Question of Human adaptability

Mjeck
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Question of Human adaptability

I am an atheist and believe in Evolution - So there is no creationist agenda.  I suppose I will post this in freethinkers if creationists take over this thread.  Anyway, I have a question about understanding man as an animal. 

When you see animals, you can see how mutations and adaptability have helped them in their certain circumstance.  Even monkey's, if they are in the jungle, or high on top a rugged mountain, you can see how they've adapted to that specific environment.   How come I do not see that trait in humans?  It seems that they're suited to every environment and climate on the whole of the earth.  Humans are the same throughout each corner of the earth, with little change.  That's certainly not something you'd see in other animals.

 That is not a subtext or lead in for a creationist.  I truly want to know how it is that we as animals seem to have broken away from every other animal.  That could end up being a larger question regarding consciousness, language, etc; however, I would like to keep it narrowed to adaptability.

 

 


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skin pigmentation?

skin pigmentation?


triften
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Mjeck wrote: When you see

Mjeck wrote:

When you see animals, you can see how mutations and adaptability have helped them in their certain circumstance. Even monkey's, if they are in the jungle, or high on top a rugged mountain, you can see how they've adapted to that specific environment. How come I do not see that trait in humans? It seems that they're suited to every environment and climate on the whole of the earth. Humans are the same throughout each corner of the earth, with little change. That's certainly not something you'd see in other animals.

That is not a subtext or lead in for a creationist. I truly want to know how it is that we as animals seem to have broken away from every other animal. That could end up being a larger question regarding consciousness, language, etc; however, I would like to keep it narrowed to adaptability.

 

If you look at where humans started (African plains) you can see adaptations for hunting and living on the plains. For example, standing upright gives us better visibility (and frees up our hands for tool usage.) Our large brains shed a lot of heat, meaning we can operate in the heat and helps us chase down animals. IIRC, our eyes are well suited to shifting focal distance, i.e. switching between close-up and scanning the horizon, quickly

I was under the impression that some populations *have* made subtle adaptations. Some people are better suited to different diets than others. The genes for sickle-cell anemia persisted in areas prone to malaria. That sort of thing. No shaggy people in the arctic or long limbed jungle dwellers.

-Triften 


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Mjeck wrote: I am an

Mjeck wrote:

I am an atheist and believe in Evolution - So there is no creationist agenda. I suppose I will post this in freethinkers if creationists take over this thread. Anyway, I have a question about understanding man as an animal.

When you see animals, you can see how mutations and adaptability have helped them in their certain circumstance. Even monkey's, if they are in the jungle, or high on top a rugged mountain, you can see how they've adapted to that specific environment. How come I do not see that trait in humans? It seems that they're suited to every environment and climate on the whole of the earth. Humans are the same throughout each corner of the earth, with little change. That's certainly not something you'd see in other animals.

That is not a subtext or lead in for a creationist. I truly want to know how it is that we as animals seem to have broken away from every other animal. That could end up being a larger question regarding consciousness, language, etc; however, I would like to keep it narrowed to adaptability.

 

 

Well, first I'll reiterate what triften said before. We can assess the shape of the human body and how it functions and judge what type of environments we were originally adapted to. Much like our cousins, the apes, we have fingers for gripping, suitable for an arboreal lifestyle. We also have flat-feet though, indicating that we divided our time between tree and ground, unlike monkeys and apes, whose feet tend to be like a second pair of hands (we can still see that the structure between the two types of feet is very similar though). Our eyes are located on the front of skull, suggesting that we are adapted to act as predators, but this could also be necessary for treetop navigation. Our teeth obviously show that we're adapted to many kinds of food. We also have color vision, which allows us to identify when berries and fruits are ripe, etc. (Which in turn helped these plants to exaggerate this effect across generations, so this is an example of co-evolution [I'm sure there is another better word for it that I'm just forgetting]).

You can also make observations such skin pigmentation. It's no coincidence that the closer you get to the equator, the darker the skins get. The further away you travel from the equator, the lighter the skin pigmentation becomes.

You can also observe body types between, say, Inuits and Ethiopians. Inuits tend to be more stocky and chubby, which is suitable for a cold climate. Ethiopians tend to be tall, lanky, and skinny, so they retain less heat.

