Is human evolution over?

Fighting Irish

kiffer wrote: »

Good? Backward?
You seem to think that there is a goal...
.

But isn't evolution where we evolve to be better and stronger and live longer?

I'm crap at talking english and getting my point across, but what i'm trying to say is how can we evolve "for the good" with the way things are

coffee_cake

Fighting Irish wrote: »

But isn't evolution where we evolve to be better and stronger and live longer?

I'm crap at talking english and getting my point across, but what i'm trying to say is how can we evolve "for the good" with the way things are

Doesn't have to be good, just different

Tar.Aldarion

Fighting Irish wrote: »

But isn't evolution where we evolve to be better and stronger and live longer?

That's just comic book evolution.

kiffer

Fighting Irish wrote: »

But isn't evolution where we evolve to be better and stronger and live longer?

No...Put very(ie too) simply: Evolution is where whoever survives to breed, eventually outbreeds those that are less able to survive to breed... Depending on the environment that might be the strongest or the smallest, needing the least food and can hide the best...

We're not evolving towards some sort of super human goal.

Fighting Irish wrote: »

I'm crap at talking english and getting my point across, but what i'm trying to say is how can we evolve "for the good" with the way things are

Dades

Greg Bear's SF book "Darwin's Radio" is good read if you like this sort of thing.

The concept is that in humans huge evolutionary change can happen in a single generation to leave the rest of humanity behind.

The Mad Hatter

Dades wrote: »

Greg Bear's SF book "Darwin's Radio" is good read if you like this sort of thing.

The concept is that in humans huge evolutionary change can happen in a single generation to leave the rest of humanity behind.

Like X-Men?

Flamed Diving

God, I hate such pompous, arrogant reasoning. As if humans are somehow the apex of the animal kingdom. We are nothing of the sort. Nor is can we inhabit any part of the planet. We merely live on the crust of a planet, on a constant climatic knife-edge.

It boils down to this:

Mutation + Natural Selection = Evolution

Neither of these has stopped, or ever will stop, as long as a living carbon molecule exists.

End of story.

Sparks

Tar.Aldarion wrote: »

That's just comic book evolution.

Not the 'better' bit - but you have to be careful about the meaning of the word 'better'.

In the developed world i can't see how we our evolving, our vision, hearing, etc etc are only gonna get worse
Unless I'm looking at this wrong and not thinking of something

You're forgetting about the relatively recent discovery of tetrachromatographic vision* found in some humans in the UK.


*Instead of three kinds of 'cones' in their retinas, they have four - hence they have greater definition between shades of red. Highly useful for mothers to discern when baby is feverish apparently.

Overheal

iirc it was only in the last 10,000 years or so that humans developed a resistance to long term ingestion of lactose. We weren't built for milk and cheese. Similarly our ancestors weren't built to eat meat. But we learned to hunt and we learned to rear livestock and sow crops. The thumb was an advancement which allowed us to use tools and is responsible for oh so much.

Seems silly to think we aren't still evolving. Especially as we go into space, I suspect our bodies will adapt to the changes in gravity both in deep space and on other planets. Our legs may grow useless over uncounted generations in zero gravity. perhaps we will have 4 arms where once animals on our planet had 4 legs. Our cousins already have very good use of their feet but thats not to say we can't go one further, or evolve backward.

The Whale, a swimming mammal. Scientist have recently been unearthing more and more proof that the Whale was once a creature that evolved from the oceans, became a land mammal and then once more took to the oceans over millions of years.

The possibilities are endless really. Far from over.

AlanSparrowhawk

Naz_st wrote: »

The fact of evolution is that organisms change from generation to generation. But "Evolution" in the sense of the Theory of Evolution is a lot more than that and is predicated on the concept of Natural Selection (in fact it was the Natural Selection part of Darwins work that was the most revolutionary at the time).

Natural Selection is the mechanism of evolutionary change. To summarise it:

"Parents possessing certain traits that enable them to survive and reproduce will contribute disproportionately to the offspring that make up the next generation.
To the extent that offspring resemble their parents, the population in the next generation will consist of a higher proportion of individuals that possess whatever adaptation enabled their parents to survive and reproduce."

