The Future of Human Evolution.

[Lemur866]

@Dr. PoopiePants

As noted in my OP, my choice is “B”. (humans will evolve minimally in 1-million years).

Let me align my position with a few mechanisms of evolution:

Adaptation:
In our not-too-distant past, humans crossed a watershed mark: from adapting themselves to the environment to adapting the environment to themselves. IMO, this renders adaptation, as a mechanism of biological evolution, virtually directionless.

I disagree. For the most part, humans today are pretty much identical to the hunter-gatherers of 20,000 years ago. However, we live in a completely different environment. We are surrounded by strangers, we eat a completely different diet, we are exposed to much more disease, people die because of the availability of drugs, people are saved because of the availability of drugs, people are killed in car crashes but not by wild animals, we travel around the world mixing diseases, cultures, and genes. The different environment means a different selective regime. Ever notice how some people just can’t take modern life? Send them out to live in the forest with a few friends and they’re fine, but ask them to work 9-5 at a desk job and they end up in a clock tower with a rifle. Ever notice how some people kill themselves with drugs and alcohol? Ever notice how some people have lots of sex, and yet never become parents? Ever notice how some people have no kids, while other people have 2.1 kids, while other people have 7 kids?

What is natural selection? The simple observation that organisms vary, that a portion of that variation is genetic, that not all organisms survive to reproduce, and that therefore any organism that reproduces is going to have their genetic variation overrepresented in the next generation. We haven’t repealed natural selection through technology. People vary, people have more or fewer kids, any genetic variation that increases the likelihood that people will have more kids is likely to be overrepresented in future generations.

Gene Flow:
As geographical and cultural barriers continue to erode, genes flow more freely. As species go, humans exhibit a high degree of heterogeneity (only dogs and perhaps a few other domesticated species exhibit more variability), but, as our specie matures, the trend certainly seems to be toward homogeneity. We’re becoming mongrelized. Our mutt-people progeny, though prosaic, will no doubt be genetically fit…and they will fetch well. We are converging as a species, not diverging.

Humans do NOT have a high degree of heterogeneity. That’s a myth. And neither do dogs, when compared to wild species. Dogs appear very variable, but the visible variation in dogs is typically caused by only a few allele changes. Change one allele and you get short legs, change another and you get curly coat, change another and you get white fur. Wild populations of wolves may LOOK a lot alike, but they have more genetic variation than dogs. And most domestic animals are the same…they may show an amazing variation in coat, or size, but they are invariably very similar to each other genetically.

And this isn’t surprising. Think of all the organisms out there with dozens of subspecies, with arguments between biologists whether a particular subspecies is really a different species. For instance, wolves and coyotes can interbreed, although they usually don’t. Does that make coyotes a different species, or only a different subspecies? Humans have nothing like that level of genetic diversity, human diversity is usually quite literally only skin deep. Domestic animals are usually only a small subset of a wild population. A few founder individuals were domesticated a few thousand years ago, and through the founder effect lost most of the genetic diversity present in the wild population. So humans aren’t losing genetic diversity through outbreeding, we don’t have much genetic diversity to start with.

Genetic Drift:
IMO, genetic drift in our large, increasingly homogenous, mobile population makes the fixation of mutated alleles impotent.

It’s true that in a large population with lots of mixing we won’t have isolated populations any more. And the larger the population the longer it takes for a mutant allele to become fixed, and that genetic drift could eliminate the mutant allele even if it is highly favorable.

Mutation:
My guess is that the rate of copying error mutations will remain stable, while the rate of exposure-type mutations (i.e. radiation, chemical) will rise in our increasingly polluted environment. However, more mutations in toto does not necessarily translate into more or greater change. In this regard, the more important variable is the degree to which alleles become fixated, as opposed to being diluted to oblivion.

Yes, the mutation rate isn’t going to change much, even with more chemicals and radiation in the environment. But genes don’t get “diluted”. Either a gene is present or it isn’t.

Natural Selection:
>>A) Ecological Selection: The concept of survival of the fittest is not relevant to our species any more. The genetic make-up of people who survive and reproduce today is broad and heterogeneous - weak and strong alike pass their alleles into future generations. Sociology, hard science and technology will increasingly negate the drive of ecological selection. Technology adapts; biology doesn’t need to.

As long as different people have different numbers of children we will have natural selection. That doesn’t mean we’ll have natural selection in a consistent direction, or that we’ll have selection for the things that people imagine we will, but we’ll have natural selection. We know for instance that people whose ancestors came from the Old world typically have much more resistance to infectious diseases from the Old world.

