Philosophical Question about Human Evolution

[Dak]

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.

 

I'm sorry, but you've missed the point that i made earlyer.

 

NS is a tautology: if a trait does not prevent it's possessors from passing it on, then that trait is not too bad.

 

It's not possible for us to technologically accidentally push 'bad' traits through NS; it's only possible for us to 'neutralise' bad traits and stop them being bad, at which point they are no longer suppressed by NS, but also they're no longer bad so this doesn't matter.

[SkepticLance]

To Dak, foodchain and iNow.

 

I think you guys may not quite have taken on board the extent to which I am making my point.

 

Once humanity learns to carry out large scale genetic modification of our own species, natural selection in humans will become a non-event. Anthropogenic changes will operate so drastically and so rapidly that NS will not get a look in.

 

Natural selection will become the ultimate has-been, in relation to Homo sapiens. The reason, of course, is time spans. A process that takes hundreds or thousands of generations simply will have an impact so trivial by comparison, that its impact becomes one divided by infinity.

[Mr Skeptic]

SkepticLance, don't confuse evolution and natural selection.

 

---

 

Humans have been bypassing natural selection for quite a while. Artificial selection, and sexual selection, need not have anything to do with fitness. You could still say that is just a subset of natural selection, but it can clearly lead to trouble. We could end up with human peacocks, for example.

[SkepticLance]

To Mr. Skeptic

 

I do not confuse the two. The thread has been talking about natural selection as the driver of evolution. I am talking about ongoing evolution which will be driven by human efforts instead of NS. Human evolution will be faster than ever. Just not influenced by NS.

[Dak]

To Dak, foodchain and iNow.

 

I think you guys may not quite have taken on board the extent to which I am making my point.

 

Once humanity learns to carry out large scale genetic modification of our own species, natural selection in humans will become a non-event. Anthropogenic changes will operate so drastically and so rapidly that NS will not get a look in.

 

Natural selection will become the ultimate has-been, in relation to Homo sapiens. The reason, of course, is time spans. A process that takes hundreds or thousands of generations simply will have an impact so trivial by comparison, that its impact becomes one divided by infinity.

 

ah, i see.

 

Yes, if we manually choose the alleles to propagate/not propagate, then we'd be replacing NS with artificial selection.

 

I'd be very surprised if we'd ever do this, at least in the near future, simply because it's a dumb idea. Most geneticists know -- and understand why -- eugenics is a bad idea. maybe fixing the odd unquestionably bad trait here and there (which we're allready doing), but not a whole-sale displacement of NS.

 

iirc, the proposed EU charter on human rights has something in it against eugenics, for example.

[SkepticLance]

To Dak

 

Ethical concerns are always the first to disappear. 35 years ago, human reproduction by artificial insemination was considered immoral. Now it is very widespread, and widely accepted as OK. In Victorian times, the word 'damn' was considered to be so evil that its use condemned the user instantly to eternity in Hell. Today it is in such widespread use that it is unremarked.

 

In the same way, once genetic manipulation of humans becomes easy and practical, it will slowly creep into widespread useage, and become accepted as normal.

 

We will begin with deletion of nasty genes like those for multiple sclerosis, and Lou Gehrig's disease. Then we will move on to inserting genes that will enable a child to have a normal life, untainted by unsocial physical traits. Then we will insert genes for beauty, athleticism, intelligence etc.

 

Personally, I only regret that I did not get all these myself at conception, so that I would now be a devastatingly handsome, athletic genius. Alas......

[Dak]

To Dak

 

Ethical concerns are always the first to disappear. 35 years ago, human reproduction by artificial insemination was considered immoral. Now it is very widespread, and widely accepted as OK.

 

Yes, but now we understand artificial insemination -- and the (lack of) ramifications therein -- better.

 

I don't see this as ethical concerns eroding; rather, justified caution in the face of the unknown giving way to the knowledge that it's harmless.

 

In the same way, once genetic manipulation of humans becomes easy and practical, it will slowly creep into widespread useage, and become accepted as normal.