Now, for natural selection to occur, there must be:
a) an inheritable variation of some trait (eye colour, hand size, etc)
b) a differential in the survival and reproduction rate of an organism associated with the possession of that trait.

(and the differential works both ways: traits that lead to a higher survival & reproduction rate are selected for more often, traits that lead to a lower survival & reproduction rate are selected less often)

I think we now live in a society that has negated (or at least massively limited) this concept of natural selection. There are no traits anymore that make it more or less likely to enable an individual in society to survive or reproduce: we have corrective engineering (e.g. glasses, braces, artificial implants) or corrective surgery (e.g. laser eye surgery, appendectomy, transplants) for most disabilities. You can't even say that being especially good-looking or smart are traits that are naturally selected for since we no longer live in small geographically disconnected communities - there a 6 billion people that are connected in a global community. Even the ugliest can find someone! And if they can't - there's always mail order brides!
Finally, the concept of monogamy limits somewhat the effects of natural selection also.

So I would suggest that the minimising of the concept of natural selection in westernised society means that "Evolution" in the sense of the evolution of the species as per Darwins theories, is over (or, more accurately, dormant, awaiting environmental disruption). But, as another poster linked to, unnatural selection may be beginning (IVF, Cloning, Genetic tinkering), so in that sense it may not be over yet...

this is worth repeating

pinksoir

What is the deal with the human brain? How has it evolved to have so much potential that hasn't been realised yet? Was there a point, or points, in our evolutionary past at which all of the unused parts of the brain were active and it is just that now we don't use them any more? Is it down to the way in which we educate, and the way in which our systems and institutions are set up that somehow hinders the brains potential?

Basically, how did the brain evolve to be so amazing and advanced without us using all of it?

This confuses me no end.

AtomicHorror

Stopping evolution is like stopping the weather. It's always going to do something unless you take away the system entirely. In the case of weather that means removing the atmosphere. The only way to stop evolving is to go extinct, stop varying inheritably or stop replicating altogether. Stability of environment is irrelevant, as is reliance on technology.

AtomicHorror

pinksoir wrote: »

What is the deal with the human brain?

The "humans use only 10% of their brains" thing is a myth but sadly one repeated so often that the general public think it's science. It's good fodder for films and TV, but it's basically garbage.

pinksoir

So we do use all of our brain then? Thank jaysus for that, I can sleep again.

ScumLord

Overheal wrote: »

iirc it was only in the last 10,000 years or so that humans developed a resistance to long term ingestion of lactose. We weren't built for milk and cheese. Similarly our ancestors weren't built to eat meat. But we learned to hunt and we learned to rear livestock and sow crops. The thumb was an advancement which allowed us to use tools and is responsible for oh so much.

Seems silly to think we aren't still evolving. Especially as we go into space, I suspect our bodies will adapt to the changes in gravity both in deep space and on other planets. Our legs may grow useless over uncounted generations in zero gravity. perhaps we will have 4 arms where once animals on our planet had 4 legs. Our cousins already have very good use of their feet but thats not to say we can't go one further, or evolve backward.

But the problem there is when we do go to space we won't be floating around in zero gravity we will find a way of creating gravity.

Humans are adapting their environment to suit them selfs, more and more the environment is having less of an effect on us. We won't have the need to evolve any changes to survive in space because we'll be cocooned in an environment of our own design.

The current human body design is one of the best animal bodies that the planet has ever seen IMO. Our abundance is evidence of that.

Mickeroo

ScumLord wrote: »

Humans are adapting their environment to suit them selfs, more and more the environment is having less of an effect on us. We won't have the need to evolve any changes to survive in space because we'll be cocooned in an environment of our own design.

The current human body design is one of the best animal bodies that the planet has ever seen IMO. Our abundance is evidence of that.

