Is the current human species the result of artificial selection?

[tonyxon22]

Is the current status of human species the result of a self-inflicted and unconscious artificial selection?

We have heard about many cases of artificial selection, where the hand of the man “created” a new species by selecting individuals with particular characteristics of its interest and reproducing them, such as dogs, cows, many seeds and plants, etc.

However, does the human species artificially selects itself without being aware of it? Why does human species keeps moving on and pushing really fast the frontiers of its own capabilities, not only in the intellectual level, but also biophysically? Records of speed on running, jumping, swimming, throwing javelins, etc, are broken frequently. Are this increase of capabilities the result of an artificial selection? Or where our ancestors capable of doing everything we do today, if they had the same environmental conditions?

Also, is it wrong to consider the achievement of certain technology development a part of our biological evolution? For example sometimes I see the Internet as one step in the evolutionary history of human species, since it has completely changed human life (at least for a large percentage of the individuals). In a way, it is a form of adaptation to environmental challenges. Although it’s hard to think of its appearance as the result of a random mistake in the copy of the genetic code, which makes it dubious to be considered as a mutation that is, by chance, better adapted, it has also proved to increase the overall performance of the human species in terms of communication and access to information, which is pretty much what makes us human.

Does the “selection” mechanism have a biological boundary, that limits what is considered to be evolution only by the comparison of characteristics of the phenotype? Or is it also measurable in abstract quantities such as the average intelligence of a species? And if that is the case, are tools of our own creation part of the observable phenotype?

 

[Ryan_m_b]

The thing that you have to bear in mind the most is that evolution works via reproduction. It doesn't matter what we do, what we make, or how many records we break unless it has a measurable effect on allele frequency over time it isn't a factor in evolution. With regards to the tools we make some, such as Dawkins, argue that we should extend the definition of phenotype beyond biology. He uses the term extended phenotype which would include the internet. But the internet itself isn't an evolutionary step, we evolved greater intelligence because it gave us a selective advantage (both naturally and sexually) which in turn allowed us to create tools. Tools give us a selective advantage too but the underlying mechanism is intelligence. Does that make sense?

 

[/AH]

Interesting thought.

One view is that our shared technology helps a larger portion of us "survive", but it does not (have to) mean that individuals that are more adapted/involved with technology have a greater change of surviving or have more offspring.
(A smarter person does not have a higher change of surviving nor do they produce more offspring). EDIT: at this point in time
This is where the comparison with strictly "biological selection" breaks down. And i therefore doubt we are significantly smarter / stronger etc. than our ancestors several 1000's of years ago.

We do however have an ever increasing possibility to put our skills to use to advance technology. And from this point on it kinda snowballs, advancing technology increases the population and increases the time we can invest in advancing it even further.

So while technology evolves i don't think it's because humans evolve, but because we invest time in it.

 

[mheslep]

... advancing technology increases the population ...

Increases population from the point of subsistence, but once advanced enough to grant survival of most children into adulthood advanced technology and advanced civilization tend to *stop* population growth. At least that is the observed correlation of the last century.

 

[Ygggdrasil]

Records of speed on running, jumping, swimming, throwing javelins, etc, are broken frequently. Are this increase of capabilities the result of an artificial selection? Or where our ancestors capable of doing everything we do today, if they had the same environmental conditions?

No genetic explanation is required to explain why many of these records get broken. Indeed, many of these changes are occurring over a timescale much to short to have been due to genetics alone. A major factor in explaining why new records gets set is just that there are more people with the resources to train at these areas. You increase the population of people, you increase the chance of finding an outlier who performs this task better than anyone in history. Looking at how the world record times for running a mile change as a function of "person years" since 1913 demonstrates this idea quite nicely.

That is not to say that artificial selection won't have a role in the future of human evolution. In the near future, preimplantation genetic diagnosis and screening could be routine, allowing parent to have some choice over which of their traits they pass onto their offspring. Of course, while the technology exists to screen embryos (and likely soon, to engineer embryos), the bottleneck is in our understanding of the genetics of complex traits like intelligence. Even if we had a safe and effective method to arbitrarily engineer the genome of a human embryo, we would still wouldn't really be able to engineer a super genius because we wouldn't know which genes to change.