Going back to teeth for a moment, when we examine the fossil skulls of native americans, we can see that the older skulls tend to have very broad, flat teeth (as hunter/gatherers they ate a lot of nuts and such, so strong grinding teeth were important). If we begin examining the skulls around the time when the native americans began farming maize, we see the teeth becoming smaller and developing more dental problems (cavities, etc). There is also a strong correlation between tooth shape and the use of fire. Larger teeth tend to be found in human skulls in australia since fire was discovered later there.

 

But the reason we don't see humans so precisely adapted to certain ecological niches in the way some animals seem to be is simply because we're clever and mean.

When a bear wanders into an extremely cold place, he makes the best of it, and after a few generations, and a lot of bears dying, the strong ones survive and pass on their traits, and eventually the cold environment doesn't seem so bad anymore.

When a human walks into a cold environment, he sees a bear and says, "Hey, he's warm because of that thick coat."

*stab, stab, kill*

Thanks, bear!

There's no need for us to evolve in the way that a lot of animals do, because we are incredibly clever when it comes to exploiting and making use of our environment. 

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Quote: Even monkey's, if

Quote:
Even monkey's, if they are in the jungle, or high on top a rugged mountain, you can see how they've adapted to that specific environment.   How come I do not see that trait in humans?  It seems that they're suited to every environment and climate on the whole of the earth.  Humans are the same throughout each corner of the earth, with little change.  That's certainly not something you'd see in other animals.

You've got a very myopic view of humanity.  We've been around for several hundred thousand years as a species, and until remarkably recently in that history, we were hunting grubs in the savannah of North Africa.  Before we discovered tools, we couldn't make clothes, and were ill suited for most environments outside of the subtropical savannah.  It's worth noting that we also weren't anywhere but the savannah.

Tools were the adaptation that allowed us to spread to so many environments.  Agriculture was the first of many adaptations that allowed us to spread incredibly rapidly and become a top predator.

Also, you must remember that humans have not had time to evolve since we started making cities.  Evolution takes many tens of thousands of years for creatures with such long lifespans and low birth rates.  We've only been making cities for 10,000 years (ish).

So, the short answer to your question is this:  Our brains are the adaptive mechanism that you can see in humans.  Otherwise, we're just particularaly mal-adapted primates.  Speaking of primates, you can see in our anatomy the same kinds of adaptations as other primates, but they go much farther back, to our pre-human common ancestor.

 

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Actually there is some

Actually there is some evidence that proposes that we are a transitionary species and that our evolutionary change is speeding up.  We are currently turning into another species.

Yeah, like Hamby said, we are the first known creature to really take a huge advantage of tools.  Other animals are known to use tools, like chimps with twigs or crude spears, gorillas with leaves to serve as a hat during rain, otters using rocks to open clams, etc.  But humans really go all out with it.

[Shameless Plug]

BTW, did you know that I am the proud new owner of an Acheulean handaxe made and used by Homo Erectus anywhere from 1.2 million to 500,000 thousand years ago?  It's considered the "swiss army knife" of the paleolithic.

[/Shameless Plug]

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Watcher wrote: Actually

Watcher wrote:

Actually there is some evidence that proposes that we are a transitionary species and that our evolutionary change is speeding up. We are currently turning into another species.

All species are currently transitional and are currently evolving into other species. Or are you indicating some kind of divergence?

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Quote:

Quote:
All species are currently transitional and are currently evolving into other species. Or are you indicating some kind of divergence?

I've watched Heroes. I know what's happening...

Seriously, though, it's a solid point. All species are technically transitional, but there needs to be a caveat. Adaptation is a response to a need for adaptation. If a species, say a shark, or cockroach, was already nearly perfectly adapted to its environment, you're not going to see much development. Mutations will virtually all be less effective if a creature is nearly perfectly adapted. This is why some species, like alligators, look so similar to their ancient relatives.

As humans have conquered nearly every environment on earth, and because we don't stay isolated for long enough for true speciation to occur (consider, you'd need a population with no influx or outflux of genetic material for hundreds, maybe thousands of generations!) it's unlikely that we're undergoing any kind of speciation.

 [edit: Oh, I suppose one could propose that because of modern medicine, we are not being selected "naturally" anymore, and that it's causing n altered rate of mutation, or something like that.  I think that's all semantics, though.  If medicine isn't a result of our natural brains, what is it?  In other words, any change is technically a natural change.]