Humans(for the most part) don't adapt to environments,they dig them up,bulldoze them over and build cities on them. We've only adapted to living in comfortable houses. Without a weapon of some sort to protect oursleves most medium to large size animals would make short work of us, and some of the small ones make short work of us as it is. Our abundance and ingenuity is the only advantage we have.

AtomicHorror

ScumLord wrote: »

Humans are adapting their environment to suit them selfs, more and more the environment is having less of an effect on us. We won't have the need to evolve any changes to survive in space because we'll be cocooned in an environment of our own design.

It's a reciprocal thing. As I said before, you can't stop evolution whilst staying human nor can we create environments that eliminate selection for all traits. We will always be undergoing some selection or drift which means that the way that we modify our environment will also change over time to suit how we evolve.

ScumLord wrote: »

The current human body design is one of the best animal bodies that the planet has ever seen IMO. Our abundance is evidence of that.

Animals no. Insect species disagree. Vertebrates, probably. We seem to have that one down. Mind you, if we're keeping score, some of our domesticated vertebrates are significant challengers to that. Their evolutionary strategy is that they are useful to us. Result being an estimated 1.3 billion cows in existence at any given time. If we convert that to genome copy numbers I suspect they outnumber us due to sheer biomass.

AtomicHorror

Mickeroo wrote: »

Humans(for the most part) don't adapt to environments,they dig them up,bulldoze them over and build cities on them. We've only adapted to living in comfortable houses. Without a weapon of some sort to protect oursleves most medium to large size animals would make short work of us, and some of the small ones make short work of us as it is. Our abundance and ingenuity is the only advantage we have.

It's also an adaptation to our environment.

Naz_st

AtomicHorror wrote: »

Stopping evolution is like stopping the weather. It's always going to do something unless you take away the system entirely. In the case of weather that means removing the atmosphere. The only way to stop evolving is to go extinct, stop varying inheritably or stop replicating altogether

AtomicHorror wrote: »

It's a reciprocal thing. As I said before, you can't stop evolution whilst staying human nor can we create environments that eliminate selection for all traits.

But what traits are being "naturally selected" for in our current westernised environment? It seems to me that medical science, technology and population size has significantly hamstrung the process of natural selection...

Stability of environment is irrelevant, as is reliance on technology.

Surely environment (and it's stability) is a fundamental catalyst of evolution by natural selection? Otherwise, what is a trait being naturally selected for?

CerebralCortex

Naz_st wrote: »

But what traits are being "naturally selected" for in our current westernised environment? It seems to me that medical science, technology and population size has significantly hamstrung the process of natural selection...

Would agree though that in human society there are things in it's environment and corresponding human traits that make it both difficult and easy to have offspring?

Naz_st wrote: »

Surely environment (and it's stability) is a fundamental catalyst of evolution by natural selection? Otherwise, what is a trait being naturally selected for?

Naz_st

CerebralCortex wrote: »

Would agree though that in human society there are things in it's environment and corresponding human traits that make it both difficult and easy to have offspring?

I assume that was a question missing a "you" at the beginning?

I think that the answer to that is extremely complex and I don't think it can be clearly linked to a genetic "trait". In Western society circumstance and social convention can make the age at which a relationship is "ready for kids" counter-productive to actually having them. But even in these circumstances there are a whole host of fertility treatments and options available that substantially mitigate the difficulties that arise.

CerebralCortex

Naz_st wrote: »

I assume that was a question missing a "you" at the beginning?

I think that the answer to that is extremely complex and I don't think it can be clearly linked to a genetic "trait". In Western society circumstance and social convention can make the age at which a relationship is "ready for kids" counter-productive to actually having them. But even in these circumstances there are a whole host of fertility treatments and options available that substantially mitigate the difficulties that arise.

All of which are a result of human nature and evolution(?)* Important to note that this is the case in Western society.

*I think Dawkins deals with this idea in The Extended Phenotype. I haven't read it myself but I have read The Selfish Sene which gives a good insight in the process of evolution and natural selection in the last chapter he references The Extended Phenotype.

Naz_st

CerebralCortex wrote: »

All of which are a result of human nature and evolution(?) Important to note that this is the case in Western society.

