The flaws of evolution

Originally posted by Aphex_Twin


It's the very details I'm talking about. Untill we find them we won't be sure to say evolution actually works.

So basically, you withdraw to "missing details?"
The falsification principle by Popper shows that we cann't be sure about ANYTHING.
Science don't mean: "We know everything!",
it means "We are trying to find out how things work, establishing good theories and running experiments to check them".

This way (by applying the scientific method), we find out more and more about the universe.
Evolution is a theory, a good theory but still there are many details missing, agreed. Finding them is called scientific progress.
If you don't accept Evolution, you are free to do so, but you have to come up with a better, scientific theory (one that explains more details and makes better, in principle revisable predictions), otherwise no scientist will accept it.
 
Originally posted by Belisar


So basically, you withdraw to "missing details?"
The falsification principle by Popper shows that we cann't be sure about ANYTHING.
Science don't mean: "We know everything!",
it means "We are trying to find out how things work, establishing good theories and running experiments to check them".

This way (by applying the scientific method), we find out more and more about the universe.
Evolution is a theory, a good theory but still there are many details missing, agreed. Finding them is called scientific progress.
If you don't accept Evolution, you are free to do so, but you have to come up with a better, scientific theory (one that explains more details and makes better, in principle revisable predictions), otherwise no scientist will accept it.

It can be just theese tiny details that would turn the whole theory on it's head. I am not against evolution. What I'm trying to say is that it is, like all accepted theories, incomplete. What we must do is not readily accept theories, but rather constaltly question them all. This is the only way we can improove our knowledge.

Call it an excersise in doubt... ;)
 
Originally posted by Aphex_Twin

What I'm trying to say is that it is, like all accepted theories, incomplete. What we must do is not readily accept theories, but rather constaltly question them all. This is the only way we can improove our knowledge.

No offense, but you come to late. We are already doing exactly that, every day. ;)
 
Originally posted by Aphex_Twin
All right, WillJ, you're on.

Evolution is the best theory to explain the apparition and behaviour of life we have at present moment. It is however, like all models flawed, but, as we don't have any better alternative, we have to accept it.

I have here 3 arguments brought up by creationists that may disproove evolution alltogether, lest show that there are some inconsistencies. The first two can be easily refuted, the third, a bit harder.

First: (A more theological argument) Such complexity like that encountered in biology couldn't possible have occured without an "architect" having designed it.

Second: (Social creatures)
Creatures such as bees or ants downright defy evolution. How can members of a society of creatures give up breeding and instead dedicate their life to the hive/ant-hill/... ? Shouldn't there be "survival of the fittest", and have all members of the hive compete for breeding?

Third: (Genetics)
Genetic mutations don't occur that frequently. The DNA molecule is quite stable. For one creature to "evolve" into another it would have to have several members of the species develop the same mutation over the same period of time. If just one member does, then the mutation will have a 50-50 chance of it being passed to the first off-springs, and they would have a 25-75 chance of passing it along, their off-spring a 12.5-87.5 chance to do the same. The "defect" eventually diffuses through the gene-pool of the species.


For those who have additional counter-arguments, please share them with us.

Hhhmm. I agree. You're right.

After all, I can't explain these things with complete 100% accuracy and know for sure that I am right. There are many mysterious things I don't understand.

Thus, the only logical conclusion is that some magical being is responsible.
 
Originally posted by Aphex_Twin
All right, WillJ, you're on..

I'll take that as an invitation to myself too... ;)

Originally posted by Aphex_Twin
Evolution is the best theory to explain the apparition and behaviour of life we have at present moment. It is however, like all models flawed, but, as we don't have any better alternative, we have to accept it.

I have here 3 arguments brought up by creationists that may disproove evolution alltogether, lest show that there are some inconsistencies. The first two can be easily refuted, the third, a bit harder.

First: (A more theological argument) Such complexity like that encountered in biology couldn't possible have occured without an "architect" having designed it..

