Philosophical Question about Human Evolution

[mooeypoo]

Here I am again, posing such question. I think we spoke about this before, but not for a while, and I'm still unsatisfied with teh asnwers. I think the reason is my own lack of properly explaining the question that's bugging me.

 

So I'm giving it another try.

 

We (humans) are part of nature. We're also quite resourceful, so I don't think we'll go extinct any time soon, unless some catastrophe happens (hence, regardless of my attempt to define what I see as the "problem" that leads to my question, I don't think we'll die off as a species because of that so called "problem") - so don't take this as a 'doomsayers' hypothesis.

 

I'm just wondering here.

 

 

It seems that we are sort-of circumventing Natural Selection in our own evolution; that means that instead of Nature "selecting" the most-adapted qualities and having the non-adaptive qualities die off or not reproduce, we allow all sorts of "defects" to continue existing - from having eyeglasses to being born with mental retardation.

 

(Please don't take my description as if I recommend killing of - or stopping the aid to- anyone who has "defects". I am NOT. I'm just trying to make my point.)

 

 

Since we also developed our own sense of morality (that doesn't seem to exist MUCH in nature in terms of "allowing" defects to continue existing/multiplying), I don't see this situation changing. I don't think it SHOULD change, either, ethically speaking, but this thread is not about ethics. It's about evolution.

 

I'm wondering, then: What do you think the outcome of this situation will be in the long run? I've heard in a science radio show (forgot where) once the idea that we might ahve to rely much much more on technology to keep our existence - so perhaps "bionic" people, or genetic engineering to the level of practically 'replacing' nature, etc.

 

Do you think this is going to have a long term effect on our evolution? Are we not allowing our own species to adapt to nature (that we also change quite rapidly, too, without allowing ourselves to "get used"/"evolve"/"adapt" to the changes)? How do you see humanity in a few million years? Where do you think we're going with this Human Selection as opposed to "Natural Selection" ?

 

Anyways, this is just a theoretical, philosophical thought. Please don't get into an ethical discussion here, it might be an interesting one, but it's not my point at all. I'm strictly thinking about evolutionary changes and "path" here.

 

So.. speak philosophy, not ethics. We can open a new thread for ethical evolution choices if you think it's interesting enough to discuss.

 

~moo

[PhDP]

I don't have much time, I have tons of emails to write, but a couple of things,,,

 

#1 - Selection is most effective in large populations, otherwise genetic drift is a major and dangerous force. We're fairly big animals, our cousins; gorilla, chimps, maintain very small population compared to us, so drift will likely push slightly and even mildly deleterious mutations to fixation (=very bad thing, it's one of the worst thing about being large). So, yes, our technology allows us to minimize the effect of some slightly deleterious mutation, but it also allows us to maintain population so large that drift will never push deleterious mutations to fixation.

 

#2 - By removing some constraints, technology might in fact favor really advantageous mutations. Let's just look at a concrete example; the human brain. Our brain requires a lot of energy, and we have to take this energy somewhere. One very credible theory is that we had to reduce the size of our digestive system to 'pay' for our large brains. Of course now we have plenty of energy, so we could evolve larger brains without having to lose a leg.

 

#3 - Sexual selection is still effective, and because of #1 and #2, it's likely very effective considering our size.

 

#4 - Diversity will be higher (actually, this is very important for adaptation).

 

#5 - And lastly, who cares if our vision gets a little worst ? I could name tons of mild defects that have become irrelevant because of technology, but none of them are really important compared to the advantages. We live in a world with a lot less violence than our ancestors, it'll likely favor intellectual skills even more than before (BTW, I think evolution will likely lead to further feminization of men).

[SkepticLance]

Mooeypoo

 

Your basic idea is correct. Humans have not quite removed natural selection, and there are always certain factors being selected for. It is unlikely this selection will have much impact, though, since human society is changing so ridiculously rapidly. An evolutionary trend today may be reversed tomorrow. So we can say that evolution on our species is not significant at all right now.

 

There is also the fact that harmful traits, that once would be removed from the gene pool, now can survive and increase. For example : it does not take much observation to note that intelligent and educated people have fewer children on average than those of lesser intellectual potential. Will this lead to a genetically dumbed down Homo sapiens? Will this evolutionary trend lower our average intelligence?