 

We will begin with deletion of nasty genes like those for multiple sclerosis, and Lou Gehrig's disease. Then we will move on to inserting genes that will enable a child to have a normal life, untainted by unsocial physical traits. Then we will insert genes for beauty, athleticism, intelligence etc.

 

hmm... that's still quite a jump, and i still can't see us making it (unless we're talking waaaaaaaay in the future). espescially compared with safer alternatives, such as in vitro selection of zygotes -- effectively early abortion for any zygotes that would be phenotypically Lou Gehrig, for example.

 

Still 'eugenicky', but at least letting recessive alleles remain in the population, and not replacing NS per se (rather, adding a small artificial layer on top of it).

 

to significantly displace NS by the means you suggest would require that most people stop reproducing via sex, and/or that most people submit their foetus to peri-natal genetic screening. Not going to happen imo, both because most people won't do it, and because most geneticists/doctors will understand why eugenics-level genetic 'tinkering' is stupid.

 

maybe waaaay in the future, when we have a better understanding of the exact effects, we will utilise eugenics and completely replace NS with artificial selection, but even then we'll still be subject to NS (i.e., if we screw it up, we'll die); faced with this, i can't imagine the knowlegable geneticists who'd have to do it agreeing to do it in such a way that'd reduce our diversity, or at such a speed that NS would 'catch up' by killing us all

 

As i said, we litterally cannot remove ourselves from the effects of NS. if we are not fit enough to survive, we will not.

[SkepticLance]

Dak

One couple in five in today's world is infertile. Many are already going to IVF to have kids. The next step is for those people to add a little gene manipulation as part of the IVF.

 

If only one in ten children as a result are genetically modified, then over time and many generations, the relevent genes will increase in frequency through the population, till every individual has 'superior' genes are part of their make-up.

 

I could even suggest there may come a time when, for humanitarian reasons, no couple will be permitted to have children without those children at early embryo stage being modified to make sure they do not begin life with nasty genetic handicaps.

 

Over the past 100 years, human reproduction has changed massively. From 'if you caint have em, tough!' we have moved to a stage with numerous reproductive interventions - from fertility drugs to IVF to embryo selection to AI to egg donation etc. We can predict that the next 100 years will see just as many, and probably more, massive changes in medical technology for human reproduction. It is only a matter of time before genetic manipulation is a part.

[Mr Skeptic]

The whole point of natural selection is that we already keep superior genes and eliminate inferior genes. If we can't understand why some genes are superior, then that doesn't mean we should go about eliminating them. Of course, since the environment has changed so much due to modern technology, some genes are currently a disadvantage. However, I see no wisdom in eliminating these and so making ourselves genetically dependent on our technology.

[iNow]

I think you guys may not quite have taken on board the extent to which I am making my point.

 

Once humanity learns to carry out large scale genetic modification of our own species, natural selection in humans will become a non-event. Anthropogenic changes will operate so drastically and so rapidly that NS will not get a look in.

 

No, I didn't miss your point at all, I just disagree. Despite the fact that humans might be genetically modifying themselves, there will still be errors, there will still be mutations, and there will still be forms of life created which just can't/won't survive. Ergo, natural selection is still occurring.

 

I don't discount the idea that it will play less of a role if your scenario comes to pass, I am just saying that you are mistaken to think that it will be a "non-event" or that it "will not get a look in."

 

No matter how good we become at genetic modification, we will still end up with some organisms better suited to the environment than others, and therefore natural selection (while being much more artificial due to the GM activities of humans) will still occur.

 

 

 

 

As i said, we litterally cannot remove ourselves from the effects of NS. if we are not fit enough to survive, we will not.

 

Precisely.

Edited June 22, 2008 by iNow
multiple post merged

[SkepticLance]

iNow said

 

" I am just saying that you are mistaken to think that it will be a "non-event" or that it "will not get a look in." "

 

Let me rephrase. Evolution by natural selection is always present. However, everything is relative. Once human induced genetic modification of humans takes off (in perhaps another hundred years???) the impact of NS relative to the impact of GM will be very small.