A few billion years could have been enough to let life develop, I can't prove it though. That doesn't bother me though, you can't prove an 'architect' exists either. :D

Originally posted by Aphex_Twin
Second: (Social creatures)
Creatures such as bees or ants downright defy evolution. How can members of a society of creatures give up breeding and instead dedicate their life to the hive/ant-hill/... ? Shouldn't there be "survival of the fittest", and have all members of the hive compete for breeding?.

All individuals in the colony have the same genetic make-up so their genetic traits are being carried on even though the offspring isn't theirs.

Originally posted by Aphex_Twin
Third: (Genetics)
Genetic mutations don't occur that frequently. The DNA molecule is quite stable. For one creature to "evolve" into another it would have to have several members of the species develop the same mutation over the same period of time. If just one member does, then the mutation will have a 50-50 chance of it being passed to the first off-springs, and they would have a 25-75 chance of passing it along, their off-spring a 12.5-87.5 chance to do the same. The "defect" eventually diffuses through the gene-pool of the species..

A mutation that is beneficial (on which evolution thrives) will have a bigger chance than 50% to be carried over. Beneficial can mean anything but in the end the individual has a better chance of passing on it's genes than an individual without the mutation. Indeed non-beneficial mutations diffuse through the gene-pool.

Originally posted by Aphex_Twin
For those who have additional counter-arguments, please share them with us.

Can't help you with that...
 
Just going back a bit:

"How did, for instance, snakes develop a "third eye" that can see in infra-red. Quite a radical improovement, that couldn't have been achieved in slow, incremental steps throughout millions of years. What's the good of having an organ that will only work after 1 million years of "refinement"? Just drag it along and see what happends?" - Aphex Twin

This is easy. Infra-red is the same as heat. We can all feel heat. All it requires is that the ability to feel heat is refined. In any case it's part of the broad spectrum of radiation. We can see light, which is part of the same spectrum. Infra-red is just a different frequency. Just as dogs can hear different frequencies than us, snakes can see different frequencies than us.

Just BTW there is another type of 'The Universe Has Always Existed' theory, which is that matter is continuously being created at the 'centre' of the universe. But in light of the Cosmic Background Radiation experiments, I think a Big Bang is more likely.

Aphex_Twin, or someone else, please post some more criticisms or apparent flaws for debate. I like the idea that we are not debating Creationism here, just Evolution. Let's keep picking away and see if something unravels, or see if things can be refuted.

Here's one. DNA is like software, it contains instructions for making living things. Proteins are the hardware, the bits that get the job done. I think this is correct, if it's wrong please explain the truth, but I think it's right.

So how can this be? Are we expected to believe that the two arose to help each other out at exactly the same time. DNA needs proteins. Proteins need DNA. If they are inseparable for the purposes of life, doesn't this raise a massive original problem of how they joined together in absolute mutual dependency? Surely one without the other would be useless?
 
Originally posted by polymath
Here's one. DNA is like software, it contains instructions for making living things. Proteins are the hardware, the bits that get the job done. I think this is correct, if it's wrong please explain the truth, but I think it's right.

So how can this be? Are we expected to believe that the two arose to help each other out at exactly the same time. DNA needs proteins. Proteins need DNA. If they are inseparable for the purposes of life, doesn't this raise a massive original problem of how they joined together in absolute mutual dependency? Surely one without the other would be useless?
Well, that's not completely true.. For the most part, yes, the nucleic acids are the 'brains' of the cell and the proteins are the 'brawn'. However, there are many examples, even in your own cells, of functions that are performed not by proteins, but by RNA. Catalytic RNAs are called ribozymes, and though they aren’t that common, they do some important tasks. For example, (just a quick summary) the assembly of proteins themselves is carried out at ribosomes (don’t ask me who named these things..) which match the code of the messenger (mRNA) strand and the transfer (tRNA) segment carrying the appropriate amino acid (protein building block). These AAs are then linked together to lengthen the steadily-growing protein chain, which eventually folds into its native configuration. Precisely how some of this stuff happens is still a mystery, but it is known that much of the structure of the assembling ribosome is actually not protein but ribosomal RNA, (rRNA) the 3rd type.