 

In fact, these are all temporary trends. Evolution takes hundreds of generations. In human terms, thousands of years. Any trend such as towards lower IQ will not have time to have any real impact before the next major change in human society.

 

The next big factor affecting our evolution is likely to be genetic modification of humans. I predict, within 100 years, human reproduction will be preceded by a little gene tinkering to make sure that the new offspring is good looking, athletic, intelligent, immune to lots of diseases etc. The net effect after very few generations will be a human population that is genetically 'superior' to the current one, in many profound ways.

 

Give a few centuries and human society will be virtually unrecognisable, but probably much 'nicer' than what we have now.

 

Some people claim that such tinkering will benefit only the rich. This will initially be true, but not for long. Development leads to new technologies becoming cheaper and more widely available. In time, even the poor can have their offspring genetically 'improved'.

[mooeypoo]

Mooeypoo

 

Your basic idea is correct. Humans have not quite removed natural selection, and there are always certain factors being selected for. It is unlikely this selection will have much impact, though, since human society is changing so ridiculously rapidly. An evolutionary trend today may be reversed tomorrow. So we can say that evolution on our species is not significant at all right now.

 

Wouldn't that be a bad thing considering the environment changes so rapidly? Change of environment without evolution to the species ==> won't that result in humans not being adapted to the environment?

 

That's also my main point in the question -- we seem to be changing our environment very quickly and quite dramatically, and yet not "allowing" our own evolution, in the sense that we don't allow mutations much (genetics kindof prevent them nowadays before birth..) and not allow quite natural selection much... so if we're not evolving but our environment is changing, what would happen to our species in a few thousands/million years..?

[omnimutant]

I like this topic.

 

Wouldn't that be a bad thing considering the environment changes so rapidly? Change of environment without evolution to the species ==> won't that result in humans not being adapted to the environment?

 

No, and here is why. I feel that we have replaced our Natural Evolution with technology to the point that regardless of what mutations have been spawned we seem to be pretty good a combating them with technology, medical or other wise. We are an extremely adaptive species regardless of environmental changes. I've read/heard though common sources (nothing to quote sorry), that we have not actually had a major evolutionary change in our species since we developed as modern Humans. Yet we still survive. Human beings have populated even the harshest terrains on the planet, including Ice ages, major heat waves, droughts, You name it. Through time, we've increasingly create technology to survive harsher and more rigorous environments, weather it be the deepest of Oceans to other Planets (well OK the moon, but Mars is on the Horizon!).

 

Now one could make the case that without the Tools found in todays technology we could not survive in a Hunter/gather situation, in the unlikely event of some major catastrophy wiping out like 99% of the population. I again would disagree. It is our in our nature to create / adapt. The fact is that even in a world catastrophy there would always be enough trash/debris around that could it be modified, with enough tinkering, to serve as needed for basic survival. Again we would adapt, mate, and repopulate the earth.

 

The Key to our survival is and always has been technological adaptations, especially in the worst of environments.

 

Thats my take on it anyway.

[iNow]

The challenge is that technology makes things simpler and tasks less complex/time consuming.

So, we don't need as much energy or intelligence to perform those tasks.

Next, more people of lower intelligence are able to survive as a result of said technology.

They breed at a faster pace than intelligent people.

In a few centuries, you no longer have intelligent people in great enough numbers to create new technologies and handle any new problems.

The world is full of idiots using old technology.

You've reached a plateau, and all of the idiots die, but they were all that was left, so bye-bye humanity.

 

 

That's my "back of a napkin at the pub" calculation on the OP.

[omnimutant]

I'm not sure the messurable amount of intelligence has anything to do with Evolution, as much as the right kind of brain functions to accomplish technology. Which we all have. Even beings born with the mutations that cause mental retardation are capable of technology, but thats not what were talking about here. I don't see how the mating of two people with lower intelligence "scores" cannot lead to a "smarter" offspring. Was Isac Newtons Father and Mother as intelligent as Newton? Probably not. I fail to see the relevance here.