[Mr Skeptic]

I do not confuse the two. The thread has been talking about natural selection as the driver of evolution. I am talking about ongoing evolution which will be driven by human efforts instead of NS. Human evolution will be faster than ever. Just not influenced by NS.

 

I agree that GM will take over the role of mutation for almost all of human evolution (and likewise for domesticated plants and animals). However, GM itself has nothing to do with selection; it is only a source of new genetic data. Hence, it would replace mutation, not natural selection. In saying GM would replace NS it looks like you are confusing the two. Now, I know that you know the difference, but some people are easily confused on that subject and it is best not to give them excuses/ammunition.

[Dak]

Let me rephrase. Evolution by natural selection is always present. However, everything is relative. Once human induced genetic modification of humans takes off (in perhaps another hundred years???) the impact of NS relative to the impact of GM will be very small.

 

OK, lets try a slightly different angle:

 

for quite some time, we've been selectively breeding bananas to be fatter and straiter. in doing so, we've -- to an extent and temporarily -- replaced NS with artificial selection. in doing so, the result is a lack of genetic diversity: one species/strain of bananas (the main one we used to eat) is now all but extinct, fallen to the panama disease. The other main species/strain of edible bananas (the one we mainly eat now -- cavendish, iirc) are:

 

extinct in asia due to the latest strain of panama disease

suffering, in africa, due to top banana-bunchy disease (i kid you not)

suffering, in africa, from black rot

 

black rot is interesting because the bananas, lacking genetic diversity, cannot adapt to become resistant to it, whereas the black rot fungus is still adapting and evolving, so, over time, is becoming more resiliant to the fungisides used to combat it.

 

so, even tho we've temporarily lessened NS's effects on the banana, ultimately NS remains, and has killed off one species/strain, and is in the middle of doing the same to the other main strain.

 

given that we have this example, i really, really can't see humans being stupid enough to lessen NS's effects on us in any artificial way. maybe centuries in the future, but not with our current technology and understanding. it'd just be too stupid.

 

another example is sickle-cell anaemia: bad in one context, but -- in the presence of malaria, which it grants immunity to -- is good (possibly required: i can't recall if we can cure malaria).

 

btw, sickle-cell anaemia, and the fact that our current technology makes it less fatal and thus stops NS from supressing it, is sort of an example of one aspect of what lucaspa said earlyer about the removal of evolutionary supression allowing for genetic diversity and the possible spread of benificial mutations (tho his actual point was completely different).

 

so, yeah, i can't see humans actually doing what you suggest and using eugenics to any great degree.

 

No, I didn't miss your point at all, I just disagree. Despite the fact that humans might be genetically modifying themselves, there will still be errors, there will still be mutations, and there will still be forms of life created which just can't/won't survive. Ergo, natural selection is still occurring.

 

However, it would be possible to remove NS to the point where -- whilst it still applies to us -- applies to us by killing us en mass (see: bananas).

 

So i guess we could stop NS forcing us to evolve/adapt, even if we can't stop it from applying to us, tho it'd take gross stupidity on our part to do so.

[SkepticLance]

To Dak

 

Your banana example is kind of interesting. The natural banana is pretty much inedible, being full of hard seeds. However, there is a rare mutation which results in a seedless variety, which normally dies out due to lack of progeny. Under human cultivation, these seedless ones are cloned, by using cuttings or buds from the base of the tree.

 

There have been three seedless varieties.

1. Gros Michel. The best. Sweetest and best texture. Sadly, not immune to Panama disease. It died out.

2. Plantain. Basically a cooking banana. Not eaten much in the west.

3. The Cavendish. The second best that replaced the Gros Michel. The one we are all familiar with.

 

Our current favourite is now coming under attack by Sigatoka disease. This is rife in Uganda, where the main banana crop is seriously threatened, and may spread to all banana growing areas of the world, controllable only by massive fungicide sprays. However, the major hope for the future is a new GM type of Cavendish, immune to Sigatoka disease.