>>B) Sexual Selection: I believe that contemporary human sexual selection is, and will continue to be, the major impediment to evolutionary change for our species. Sexual drive may be instinctual for all species, but mate selection is not necessarily so, at least not for the most sapient of species – H. sapiens. We choose mates by free will, logic and emotions…and sometimes coercion. I posit the following:
Increased sapience = increased free will mate selection = decreased directed allele fixation = evolutionary homeostasis.
Human breeding crosses all borders (i.e. geographic, ethnic, cultural). Nearly every expressed human trait is attractive to someone and therefore likely to be bred and passed into future generations: fat/skinny, short/tall, aggressive/passive, smart/dumb…if it walks on two legs, someone will nail it (on second thought, even bipedalism isn’t a prerequisite for some). As opposed to instinctual sexual selection, which is predictable and positively directed, free will sexual selection is random and virtually directionless. Break-out, species-altering traits are unlikely to fixate in this chaotic brew of genetic stew.

Look, does everyone really have the same opportunities to mate and have kids as everyone else? No, of course not. And even if this were so, it wouldn’t be a recipe for stasis, because if it were true it would be a completely different selective environment than has ever existed before. It would be a huge change. Removal of selection is a change in selection.

[Sal_Ammoniac]

By coincidence (or not!) the NY Times has an article today on human evolution. (You may need to register to see the site.) Apparently scientists have been able to identify quite a bit of recent evolution.

[Tibby]

@Lemur866

I disagree. For the most part, humans today are pretty much identical to the hunter-gatherers of 20,000 years ago. However, we live in a completely different environment. We are surrounded by strangers, we eat a completely different diet, we are exposed to much more disease, people die because of the availability of drugs, people are saved because of the availability of drugs, people are killed in car crashes but not by wild animals, we travel around the world mixing diseases, cultures, and genes. The different environment means a different selective regime. Ever notice how some people just can’t take modern life? Send them out to live in the forest with a few friends and they’re fine, but ask them to work 9-5 at a desk job and they end up in a clock tower with a rifle. Ever notice how some people kill themselves with drugs and alcohol? Ever notice how some people have lots of sex, and yet never become parents? Ever notice how some people have no kids, while other people have 2.1 kids, while other people have 7 kids?

What is natural selection? The simple observation that organisms vary, that a portion of that variation is genetic, that not all organisms survive to reproduce, and that therefore any organism that reproduces is going to have their genetic variation overrepresented in the next generation. We haven’t repealed natural selection through technology. People vary, people have more or fewer kids, any genetic variation that increases the likelihood that people will have more kids is likely to be overrepresented in future generations.

I’m not sure that I fully understand the point of your disagreement here. My point is that we are staying virtually the same, biologically, despite our greatly changing environment – you seem to be making the same argument. When I point out that humans adapt their environment rather than adapting to their environment, I’m not suggesting that our environment remains static – far from it, we’re changing it a great deal (emphasis: **we’re **changing it). As opposed to other species (and ours, in the past), we are no longer at the mercy of the environment to quite the same degree - at least not to a degree necessitating more than minimal biological adaptation. Yes, we live in a completely different environment than we did 20,000 years ago, but have we changed very much biologically in the intervening years? I suggest that our species has changed minimally since our hunter-gatherer days and those changes have been mostly in the realm of immunology/resistance etc. Admittedly, 20,000 years is a short period of time with regard to evolution, but I don’t see even the flicker of a tendency for our species to undergo anything as radical as speciation in many times that time-period.

Futhermore, the environmental hazards that we are at the mercy of, I believe, are more “democratic” than the hazards that befall other species. Let me use your comparison of being killed by car crashes vs. wild animals as an oversimplified example:

1. Traits that tend to prevent you from being killed by a saber tooth tiger: Being smart. Being fast.
2. Traits that tend to prevent you from being killed in a car crash: Being sober. Being neither a male teenager nor a senior citizen. Being lucky.
   In an environment rich with saber tooth tigers, I predict a strongly directional evolutionary tendency: smart, fast people will survive and breed more readily leading to smarter, faster progeny. In an automobile rich environment, however, predictions are much more hazy and less directional: Perhaps, the gene linked to alcoholism will be slowly extinguished…maybe, maybe not. Another way to look at it is that the mechanisms of evolution in other species tend to be more aligned in the same direction, whereas the mechanisms of evolution in modern humans tend to be multidirectional…and therefore directionless.