 

Also let me add that while technology does exist to make living conditions easier, it does not force us to be less intelligent to use them. In fact I'd say quite the opposite. I cite the "Blinking VCR" as a comical example. Technology, while making our lives easier might in fact require a higher intelligence to use properly. That throws the whole "use it or lose it" theory out the window as far as I can tell.

[Edtharan]

When you take pressure off a species, like say a large predator goes extinct, the species does not stop evolving. What happens is that because of the less pressure, the genome has more freedom to explore the possibilities.

 

A good example is after any mass extinction. The species would rapidly develop new "designs" as the level of fitness selection was relaxed enough for "non-optimal" mutations to survive where in a high pressure environment they would not have allowed the individuals to survive.

 

Humans are experiencing this at the moment. We, due to our technology, have been able to remove a lot of selection pressure from us as a species. Now mutations are occuring that would, without our technology, be below the survival threshold.

 

WHen, or if, the selection pressures return the human genome will have diversified enough that some of us are likely to survive (and they will be different pressures that existed before technology). As there will be many solution to these pressures and many different types of pressure, you would expect that humans will separate into several subspecies at that point.

 

This is probably the best argument against any form of Eugenics. Eugenics tries to reduce variation in the gene pool, where as variety in the gene pool is essential for a species to be able to survive variations in their environment.

 

For instance: Genes that increases the likelihood for obesity might be a bad thing when there is a lot of food available, but if there was a major disruption in food supply, these people would be more likely to survive as they have more fuel reserves to call upon.

[SkepticLance]

Evolution never stops. Humans have undergone evolution over the past few thousand years. A good example is the lactose tolerance that has evolved in Europeans, since they started tapping cow's milk as a food source.

 

However, in the future, natural evolution is unlikely to play much of a role in future genetic change in humans. We will take care of that ourselves, as soon as we develop genetic technology sufficiently. I predict within 100 years we will be profoundly modifying ourselves with this technology. It will be for the better, since we are such incredibly fallible and imperfect beings, and major improvements are very obvious.

[Dak]

#5 - And lastly, who cares if our vision gets a little worst ? I could name tons of mild defects that have become irrelevant because of technology, but none of them are really important compared to the advantages. We live in a world with a lot less violence than our ancestors, it'll likely favor intellectual skills even more than before (BTW, I think evolution will likely lead to further feminization of men).

 

to add to this (and expand on what Edtherian said): 'natural selection' is a tautology, and it's not possible to circumvent it as such. In as much as NS is a filter, it's possible to pass through it, or not pass through it -- how and why you managed to pass through it is, strictly speaking, irrelevent.

 

in other words, extreme short-sightedness used to be a problem, and would probably have prevented large numbers of short-sighted people from passing the NS test (e.g., they'd either not survive to reproduce, or they'd not be sexually selected, at least in as high a frequency as normally-sighted people). it's important to realise that the very reason that NS worked to suppress short-sightedness was because it was a huge disadvantage.

 

If we're in the situation now where NS can't 'see' short-sightedness (hehe), it's because short-sightedness is no longer a problem, as it's trivially fixable with technology. in which case, it's completely unneccesary for NS to supress this non-disadvantage. so it doesn't.

 

iow, if NS isn't 'working' to supress certain traits, it is tautologically unneccesary to suppress these traits. may as well accept simpler eyes that are boosted by technology in order to unburdon our genome and eyes. if our eyes ever degenerate to the point where they're problematic, then NS will, tautologically, start exerting force upon eyes again, to stop them becoming any worse (i.e., it'll start working to supress disadvantageous traits if/when these traits genuinely become disadvantageous).

 

sorry if that was a bit waffly

[foodchain]

Here I am again, posing such question. I think we spoke about this before, but not for a while, and I'm still unsatisfied with teh asnwers. I think the reason is my own lack of properly explaining the question that's bugging me.

 

So I'm giving it another try.

 

We (humans) are part of nature. We're also quite resourceful, so I don't think we'll go extinct any time soon, unless some catastrophe happens (hence, regardless of my attempt to define what I see as the "problem" that leads to my question, I don't think we'll die off as a species because of that so called "problem") - so don't take this as a 'doomsayers' hypothesis.