 

So this example actually points out the importance and the future with GM as a major tool. Natural selection is simply not applicable to cultivated bananas. The natural ones are inedible, and the cultivated ones are clones, lacking the genetic variation that NS works on. Thus, only GM can solve the problems of new diseases.

 

Dak.

Hate to say it, but your last two sentences from your last post are simply incorrect. Natural selection is of very problematic value to Homo sapiens since it takes too long - hundreds or thousands of generations - of no value in a rapidly changing environment, which we have created. However, applying GM to humans allows rapid adaptation to the new environments. Something NS cannot do.

 

Of course, social and technological change is also part of the equation. These changes permit human survival and success when NS cannot do so, by virtue of being too damn slow.

 

If we rely on NS, we will become extinct!

[Dak]

So this example actually points out the importance and the future with GM as a major tool. Natural selection is simply not applicable to cultivated bananas. The natural ones are inedible, and the cultivated ones are clones, lacking the genetic variation that NS works on. Thus, only GM can solve the problems of new diseases.

 

Yes, but you have to remember that this is an artificially created situation, resulting from human selective-breeding.

 

'natural' bananas could adapt quick enough to survive diseases without GM. GM is only neccesary to correct problems resultant from over selectively-breeding bananas.

 

in fact, the claim that only GM can solve the problems of new diseases -- when NS has been working out ways to counter both new diseases and new immune systems for aeons -- is kinda silly, unless you meant just in the banana population.

 

Hate to say it, but your last two sentences from your last post are simply incorrect. Natural selection is of very problematic value to Homo sapiens since it takes too long - hundreds or thousands of generations - of no value in a rapidly changing environment, which we have created.

 

Umm... how, exactly, would we rapidly change our environment to such an extent that we'd extinctify ourselves? espescially given that most changes that we make to our environment are benificial to us (availabililty of medicine, for example)?

 

Also, natural selection doesn't need to be slow, and is (again, kinda tautologically) fast when it needs to be. look at the black death, and the sudden increase in delta-9 (i.e., black-death-proof) alleles in just the time it took for the BD to rip through europe and for people to then repopulate. a majour shift in allele frequencies over about 1 or 2 generations, thanks to NS.

 

I can't help but notice that we've gone off-topic: from discussing the repercussions of allowing a few 'disadvantageous' traits to pass through NS, to somehow claiming that NS doesn't work fast enough for humans.

 

could you tie-in to the OP with your responce please, if possible.

[lucaspa]

lucaspa

 

You seem to have a strong faith in natural selection. I have a much stronger faith in human ingenuity.

 

Not "faith". Data. The data says that natural selection is smarter than human ingenuity. Humans turn to natural selection to get designs when their ingenuity can't find a solution. Look up http://www.genetic-programming.com

 

"There are properties that humans have great trouble designing into a system, like being very efficient, using small amounts of power, or being fault tolerant. Evolution can cope with them all." Evolving A Conscious Machine BY Gary Taubes Discover 19: 72-79, July 1998

 

When GF Joyce wanted to design a DNA enzyme, his ingenuity was completely inadequate to the task. He had no idea how to do this. So what did he do? He used natural selection! And got a DNA enzyme: 10. Breaker RR, Joyce GF.A DNA enzyme that cleaves RNA. Chem Biol 1994 Dec;1(4):223-9

 

Natural selection simply cannot keep up with the demands that our rapidly changeing society requires.

 

I don't see any genetic changes that our society demands. In fact, the whole point of the opening post is that our technology is working so that genetic changes are not needed.

 

So what genetic changes do you think our society is demanding in H. sapiens?

 

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.

 

I fail to see why changes in technology or social structure require genetic changes. As I said, since humans call upon natural selection when their ingenuity is insufficient, I fail to see why you think human ingenuity should substitute for natural selection in picking the alleles in the human population.