@Lemur866

Humans do NOT have a high degree of heterogeneity. That’s a myth. And neither do dogs, when compared to wild species. Dogs appear very variable, but the visible variation in dogs is typically caused by only a few allele changes. Change one allele and you get short legs, change another and you get curly coat, change another and you get white fur. Wild populations of wolves may LOOK a lot alike, but they have more genetic variation than dogs. And most domestic animals are the same…they may show an amazing variation in coat, or size, but they are invariably very similar to each other genetically.

And this isn’t surprising. Think of all the organisms out there with dozens of subspecies, with arguments between biologists whether a particular subspecies is really a different species. For instance, wolves and coyotes can interbreed, although they usually don’t. Does that make coyotes a different species, or only a different subspecies? Humans have nothing like that level of genetic diversity, human diversity is usually quite literally only skin deep. Domestic animals are usually only a small subset of a wild population. A few founder individuals were domesticated a few thousand years ago, and through the founder effect lost most of the genetic diversity present in the wild population. So humans aren’t losing genetic diversity through outbreeding, we don’t have much genetic diversity to start with.

Point well taken about some other species being more variable than humans (particularly when compared with subspecies). However, my point was not really to quantify human genetic variability or compare it to that of other species, but to argue the direction I believe it is going in: I foresee the current and future human gene flow schemata leading us toward less variability over time. We are somewhat variable now (how much is not important), but down the road; we will be less variable.

@Lemur866

Yes, the mutation rate isn’t going to change much, even with more chemicals and radiation in the environment. But genes don’t get “diluted”. Either a gene is present or it isn’t.

Perhaps “diluted” was a poor choice of words. I did not mean that the genes themselves get diluted, rather the probability of an allele becoming fixed becomes “diluted” (IOW, it becomes less probable, or in your words, “drives the allele to extinction”).

@Lemur866

Look, does everyone really have the same opportunities to mate and have kids as everyone else? No, of course not. And even if this were so, it wouldn’t be a recipe for stasis, because if it were true it would be a completely different selective environment than has ever existed before. It would be a huge change. Removal of selection is a change in selection.

I’m arguing that humans will evolve minimally (choice “B”), not that that we will cease evolve at all (choice “A”). Of course our species will never reach a level of 100% evolutionary stasis, but I believe that it will be static relative to most other species (i.e. those that will evolve to a greater extent). And I believe that it will be static enough to prevent speciation – even in 1-million years. I predict that the minimal biological changes that we will experience will be in realms such as: drug/microbial resistance, atavistic organs and perhaps atrophy of secondary sexual characteristics (I’m guessing at a tendency toward androgyny in the future). I don’t predict the transmogrifying type of changes that many others think are in our future (e.g. big, brainy heads).

[Blake]

@Dr. PoopiePants

As opposed to other species (and ours, in the past), we are no longer at the mercy of the environment to quite the same degree - at least not to a degree necessitating more than minimal biological adaptation.

That maybe true, but the point you don’t seem to understand is that the rate of evolutionary change isn’t dictated primarily or even significantly by the necessity of biological adaptation as you seem to think. The rate of evolutionary change is dictated almost entirely by differential reproductive rates and nothing more.

To illustrate this for you, consider the New Zealand black duck. A fairly typical generalist duck. Lived in New Zealand for hundreds of thousands of years. Its form and function are both well suited to its environment. The species is quite clearly capable of surviving in its environment without more than minimal biological adaptation being necessary. But then someone introduced the European mallard, and the European mallard is rapidly hybridizing with the New Zealand black duck. AT the current rate within 200 years there will be ne New Zealand black ducks left. The black duck population of New Zealand will have evolved into and entirely different species. So as you can see, evolutionary change can occur extremely rapidly even when no biological adaptation is necessary for survival.

The problem you seem to be making, and it’s a common one, is your assumption that any genetic change must be necessary for survival reproduction in order to be come fixed in a population. That simply isn’t true. The mallard doesn’t have any traits that are necessary for survival that isn’t present already in NZ black ducks. All it has are traits that are advantageous in reproduction. Any NZ black duck will survive to reproduce just as well as any mallard. The only difference is that mallards breed just a tiny bit faster. The mallard trait isn’t necessary for survival. It is simply advantageous. Yet the mallard trait will become universal and the NZ species will evolve into an entirely new species within centuries as a result.
And I think this is the point you are struggling with. It doesn’t matter no traits at all are necessary for humans to survive. All that matters is that a trait is advantageous.

Admittedly, 20,000 years is a short period of time with regard to evolution, but I don’t see even the flicker of a tendency for our species to undergo anything as radical as speciation in many times that time-period.

There is no doubt that our species did undergo speciation les than 10 times that time period. H, sapiens is less than 200, 000 years old.