 

[Windadct]

It depends on what you mean by artificial...IMO - anything we ( humans) do to ourselves is a result of our own evolution, so selection is not really artificial. I see Artificial Selection as being the outcome of the Selection process being manipulated by an outside "intelligent" force, as with a purpose. So humans can take wild dog from Africa and mate with north american wolf - that is artificial. But a person getting on a plane ( technology developed by humans through our own evolutionary process) and mating with an Inuit, even if for a non-romantic or or technical reason ( gene study) - is not artificial, it is humans beings being human beings. ( sorry could't resist the word play.)

 

[tonyxon22]

But the internet itself isn't an evolutionary step, we evolved greater intelligence because it gave us a selective advantage (both naturally and sexually) which in turn allowed us to create tools. Tools give us a selective advantage too but the underlying mechanism is intelligence. Does that make sense?

Yes, that makes sense. What I understand from your idea is that the selective advantage of the human species is the intelligence. All the tools and creations (as the Internet) that are an extension of the phenotype appear as a consequence of intelligence, but do not take roll in the selective advantage.

However that is exactly where my doubt finds space to breath. How can we be sure that intelligence continues to be the main selective advantage operating even above the advantages given by the simple application of tools, which "do not require great intelligence" .

So while technology evolves i don't think it's because humans evolve, but because we invest time in it.

If we consider technology as an extension of the phenotype, its evolution becomes our evolution. Moreover, if humans are investing time in technology which traduces in the acceleration of its evolution, then (for me) the artificial selection is operating stronger than ever before.

I understand that it is rather an abstract concept, but I see it as if “intelligence itself” is pushing to its own growth, leaving behind the biological limitations.

That is not to say that artificial selection won't have a role in the future of human evolution. In the near future, preimplantation genetic diagnosis and screening could be routine, allowing parent to have some choice over which of their traits they pass onto their offspring. Of course, while the technology exists to screen embryos (and likely soon, to engineer embryos), the bottleneck is in our understanding of the genetics of complex traits like intelligence. Even if we had a safe and effective method to arbitrarily engineer the genome of a human embryo, we would still wouldn't really be able to engineer a super genius because we wouldn't know which genes to change.

Yes, of course. But this will be a much more straight forward artificial selection of genes, not an unconscious process. However, there is no way to predict the adaptation capability of an individual for which the genes have been subjectively chosen. This artificial selection seems to me a lot more like an art form (the art of creating a human beings with specific characteristics) than a mechanism to improve the adaptation of the individual.

I see Artificial Selection as being the outcome of the Selection process being manipulated by an outside "intelligent" force, as with a purpose. So humans can take wild dog from Africa and mate with north american wolf - that is artificial. But a person getting on a plane ( technology developed by humans through our own evolutionary process) and mating with an Inuit, even if for a non-romantic or or technical reason ( gene study) - is not artificial, it is humans beings being human beings. ( sorry could't resist the word play.)

Artificial selection does not need a purpose. I agree that many times we have done it with a purpose, but many other times we haven't (when I say “we” I'm talking about the human species). That is why I think that if the human being is being affected by artificial selection, it pretty much seems to be an unconscious process.



After a little bit of thought, I feel tempted to say that one important element in this discussion would be to analyze what it means, for the average human, to be better adapted. With most of the individuals of the species living in complex society models, which suffer huge impact from economic dynamics, can we make a list of characteristics that differentiate a better adapted individual?
Are high intelligence and emotional coefficients, which come from the old slow natural selection, warranty of better adaptation? If the characteristics obtained by natural selection are not providing better adaptation, What is then?
Can humans be very well adapted and have great chances of matting and reproducing just by taking advantage of the use of technology (extension of phenotype), even if they don't have great intelligence and emotional coefficients?

 

[Ryan_m_b]

Yes, that makes sense. What I understand from your idea is that the selective advantage of the human species is the intelligence. All the tools and creations (as the Internet) that are an extension of the phenotype appear as a consequence of intelligence, but do not take roll in the selective advantage.

However that is exactly where my doubt finds space to breath. How can we be sure that intelligence continues to be the main selective advantage operating even above the advantages given by the simple application of tools, which "do not require great intelligence"...