 

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

 

No. Humans could decide to eliminate particular alleles from the population -- such as the alleles for Lou Gehrig's disease or achondroplasia. NS would have no say.

 

Humans could also decide that everyone must have a particular allele. In that case NS is also not the decider because there are no longer different alleles to choose from. Only 1 allele in the population.

 

Dak

One couple in five in today's world is infertile. Many are already going to IVF to have kids. The next step is for those people to add a little gene manipulation as part of the IVF.

 

If only one in ten children as a result are genetically modified, then over time and many generations, the relevent genes will increase in frequency through the population, till every individual has 'superior' genes are part of their make-up.

 

That's the problem -- whether those alleles (not "genes", if you are going to advocate this, you should at least know the correct terms) are really "superior". As I keep telling you, "superior" only applies to the particular environment. There is no such thing as a universally "superior" allele. But your argument is based upon the mistaken premise that this is so.

 

What you now have is a decrease in diversity: only 1 allele where before there were several. What happens if the technology or society changes? The new environment would favor one of the alleles that you have now lost because you, in your hubris, decided you were smarter than natural selection and decided you needed to genetically modify humans when that was unnecessary. So, in the new environment, the alleles necessary for survival are not present. That's how species go extinct, you know: the environment changes and the population does not have the necessary diversity on hand. Or maybe you don't know. Just as you didn't know that humans use natural selection when their ingenuity isn't good enough.

 

Over the past 100 years, human reproduction has changed massively. From 'if you caint have em, tough!' we have moved to a stage with numerous reproductive interventions - from fertility drugs to IVF to embryo selection to AI to egg donation etc. We can predict that the next 100 years will see just as many, and probably more, massive changes in medical technology for human reproduction. It is only a matter of time before genetic manipulation is a part.

 

The changes you have described so far have been to increase genetic diversity. People who could not pass on their alleles due to infertility now can. Thus the alleles that would have been lost stay in the population. From an evolutionary standpoint, that is good.

 

But the next stage you advocate is a massive decrease in diversity. You are advocating picking particular alleles, then manipulating genomes such that everyone has those alleles. That means that all other alleles are gone from the population.

 

The data from evolutionar biology is clear: the species that do best are the generalists with the most genetic diversity. As species become more and more adapted to a particular niche and lose diversity due to purifying selection, the more vulnerable they become to extinction. If the particular niche changes, the species doesn't have the genetic reserve of possible designs to meet the new environment.

 

Your banana example is kind of interesting. The natural banana is pretty much inedible, being full of hard seeds. However, there is a rare mutation which results in a seedless variety, which normally dies out due to lack of progeny. Under human cultivation, these seedless ones are cloned, by using cuttings or buds from the base of the tree.

 

Your example points to the problem we are trying to get you to see: genetic manipulation got you into the problem of sensitivity to changes in the environment. The natural banana is not in danger of being exterminated by these diseases, is it?

 

The problem is the result of the genetic manipulation you want to inflict on humans! Then you expect GM to get you out of the problem GM created in the first place! " So this example actually points out the importance and the future with GM as a major tool. Natural selection is simply not applicable to cultivated bananas. The natural ones are inedible, and the cultivated ones are clones, lacking the genetic variation that NS works on. Thus, only GM can solve the problems of new diseases.

 

You forget that humans did not have to decide to eat bananas to begin with! Nor were we required to use GM on bananas.

 

So, if we don't use GM on humans, we won't have the lack of genetic diversity that we inflicted on the banana!

 

Hate to say it, but your last two sentences from your last post are simply incorrect. Natural selection is of very problematic value to Homo sapiens since it takes too long - hundreds or thousands of generations - of no value in a rapidly changing environment, which we have created. However, applying GM to humans allows rapid adaptation to the new environments. Something NS cannot do.

 

1. Natural selection doesn't take that long. It can operate much, much faster than that.

2. NS can do rapid adaptation if there is genetic diversity in the population. But what you are advocating is reducing genetic diversity.