So, in theory, proteins wouldn’t be needed for life, and nucleic acid organisms could be fully self-replicating. This theory is called the “RNA world”, because it proposes that early organisms primarily used RNA. No such microbes exist today, at least not that anyone’s found, but it’s possible that modern cells contain some remnants of their original design.

So, I hope that explanation did it justice, and that you found it informative and not too boring. ;)
 
I follow the theory of evolution as far as micro-evolution. That is that within a species, certain differences can evolve so that the creature adapts better to its environment. This would include such things as skin colouring/camouflage, prioritising of senses resulting in a tendency for certain senses to evolve better (such as smell/hearing for a dog), amounts of body hair and lengths of tails/legs etc. Such things happen over a long period of time and explain the differences of different types of animals in a certain species ie different breeds of dogs. As far as this goes, evolution seems reasonable.

Where I draw the line is macro-evolution, ie that one species can evolve into another. I think it's entirely unrealistic, and as far as I know, goes against our current scientific knowledge. Lizards (as used in one example) can interbreed, but would never evolve into snakes. If two animals are too diverse, they cannot breed or their offspring is sterile.

I think the best example of evolution is the theory itself. It manages to modify and re-invent itself whenever its proved wrong or new science is discovered.
 
Bobgote - maybe we should just meet up for a coffee and go over this!

Macro-evolution is the extension of the micro-evolution you already accept. A particular species of lizard won't evolve into snakes, however a small population of these lizards may get separated so they cannot interbreed, the location of one of these populations might suit lizards with shorter legs, so those individuals survive slightly better and do a better job at passing on genes. This environment may continue to suit lizards with smaller and smaller legs until suddenly you have a species that looks very much like a snake, originating at the lizards that were separated.

The often quoted claim is that suddenly a completely new species is born in one generation, eg, a rabbit giving birth to an elephant (and quite likely requiring some psychotherapy after!!). That's not what ToE is about, it is the small changes amounting to a big enough change to make interbreeding either phsyically or behaviorally (crikey, is that even a word??!!) impossible.
 
Originally posted by Ado
Macro-evolution is the extension of the micro-evolution you already accept. A particular species of lizard won't evolve into snakes, however a small population of these lizards may get separated so they cannot interbreed, the location of one of these populations might suit lizards with shorter legs, so those individuals survive slightly better and do a better job at passing on genes. This environment may continue to suit lizards with smaller and smaller legs until suddenly you have a species that looks very much like a snake, originating at the lizards that were separated.
but the lizard will never become a snake, they are still genetically different - and that's where my line is drawn :)


The often quoted claim is that suddenly a completely new species is born in one generation, eg, a rabbit giving birth to an elephant (and quite likely requiring some psychotherapy after!!). That's not what ToE is about, it is the small changes amounting to a big enough change to make interbreeding either phsyically or behaviorally (crikey, is that even a word??!!) impossible.
you missed the 'u' in behaviourally, but it is a word.
I was never saying that the theory proposed that it happen in one step - but animals have to be fairly similar types to be able to breed at all, you can get slight changes, but you can't change the species altogether. look at the horse/donkey thing - while they certainly look fairly similar and are genetically similar, their offspring is sterile (unless someone starts playin around with the genes).
 
(Fanks, spellink whas neva a specaltie) :)

Exactly my point though, evolution will not now give you a snake-like creature genetically identical (or close enough to qualify what I think you mean) to a current snake. The only way to do this would be to begin with the ancient origin for snakes and try to follow the same evolutionary path.

After all, rattlesnakes and taipans are genetically different, just as humans and mosquitoes are - they are just closer together, they share a common ancestor.