Are high intelligence and emotional coefficients, which come from the old slow natural selection, warranty of better adaptation? If the characteristics obtained by natural selection are not providing better adaptation, What is then?
Can humans be very well adapted and have great chances of matting and reproducing just by taking advantage of the use of technology (extension of phenotype), even if they don't have great intelligence and emotional coefficients?

Actually you could argue that intelligence has not been a driving force for human evolution for quite some time. Rather our recent (last ten thousand years or so) history has instead been driven by sexual selection and the occasional plague.

Sexual selection and human cultural practices regarding reproduction have the greatest effect on evolution. In the western world most people have two children if they do have kids, regardless of anything else. It simply fits within our cultural requirements, and most people who want kids have them. The point then is to ask whether or not sexual selection is even having a measurable impact on our evolution given that there are few people who don't get to pass on their genes equally as much as anyone else.

 

[Ophiolite]

Is the current status of human species the result of a self-inflicted and unconscious artificial selection?

Artificial selection that is unconscious has a formal name. We call it natural selection.

 

[Ryan_m_b]

Artificial selection that is unconscious has a formal name. We call it natural selection.

Or it could be sexual selection. Either way you're right, the definition of artificial selection usually includes intention to breed a particular trait.

 

[tonyxon22]

Artificial selection that is unconscious has a formal name. We call it natural selection.

No, selective breeding is a conscious process. Artificial selection is not necessarily a conscious process, and it may also produce unintended results, which could be desirable or undesirable, or sometimes even results that are not even noticed.

http://en.wikipedia.org/wiki/Samurai_crab

 

[Ryan_m_b]

No, selective breeding is a conscious process. Artificial selection is not necessarily a conscious process, and it may also produce unintended results, which could be desirable or undesirable, or sometimes even results that are not even noticed.

http://en.wikipedia.org/wiki/Samurai_crab

Artificial selection and selective breeding are most often used synonymously. The case of heikegani is an example of natural selection, the fact that humans were driving the selective pressure does not in itself make it artificial. Or arguably it is a case of intentional artificial selection. It is not a mixture of both. In fact the only reference to anyone ever referring to it as artificial selection is from a popular science TV show.

It's worth bearing in mind that artificial selection can produce unintended side effects but you end up lowering the utility of the term when you start applying it to most of human reproduction.

 

[tonyxon22]

By introducing the crabs I didn't intend to deviate the discussion. Yes, the only reference of artificial selection in this case is a TV show, but there could be other cases. That is why I am asking the original question of the thread.

In the case of the crabs, the mechanism that influenced the evolution of that very particular carapace can be considered "artificial" from the point of view that it is the result of arbitrary human intervention. That configuration does not bring any extra adaptation to the natural environment of the crap other than the fact of not ending in the soup of a human.

Is the same kind of mechanism acting, either consciously or unconsciously, on the human species?

 

[Ryan_m_b]

In the case of the crabs, the mechanism that influenced the evolution of that very particular carapace can be considered "artificial" from the point of view that it is the result of arbitrary human intervention. That configuration does not bring any extra adaptation to the natural environment of the crap other than the fact of not ending in the soup of a human.

That absolutely is an example of an adaptation that aids survival. Shells with more of that pattern allow a crab to live and thus pass on its genes. That's little different to an organism surviving because its shell colour is slightly more camouflaged. Sure the reason is thanks to humans being arbitrary but it's still arguably natural selection.

Alternatively it could be called artificial selection deliberately for that pattern given that local fisherman were actively killing crabs without it. So it's one or the other, but calling it accidentally artificial selection doesn't really get you anywhere.

Is the same kind of mechanism acting, either consciously or unconsciously, on the human species?

I don't understand what you're really asking here. Humans aren't selectively breeding (see also: the discredited eugenics movement). Thanks to technology not a lot of natural pressures act on us so we're left with sexual selection. But as I pointed out earlier due to cultural demands in many places of the world most people reproduce and most people have the same amount of offspring. This would dampen how strongly selective pressures are on humans.

But there are other effects in evolution beyond selection: genetic drift and gene flow could be having a far greater effect given the greater ease of travel.