3. So far, our "rapidly changing environment" has been met with changes in technology. What changes do you foresee that would require genetic changes in humans that could not be met by technology?

 

4. Rapid changes due to NS results from most of the population dying before reproduction. Only the few individuals with the necessary designs survive. So yes, H. sapiens could rapidly adapt. We would lose our civilization, but the species would adapt. Skeptic, I think you need to realize that you are combining 2 different things: keeping a large population and, thus, civilization, and adaptation. You are working with the premise that both must be present. No. H. sapiens can (and has in the past) adapted rapidly but does so without the modern technological civilization.

 

These changes permit human survival and success when NS cannot do so, by virtue of being too damn slow. If we rely on NS, we will become extinct!

 

Actually, you have this backwards. If we rely on your vision of picking alleles and reducing diversity, then we become extinct. With NS the human species would survive even if technological civilizaition did not. Under your scheme, if we ever lose the technological civilization (the particular environment you have picked alleles for), we also lose the species.

Edited June 24, 2008 by lucaspa
multiple post merged

[iNow]

We seem to be approaching this from different "reference frames." I won't argue your points against mine, because we are both saying slightly different things, and I agree with both.

[Mr Skeptic]

Not "faith". Data. The data says that natural selection is smarter than human ingenuity. Humans turn to natural selection to get designs when their ingenuity can't find a solution. Look up http://www.genetic-programming.com

 

No, we don't. Natural selection requires living organisms to function on. It turns out that us humans are clever enough to have designed genetic algorithms which function similar to evolution. However, all it is is a specialized trial and error system. (And that should be no surprise, that we turn to trial and error when we don't know what we're doing.) The program is told how to create random "solutions" to the problem, how many random solutions to create, how many of these to keep/discard, how to pick the best of these (a fitness function), and how to create new solutions based on the most successful of the previous generation of random solutions. All it is is an algorithm for doing trial and error on a massive scale, and it needs to be told how to do it.

 

It is also not the only way we can solve a problem we know nothing about. We can also use a neural net, for example. Neural nets require even less knowledge from the humans using it; all they need is to be told whether they got a correct answer or not.

 

So what genetic changes do you think our society is demanding in H. sapiens?

 

I can think of several that would be useful. An increase in intelligence would be nice. No changes are strictly necessary, but many new ones would be advantageous now whereas before they would have been disadvantageous. Some old alleles are currently rather counterproductive.

 

Of course, the solution here is for genetic engineering to create new alleles, but not to use artificial selection to reduce our diversity. And keeping some of the original diversity in eg sperm banks would be a wise precaution.

 

---

 

I think (and hope) that everyone agrees that genetic diversity is of incredible value, and that artificially reducing it is potentially disastrous. Genetic engineering itself increases diversity and can do so faster and in different ways than mutation. As we increase our knowledge of genetics and technology in general, our ability to do genetic engineering will increase significantly. It is likely that in the future, the majority of new diversity in humans will be a result of genetic engineering rather than mutation. This, of course, will have nothing to do with natural selection, other than giving it new diversity to work on.

 

I still can't figure out how people are saying that GM will replace NS. It makes as much sense as saying that mutations will replace natural selection (ie, none).

[SkepticLance]

To lucaspa

 

I will make you a concession in this argument. I overstated my case earlier in saying that GM would be necessary for future human survival, and that we risked extinction without it. You pointed out, correctly, that increases in technology may be sufficient. OK. Concession made.

 

Let me rephrase. Changes to humans in the future by GM will seen to be very desirable. And of course, whatever we debate there will have no impact on what actually happens. Posterity will do as posterity decides regardless of anything we might think. I happen to think they will adopt human GM, because many changes are desirable.

 

Some of those changes are obvious and have already been listed. Getting rid of tendencies to certain genetic diseases. Increasing resistance to cancer. Creating resistance to AIDS, malaria etc etc. In addition, there will be traits such as higher intelligence, athleticism, good looks etc.