 

I'm just wondering here.

 

 

It seems that we are sort-of circumventing Natural Selection in our own evolution; that means that instead of Nature "selecting" the most-adapted qualities and having the non-adaptive qualities die off or not reproduce, we allow all sorts of "defects" to continue existing - from having eyeglasses to being born with mental retardation.

 

(Please don't take my description as if I recommend killing of - or stopping the aid to- anyone who has "defects". I am NOT. I'm just trying to make my point.)

 

 

Since we also developed our own sense of morality (that doesn't seem to exist MUCH in nature in terms of "allowing" defects to continue existing/multiplying), I don't see this situation changing. I don't think it SHOULD change, either, ethically speaking, but this thread is not about ethics. It's about evolution.

 

I'm wondering, then: What do you think the outcome of this situation will be in the long run? I've heard in a science radio show (forgot where) once the idea that we might ahve to rely much much more on technology to keep our existence - so perhaps "bionic" people, or genetic engineering to the level of practically 'replacing' nature, etc.

 

Do you think this is going to have a long term effect on our evolution? Are we not allowing our own species to adapt to nature (that we also change quite rapidly, too, without allowing ourselves to "get used"/"evolve"/"adapt" to the changes)? How do you see humanity in a few million years? Where do you think we're going with this Human Selection as opposed to "Natural Selection" ?

 

Anyways, this is just a theoretical, philosophical thought. Please don't get into an ethical discussion here, it might be an interesting one, but it's not my point at all. I'm strictly thinking about evolutionary changes and "path" here.

 

So.. speak philosophy, not ethics. We can open a new thread for ethical evolution choices if you think it's interesting enough to discuss.

 

~moo

 

I do not think that will occur. I think the issue you bring up with population however will occur. What I mean is simply as our population grows and NS as you put it is not performing constant strong selection on such that those individuals will I guess be "allowed" to live. One of the problems though to bring up is that NS is some unphysical force. If someone with glasses is doing well like say Bill Gates then, well, he is doing right? Then again I how do you label NS in any modern human culture, as it would relate to biotic or abotic variables.

 

I would also have to say that at least human civilization is doing well enough to have such large populations. Saying that I still think variability is the environment over time will still be the big test.

[omnimutant]

One of the problems though to bring up is that NS is some unphysical force.

I would not call it a force. NS is just a misleading name we put on a cycle of random mutations. It's not that some force picks which mutations we need or anything.

 

Random mutations always happen, and because of the conditions in the environment, those mutations in a species either live or die. If they live and propagate, over time, they might grow to dominate the species(the mutation happened to work out better for survival then the previous "norm" of the species). That mutation then becomes the norm until another mutation dominates. This is why there is so much variations in certain species of animals all over the world. When it's said that they "adapt" for survival, one should really say, they were randomly better at survival in their current environment.

 

Of course, Creationists might have a differing view on this since it kind of kills the God concept in a way.

[Mr Skeptic]

I'd agree with those who said that there is little problem in allowing/helping people to survive despite genetic defects. It will allow more diversity, potentially giving us new abilities, or at least resistance to more diseases. In any case, they are still a disadvantage, especially for having children as opposed to just surviving, so they are unlikely to replace better genes.

 

A more worrying aspect is that rich people are not having tons of children. Being rich generally means the rich person has good traits (hard working, intelligent, socially connected, genes from a parent with good traits, etc). It's pretty much a measure of how successful they are. If they used their resources to have more children, then these good traits would be passed on to more people. Instead they frequently have less children.

 

In any case, I doubt that this will become a problem before we figure out how to change our genes intentionally, then both these problems will become irrelevant.

[foodchain]

I'd agree with those who said that there is little problem in allowing/helping people to survive despite genetic defects. It will allow more diversity, potentially giving us new abilities, or at least resistance to more diseases. In any case, they are still a disadvantage, especially for having children as opposed to just surviving, so they are unlikely to replace better genes.

 

A more worrying aspect is that rich people are not having tons of children. Being rich generally means the rich person has good traits (hard working, intelligent, socially connected, genes from a parent with good traits, etc). It's pretty much a measure of how successful they are. If they used their resources to have more children, then these good traits would be passed on to more people. Instead they frequently have less children.