1. Traits that tend to prevent you from being killed by a saber tooth tiger: Being smart. Being fast.
2. Traits that tend to prevent you from being killed in a car crash: Being sober. Being neither a male teenager nor a senior citizen. Being lucky.

Absolutely incorrect.

Having good reflexes will prevent you from dying in a car accident just as surely as being fast will prevent you being killed by a predator. In both cases the trait won’t guarantee survival, but it is advantageous in survival. And you mention being sober. Yet an ability to resist toxins like alcohol has a genetic component, so even using your own conditions the ability to prevent car crashes is going to genetically favour some individuals.

In an environment rich with saber tooth tigers, I predict a strongly directional evolutionary tendency: smart, fast people will survive and breed more readily leading to smarter, faster progeny. In an automobile rich environment, however, predictions are much more hazy and less directional: Perhaps, the gene linked to alcoholism will be slowly extinguished…maybe, maybe not.

You assert this as though it is fact, but I am willing to bet thousands of dollars that you can provide no evidence at all to support the claim.

Why would having good reflexes be more likely to be evolutionarily selected by predators than by automobile accidents? Such an assumption makes no sense at all.

Another way to look at it is that the mechanisms of evolution in other species tend to be more aligned in the same direction, whereas the mechanisms of evolution in modern humans tend to be multidirectional…and therefore directionless.

Can you provide any evidence for this claim? It certainly makes no sense logically.

I foresee the current and future human gene flow schemata leading us toward less variability over time. We are somewhat variable now (how much is not important), but down the road; we will be less variable.

This runs counter to everything you have said previously.

You have been uniformly arguing that there is no significant reproductive sorting of any human genetic traits. If we assume that is true then no genes that evolve can be selected against to any significant extent: all novel mutations will survive equally within the population. If we accept everything you have been arguing to this point we are forced to conclude that humans can only become more variable.

Yet now you tell us that you predict humans will become less variable. How is that even possible? You’ve just told us that no mechanisms will select against outlier traits to any significant degree. So how can variability possibly become less? What process is removing traits to decrease diversity?

Perhaps “diluted” was a poor choice of words. I did not mean that the genes themselves get diluted, rather the probability of an allele becoming fixed becomes “diluted” (IOW, it becomes less probable, or in your words, “drives the allele to extinction”).

That doesn’t make any sense. If we accept your claim that there are no significant processes working to select trait survival then all alleles will become fixed.

[Tourt_Eroglik]

"Another way to look at it is that the mechanisms of evolution in other species tend to be more aligned in the same direction, whereas the mechanisms of evolution in modern humans tend to be multidirectional…and therefore directionless. "

What are you talking about? Evolution has no direction. Orthogenesis has long been a topic of silliness.

It is because of this lack of direction that this thread and any other speculative discussion of this nature is ridiculous. Those pop science magazine articles in which the “experts” predict life in a million years are absurd.

Enough.

[Tourt_Eroglik]

Sorry, that wasn’t so clear.

Selection acts on the differential success in passing on genes. That’s it. How do you get any sort of “direction” from that?

[gazpacho]

1. I’ll accept that Wilt may be as old as me or older, but I doubt very much that he has had as many ejaculations as I’ve had. Jerking off takes way more energy than copulation.

You know, if this is your attitude it is no wonder you spend more time jerking off than screwing women.

[Blake]

@The Flying Dutchman

I’ll accept that Wilt may be as old as me or older, but I doubt very much that he has had as many ejaculations as I’ve had. Jerking off takes way more energy than copulation.

Cite?

But let’s assume it does, so what? How is it in any way relevant.

Given the stereotype of the sexual successes of black NBA players and the ongoing debate on whether or not their athletic prowess is due to genetics…

What debate? Where? Enegaged in by whom?

Has anyone ever, in the histrory of the world, disputed that the prowess of athletes, of any ethnicity, has a strong genetic component?

Can you point to somehwhere where such a debate is occuring?

Today, whether or not, to have a child is ultimately a woman’s choice, and who the father is involves far more complicated and relevant criteria than sexual fitness.

Cite? Please I would like to see evidence that there are factors more relevant than “sexual fitness” in deterining mate selection.

My biggest fear for future generations is the rising cost of medical care because nature’s method of discontinuing genetic fuckups, even minor ones, is increasingly is being thwarted by advanced medicine.

Is it? Can we see some evdience of this? I’d really like to see some evidence that ‘genetic fuckups’ are being continuedmore now than in the past.FIrstof course you are goinmg to have to explain what a ‘gentic fuckup’ even is. I don’t recall ever hearing the Prof use that term in genetics class.

I hate myself for even suggesting this, but it has to be said.

