Poll: Rate of Human Evolution

[Kortney]

As the graph shows we've actually shrunk on average when compared to humans when in the "hunter and gathere" stage of evolution and average height fluctuates based on several factors including availability of things such as food, shelter, clothing, medical care etc. Effectively, the healthier the civilisation the taller they will be (this isn't a golden rule but it generally holds). Since we have excellent medical care, and food readily available in developed countries we have started to grow.

This is true. All it takes is to do a visit to various heritage building around the world and you can see it for yourself. The doorways in a few English castles I have visited are extremely short, so short that most males have to really bend down to make it in.

 

[Crimson_Dragoon]

Here's the problem with trying to apply natural selection to humans: we're humans (and therefore many of the things we do don't count as "natural") and we don't follow many of the assumptions of natural selection. Survival of the fittest doesn't really apply to most human societies.

 

[Phoenixlight]

Humans don't evolve, technology does.

 

[philosophicalbastard]

Since I follow the philosophy of Tengen Toppa Gurren Lagann I'd say evolution is increasing in speed.

 

[instantbenz]

Our existence is too easy. Human evolution is slowing. I'm going by Idiocracy.

 

[Jake the Snake]

I'm sure all of our internal processes are still fully evolving. It'll take forever, but I'm sure our bodies are being changed to require less exercise and can take in more food. Just a theory based on how Americans keep making people eat more and more.

 

[Mimssy]

Red Queen Hypothesis- a species is constantly evolving to stay where they are.

There is no goal in evolution.

Unless I'm very much mistaken the RQH is based on co-evolved species. So rabbits may evolve just to continue existing so they aren't wiped out by the foxes. Or a host evolves to enable itself to remove parasites which evolve in kind simply to be able to remain on the host.

Humans no longer have this co-evolution, we are competing with nothing and therefore have no arms race to compete in.

It can be between predator/prey, parasite/host, or within a species. Just because we are not in competition with another large primate does not mean that our species cannot suffer great losses at the mercy of a disease. Our immune system must keep evolving.

 

[Dags90]

That there is some sort of "rate" at which evolution normally occurs that can "speed up" and "slow down" is baseless.

 

[Peteron]

We are most likely going to become weaker physically and perhaps even loser hair. This is an estimate of mine, based on our reliance of technology and clothing. Only a hypothesis of course, but we will definitely continue to evolve, even if the changes are small.

 

[ajofflight]

Evolution itself never changes speed, since we evolve to suit our surroundings, and our surroundings have been changing, though it may appear slight. We will evolve at the exact same rate now as we always have and always will, or at least that's my opinion.

 

[CrystalShadow]

Our situation really isn't anything new, in terms of evolution.

'Survival of the fittest' applies when times are difficult. If there's lots of competition for very limited resources, only the strongest survive.

HOWEVER, there is another situation, and it's the one humans are currently in:

When there are lots of available resources, and little, if any meaningful competition (either from others of the same species, or other species), 'survival of the fittest' takes a back seat, and instead we basically allow everything to survive and breed presuming it isn't so weak that it dies spontantiously anyway. (And even then, these days we make a lot of effort to keep those kinds of people alive regardless.)

A species in this situation has 2 things going for it, even though it would seem like a waste of resources to keep the 'weak' alive.
Firstly, mutations - If you keep even weak members of a species alive, and even allow them to breed, there is a much larger pool of potential mutations. While a lot of these will be negative, you might stumble across a few beneficial ones, and they actually stand a chance of surviving, especially if a 'weak' member of the species breeds with a much better one.

Secondly, and this is crucial, and often overlooked - Adaptations, and who is considered the most 'fit' (in terms of 'survival of the fittest'), is circumstantial. What's good for one situation, is bad for another.
For instance, being physically strong is very important if all you have are your bare hands, but less so if you have a large number of companions, and really impressive tools at your disposal.
If you were a hunter, being strong, and fast, but having poor social skills, would be fine.
Take that same hunter, and put them in a huge society, where the main thing you need is to be able to interact well with others, and that same person would probably end up in jail.