 

In any case, I doubt that this will become a problem before we figure out how to change our genes intentionally, then both these problems will become irrelevant.

 

Thats the thing though, how do you label good genes, how do you know how NS is operating on any particular human population? More so down to an individual level.

 

I personally have no clue, for instance with bill gates you know the guy is super rich, one of the richest people in the world actually. On the flip side the blue screen of death sucks and computers are not environmentally friendly by any means. In fact they typically get sent to third world counties where the poor can work in contact with poisonous compounds breaking them down while having no protection or subsequent healthcare. So in a science fiction type of tone maybe overpopulation and money spell disaster like ice ages, but such is speculation. I just do not understand how you would actually denote NS on a small level. I would surely degree that a crippling disease in an individual might not allow that person to live in say a era of the caveperson, but then again living past thirty was probably considered a miracle in those times.

[SkepticLance]

Actually, living past 30 as miracle is something of an urban myth. In prior, less medicalised, times, average life span has often been less than 21. However, the main contributor to low average life span has been high child mortality. Those who manage to live to adulthood had a pretty good life expectancy.

 

The bible (ultimate authority!) says : "The span of a man is three score years and ten." That suggests that, about 2500 years ago, if a male reached adulthood, he had a very good chance of living to 70. Presumably the span of a woman was a little more - perhaps 75?

[Edtharan]

One of the problems though to bring up is that NS is some unphysical force.

Natural Selection is not a force, but a process. A process can involve many different forces (all of them completely physical and known), but can also be very complex (to the point where it is far easier to refer to the process as an entity/force than to list all the real forces going on).

 

This is what we do with Natural Selection.

[PhDP]

Natural Selection is not a force, but a process

 

It can be seen as a force, and it is by many people.

[nstansbury]

I thought this was a great post, and summed up the issues very well: http://www.scienceforums.net/forum/showthread.php?t=33576&p=416381

[Edtharan]

It can be seen as a force, and it is by many people.

I am not saying that people don't think of it as one. But that if they do they are incorrect.

 

Someone may want to see an avalanche coming at them as just a figment of their imagination, but if they are about to be flattened by one, that does not make it disappear.

 

Reality is not determined by how we wish it to be.

 

Evolution may be seen by some as a "Force" but it is definitely not a "Force" in the scientific sense.

[lucaspa]

I would not call it a force. NS is just a misleading name we put on a cycle of random mutations. It's not that some force picks which mutations we need or anything.

 

You forget selection. Natural selection is a two step process:

1. Variation. Mutations are one source of variation

2. Selection

 

The environment picks which mutations work in that environment. The variation is random with respect to the needs of the individual or population, but the selection is deterministic.

 

When it's said that they "adapt" for survival, one should really say, they were randomly better at survival in their current environment.

 

They were not randomly better at survival, the variation was deterministically better at survival. IOW, it was a better design than the other variations.

 

Of course, Creationists might have a differing view on this since it kind of kills the God concept in a way.

 

Creationists have a differing view because it kills the idea that the designs in plants and animals are the result of direct manufacture by deity. It does not kill the "God concept". Instead, natural selection becomes the secondary cause used by God to get design.

[PhDP]

Reality is not determined by how we wish it to be.

 

What I meant was; some evolutionary theorists see selection/drift/mutations/[insert mechanism] as forces acting on the genetic structure of a population. I do. Of course, we have to be careful about this kind of metaphor, but I think it's apt as long as you keep in mind the statistical nature of these 'forces'.

[lucaspa]

It seems that we are sort-of circumventing Natural Selection in our own evolution; that means that instead of Nature "selecting" the most-adapted qualities and having the non-adaptive qualities die off or not reproduce, we allow all sorts of "defects" to continue existing - from having eyeglasses to being born with mental retardation.

 

I've dealt with this before. Traits are only "good" or "bad" in relation to particular environments. Our technology is part of our environment; it is "nature".