No, it didn’t because it is so evidently nonsense.

[The_Flying_Dutchman]

@Blake

Cite?

I withdraw my comment

@Blake

But let’s assume it does, so what? How is it in any way relevant.

I withdraw my comment

@Blake

What debate? Where? Enegaged in by whom?

I withdraw my comment

@Blake

Has anyone ever, in the histrory of the world, disputed that the prowess of athletes, of any ethnicity, has a strong genetic component?

I withdraw my comment

@Blake

Can you point to somehwhere where such a debate is occuring?

I withdraw my comment

@Blake

Cite? Please I would like to see evidence that there are factors more relevant than “sexual fitness” in deterining mate selection.

I withdraw my comment

@Blake

Is it? Can we see some evdience of this? I’d really like to see some evidence that ‘genetic fuckups’ are being continuedmore now than in the past.FIrstof course you are goinmg to have to explain what a ‘gentic fuckup’ even is. I don’t recall ever hearing the Prof use that term in genetics class.

I withdraw my comment

@Blake

No, it didn’t because it is so evidently nonsense.

Cite?

[Blake]

So long as we have that cleared up thatit was yet another post made by the Flying Dutchman that was incorrect from end to end in which he stated numerous points as fact that turned out to be nothing but his erroneous beliefs.

That’s the main thing. It might be better if you refrained form posting such as fact in future though.

[Bryan_Ekers]

The human species has no more pressure on it to change than oysters or cockroaches. We’re successful in our current position and neither of the two major selectors are at play:
[list=#]We don’t have to get better at stalking to catch prey.
[li]We don’t have to get better at hiding to avoid predators.[/list][/li]Barring a major die-off through war, pandemic, asteroid hit, etc. there’s no opportunity for a subset of humanity with some specific genetic advantage to thrive while all others get selected out. Genetic engineering is by far the most likely mechanism that will drive our evolution, starting with eliminating undesirable traits. In a million years, I bet humans will be taller, healthier and live a lot longer, but there’s no incentive for us or the environment to change the basic form.

[Blake]

@Bryan Ekers

The human species has no more pressure on it to change than oysters or cockroaches.

And no less either.

[quote]
We’re successful in our current position and neither of the two major selectors are at play:
[list=#]We don’t have to get better at stalking to catch prey.
[li]We don’t have to get better at hiding to avoid predators.[/list][/li][/quote]

Wherever did you get the idea that those are the two major selectors of humanity? Can I please see a reference for this claim?

It seems fairly evident to me that social ability and disease resistance are and always have been far greater selectors than either hunting ability or ability to avoid predators. I will be interested in seeing any evidence that predator avoidance or hunting ability have been considered the major factors by any biologist.

Barring a major die-off through war, pandemic, asteroid hit, etc. there’s no opportunity for a subset of humanity with some specific genetic advantage to thrive while all others get selected out.

Once again, can we see some evidence for this claim? Why do you believe that humans are the only species on the entire planet where only catastrophic removal is capable of gene selection? How could this even be true?

… there’s no incentive for us or the environment to change the basic form.

Once again, I would like to see some evidence for this claim. How can you or anyone else possibly know this? How can you know that there is not more incentive for us or the environment to change the basic form of our species than for any other species in the history of the planet?

[Tourt_Eroglik]

@Blake

I will be interested in seeing any evidence that predator avoidance or hunting ability have been considered the major factors by any biologist.

Not that I agree with the silly comment to which you’re replying, but if you want, I could provide you with hundreds, if not thousands, of papers that demonstrate the role of predation in natural selection. It’ll cost you, though.

What I don’t get is why the poster you’re replying to doesn’t understand that evolution is driven by a differential contribution to future generations, and that predation avoidance and foraging efficeieny are clearly not the only two factors involved in that.

[Blake]

@Tourt Eroglik

…I could provide you with hundreds, if not thousands, of papers that demonstrate the role of predation in natural selection. It’ll cost you, though.

Yeah sure you can. :rolleyes:

If you can provide even one refrence that demonstrates that predation plays a major role in natural selection for H. spaiens that will be sufficient. But of course you can not do so.

[Der_Trihs]

[QUOTE=Bryan Ekers]

[list=#]We don’t have to get better at stalking to catch prey.
[li]We don’t have to get better at hiding to avoid predators.[/list][/li][/quote]
Unless the predators/prey in question are human. We still compete with ourselves, and we’re more effective against one another than animals have ever been. Note that from an evolutionary point of view, it doesn’t matter if you fail to produce offspring because a lion eats you, or because your neighbor talks his way into your wife’s bed and she has his children instead of yours. However, as you also say :

@Bryan Ekers

Genetic engineering is by far the most likely mechanism that will drive our evolution, starting with eliminating undesirable traits. In a million years, I bet humans will be taller, healthier and live a lot longer, but there’s no incentive for us or the environment to change the basic form.

