Will humans continue to evolve?

[Korto]

Saw some bloke on a TV show once (terrible start, I know, so I'll keep my claims modest) who said, as stated above, that despite claims of the death of evolution, it was in fact affecting man faster than ever before. (shrug. That's what he claimed. Don't know myself).
He also gave examples of things to look out for in the future. One was, with women putting off having children till later in life, evolutionary changes making later pregnancies more successful.
I personally have a feeling that, with children becoming more a choice than a necessity, there will be an evolutionary push towards a greater desire for children.

[Forum Troll]

Who is more likely to have a large number of children and thus be more favored by natural selection now? A 130 IQ computer nerd or a 90 IQ trailer park resident? The former most likely has no more than one or two children if any at all, the latter often has several children.

A comedically exaggerated version of the future consequences of this was depicted in the film Idiocracy.

Countering that will be one of the side benefits of genetic engineering, as otherwise the species would become pretty screwed up over time as long as the modern environment was sustained.

That's correlated with lower education more than anything else though, so it's very questionable whether it amounts to a meaningful genetic selection pressure. The trailer park resident in your example is probably the way he is because he grew up in a trailer park, not because he has some sort of congenital brain defect.

Intelligence is not entirely but largely influenced by the environment provided for children by their parents during the first few years after birth, particularly the early years of brain development before they even go to school and start public education.

Example: Baby A's parents systematically teach the baby words in context. Baby B's parents mostly just spew at the baby thousands of words with rarely any context to tell what an individual word means, where even an adult would have a hard time learning a new language. Baby C's parents mostly ignore the baby aside from dealing with physical needs. In these examples, baby A would learn to talk earlier. Similar examples could be made with almost anything else, such as learning numbers.

Environment is almost heritable, though, as people raised poorly or well by their parents are most likely to do the same to their children, though obviously outside factors like good parenting classes can improve the situation.

However, also, when it comes to nature versus nurture, such are not mutually exclusive, rather combined factors both influencing intelligence according to the general research (example: studies of identical twins raised apart in separate families), and there are a lot more nuances than just whether someone has a "congenital brain defect." Serious scholarship wouldn't argue that average differences are 100% environment and 0% genetics, just as it wouldn't argue that they are 0% environment and 100% genetics.

In time, it is technically possible to reduce the inequalities. Enough education focused specifically on parenting methods could teach people to be better parents, provided they have the devotion, and standard genetic engineering someday available to all could prevent being disadvantaged by mere chance, raising the intelligence of the whole species. It's a matter of working against natural selection, though. From the aspect of natural selection alone, irresponsible behavior, lack of responsible birth control or family planning, and just having more kids than can be properly raised all increase reproductive fitness in the modern world.

[Erik von Nein]

There actually is quite unequal reproductive success today. From the natural selection standpoint of which genes become more prevalent, reproductive "success" is primarily a function of somebody's number of children. *snip supporting paragraphs*

Very true. I was thinking of something different when I typed that. Silly me.

[hongi]

As has already been mentioned, as long as people keep reproducing, evolution will take place. Even if natural selection no longer has as much power over the species as it once did, other mechanisms like genetic drift will come into play.

For speciation to take place, we need a geographical obstacle that separates two populations. If you give it time, mutations alone (100 mutations in every individual iirc) will differentiate the two populations from one another. The changes will happen quicker if the environments are very different from one another...given all that, it seems obvious that if we want human speciation, we have to look to space. There are massive distances so it becomes easier to isolate populations genetically (barring FTL) and there may even be room for (un)natural selection; we could tinker with our genetics to make us better suited for some planets. All we have to do is favour certain traits that are more useful on this planet over others.

[Akkleptos]

but my point is an organism probably isn't going to change drastically if it has no reason to do so. Humans have little reason to change, as we use our technology to eliminate the need for environmental adaptation (which includes biological factors like predators - killing off or keeping away things that are dangerous to us with technology is one of the first things we try to do).

So true. However, while it's true that -as Gordon V. Childe suggested- mankind as a species has stopped adapting to the environment in favour of adapting the environment to it, there is a definite lack of need for certain traits that natural selection in previous times would deem necessary. I'm talking about things like teeth, for example. Many people now are being born with with a genetic makeup that doesn't have them grow the full, traditional set of teeth (I'm one of them, having never grown my last set of molars), and that is in no way affecting their ability to breed. People with genetic traits that in prehistoric times (when most of the evolutionary process that made us Homo Sapiens took place) might have been absolute deal-breakers are now able to reproduce just fine.