Could you clarify - I'm not getting your point...

CerebralCortex

Naz_st wrote: »

I assume that was a question missing a "you" at the beginning?

Yes.

Naz_st wrote: »

I think that the answer to that is extremely complex and I don't think it can be clearly linked to a genetic "trait". In Western society circumstance and social convention can make the age at which a relationship is "ready for kids" counter-productive to actually having them. But even in these circumstances there are a whole host of fertility treatments and options available that substantially mitigate the difficulties that arise.

Naz_st wrote: »

Could you clarify - I'm not getting your point...

What I mean is, from what I've read(Dawkins and to a lesser extent Dennet) is that the above in bold can be influenced by the gene. Apparently all the individual gene cares about is replication (it doesn't really care it just does replicate). What is good for one genes replication could be disaster for another or a group of genes.

Naz_st

CerebralCortex wrote: »

What I mean is, from what I've read(Dawkins and to a lesser extent Dennet) is that the above in bold can be influenced by the gene. Apparently all the individual gene cares about is replication (it doesn't really care it just does replicate). What is good for one genes replication could be disaster for another or a group of genes.

Ok, I think I see where you're coming from now.

If you are implying that an individual gene is somehow responsible for circumstances related to western societal and religious convention, then I would have to disagree.

I know Dawkins has argued that behavioural aspects of animals within a society could be linked to genes at some level (he even alludes to this with regard to the independent ubiquity of religion across all societies and throughout history) but the degree to which any human societal or psychological behaviour can be linked to genes is murky at best. And even if certain behaviours can be linked to genes, I think the link between societal convention (as distinct from behavioural aspects of the phenotype) is even more tenuous.

For example of the difference between the two, I think (AFAIK from one of Dawkins' books, probably the God Delusion) Dawkins suggests that the behavioural trait of being "credulous" has a survival advantage for humans as it enables us to believe unquestioningly what we are told as children by our parents: "don't do X, it's dangerous" will be taken as truth without testing the bounds of how dangerous or why (sort of the genetic opposite of "curiosity killed the cat"!). He goes on to suggest that this "credulity" manifests itself in adults as a lack of defence to the concepts of religion, since any authority figure can substitute the place of parents later on. Now this behaviour (credulity), even if it could be definitively linked to genes, is not the same as the resulting (very diverse) societal conventions that spring from it.

Also, you should have a look into the concept of "memes", which (as currently theorised) evolve and spread within a society from generation to generation in much the same way as genetic information, but without the necessity of changes in the genotype. Again, I think Dawkins references them in both the Selfish Gene and the God Delusion.

[Edit: Apparently Dawkins didn't just reference Memes in "The Selfish Gene", he introduced the term! (according to Wikipedia anyway)]

ScumLord

Mickeroo wrote: »

Humans(for the most part) don't adapt to environments,they dig them up,bulldoze them over and build cities on them. We've only adapted to living in comfortable houses. Without a weapon of some sort to protect oursleves most medium to large size animals would make short work of us, and some of the small ones make short work of us as it is. Our abundance and ingenuity is the only advantage we have.

I don't know about that now, it's true allot in the west have become very lazy but most animals do fear us. If you come across a lion in Africa today its just as afraid of you and will more often than not back down from confrontation with us.

To say we'd be useless without our weapons is like saying lions would be useless without without their teeth. Weapons have been a part of us even before we where fully human. When you take this into account I'd always bet on the human because we'll always find the right tool for the job. African tribes always killed lions, prehistoric humans brought down mammoths if they where as aggressive as modern elephants that's no small feat.

We can swim and climb, making us pretty much all terrain. Our heat management is one of the best out there giving us huge advantages over other species.

In modern times we've really pushed the human body to it's real limits with martial arts and pakour but even without these an ancient human would be a formidable opponent to any animal even on our own (which would rarely happen), your looking at a fairly large animal with two limbs for beating and a knowledge of how to hurt things.