 

Will this decrease genetic diversity? It depends on where the added genes (or alleles if you want to be picky) come from. For example : if humanity moves into space, setting up a number of space elevators (remember we are looking ahead more than 100 years) and building habitats in space, then we will need to overcome the massive increase in hard radiation, that would cause a current astronaut to develop fatal cancer within 5 years of exposure.

 

But there are numerous organisms with genetic mechanisms for rapid DNA repair that can stand 1000 times the hard radiation we can. To insert such genes into humans would both increase genetic diversity and give the resistance to radiation that would be needed.

 

If we increase resistance to cancer, that may be by adding genetic material rather than deleting - thus increasing diversity. Similarly for many other GM changes. They may increase, not reduce genetic diversity.

 

There is no special sin in adding foreign genetic material. Our 'junk' DNA already contains lots of it, courtesy of certain viruses. There is even a prairie rodent that has had snake DNA identified in its DNA, showing that viruses can transfer DNA from one species to another. I predict that more such examples will be discovered, and quite likely in humans.

 

Finally, my point about the speed of NS stands. Even if it can be achieved in less than thousands of generations, in humans with a generation time of 20 to 25 years, it is still too damn slow. Desirable changes that are going to take hundreds of years at best, and more likely thousands, are simply not acceptable.

[PhDP]

Lucaspa,

 

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.

 

Nonsense. The importance of drift (as shown in the equation I wrote there) depends on 'N' and 's'. If 's' is very low (and it often is, BTW), then drift will be important even in large populations. If 's' is very high, then even a population size of 50 could be too much for drift to matter. I have no idea where you got the number "50", but I would really like to know where you got that. Futuyma for calculation ? I highly doubt he derived the necessary equations for the reasoning I made, which is based on the diffusion approximation. Futuyma's book is a very good introduction, but it's a very elementary introduction.

 

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.

 

Technically, it's true. But you completely missed my point. I'm not talking about adaptation, I'm talking about the perils related to the fixation of slightly deleterious alleles. Selection is very ineffective against them in small populations (again, just look at the equations!). Lynch called this one of the genomic peril of evolving large body size; we're vulnerable to these dangerous mutations. However, because of our technology we managed to reach a very high population size, much higher than expected for animals of our size.

[Edtharan]

No, we don't. Natural selection requires living organisms to function on.

Actually, I disagree. There is nothing in the theory of evolution that states: "Must only occuring in living organisms".

 

Also, there is nothing "special" about life. Life is a series of chemical reactions. There is no "Elan vital" that turns non living matter into living matter.

 

Finally, it is possible to create a biological computer that can perform operations using DNA. You could then program a genetic algorithm into this computer and run the program. This "program" could be for anything, optimising the hull design for a boat, adding fault tolerance into a system etc. The exact same problems that are handled by current genetic algorithms.

 

So, what is needed for Evolution to happen:

1) Reproduction. There must be some way for an entity to copy itself and pass on the information needed to replicate (even if this means hijacking some other process - as a virus does).

 

2) Variation. Each entity must be able to include variations in its "instruction set" that it passes down when it copies itself.

 

3) Selection. There must be some way that undesirable solutions can be eliminated and desirable solutions can be retained.

 

However, all it is is a specialized trial and error system.

How is that different from Evolution? Evolution also works by trail and error too.

[foodchain]

I think (and hope) that everyone agrees that genetic diversity is of incredible value, and that artificially reducing it is potentially disastrous. Genetic engineering itself increases diversity and can do so faster and in different ways than mutation. As we increase our knowledge of genetics and technology in general, our ability to do genetic engineering will increase significantly. It is likely that in the future, the majority of new diversity in humans will be a result of genetic engineering rather than mutation. This, of course, will have nothing to do with natural selection, other than giving it new diversity to work on.

 

I still can't figure out how people are saying that GM will replace NS. It makes as much sense as saying that mutations will replace natural selection (ie, none).