Convergent evolution is observable, where animals from very different origins have evolved similar traits in order to survive the best, given the environment. Dolphins are not fish, but they have fish-like features. John Howard is not human, but has human traits (couldn't resist, sorry...).

I hadn't read the full thread (still haven't) and didn't mean to imply that you were suggesting suddenly speciation - apologies. I'm trying to balance work and posting intelligently and failing horribly. I've had this debate a number of times and some crackpots throw this one out a fair bit.

The horse/donkey (zebra) issue is a classic one. Generally donkeys and horses would not mate in the wild, that in itself enough to satisfy some definitions of species. The claim is that both shared a common ancestor before either or both deviated to fill a particular environmental niche to the point that the combination of gametes can spit out a viable offspring, but that offspring cannot reproduce.

If we say for the discussion that horses are identical to the ancient ancestor and donkeys were the ones to split, you could theoretically (over a long period) re-create the speciation of the donkey by exerting the same environmental pressures on a group of horses where donkey-like traits offer the better chance of survival. You don't breed different species to create a new one, you change the conditions that define survival.

The anti-evolutionists often point to the wording or the definitions coming from science, but these come from us, from humans. The sky is blue - if I lacked the correct words to convey this it would not change the fact that the sky is blue.
 
"Originally posted by Gingerbread Man
The fault with the ToE is that they assume that if there is no proof or evidence for it, then it couldn't happen. That is, unless this unproven thing favours it.
--------------------------------------------------------------------------------
huh? "

I dont know what I was writing either then. Whatever I was saying, is lost to me. I think what I may of been saying is that in many cases ToE assumes something is right because there is no proof against it, and then assume something is wrong because there is no proof for it. example:
Someone said there is no proof that the universe wasn't infinite, so it must be infinite.
Then you say God couldn't exist, because there is no proof for it.
It is a big double standard.

Though what I am saying is that a good mutation is very remote, almost impossible. Could be one in a million, in a billion, in a trillion, I dont exactly know, but it is extremely remote. So remote that it would be assimilated, weakened, and be taken down by bad mutations.

Just look at humans. There are many genetic disorders. Now, just for a moment think of the ones that aren't hereditory, in other words, a genetic mutation. Do they ever advantage the person who gets it? If it did, are there problems that go along side it? Did the person pass it on to another generation that benefitted from it? If there is a case of this, I haven't heard it.

The idea (at least to me) of creationism is that humans started out perfect. We were all strong, tall, agile, and lived to very old ages. Today we see people who are taller or stronger than us genetically, because over time we lost the genes that made us strong and tall. Colored-skin people retained the genes that give them their colour, and the genes that give them better aerobic ability, which is why they whoop white people's a$$es in many sports.

The reason you may be genetically taller or stronger than somebody else is not that once between generations a mutation made you suddenly taller and stronger, like X-men, (or even gradually throughout generations, like inbreeding) it is because you retained the genes that make you bigger and stronger.

This also fits in well with the idea that there were few humans to start with, but now there are many. Interbreeding is now banned, because when two people have the same bad genes the bad genes can come to effect, or more of an effect than they were already affecting, and potentially disadvantage the child with mutations. Or even kill it. It is also why some couples have disabled children - they both have a bed gene that they shared, and when the child is conceived and the genes are checked against each other, the error is passed through and disables or kills the child. But if tens of thousands, maybe millions and millions of years ago (of course, we are not sure) everyone's genes were less corrupted, maybe perfect, humans could live in communities where they have children with their parent's sibling. Of course, now it is illegal, and very wrong, to do that, because of shared bad genes.
 
“First: (A more theological argument) Such complexity like that encountered in biology couldn't possible have occured without an "architect" having designed it.”

Just because we can’t explain something now doesn’t mean we will never be able to explain it (you didn’t give any specifics to argue against here). Humans are simple and really not very smart. It takes great effort over many generations (standing on the shoulders of giants) to figure out things that now seem simple to us.