AtomicHorror

Naz_st wrote: »

But what traits are being "naturally selected" for in our current westernised environment? It seems to me that medical science, technology and population size has significantly hamstrung the process of natural selection...

Any and all traits leading to death prior to reproduction (be that due to old age or whatever) are being selected against. If death prior to reproduction is happening at all, natural selection is happening.

Naz_st wrote: »

Surely environment (and it's stability) is a fundamental catalyst of evolution by natural selection? Otherwise, what is a trait being naturally selected for?

I mean irrelevant in that it does not have the capacity to halt evolution. Even a perfectly stable environment does prevent the emergence of new traits by mutation. And as long as new traits are emerging, positive or negative selection will occur, regardless of the stability of the environment. Nor does a stable environment eliminate the variation caused by the simple act of reproduction and the resulting recombination of genes. A gene in one combination may be selected for very differently in another combination, irrespective of the stability of the environment.

Naz_st

AtomicHorror wrote: »

Any and all traits leading to death prior to reproduction (be that due to old age or whatever) are being selected against. If death prior to reproduction is happening at all, natural selection is happening.

This holds in evolutionary terms only if death prior to reproduction is happening for reasons related to an individuals genes. I mean you can't be genetically pre-disposed to being hit by a bus!

Also, isn't your definition of natural selection is a little too wide for the purposes of evolution as it would seem to include any non-genetic congenital disorders (e.g. spina bifida)?

But even if you use the absolute terms of natural selection as you have defined it, modern medicine has vastly increased the lifespan (and ergo liklihood of reproduction) for a whole host of specific genetic disorders that would have been naturally selected against in the past (e.g. haemophilia, sickle-cell anaemia, cystic fibrosis).

Add to that the vastly increased lifespan for the more complex, non-Mendelian genetic disorders that, while not necessary linked to specific genes directly, certain people would seem have a genetic pre-disposition towards (e.g. heart disease, cancer).

Is this not a strong argument for the current state of medicine and technology homogenising the probability of survival and reproduction to the point of severely stunting the effectiveness of natural selection, and by implication, evolution?

I mean irrelevant in that it does not have the capacity to halt evolution. Even a perfectly stable environment does prevent the emergence of new traits by mutation. And as long as new traits are emerging, positive or negative selection will occur, regardless of the stability of the environment.

What about Kettlewell's famous peppered moth experiment - without the instability in the environment (the blackening of the trees around industrialised areas), the "selection" of the black moth would never have occurred.

Overheal

ScumLord wrote: »

But the problem there is when we do go to space we won't be floating around in zero gravity we will find a way of creating gravity.

Humans are adapting their environment to suit them selfs, more and more the environment is having less of an effect on us. We won't have the need to evolve any changes to survive in space because we'll be cocooned in an environment of our own design.

The current human body design is one of the best animal bodies that the planet has ever seen IMO. Our abundance is evidence of that.

Youre assuming we find the way to generate artificial gravity. Or Warp Drive. Or de-pollute the planet, before evolution occurs. As the ozone layer depletes expect human skin to adapt. As pollutants continue filling the air expect our lungs to adapt. We can't spend the rest of our lives in sterile indoor environments - though we can try. Eventually something will give.

For instance, artificial gravity or not I think you'll find that the human brain develops in leaps and bounds in its capacity for spatial reasoning and the like. How long can it be before mathematics become part of our genetic memory and instinct? How long before we adapt to eating synthetic foods or dietary supplements in lieu of actual food, which is space constraining - we just doing have the cargo space in a deep space ship to stuff 3 square meals a day when we can fit all of the same nutrition into a pill if need be. Electromagnetic Waves? Micro Waves? Radio? Cell Phones? Wi Fi? I can't imagine it has Zero Impact on the human body. The effect may be miniscule and not harmful, but it will still trigger a change in the evolutionary path we take. What says the human body doesnt over thousands of generations learn to listen to, interpret and communicate on these frequencies? Just like insects learned to be thermotropic in order to help them find food sources what says in deep space we dont become naturally sensitive to radio signals to guide us to likely sources of civilization?