 

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Humans ARE adapted to

Humans ARE adapted to specific environments, its simply that these adaptations, typically only evident in indigenous poplulations have been diluted in our perception by modern technology and globalization.

 Just a few examples:

1) skin pigmentation, as the human race migrated out of Africa, a trade off was made between protection from the sun and manufacturing vitamin D. We require exposure to UV to make vit D, but too much UV gives us cancer - hence indigenous populations in clines where there is less UV exposure have lighter skin to keep up with vit D production, while more equatorial populaitons have darker skin. Notable exceptions can be found in northern COASTAl indigenous populations, as fish are great source of vit D.

2) lactose tolerance. Populations who rely heavily on cattle have higher lactose tolerances than those that do not.

3) sickle cells. Tropical indigenous populaitons have the sickle cell adaptation to combat malaria.

4) adaptation to altitude. Indignous populations in mountain regions tend to be shorter, have higher lung capacity and higher blood cell density than populaitons in lower clines. Himalayan sherpas are an excellent example.

In the industrialized, global scheme of things, such things are easy to miss. Keep in mind how recent such industrializaiton is though, and look at indigenous populations whenever possible and the differences in adapation to specific environs are obvious.

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Archeopteryx wrote:All

Archeopteryx wrote:

All species are currently transitional and are currently evolving into other species. Or are you indicating some kind of divergence?

There is an important distinction that needs to be made for you guys to get what I'm saying.

There are two main stages in a species.  A stable time of little to no evolution and an instable time of very rapid evolution that ends with a new species.

We are not currently in a stable time for our species.  Our evolution is rapidly speeding up.  We are turning into a new species.

Yes all creatures(if they survive) have the potential to be considered a type of transitional creature.  However if they are stable they are not ACTIVELY a transitional animal, just a POTENTIAL transitional animal.

Humans are an actively transitional creature right now.

However there will be no divergence between humanity because we interbreed too much.

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Watcher, How do you gauge

Watcher,

How do you gauge the speed of a species' evolution? What is considered fast? It seems like it's a bit hard for little old us to judge that very well. Especially since we've been examining genomes for not very long.

-Triften 


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triften

triften wrote:

Watcher,

How do you gauge the speed of a species' evolution? What is considered fast? It seems like it's a bit hard for little old us to judge that very well. Especially since we've been examining genomes for not very long.

-Triften 

I personally cannot gauge the speed of a species' evolution.  I leave that to the experts in the appropriate fields.  I am a computer specialist.  I claim no specialization in evolution or biology.

I speak of such things from what I have learned reading studies by biological and evolutionary specialists.

So I may be reading false information, misunderstanding true information, or any shade inbetween.

I'm an enthusiastic "armchair" layperson to evolution and specifically human evolution.  So I am no ultimate authority on the matter in the least.  I concede the possibility that I am seriously mistaken in this matter.

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triften
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Watcher wrote: I'm an

Watcher wrote:

I'm an enthusiastic "armchair" layperson to evolution and specifically human evolution. So I am no ultimate authority on the matter in the least. I concede the possibility that I am seriously mistaken in this matter.

Not a problem. Do you recall where you might have read it? I mean, maybe someone has determined some standard rate of change or something.

-Triften 


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Good thread and great

Good thread and great points by everyone involved.

 I wonder if this answers the original posters questions.
 

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triften wrote:Not a

triften wrote:
Not a problem. Do you recall where you might have read it? I mean, maybe someone has determined some standard rate of change or something.

-Triften 

http://news.nationalgeographic.com/news/2007/12/071211-human-evolution.html

"The researchers' analysis found that 7 percent of human genes have been undergoing rapid, recent evolution.

If humans had always evolved at this rate, the difference between modern humans and chimps should be 160 times greater than it really is."

http://news.bbc.co.uk/2/hi/science/nature/7132794.stm

"Humans have moved into the evolutionary fast lane and are becoming increasingly different, a genetic study suggests.

In the past 5,000 years, genetic change has occurred at a rate roughly 100 times higher than any other period, say scientists in the US.

This is in contrast with the widely-held belief that recent human evolution has halted."

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Thanks for the links,

Thanks for the links, Watcher!

I think that the National Geographic link answers most of the OPs questions, too! (A source! How quaint! Smiling )

-Triften