“Second: (Social creatures)
Creatures such as bees or ants downright defy evolution. How can members of a society of creatures give up breeding and instead dedicate their life to the hive/ant-hill/... ? Shouldn't there be "survival of the fittest", and have all members of the hive compete for breeding?”

The genetics of eusocial creatures have been well worked out. Especially in the case of insects (its easier when you can have clones or thousands of siblings), mammals are harder to explain (the naked mole rat for example) but still we know a lot about potential evolutionary benefits, think ‘selfish gene’ here.

“Third: (Genetics)
Genetic mutations don't occur that frequently. The DNA molecule is quite stable. For one creature to "evolve" into another it would have to have several members of the species develop the same mutation over the same period of time. If just one member does, then the mutation will have a 50-50 chance of it being passed to the first off-springs, and they would have a 25-75 chance of passing it along, their off-spring a 12.5-87.5 chance to do the same. The "defect" eventually diffuses through the gene-pool of the species.”

This is simplistic. Some portions of our genome change very frequently and others don’t, further we have multiple copies of many genes and which are activated is a gene-environment interaction that we don’t understand very well yet. Many mutations can survive within a gene pool, even ones that don’t have any beneficial effect. This is because they may associate with other genes that do have a reproductive benefit. In general what we think of as a ‘species’ initiates through some kind of reproductive isolation, be it genetic or environmental.

“Rarely, if ever, is a new gene or sequence of DNA created between a generation.”

This is simply baloney. Where did you get this idea? (the "if ever" part especially, you need to define what you mean by rarely).

“Cell mutation is generally LOSING gene information, having it corrupted as it is passed on. I dont see how any advantageous thing could come out of these mutations.”

Again, who has been teaching you genetics? Or have you been making it up as you go along?

“We are degenerating from the greater humans that preceeded us. And that is one thing that we can prove.”

Now that is funny. Evolution is an ‘always forward never straight’ sort of process. It isn’t going anywhere in particular. In what sense do you think we are degenerating? What is a ‘greater human’?

“But all good things come to an end, the nurturing will dissapear, and they will be in the harsh conditions, unprepared. And there goes the least corrupted programs.”

No this is in fact a mechanism of evolution. As the environmental conditions change, different parts of the gene pool for a specific organism will benefit. Thus the gene pool shifts. If we happen to physically isolate what was originally one gene pool and then they experience different environmental conditions – bang! New species!

“With sexual reproduction you need several members of a community to develop the same mutation, in order to sustain the new species.”

Again, you need to go back and read your genetics text over again. Why would this be? Who has been feeding you this line?

“Where I draw the line is macro-evolution, ie that one species can evolve into another. I think it's entirely unrealistic, and as far as I know, goes against our current scientific knowledge.”

No it doesn’t. Current scientific thinking is that there is no difference between macro and micro evolution. The term macro evolution is really one that is useful for fossil studies but not genetic ones. To answer this more you need to define what you mean by ‘species’.

“Though what I am saying is that a good mutation is very remote, almost impossible.”

This is a value judgment and nature doesn’t have any values. It’s all about reproductive success, that’s all folks.

“Today we see people who are taller or stronger than us genetically, because over time we lost the genes that made us strong and tall. Colored-skin people retained the genes that give them their color, and the genes that give them better aerobic ability, which is why they whoop white people's a$$es in many sports.”

Bizarre, the superficial traits that you mention are more strongly affected by environment than genetics. There are no individual genes that make us strong or tall. Even if there were it seems that it is more important to be smart than strong or tall if you are talking about the difference between modern humans and their ancestors. You should really look into the difference between genotype and phenotype as well it will help some of your confusion.