 

What we do with our technology and "defects" is to keep genetic diversity in the population. My favorite example is Stephen Hawking. Lou Gehrig's disease and, without technology, would have died in his early teens. With technology, he had kids. So, let's balance the possible cost of having the Lou Gehrig "defective" alleles in the population vs having Hawking's alleles for intelligence. Can you decide which is better? No. But natural selection can.

 

Relax. Natural selection is much smarter than we are. Just let it do it's job.

 

IF we ever lose our civilization and technology, then natural selection will adapt the population to those new (old) conditions. In the meantime, while technology keeps what you consider "defects", it also keeps new possibly beneficial traits so that they can show their worth in this new environment that includes our technology.

 

#1 - Selection is most effective in large populations, otherwise genetic drift is a major and dangerous force.

 

Sorry, that's wrong. Natural selection is most effective in smaller populations. For genetic drift to be a major player, the effective breeding size of the population must be less than 50 individuals. That doesn't happen often. See Futuyma's Evolutionary Biology for the calculations.

 

The larger a population, the more generations it takes for an allele to become fixed by natural selection. That's why Gould and Eldredge proposed that most phenotypic evolutionary change happened in small, isolated populations during speciation (Punctuated Equilibrium). Large populations are resistant to change. Partly due to the size and partly because, in order to get large, the population had to be well-adapted to the environment. This means that they are now subject to purifying selection -- which resists change.

 

You guys tend to think about evolution as changing the entire human population. But that isn't how evolution usually works. The large population stays the same. Change comes in small, isolated populations. So, if you want changes in humans, look to isolated populations like the !Kung, the Andean or Himalayan highlanders, or populations living on small islands in the Pacific. That's where the next species of Homo will arise.

 

That's how it happened in human evolution. We didn't have one large population that evolved from A. afrarensis to H. habilis to H. ergastor to H. sapiens. Instead, we had an isolated population in Africa that did this. When Homo ergastor migrated out of Africa we got a plethora of new species: H. antecessori in Spain, neandertals in Europe, Pekenensis in China, erectus in SE Asia, and floriensis on one particular island. All were eventually replaced by sapiens migrating from Africa. Sapiens would have split into many new species except that our technology includes transportation and subsequent gene flow between populations.

 

#4 - Diversity will be higher (actually, this is very important for adaptation).

 

It's important in providing the raw material for future adaptation. It means that there are more possible designs present in the population to meet unforseen future needs. Mooeypoo is looking at designs that were effective 50,000 years ago. That population didn't include alleles to be resistant to HIV: the current population does. Nor did that population need alleles to various toxins now present in the environment: such as dioxins. Because humans used fires in confined spaces that produced smoke, we had pretty good antioxidant systems. That became useful when humans invented smoking tobacco -- particularly cigarettes. If we eliminate known "defects" now, we may lose the alleles the population may need in the future.

[SkepticLance]

lucaspa

 

You seem to have a strong faith in natural selection. I have a much stronger faith in human ingenuity. Natural selection is just too damn slow! Our species has existed for about 200,000 years, and genetic variation in different populations has simply resulted in a few small differences in skin pigmentation and other minor effects. Natural selection simply cannot keep up with the demands that our rapidly changeing society requires.

 

However, human ingenuity can. Society is changing at a break-neck pace, due to changes in technology and social structure. In the near future, human genetics will also change in order to permit the required adaptation. This genetic change will be the result of human intervention in our own genetic development. Natural selection will not get a look in.

[iNow]

I think there's a pretty clear misunderstanding underlying many of these posts.

 

Even if humans start changing things, natural selection will still be the decider in which of those things remain and which get discarded.

[foodchain]

I think there's a pretty clear misunderstanding underlying many of these posts.

 

Even if humans start changing things, natural selection will still be the decider in which of those things remain and which get discarded.

 

Right, so its pretty much why a penguin looks the way that it does vs. being more purely avian. this is also why such a phenotype ultimately comes to being so prevalent in the population including heredity like genes. So if you have a particular set of factors weighing in as selection variables they will have an impact, much like the introduction of say technology as something that could be used by say humans. The use of tools by in large has allowed us to basically move to where we are at, though as evidenced by say the cold war if you will its not free from peril, or the human race collectively that is.