AtomicHorror

Naz_st wrote: »

This holds in evolutionary terms only if death prior to reproduction is happening for reasons related to an individuals genes. I mean you can't be genetically pre-disposed to being hit by a bus!

Yes you can. Your depth perception is a polygenetic trait, as are your capacities to judge motion, identify patterns (is that a bus?), weigh up risk and even feel fear. When you get hit by a bus, there's a good chance a whole bunch of genes or gene combinations are being selected against.

Naz_st wrote: »

Also, isn't your definition of natural selection is a little too wide for the purposes of evolution as it would seem to include any non-genetic congenital disorders (e.g. spina bifida)?

Spina bifida does seem to have some genetic element, but I take your point. Assuming the reduced likelihood to reproduce or survive contains absolutely no inherited influencing factor then sure, it's not natural selection. But let's face it, there's bound to be some influence on the reproductive rate that comes from something inherited. What if the spina bifida were due to an inheritable aversion to folate intake expressed in the mother? Or what if spina bifida sufferer A has some unrelated genetic traits which make him marginally more likely to reproduce (assuming reproductive function has been preserved) than sufferer B?

Naz_st wrote: »

But even if you use the absolute terms of natural selection as you have defined it, modern medicine has vastly increased the lifespan (and ergo liklihood of reproduction) for a whole host of specific genetic disorders that would have been naturally selected against in the past (e.g. haemophilia, sickle-cell anaemia, cystic fibrosis).

Yes, it has increased the likelihood of reproduction for a great many genes. But it has absolutely not eliminated selection for and against them in various environments. CF sufferers still have an average life span that ranges from 20-40 years, which means that they're undergoing negative selection.

Naz_st wrote: »

Add to that the vastly increased lifespan for the more complex, non-Mendelian genetic disorders that, while not necessary linked to specific genes directly, certain people would seem have a genetic pre-disposition towards (e.g. heart disease, cancer).

Is this not a strong argument for the current state of medicine and technology homogenising the probability of survival and reproduction to the point of severely stunting the effectiveness of natural selection, and by implication, evolution?

Well that sort of suggests that there is such a thing as "effective natural selection" or "effective evolution". Is that not suggestive of a teleology? If we consider "effective selection" to be the elimination of traits which reduce reproductive success under condition X, then why would we define "effective selection" in the same terms under condition Y? Effective selection or evolution, if such a thing exists, can certainly not be defined in any absolute terms. If our evolution has resulted in us generating a society and environment in which more traits can be reproductively successful than by what criteria can we say that the effectiveness of selection has been reduced? Sure, we can speculate about catastrophic collapses of that society, as much as we could talk about major natural disasters, but those are unknowns. We could no more account for these when under mild selection than we could under strong selection. And indeed it seems intuitive to me that a pool of humans extant in great numbers and expressing a very wide range of genotypes is far better prepared for some hypothetical selective environment than a heavily-pruned population. There are plenty of "detrimental" traits in existence which could suddenly become very beneficial under all manner of circumstances.

Big digression there. Let's imagine we could homogenise the environment-influenced reproductive rates of all current genotypes. What happens then? For one thing we get genetic drift. The random rise and fall in frequencies of genes based on chance effects in reproduction and not influenced by environment. Genetic drift can result in the loss of genes from the gene pool by chance, which causes evolution. Then there's sexual selection. That gene that doesn't kill you but causes those unsightly ear hairs of yours mean that the boys don't fancy you. Reproductive success is modulated, and we get evolution. And then there's mutagenesis. New mutations arise and become subject to natural selection, sexual selection and genetic drift whilst you try to figure out how to homogenise it relative to other genes.

What about Kettlewell's famous peppered moth experiment - without the instability in the environment (the blackening of the trees around industrialised areas), the "selection" of the black moth would never have occurred.

Indeed, what of it? If the environment had not changed there'd have been no need for the selection in the first place. Also, evolution does not always act to change (that will even happen when there's no selection due to drift for example), sometimes it acts to conserve (countering drift).