Anyway, since who is or is not 'the fittest' varies by circumstance, when the pressure is off, it makes sense to keep as many variations around as possible, so that when times get tough, there's someone around who fits whatever the new circumstances happen to be.

 

[Ampersand]

It would take many hundreds of generations for there to be a noticable difference of course but it is an unfortunate fact that because of the equal oportunities life style that our society holds human evolution isn't necessarily going to make us better.

 

[WanderingFool]

I put other, because I havent a clue... seems stable...

 

[Ampersand]

However, as humans have progressed into the modern age we generally now adapt our environment to suit our needs.

Look at that. You perfectly Described the actions of Parasites. Humans are no longer evolving. We never reached our Apex we just stopped. It is no longer Survival of the fittest for us because if you have diabetes and lose a leg don't worry. They have the power scooter.

Human evolution hasn't stopped, only the selection process has.
In lue natural selection however, it's possible to use genetic screening to decide for ourselves which genetic trates are to be passed down to newer generations. Genetics can even be manipulated to create new trates.

I'm not sure how i feel about that though. Seems like kind of a moral grey area to me but it's still kind of interesting.

 

[Naheal]

Other: Not enough information.

 

[webby]

That there is some sort of "rate" at which evolution normally occurs that can "speed up" and "slow down" is baseless.

I'm not saying there's a rate that evolution normally occurs at. It's a comparative discussion. Put simply "compared to the average rate of human evolution that we have witnessed over the last about 7 million years, will our current living conditions speed up, slow down or stall that process?" This "rate of evolution" being the amount of allele mutations that make it into the population, over long periods of time it is a measurable quantity performed by comparing the genetic make up of one species with the genetic make up of the species it evolved from. I'm aware we can never actually know this answer because it will be too slow for anyone to witness, it's simply a question to gauge other peoples opinions.

Snip

This is a valid point. At times when resources are plentiful and threats are scarce all animals build up the population and get a wide variety of genetic mutations. This variety enables creatures to survive devastating events that may otherwise wipe out the species. A simplified example is if there is a population of bears, 98% have a thin coat and 2% have a thick coat. Suddenly there's a savage temperature swing and the bears with the thin coat start to die off leaving on the thick coated bears alive. However, this is an example of evolution by catastrophe and on the whole is not something we as humans have to worry about too much because we have control over our environment.

If that continues it means that individuals will continue to obtain these allele mutations, some of which will be beneficial, some negative and some will change nothing. Unless there is a drastic change in something (introduction of a new predator, downfall of society, 2012 disaster actually being real etc) these new mutations will take an exceedingly long time to diffuse into the population if they ever do. Again, I'm aware that this is kind of the point, however this kind of backs up my point that overall very little change will be witnessed.

Think of a bell curve, the vast majority will be in the centre "average" part of the distribution. With the weak surviving right along with the strong (I don't just mean physical strength, I mean intellect, team work, any trait basically) then that norm will never shift without some form of outside influence. Since my assertion was that humans have a solid control on outside influence this seems unlikely. Meaning yes, the weak can have offspring that are part of the norm, but this means the strong can have offspring that are weaker. Both of these are steps back to "the norm".

I'm not claiming this is something ground breaking or new and it has obviously occurred throughout the ages, my question is whether, in the modern age, our monopoly over the environment we live in can be broken thus ending the (for lack of a better word) "stagnation" of evolution away from the norm.

Also, talk of a hunter being in a different society isn't really relevant as that's more cultural evolution than physical or mental. Our cultural acceptances of what is right or wrong have changed which has nothing to do with our brain capacity or physical attributes. I suppose this could slide into a case of nature vs nurture, but in my opinion cultural evolution is not linked to physical evolution. There are still stories of holiday makers in places such as Dubai that get arrested and jailed for breaking local laws that they are unaware of or that our society no longer deems acceptable. Does that mean that humans in some developed countries are "more evolved" than humans from developing countries??

 

[CrystalShadow]

That there is some sort of "rate" at which evolution normally occurs that can "speed up" and "slow down" is baseless.