Which as I said earlier, kind of renders this discussion moot.

[Tibby]

@Blake

That maybe true, but the point you don’t seem to understand is that the rate of evolutionary change isn’t dictated primarily or even significantly by the necessity of biological adaptation as you seem to think. The rate of evolutionary change is dictated almost entirely by differential reproductive rates and nothing more.

To illustrate this for you, consider the New Zealand black duck. A fairly typical generalist duck. Lived in New Zealand for hundreds of thousands of years. Its form and function are both well suited to its environment. The species is quite clearly capable of surviving in its environment without more than minimal biological adaptation being necessary. But then someone introduced the European mallard, and the European mallard is rapidly hybridizing with the New Zealand black duck. AT the current rate within 200 years there will be ne New Zealand black ducks left. The black duck population of New Zealand will have evolved into and entirely different species. So as you can see, evolutionary change can occur extremely rapidly even when no biological adaptation is necessary for survival.

The problem you seem to be making, and it’s a common one, is your assumption that any genetic change must be necessary for survival reproduction in order to be come fixed in a population. That simply isn’t true. The mallard doesn’t have any traits that are necessary for survival that isn’t present already in NZ black ducks. All it has are traits that are advantageous in reproduction. Any NZ black duck will survive to reproduce just as well as any mallard. The only difference is that mallards breed just a tiny bit faster. The mallard trait isn’t necessary for survival. It is simply advantageous. Yet the mallard trait will become universal and the NZ species will evolve into an entirely new species within centuries as a result.
And I think this is the point you are struggling with. It doesn’t matter no traits at all are necessary for humans to survive. All that matters is that a trait is advantageous.

Necessary vs. advantageous: IMO, a rather nit-pick-ish semantic point as it relates to this discussion. I am aware that the process of evolution is often subtle and that advantages may sway over necessities, but, so far as my position is concerned, it doesn’t matter which one is at play. However, for the record, I feel that you may be underplaying the force of evolutionary “necessities”. Consider that plight of species that have become extinct. My guess is that the majority of them would not have become extinct had they adapted in an alternate fashion (i.e. more quickly, or in a different direction). It is not a stretch to say that their fate was dictated by a necessity of biological adaptation – one that, unfortunately for them, was not realized. You may quibble with the terminology, but I say, in those cases, evolution did not take the necessary steps to assure the survivability of their species. Conversely, those species that did survive most likely have a great deal of necessary biological adaptations in their evolutionary history that were realized. Your example of the New Zealand black duck, while interesting, has little relevance to human evolution. I foresee no alternate species or subspecies in our breeding future. Our gene flow and drift are wide open; there are no pockets of mallard-people to muddy our gene pool.

@Blake

There is no doubt that our species did undergo speciation les than 10 times that time period. H, sapiens is less than 200, 000 years old.

That fact has no bearing on our future. The conditions that I outlined in post #20 were not in place more than a few millennia ago, therefore there were no barriers to speciation when it occured. By the same token, crocodiles changed quite a bit before they became crocodiles, but they have changed remarkably little since – for many millions of years. Of course, crocodilian evolution may have taken a different turn had they mated with mallards…

@Blake

Absolutely incorrect.

Having good reflexes will prevent you from dying in a car accident just as surely as being fast will prevent you being killed by a predator. In both cases the trait won’t guarantee survival, but it is advantageous in survival. And you mention being sober. Yet an ability to resist toxins like alcohol has a genetic component, so even using your own conditions the ability to prevent car crashes is going to genetically favour some individuals.

I feel compelled to label your labeling of my tiger/car example “absolutely incorrect”, somewhat incorrect . IMO, your “good reflexes” trait is, at most, minimally advantageous with respect to increasing car crash survivability, while the “fleet-of-foot” trait is of major import with respect to increasing predation survivability. Let’s compare the two:

1. Good reflexes/car crash survivability: For one thing, I doubt there is significant variability in reflex responsiveness between non-impaired individuals of comparative age. Furthermore, drivers are not the only ones killed in car crashes -fast reflexes offer no real advantage to passengers. Also, there are multiple significant factors that may increase survivability in a car crash – I don’t consider good reflexes to be even one of the more significant ones. (Imagine a drunk driver cruising in your vicinity while you are driving on the highway. Which factor would you choose first to increase your survivability: 15% decrease in your reflex latency, surrounding airbags, a more massive vehicle, good luck). Personally, I would choose good luck first and fast reflexes last. Drunks don’t discriminate in whom they crash into- sometimes it just takes good luck to avoid random acts of impaired destruction.
2. Fast mobility/predation survivability: IMO, being fast is on the very short list of significant advantageous traits that may increase ones survivability in cases of predation. As opposed to drunk drivers, predators do discriminate against victims – they prey on the ones they are most likely to catch while expending the least amount of energy: the weak/the sick/the slowpokes. Remember the old adage: you don’t have to run faster than the grizzly bear, you only have to run faster than your companions.