So, maybe we're not talking about speciation, but rather -in the face of the lack of strong environmental natural selection pressure- a degeneration of sorts, considering that many of the traits that were absolutely necessary back in prehistory are non-issues now.

But "degeneration" is maybe too strong a term. The thing is that, with things like body hair, full dentitions, a muscular build, et cæatera becoming less and less essential to live long enough to mate, we can surely expect an increase in the frequency such traits (absences) appearing in humans. The increased rate of survival and population (human gene pool) can only slow down the occurance of such absences, but since the "original" traits are no longer necessary to ensure breeding, they're bound to become less prevalent as more and more people that don't feature them continue to reproduce.

That is, unless industrialised, technologically advanced states start allowing people (or overriding peoples' choices) to genetically select the features they want in their children. Then, evolution -as a natural phenomenon- of mankind would effectively cease -for that population- in favour of artificial selection (towards whatever we may think then to be the ideal of a human being), by means of genetic engineering.

Considering, as per the OP, a million more years of "human" history, I think it's fairly reasonable that artificial selection would have a great influence in many segments of that time table.

[TheLostVikings]

So, maybe we're not talking about speciation, but rather -in the face of the lack of strong environmental natural selection pressure- a degeneration of sorts, considering that many of the traits that were absolutely necessary back in prehistory are non-issues now.

The correct term is "Evolution," the traits are now mostly useless so we get rid of them as we evolve further. While it is a common misconception, evolution has no set goal it is working towards, it is merely an ongoing process with no end.

[Akkleptos]

The correct term is "Evolution," the traits are now mostly useless so we get rid of them as we evolve further. While it is a common misconception, evolution has no set goal it is working towards, it is merely an ongoing process with no end.

Certainly. Hence:

But "degeneration" is maybe too strong a term. The thing is that, with things like body hair, full dentitions, a muscular build, et cæatera becoming less and less essential to live long enough to mate, we can surely expect an increase in the frequency such traits (absences) appearing in humans.

So, as you say, "Evolution". Also, non-vital traits may become recessive or just become a part of that big bulk of junk-DNA that most highly evolved species have (you know, the ability to grow teeth and a long tail in birds, heritage of their reptile ancestry, for example). No specific goals to true evolution, save from survival of the species. Or, more precisely, survival of genes.

But humans will probably take control of what traits they desire for they offspring eventually in coming centuries, the trend possibly starting in wealthy, highly developed nations, then spreading slowly but constantly outwards, until the practice becomes so pervasive that for a significant portion of the population, evolution (as the natural selective process we know) will have effectively been "halted". Probably, just probably.

[Erik von Nein]

Jesus, Akkleptos, your posts are kind of painful to read. Probably through no fault of your own, but man.

First of, stop abusing the term "evolution," especially with "true" at the front of it. It's been defined in this thread already. Just use that.

Second off the only "junk" DNA is DNA that we're not sure of what it does, DNA that apparently has no use. That doesn't mean vestigial organs or genetic hold-overs from ancestral species. They're just that — vestigial organs and hold-overs.

Evolution is just a process, with various selecting factors influencing it (sexual, survival, etc). One of those selecting factors could very well be artificial, such as genetic engineering. But so long as cells continue to divided then transcription errors will occur and genetic variation will exist, so evolution will keep happening. At that every singe person in the world would have to have the exact same gene sets for there to be no variance at all.

Also, "highly evolved" is such a nonsense term. What would you consider highly evolved? Species at then ends of various phylums? Species that can survive in a wide range of environments? Intelligence? What?

[ray245]

Although I have to wonder, would most of us enjoy the concept that our descendants will look differently from us in a few million years?

Are we averse to the fact that our species will evolve and becomes a new species altogether?

[Akkleptos]

Jesus, Akkleptos, your posts are kind of painful to read. Probably through no fault of your own, but man.

Sorry. Am I making my sentences too long? Too long embedded commentary? Bad use of specialised vocabulary? I can certainly take constructive criticism, and I'm more than willing to try and make it better.

Regarding the adjective in front of "evolution", I just meant it as a contrast with what meddling in human genetic engineering might do should it become a widespread practice.

By "junk DNA" meant precisely what you say. Looking back on it, I could have used quotation marks, but that's actually how many people refer to it, though of course not technically. Not "junk" as in "useless", but rather as in "having an unknown purpose" or especially "not in use by the organism in its present state", which of course doesn't imply it couldn't resurface later on should natural selection favour it again.

But so long as cells continue to divided then transcription errors will occur and genetic variation will exist, so evolution will keep happening. At that every singe person in the world would have to have the exact same gene sets for there to be no variance at all.