 

[DiracPool]

Does the “selection” mechanism have a biological boundary, that limits what is considered to be evolution only by the comparison of characteristics of the phenotype? Or is it also measurable in abstract quantities such as the average intelligence of a species? And if that is the case, are tools of our own creation part of the observable phenotype?

You are dealing with two different issues here, which is where your confusion might be stemming from, and rightfully so, because the human condition does present an anomaly in the context of the traditional concept of natural selection. That anomaly can be seen as the bifurcation in human evolution from a strictly biological evolution to a combination of a biological evolution and a "mimetic" evolution.

https://www.amazon.com/dp/019286212X/?tag=pfamazon01-20

This bifurcation came sometime post homo erectus (there's considerable debate exactly when), and was marked by the ability of humans to use symbols to share information "across time" or "out of time" so to speak, which distinguished our cognitive capacity from that of our nonhuman cousins.

The selective advantage of memetic evolution has proven to be far more advantageous than biological evolution, which is why our brains continue to evolve in a positive direction (encephelization quotient and continued adaptive evolution of the aspm and other microcephaly related genes: (http://www.ncbi.nlm.nih.gov/pubmed/16151010), and our bodies continue to evolve in a negative direction, withering away relative to our hominin and great ape ancestors.

You're point about track records continuing to be beaten, etc., I think deals more with a trend of expansive media coverage being able to increasingly find rare individuals with outlier traits, in addition to a related increase in an incentive to develop such traits and increases in the means to train for these through largely memeticly-supported facility.

However, as the saying goes, "humans are one generation away from savagery," meaning that without the cultural environment provided my mimetic education, our natural biology would not be a great advantage to us stranded in the forest from infancy. We know this from the study of feral children.

So whether the selection mechanism has a biological boundary becomes less clear when you add this anomaly of memetic evolution. Phenotypically, it exists in the brain, but its appearance is not as salient as that, of say, some skeletal-related phenotypic trait.

 

[Ryan_m_b]

Note that memetics isn't a widely accepted model. It became popular during the late 90s/early 2000s but hasn't gained traction but a lot of criticism. Indeed the journal of memetics had to fold nearly a decade ago.

 

[DiracPool]

Note that memetics isn't a widely accepted model. It became popular during the late 90s/early 2000s but hasn't gained traction but a lot of criticism. Indeed the journal of memetics had to fold nearly a decade ago.

The idea of memes versus genes always struck a chord with me personally, but what I am referring to in the above post is more specifically the human capacity for symbolic thought and the means for which to store those cognitive constructions, share them, and pass them down through the generations via written language as well as other means. Also, the means through which this knowledge builds on previous knowledge and new, specialized scientific disciplines splinter off from previous, more general ones, etc. In addition, how other disciplines can sometimes fizzle out and go "extinct," if you will, like the field of phrenology, for example, or ironically enough, that journal of memetics, as you mentioned. I didn't even know there ever was a journal of memetics, lol. I wasn't that into it.

So maybe "memetic" is a bit buzz-wordish, and could be replaced by say, more generally human cultural learning, social education, cultural evolution, or something along those lines.

 

[Gerinski]

I would say that until now it has been rather the opposite. In the past weak individuals had little chance of surviving and reproducing but with the advance of medicine, improvement of nutrition, care and protection (heating in our homes, protection against attacks by animals, less fighting with other humans etc), now the genetically weak have basically the same chances of mating and reproducing, so in this sense the natural course of the "survival of the fittest" has been stopped for humans, now all of us, fit or not, survive and reproduce (in the developed world at least).

On the other hand now the mix of the gene pool has greatly increased with traveling and cultural mix so this has increased the genetic diversity and gives rise to more variation in the individuals. Before, people would usually mate with an individual of his-her own tribe and village.

The improvement of records and achievements has little if anything to do with genetic selection, unless you count that perhaps in modern times the children of say, a very good athlete can more easily be encouraged to follow on the parent footsteps and perhaps two very good athletes will marry and have children which possibly may have very good qualities for athletics and who will be put to train from an even younger age than the parents.