It is very likely that the reasons why “colored-skin” people “whoop a$$es in many sports” are overwhelmingly related to socioeconomics rather than genetics. There is currently no evidence to support a genetic link. There is no way to define race genetically. Here is a little quote for you to ponder:

“If you sample two random copies of a random gene from two random human beings, there is about an 86% chance they’ll be the same and a 14% chance they’ll differ. If you sample the same way, but from two human beings of the same race, the chances are more like 86.5% and 13.5%. Practically all human genetic variation lies within, rather than between, racial groups.”

Here is a link to a site where some of Luigi Luca Cavalli-Sforza’s research is summarized (he is the head of the Human Genome Diversity Project). He is a great scientist and a great man. http://www.balzan.it/english/pb1999/cavalli/paper.htm

His theory is that “The bleaching of the skin was largely a consequence of the cereal diet, which, with a dark skin, causes rickets in northern latitudes.” But not everyone agrees with that.

“Interbreeding is now banned, because when two people have the same bad genes the bad genes can come to effect, or more of an effect than they were already affecting, and potentially disadvantage the child with mutations. Or even kill it.”

Again a value judgment not imposed by nature. There are no bad genes except how they affect reproductive success. Human examples are problematic because we are so emotional and we have been able to buffer ourselves from our environment. If we look at this from a non-human perspective we find that there may in fact be an advantage to having a mechanism for generating additional mutations.
 
Thanks for that Deep Thought, very informative.

Presumably proteins do the job better, if they have effectively replaced RNA, whether that means quicker, better at copying, more versatile or somesuch?
 
Quote:
'His theory is that “The bleaching of the skin was largely a consequence of the cereal diet, which, with a dark skin, causes rickets in northern latitudes.” But not everyone agrees with that.

Would the bleaching of skin not be an evolutionary reaction to wheather? The hotter it is the darker the skin thats needed for protection against it.
 
It would have to be, I think. If it was completely environmental then all humans would be born with the same colour skin which would change depending on the climate where they lived.
 
Originally posted by Gingerbread Man
Though what I am saying is that a good mutation is very remote, almost impossible. Could be one in a million, in a billion, in a trillion, I dont exactly know, but it is extremely remote. So remote that it would be assimilated, weakened, and be taken down by bad mutations.

Why? Don't we have taleneted artists, sportsmen, etc? Aren't there millions of talented people around the world?

Just look at humans. There are many genetic disorders. Now, just for a moment think of the ones that aren't hereditory, in other words, a genetic mutation. Do they ever advantage the person who gets it? If it did, are there problems that go along side it? Did the person pass it on to another generation that benefitted from it? If there is a case of this, I haven't heard it.

That's because "mutations" is usually used in context with freaks. Everyone has mutations. Many successful have got to where they are due to mutations they had.

The idea (at least to me) of creationism is that humans started out perfect. We were all strong, tall, agile, and lived to very old ages. Today we see people who are taller or stronger than us genetically, because over time we lost the genes that made us strong and tall. Colored-skin people retained the genes that give them their colour, and the genes that give them better aerobic ability, which is why they whoop white people's a$$es in many sports.

Then how do you explain things like Roman buildings with significantly short doors, not large enough for a man of our time to pass through? And how come people in the north around the world have lost their skin color while people around the equator didn't? Also, if this theory was true, you'd have people in areas that have higher radiation shorter and and whiter because they'll have more mutations, while it's not so.

The reason you may be genetically taller or stronger than somebody else is not that once between generations a mutation made you suddenly taller and stronger, like X-men, (or even gradually throughout generations, like inbreeding) it is because you retained the genes that make you bigger and stronger.

So how come no remains of these taller, stronger humans were ever found? Go to any archeology museum and you'll find many skeletons, all of them smaller than the average modern human. You'll also see they got bigger with time at times when technological advancement was insignificant, so the only thing that could make them bigger is genes.