Oh, but certainly. Variance would still occur, inevitably. I was talking about undesirable traits being knowingly supressed and desired traits being engineered into the genetic code. That, I think, would effectively halt evolution (no adjectives) for as long as humans keep doing that. Most evident mutations would be supressed as undesirable traits (in the coming centuries, should we humans decide to go that way). Variance would still be there, but the traits it would affect would -when possible- be kept into desirable parameters.

Also, "highly evolved" is such a nonsense term. What would you consider highly evolved? Species at then ends of various phylums? Species that can survive in a wide range of environments? Intelligence? What?

I realise the term has various meanings, depending on where you look. I meant that in the sense of a complex species that has come a long way since -and compared to- single-celled organisms. By that definition, dolphins=more highly evolved than, say, fish. Mammals having an extra layer in their brains allowing for higher intellective functions that reptiles, for example, don't have. The homeothermic metabolism of an animal such as a mammal or an avian compared to the heterothermic one in an amphibian. The intrincately complex nervous system of a chimpanzee compared to the nervous ganglions of an eartworm. You know, that kind of highly-evolved animals.

Although I have to wonder, would most of us enjoy the concept that our descendants will look differently from us in a few million years?

Precisely. Would humans choose to take control of what they become (and keep it within parameters they deem acceptable) or will we believe that "natural selection knows best"? I think that's the quid of the matter, once technology and other factors make gene manipulation easy enough to become a commonplace practice.

[Erik von Nein]

Sorry. Am I making my sentences too long? Too long embedded commentary? Bad use of specialised vocabulary? I can certainly take constructive criticism, and I'm more than willing to try and make it better.

No. Apparently it was mostly miscommunication more than anything else.

By "junk DNA" meant precisely what you say. Looking back on it, I could have used quotation marks, but that's actually how many people refer to it, though of course not technically. Not "junk" as in "useless", but rather as in "having an unknown purpose" or especially "not in use by the organism in its present state", which of course doesn't imply it couldn't resurface later on should natural selection favour it again.

Well, even suppressed traits in genetic codes aren't really "junk" so much as suppressed traits. If it has an unknown purpose than it appears to be pointless, but that's more a function of not having any basis to form a hypothesis about it's function.

Sorry, I've seen far too many people use "junk DNA" improperly.

Oh, but certainly. Variance would still occur, inevitably. I was talking about undesirable traits being knowingly supressed and desired traits being engineered into the genetic code. That, I think, would effectively halt evolution (no adjectives) for as long as humans keep doing that. Most evident mutations would be supressed as undesirable traits (in the coming centuries, should we humans decide to go that way). Variance would still be there, but the traits it would affect would -when possible- be kept into desirable parameters.

Evolution, as has been defined several times, is the change in gene variance over time. If variance is occurring then evolution is occurring, whether through natural means (sexual/survival selecting) or unnatural (genetic engineering) What traits do or do not occur don't effect it in the slightest.

I realise the term has various meanings, depending on where you look.

Actually, I wasn't giving you a list of ways to define "highly evolved" I was giving you examples of what people use as definitions, meaning that the term itself is, like I said, useless.

I meant that in the sense of a complex species that has come a long way since -and compared to- single-celled organisms. By that definition, dolphins=more highly evolved than, say, fish.

Sort of. There are some incredibly complex non-mammals. A shinning example would be octopus and their ability to control pigment cells to effectively blend with their environment. It shows incredibly complexity of their systems to be able to coordinate so effectively and quickly. Their eyes are also pretty complex, as well, and are actually wired right-side up, as opposed to our eyes.

Complexity is hard to define. Oh, between a sponge and a human it's easy to see the differences in complexity and saying the human is more complex is an easy call. But between cordates? That's much more difficult to define. Some systems in individuals could be vastly more complex than others.

"Higher" also implies some sort of greater value. Would you consider blue-green algae highly evolved? It's one of the most important classification of organisms on the planet. How about photosynthesis systems? Highly evolved? It's only the basis of the entirety of the planet's biosphere, without which nearly all species would be dead.

Mammals having an extra layer in their brains allowing for higher intellective functions that reptiles, for example, don't have.

That may be true, however certain birds are a good example of species with greater intelligence than most mammals. New Caledonian crows, for example, passed a causal reasoning test better than apes, demonstrating their ability to reason was, in that particular case, greater than the apes who also were in the test. Would you then say they're more complex or more highly evolved?

The homeothermic metabolism of an animal such as a mammal or an avian compared to the heterothermic one in an amphibian. The intrincately complex nervous system of a chimpanzee compared to the nervous ganglions of an eartworm. You know, that kind of highly-evolved animals.