I'm not saying there's a rate that evolution normally occurs at. It's a comparative discussion. Put simply "compared to the average rate of human evolution that we have witnessed over the last about 7 million years, will our current living conditions speed up, slow down or stall that process?" This "rate of evolution" being the amount of allele mutations that make it into the population, over long periods of time it is a measurable quantity performed by comparing the genetic make up of one species with the genetic make up of the species it evolved from. I'm aware we can never actually know this answer because it will be too slow for anyone to witness, it's simply a question to gauge other peoples opinions.

Snip

This is a valid point. At times when resources are plentiful and threats are scarce all animals build up the population and get a wide variety of genetic mutations. This variety enables creatures to survive devastating events that may otherwise wipe out the species. A simplified example is if there is a population of bears, 98% have a thin coat and 2% have a thick coat. Suddenly there's a savage temperature swing and the bears with the thin coat start to die off leaving on the thick coated bears alive. However, this is an example of evolution by catastrophe and on the whole is not something we as humans have to worry about too much because we have control over our environment.

If that continues it means that individuals will continue to obtain these allele mutations, some of which will be beneficial, some negative and some will change nothing. Unless there is a drastic change in something (introduction of a new predator, downfall of society, 2012 disaster actually being real etc) these new mutations will take an exceedingly long time to diffuse into the population if they ever do. Again, I'm aware that this is kind of the point, however this kind of backs up my point that overall very little change will be witnessed.

Think of a bell curve, the vast majority will be in the centre "average" part of the distribution. With the weak surviving right along with the strong (I don't just mean physical strength, I mean intellect, team work, any trait basically) then that norm will never shift without some form of outside influence. Since my assertion was that humans have a solid control on outside influence this seems unlikely. Meaning yes, the weak can have offspring that are part of the norm, but this means the strong can have offspring that are weaker. Both of these are steps back to "the norm".

I'm not claiming this is something ground breaking or new and it has obviously occurred throughout the ages, my question is whether, in the modern age, our monopoly over the environment we live in can be broken thus ending the (for lack of a better word) "stagnation" of evolution away from the norm.

Also, talk of a hunter being in a different society isn't really relevant as that's more cultural evolution than physical or mental. Our cultural acceptances of what is right or wrong have changed which has nothing to do with our brain capacity or physical attributes. I suppose this could slide into a case of nature vs nurture, but in my opinion cultural evolution is not linked to physical evolution. There are still stories of holiday makers in places such as Dubai that get arrested and jailed for breaking local laws that they are unaware of or that our society no longer deems acceptable. Does that mean that humans in some developed countries are "more evolved" than humans from developing countries??

Eh. That's rather beside the point, I was merely trying to give an example, but I admit it's not a very good one.
Getting caught up in the details of it isn't really worth it.

Also, talking about "More evolved" or "Less evolved" really misses the point altogether, since it implies long-term planning, which is precisely what evolution does not have.

Terms like 'devolution' are equally rediculous.

A Human being is no more evolved than a virus, it's just different.

Are there still evolutionary pressures on human beings? Undoubtedly. Despite all our technology, or perhaps because of it, we've done some very strange things to our diet that some people have difficulty coping with.
The question with things like that is whether such things will persist long enough for any meaningful evolutionary changes to result (like for instance, the ability for adults to break down lactose evolved within the last few thousand years), or whether our technology will solve such problems before any meaningful evolutionary changes happen, or perhaps, our diet will simply continue to change.

It really depends on which factors end up dominating. Something doesn't have to be lethal for it to have an effect on a population after all, it merely has to be a disadvantage relative to something else.
If for instance, people that struggle with obesity consistently have less children than those who do not, and this has any genetic basis, then over time, the proportion of people with such genetic predisposition to obesity will be reduced.

Evolution never truly stops unless the environment is completely static, and the population is already adapted to what that environment is.
And that simply isn't the case, irrespective of our ability to modify our environment, we don't have that degree of control over it that we can halt evolution altogether.