Do you really believe that automobiles are likely to spur us to evolving better reflexes? I don’t - for a number of reasons. I have no doubt, however, that predators are directly responsible for evolving increased speed in a great many species.

[Bryan_Ekers]

@Blake

And no less either.

Well, okay, then. We agree.

[Tibby]

@Tourt Eroglik

What are you talking about? Evolution has no direction. Orthogenesis has long been a topic of silliness.

It is because of this lack of direction that this thread and any other speculative discussion of this nature is ridiculous. Those pop science magazine articles in which the “experts” predict life in a million years are absurd.

Enough.

Well, in case you haven’t heard, there happens to be this guy who goes by the name, Mr. Intelligent Designer who pulls all the strings in evolution. I thought that was common knowledge, no?

Enough

I may have fallen off a turnip truck, but I didn’t just do so.
Of course orthogenesis is a silly concept. By my use of the term “direction” I am not implying that evolution is being directed or that there is anything willful about it.(If my use of that term is not strictly in sync with the jargon of biologists, forgive me; I’m a lover not an evolutionary biologist). To my understanding of the term, patterns of positive evolutionary direction are abundant and self-evident. Let me illustrate my point:
Take the case of those species of birds whose male members exhibit ornate plumage. If I remember correctly, the female birds will always chose to mate with males who have the most ornate plumage. A male with drab plumage will be out of luck unless he is the only choice available – and even then, the female may simply decide to hold out until Mr. (B)Right shows up. In this scenario of nearly 100% ornate plumage allele selection one can readily understand how males of those bird species evolved increasingly ornate plumage- of such magnitude that they may easily be confused with being a different species from the females. In this case, and in this context, I say that sexual selection as an evolutionary mechanism in these bird species is positively directed toward increasingly ornate plumed males. It is strongly directional and predictable upon observing the mating preferences in a sampling of even one generation. Does human sexual selection choose any trait in anywhere near the same degree as female birds chose ornate plumage? I say, “no, not even close”, and. If I’m correct, I believe this affects our evolution.

@Blake

This runs counter to everything you have said previously.

You have been uniformly arguing that there is no significant reproductive sorting of any human genetic traits. If we assume that is true then no genes that evolve can be selected against to any significant extent: all novel mutations will survive equally within the population. If we accept everything you have been arguing to this point we are forced to conclude that humans can only become more variable.

Yet now you tell us that you predict humans will become less variable. How is that even possible? You’ve just told us that no mechanisms will select against outlier traits to any significant degree. So how can variability possibly become less? What process is removing traits to decrease diversity?

More alleles, less population penetration, less fixation – I don’t see the incompatibility. Virtual (but not total) evolutionary stasis coupled with a slight tendency toward convergence driven primarily by ambiguous (almost random) free-will sexual selection in a large, barrier-free population.
Let me attempt to clarify my point by comparing the aforementioned ornate bird plume allele example with a purely hypothetical (but hopefully not too far from the mark) human scenario, where the numbers are fabricated, but whose premise, I believe, is valid.
Human sexual selection with regard to the tallness allele:
8% of females actively choose mates who are more than 3” taller than they are.
5% of females actively choose mates who are within 3” of their own height.
2% of females actively choose mates who are shorter than they are (Amazon complex).
85% of females do not choose mates on the basis of height, feeling other qualities are more important (height selection in this case is purely random.)
It may be true that women prefer tall men, but with regard to mate selection, this is born out quite minimally in my scenario. Is this slight edge to tallness enough to fixate in the human population? My guess is, “no” and even if it did to any degree, I think the height change in future progeny would be minimal. Although this is a fabrication, I believe that the true height selection model is probably not far off from this one. Furthermore, I believe a similar model holds for all traits with regard to human sexual selection. There are so many different (often opposing) traits that so many women find attractive enough to factor into their mate selection, and so many of the same traits that so many other women do not find attractive enough to factor into their mate selection process that the whole process of human sexual selection is rendered virtually directionless – almost random (at least random enough to stifle allele fixation). Note that I say “virtually” as opposed to “totally”. Remember, I believe that some biological variation/adaptation will be realized in our future (choice “B”-evolve minimally), but leading nowhere near speciation.