 

Its not that we can replace NS in terms of issues like immunity from death and the universe or what not, not 100% or something and giving us a 100% predictable future. What it can do though is act like NS, such as if you make a trait for instance, something which gives a person photographic memory, for anything and everything. That trait now is part of selection I would think, acting out in the form of any individual with that trait. IF this trait were to lead on average better then others, such as those people find it easier to remember calculations for say a class, or in life in general, then would it not be a jump to conclude that selection is operating on it?

 

So the more you do this to the biosphere, the more GM works with or becomes part of in real time the process of natural selection. So to me proper conduct with GM requires a huge amount of understanding, or else i think we have a equal to if not greater chance to do something horribly wrong, possibly on a global scale, like with global warming.

 

So with an insect, if you make it a better hunter of say some other type of insect, you can change a whole lot I would think, more so in the face of change overall with the planet in general giving its history.

 

The argument that NS is not perfect by any means and that we could do better I think is possible. I do not think how NS works collectively on say the biosphere is outside of human understanding. I also do not think it would be impossible to map this to a molecular level for any giving individual or population. I also do not think we are even close to owning such a model of life yet.

[SkepticLance]

Actually, I disagree. There is nothing in the theory of evolution that states: "Must only occuring in living organisms".

 

 

Slight misconception here. We were talking about natural selection - not evolution. NS is based on the word 'natural' meaning 'occurring in nature'. Something that happens inside a computer is not natural, hence not NS. A computer program can evolve, but selection of variations has a different basis, even if it has some similarities. Ok, this is semantics, but word meanings are crucial to good debate.

[Mr Skeptic]

Sorry, I should have said aliveish/having the ability to reproduce and mutate. I don't want to get into defining life here.

 

All I wanted to say is that we don't throw circuits out into the world and wait for a better one to evolve. They can't even reproduce, so there would be no natural selection going on there. To use an evolutionary algorithm to improve a circuit, we build a computer model for circuits and program in various stuff. Since it is a formalized trial an error system, there is no surprise when some people turn to it to solve a problem they don't understand. After all, nearly everyone will revert to trial and error if they must solve a problem that they don't understand. This is not because trial and error is "smart", it is because it is a system that works even when we don't understand.

 

I strongly disagree that natural selection is smart or has any kind of intelligence or foresight. At best natural selection has hindsight, and very bad hindsight at that. However, one has to respect a few billion years of hindsight.

 

A testament to natural selection's lack of intelligence is all the extinctions that have occured, such as the extinction of the Gros Michel banana despite its early success.

[Dak]

Slight misconception here. We were talking about natural selection - not evolution. NS is based on the word 'natural' meaning 'occurring in nature'. Something that happens inside a computer is not natural, hence not NS. A computer program can evolve, but selection of variations has a different basis, even if it has some similarities. Ok, this is semantics, but word meanings are crucial to good debate.

 

as edtheiran said, anything that has persistant information (e.g., through hereditary), variation, and a selection mechanism will evolve. depending on how you define NS, it's entirely possible that something non-living will evolve via NS simply by having its variants culled according to some criteria (which, ultimately, would be rewordable as 'those that are best at not being culled will be most frequent', e.g. NS).

 

an e.g.: Selfish gene theory is, essentially, NS with (non-living) genes being the individual units that NS works on, rather than individuals.

 

I strongly disagree that natural selection is smart or has any kind of intelligence or foresight. At best natural selection has hindsight, and very bad hindsight at that. However, one has to respect a few billion years of hindsight.

 

A testament to natural selection's lack of intelligence is all the extinctions that have occured, such as the extinction of the Gros Michel banana despite its early success.

 

again, the bananas were our fault.

 

anyway, it's inherent in how NS works that the week and inefficient will die; that's what causes, over time, an average increase in fitness.

 

e.g., after the Gros Michelle's all-but died out, the average fitness of bananas increased.

 

None of this stops NS being capable of dealing with the fact that we're artificially allowing what would otherwize be bad traits to remain. Ultimately, the only way we allow them to remain is by preventing them from being so bad that NS can't cull them, so NS is still ultimately in charge of our evolution.