Would you define insects (arthropods) as being more or less highly-evolved than mammals? There is some incredible complexity to their systems that's absent from mammals.

Are you beginning to see why "highly evolved" is a term that's not very useful? If you want to say species with greater intelligence that's something that's easy to prove. However, that doesn't make them "higher" species than others, especially in my case of photosynthesizing plants/protists compared to anything (except chemiosynthesizing species).

Precisely. Would humans choose to take control of what they become (and keep it within parameters they deem acceptable) or will we believe that "natural selection knows best"? I think that's the quid of the matter, once technology and other factors make gene manipulation easy enough to become a commonplace practice.

Preventing speciation or extinction-through-speciation to occur doesn't mean that evolution ceases. So long as disease remains something that we can't control completely, for example, unequal survival with guarantee variance and evolution. Hell, people either refusing or being unable to afford such extensive processes as whole-sale genetic manipulation will guarantee evolution occurs.

[Akkleptos]

Oh, but certainly. Variance would still occur, inevitably. I was talking about undesirable traits being knowingly supressed and desired traits being engineered into the genetic code. That, I think, would effectively halt evolution (no adjectives) for as long as humans keep doing that. Most evident mutations would be supressed as undesirable traits (in the coming centuries, should we humans decide to go that way). Variance would still be there, but the traits it would affect would -when possible- be kept into desirable parameters.

Evolution, as has been defined several times, is the change in gene variance over time. If variance is occurring then evolution is occurring, whether through natural means (sexual/survival selecting) or unnatural (genetic engineering) What traits do or do not occur don't effect it in the slightest.

Yes, but gene variance can have a practical, evident effect ranging from disastrous to negligible. Genes provoking evident, disastrous effects would in all likelihood be weeded out by technicians (I've been assuming technological and scientific advances from a couple or more centuries in the future in my posts). So, variance would still be there, but it would be limited to green or blue eyes; hair colour; curly, straight or wavy hair; height; size of facial features; body build; innate talents, et cætera.

Nevertheless, the point you make about illnesses is interesting. It would depend how much medicine, medical technology and isolation and elimination of "problem genes" advance in a couple of centuries.

In any case, in such a situation, while we might still see evolution in humans -in the sense of occurence of variance-, it wouldn't be reasonable to expect the species changing as such, via natural selection. Changes would undoubtedly happen anyway, but they'd be due more to artificial selection of traits deemed desireable by the Zeitgeist en vogue than anything else.

In other words, human evolution would get hijacked by those humans with the means to control the genetic build of their offspring.

Are you beginning to see why "highly evolved" is a term that's not very useful? If you want to say species with greater intelligence that's something that's easy to prove. However, that doesn't make them "higher" species than others, especially in my case of photosynthesizing plants/protists compared to anything (except chemiosynthesizing species).

Yeah. I should have gone with "complex" instead. I knew as soon as you mentioned octopuss... octopi? I should have remembered about those while posting. So, yes: complex.

[Erik von Nein]

Yes, but gene variance can have a practical, evident effect ranging from disastrous to negligible. Genes provoking evident, disastrous effects would in all likelihood be weeded out by technicians (I've been assuming technological and scientific advances from a couple or more centuries in the future in my posts). So, variance would still be there, but it would be limited to green or blue eyes; hair colour; curly, straight or wavy hair; height; size of facial features; body build; innate talents, et cætera.

Of course. As long as any kind of variance exists there's still evolution. Just as how the coelocanth looks like the fossils we've recovered from bygone era that in no way means it didn't evolve.

Nevertheless, the point you make about illnesses is interesting. It would depend how much medicine, medical technology and isolation and elimination of "problem genes" advance in a couple of centuries.

It would have to advance quite significantly and basically be so affordable as to protect every single person on the planet for differing disease resistance from genetic mutation to no longer be a factor.

In any case, in such a situation, while we might still see evolution in humans -in the sense of occurence of variance-, it wouldn't be reasonable to expect the species changing as such, via natural selection. Changes would undoubtedly happen anyway, but they'd be due more to artificial selection of traits deemed desireable by the Zeitgeist en vogue than anything else.

In other words, human evolution would get hijacked by those humans with the means to control the genetic build of their offspring.

For the more wealthy members of society or those who actually want to use it. I imagine there would be a backlash against such a movement in general, especially by more religious members of the world. But, yes, even if every single person was genetically engineered there would still be evolution, but the variance would be controlled by artificial selection than by natural selection.

Yeah. I should have gone with "complex" instead. I knew as soon as you mentioned octopuss... octopi? I should have remembered about those while posting. So, yes: complex.

Cool. Oh, and it's just octopuses, just like the plural of virus is "viruses."