@Blake

Yeah sure you can.

If you can provide even one refrence that demonstrates that predation plays a major role in natural selection for H. spaiens that will be sufficient. But of course you can not do so.

I’m too lazy to look up references to substantiate a premise that I believe to be self-evident, and perhaps no reliable cite exists, but do you really believe that animals of prey such as the wildebeest would be a fast and agile today if not for the existence of predators?

@Der Trihs

Which as I said earlier, kind of renders this discussion moot.

I disagree. It only adds an interesting sidebar to the discussion.
Some questions concerning genetic engineering:
Do you believe that genetic engineering will coexist with, supplant, trigger, or stifle biological evolution?
Do you believe that genetic engineering will ever lead to profound biological changes capable of being passed on to progeny? I believe that societal backlash will always prevent transmogrification-type genetically engineered changes in our species. The technology will no doubt be developed and probably human-tested by rogue scientists, but wide scale implementation is unfathomable. Perception enhancement, immunological strengthening, defect extinguishments, and penile lengthening : YES; extra limbs, giant heads; nipple beer dispensers: NO.

[Tourt_Eroglik]

@Dr. PoopiePants

Take the case of those species of birds whose male members exhibit ornate plumage. If I remember correctly, the female birds will always chose to mate with males who have the most ornate plumage.

No, this is not true. That would imply a direction. That would imply orthogenesis.

A female will choose what it prefers. That is not always the most elaborate or ornate. There are other factors that a female (consciously or not) chooses when picking a mate. Predation regime and male health can greatly influence how a female chooses, regardless of how ornate the particular male is.

The most elaborate is not always the most attractive.

[Lemur866]

The thing is, our primate ancestors didn’t get away from predators by running away from them. Humans are damn slow. Ever try to chase a dog? A dog can outrun you without breaking a sweat. (Aside. Yes, I know humans have more endurance than a lot of other animals, so we may be able to run farther. Just not faster).

Humans don’t run away from predators while the predators chase them, humans avoid predators, and use pointy sticks and thrown rocks and COOPERATION to chase away predators. Any predators that killed our ancestors did so by surprising them, not by chasing them. If you have to run away from a leopard to survive, you’re already dead, because the leopard is going to catch you in about 10 seconds.

So, our early human ancestors didn’t avoid getting eaten by leopards because they were fast, they did so because they were fairly large social animals that used simple tools. A leopard might pick off a solitary human, but humans are very rarely solitary, a tribe of early people confronted with a leopard aren’t going to run and let the leopard eat the slowest member of the tribe, they’re going to yell, throw rocks, jab with pointy sticks, wave around burning sticks, and chase that sucker off by numbers and cooperation.

The more social a person is, the more likely they are to be successful. This hasn’t changed since the paleolithic, in fact it is likely even more true. We’re not competing against leopards, we’re competing against each other.

Also, I think there is a misconception about selection. It’s usually better not to think about traits being selected FOR, it’s usually more helpful to imagine traits being selected AGAINST. So let’s take our automobile accident example. Are automobile accidents random occurances? No, they aren’t, because different demographics are more likely to be involved in accidents than others. Yes, anyone can be in the wrong place at the wrong time and be killed at random by an accident. But the likelihood of being in an accident goes up if you’re an alcoholic, if you’re a thrill-seeker, if you don’t look both ways when crossing the street, if you drive aggressively rather than defensively, if you have a hair-trigger temper, if your mind tends to wander from your task rather than concentrate, if you’re easily distracted by shiny things, if you’re unable to make quick decisions.

So the idea that accidents are totally random occurances is not supportable. An environment with a lot of automobiles zooming around would create selective differences, if we imagine that humans are going to be driving cars around for the next several millenia, which we probably won’t.

And remember, the most important selective environment isn’t the physical environment, it is the environment provided by other members of our species. Even if our physical environment is fixed we are still in an evolutionary arms race with each other. And what matters is not “survival”, but rather differential reproduction. A gene that has no affect on survival but decreases the average amount of children someone has will be selected against. A gene that has no affect on survival but increases the average amount of children someone has will be selected for.

But of course, this is mostly moot. We can’t predict the future of human evolution because we can’t predict the environment future humans will face. The only certain thing is it’s not going to resemble 2006 America very much, whether we’re post-apocalyptic scavengers scratching a living from radiation-blasted wastelands, or genetically engineered superhumans, or living in a Star Trek style utopia.