This also fits in well with the idea that there were few humans to start with, but now there are many. Interbreeding is now banned, because when two people have the same bad genes the bad genes can come to effect, or more of an effect than they were already affecting, and potentially disadvantage the child with mutations. Or even kill it. It is also why some couples have disabled children - they both have a bed gene that they shared, and when the child is conceived and the genes are checked against each other, the error is passed through and disables or kills the child. But if tens of thousands, maybe millions and millions of years ago (of course, we are not sure) everyone's genes were less corrupted, maybe perfect, humans could live in communities where they have children with their parent's sibling. Of course, now it is illegal, and very wrong, to do that, because of shared bad genes.

:lol: Have you actually checked the couples who have disabled children? According to your theory they should be short and white, being less corrupt, right? Well guess what - it has nothing to do with it. As to children by two family members, it's a completely differnet issue that has nothing to do with good or bad genes.
 
Originally posted by highstreet
It would have to be, I think. If it was completely environmental then all humans would be born with the same colour skin which would change depending on the climate where they lived.

That's where evolution comes in. People with darker skin are more fitting to live in the sun. And indeed when taking someone with lighter skin color they'll be tanned as the skin adjusts itself. But aside from that, in sunnier areas, a person born with darker skin will have an easier time than someone born with a lighter skin, and as a result will be in an advantage.
 
Originally posted by WillJ
Ooh, goodie! ;)Yay, isn't that special. Unfortunately, that doesn't have anything to do with evolution. An architect could have designed the world, and let it evolve. He could have even designed how it evolved, but it still evolved.

Well, if this is true then both creatonist and evoulisnt theories is true in a way.. since the world would have been created by the arcitech just not the way many christians tought, but there is no evidence of that..


Huh? Doesn't the hive/ant-hill help them survive? :confused: "Survive," even for the species, doesn't necessarily mean "breed.

Also true.. thats a bad argument agaisnt evoultion


"Yes, but the ones that do have mutations (for the good) are more likely to survive and pass it on, moreso than the "bad" genes. Albeit it's not going to do much in a short amount of time, but in a few billion years things will probably have started to get going. ;)

No this is the good argument.. :) Yes we have had some billion years but see on the facts.. it started out as a ONE CELLED organism into something so complex that it hardly can evolve... The point isnt that they survive with the new mutated genes.. the point is that the chance of giving it to the next generation diminishes since the genes are beeing filtered away.. even the good ones.. And when have we in our history seen a evoultion as u said? a direct thingy from one species to another?? and if it was to get this mutation the chance of carrying iot one would diminish more since two of them would have to get it at the same time... and not just two but a male and a female.. and then again it would have to be a usefull mutation.. its not like xmen that they get good mutations u know.. the chanse of getting finns or swimming feet or whatever is so small that the chanse of evoulting would be infintivly small, even in a hundred of billions of years.. face it..
 
@gael – well we all are descended from people with colored skin. So the question is why some humans no longer share that trait. Darker skin may protect people from skin cancer, I have not read data to support that. I do know that light skinned people who are prone to sunburn are also prone to skin cancer. There is good data to suggest that sunburn (especially early in life) is closely linked to skin cancer. That fact alone wouldn’t be a force to push evolution unless people died of skin cancer before they could reproduce. Thus for it to have had such a large effect in such a short time (geologically speaking) would surprize me, I haven’t worked out the details however. The hypothesis is that genes associated with ‘bleached skin’ (lack of melatonin) helped to protect against rickets – which is apparently associated with a cereal diet. This is much like the link between sickle cell anemia and malaria, or the plague and certain blood types. Disease can be a powerful force for evolution, especially fatal diseases that affect children. Cavalli-Sforza is a brilliant man and I am sure he has worked this out on paper. Either way there is no reason to suspect that ‘bleached skin’ is associated with lessened aerobic ability.

Edit: did a quick search and rickets is caused by vitamin D deficiency (diet related) and is a bone disease in children (haven't had time to reproduce). I'm pretty sure vitamin D is synthesised in the skin when exposed to sunlight, so it seems melatonin supresses that to some extent. It's actually a nice theory, very multidisciplinary.
 
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