to natural selection, instead, it is the money, or ability to afford now visible to natural selection.

Let's take an example, again the genetic disease in the first paragraph. Now there is 1% population affected, and 20% of population can afford the treatment. For 1st generation, there remains 0.2% affacted population; for nth generation, there remains 0.2^n% affected; eventually the disease tends to be wipped out. This is the case of having medical technology available. Now consider no such treatment, as there is no such treatment, eveyone who got affected could not live up to reproductive age, all die, for 1st generation, the affected population quickly drops to zero. Here shows a delaying effect of medical technologies on the disappearance of inherit diseases. Now consider generalization of accessibility of the treatment, the percentage of population that can afford now raises to 50%, the nth generation of affected population raises to 0.5^n%. There shows a longer delaying effect used by wider accessibility to medical technologies, and what is important is, this is the trend nowadays. For what I say 'not visible to natural selection' arise when the accessibility to the treatment goes to 100%, the affected population remains 1% or above, due to additional mutation. One could argue such hundred percent accessibility is not realistic, but at least there should exist an equilibrium that, the accessibility rises to a level that cancel out the effect of additional mutation leading to the disease.

 

For your second quote, I could not say much, this of course should be controversial, and here I just like to speak out my view, and for the controversy and discussion continue.

 

For your third quote, it would be settled if you agree first paragraph. And I think maybe this is due to our different interpretation in medical technologies? I think medical technologies target at body, instead of environment.

Edited October 7, 2009 by dttom

[padren]

Just with regards to the Aliens vs Humans and "relative strength" deal: natural selection and evolution is often misrepresented as a cage match with species duking it out to try and place as high as they can on the food chain... which is just one of many human characterizations.

 

I think the real question that is on many people's minds is: Are we adapting (including through technology) in a manner that aids or threatens our long term viability to survive as a species?

We see the threats that disease have caused in the past, as well as large environmental shifts throughout our species' history. As such, we naturally fear that by shielding ourselves from disease through technology that we may be less naturally adapted to deal with it and if we find our environment changed in a manner that technology is no longer available (apocalyptic potentials, etc) that the end result could hurt us more than if we hadn't used technology and relied on genetic defenses to diseases.

 

Personally I am not too concerned with that, but I think that is the general concern when we talk about "good" and "bad" with reference to the impact of technology on natural selection.

 

When we think about natural selection we have ideas of what we "hope" for such as bigger brains, stronger muscles, better eyes, etc. We see those not just as things that are likely to be selected for today, but have the best chance of aiding us in the future even if the environment changes radically. We think favorably of adaptations that we (even if it is naively) see as aiding our long term survival as a species well into the unknown. Likewise, the idea of adaptations on par with peacock feathers makes us want to slap ourselves in the face and worry about the species long term survival.

 

While those are purely subjective human opinion I think they are at the core of what people mean when they talk about "good" and "bad" adaptions. It's definitely good to be clear that it is a subjective opinion and not part of natural selection itself and correct people that mistake it... once corrected it's fair to discuss those human concerns in where natural selection may take us in the future.

 

 

If I had to guess I'd say: No idea. IMO natural selection requires a very long time to have a profound impact on a species' genetics, and we are living in times too fast to really predict where it may all go.

[Sisyphus]

That's an interesting take. Natural selection, by it's nature, is only "concerned" with the present. We're thinking beings, so we can, right or wrong, be concerned about the future as well, which means we might value different traits than natural selection, even while being concerned about the same thing: survival.

 

That's not all there is to it, of course. For example, I would value intelligence whether or not I thought it would aid in long term survival of the species. And actually, it might just be harmful. As is, we seem to be just smart enough to kill ourselves off in some spectacular fashion. Dumbed down a bit, we'd just be a staggeringly successful generalist species occupying almost every ecosystem on Earth.

[padren]

That's not all there is to it, of course. For example, I would value intelligence whether or not I thought it would aid in long term survival of the species. And actually, it might just be harmful. As is, we seem to be just smart enough to kill ourselves off in some spectacular fashion. Dumbed down a bit, we'd just be a staggeringly successful generalist species occupying almost every ecosystem on Earth.

 

I think generally humans do feel like we have a pretty unique capacity to really appreciate existence in the way we do, and we'd like our descendants to share the qualities that we feel make being human so rewarding. In addition to survivability, we seek something that extends the (subjectively) better qualities we identify with.

 

 

I find there is something comforting about the idea of our descendants retaining the qualities that make them "like us" while still going forward enough to disappear over the horizon of the unknown so as to render their fate (and ultimate mortality) beyond comprehension from this vantage point.