 

[tonyxon22]

Ok, I understand and agree with most of the information given here, and by the way I appreciate that and thank you all for it. I think some elements have become clear for me and got now out of the equation (such as sexual selection, selective breeding, how breaking world records have little to do with artificial selection, etc…).

After a little insight of all the exposed ideas, however, my question still stands. And what makes it stand is the following:

If I get it right, natural selection is the process of evolution where species more adapted to their environments are naturally selected among all the arbitrary and random mutations of the genetic code. The random genetic mutations that translate into better adaptation to the environment have more chance to survive and reproduce. The random mutations that bring a less adapted individual will get eventually eliminated by the practical difficulties encountered in survivor and reproduction.

I don't understand what you're really asking here.

So, if that is correct, then what I’m really asking is:
1) How can a random mutation in the human genetic code be “naturally selected” if the environment where the selection occur is not natural?
2) What is the process by which the some characteristics are selected over others?
3) What are, in general, the main characteristics of a well adapted human being now days?
4) Can you give an example of a random mutation that gives better adaptation for an individual in the current human environment?
5) Can you imagine the next step of evolution for human species? What is it like? How is it different from us? (I understand that this last two questions can seem maybe stupid or invalid due to the lack of evidence of what is going to happen in the future and what the environment is going to be – but try to answer it just like and exercise, assuming that the environment will stay still for a while…)

For me (and that is what I’m trying to understand with your help) the answers to all this questions seem to revolve around the same idea: the direction of human evolution is dictated by the human race itself, and not so much by the surroundings. Even If we leave aside the genetic manipulation that was already discussed, the environment where the selection takes part is created and manipulated by men, so natural selection in such conditions seem improbable to me. And trying to find a way to define this process is when I come with the name of artificial selection, even when I now understand that it’s not quite that.

 

[Gerinski]

As I said before I believe that natural selection is already stopped for humans. The chances of survival and reproduction of a particular human being have little if anything to do with his genetic characteristics or his-her adaptation to the environment.
You may consider some individual which is particularly fit to our modern human environment, clever, social, physically strong and attractive, receptive to new things like the internet or social media... whatever... Will he actually have more offspring than other humans because of that? I don't think so.

 

[tonyxon22]

Ok natural selection has stopped. But what now? Evolution is not over. What mechanism is controlling random mutations now?

 

[Ryan_m_b]

1) How can a random mutation in the human genetic code be “naturally selected” if the environment where the selection occur is not natural?

An extended phenotype is still considered natural in this field, the same way that a termite colony or a birds next is. Try not to get too hung up on the definition of that word, another way of putting natural selection is reproduction with variation under environmental attrition.

2) What is the process by which the some characteristics are selected over others?

If the trait provides a reproductive advantage then it is said to be selected for. Imagine a random mutation that leads to one member of a population being more fertile. They will then have more offspring and thus the mutation will spread. Therefore it has been selected for.

3) What are, in general, the main characteristics of a well adapted human being now days?

Pretty much the same as they have been for the last few tens of kiloyears.

4) Can you give an example of a random mutation that gives better adaptation for an individual in the current human environment?

Define "current". The field of modern human evolution covers tens of thousands of years. The reason for this is that evolutionary change is gradual. If you're referring to current to mean the modern technological world (which at most has existed since the industrial revolution 2-300 years ago) then there has been no significant evolution due to the very short amount of time.

There are examples of evolution within recent millennia that you may be interested in such as the CCR5-delta-32 allele which is prevalent in European populations. It confers resistance to various forms of viral infections and the running theory is that smallpox endemics in European history selected for this. Here is a review featuring it: http://www.ncbi.nlm.nih.gov/pubmed/22312055

5) Can you imagine the next step of evolution for human species? What is it like? How is it different from us? (I understand that this last two questions can seem maybe stupid or invalid due to the lack of evidence of what is going to happen in the future and what the environment is going to be – but try to answer it just like and exercise, assuming that the environment will stay still for a while…)

Trying to guess future human evolution is futile, especially if your understanding of evolution is limited (which, no offence, yours still is). As I mentioned before factors affecting allele frequency in human populations over time such as genetic drift and gene flow will continue to have an effect, even if natural and sexual selection are minimised. How they will have an effect is not really possible to say.