Archaeologica.org

http://news.sky.com/skynews/Home/UK-New ... esearchers

This without doubt is one of my weakest subjects, but there seems to be a number of holes in that proposition.
How do we know that the number of mutations is falling?
What base line is used for measurement?
Many years ago men wouldn't lived to 35 anyway.
Can somebody help on this?

Roy.

Interesting idea. I don't necessarily agree, however. (Nor am I in any position to). I am not sure that mutations have slowed down, I have not heard any evidence of this but I can understand that mutations don't get "fixed" in our populations as they did when we were isolated communities. What this ignores is the ability to scientifically select what we may consider beneficial modifications in the future. It will no longer be natural selection but it will evolve us, nonetheless.
The writer seems to carelessly toss away the possibility of future increases in mutations due to worsening environmental conditions, too. Just because you aren't seeing it yet doesn't mean it isn't there.

I find it hard to make assumptions based on what is currently happening as though no new variables will ever enter the mix. Hominids have probably had plenty of periods of stabilization over the eons. Then things changed. I see that as a more likely scenario than "we are done".

That exactly sums up my view Patty, whether it is right or wrong will doubtless be revealed.

Roy..

My initial reaction was to recall the proposal to shut the US Patent Office in 1847 because "everything that could possibly be invented had already been invented."

Still, on reflection, if you want to consider Darwinian Evolution, it requires that a population be isolated and forced to adapt to local conditions. There are virtually no parts of the earth left isolated... for better or worse as Ish has noted elsewhere.

Add-in advances in medical science which prevent natural selection from working its harsh regimen and there could be something to this idea.

Minimalist wrote:
Still, on reflection, if you want to consider Darwinian Evolution, it requires that a population be isolated and forced to adapt to local conditions. There are virtually no parts of the earth left isolated... for better or worse as Ish has noted elsewhere.

I may have to revise that statement, Min. I was doing some research on Brazil yesterday, and found this:

http://en.wikipedia.org/wiki/Brazil

A not-updated linguistic survey found 188 living indigenous languages with 155,000 total speakers. In 2007, Fundação Nacional do Índio (English: National Indian Foundation) reported the presence of 67 different tribes yet living without contact with civilization, an increase up from 40 in 2005. With these figures, now Brazil has the largest number of uncontacted peoples in the World, even more than the island of New Guinea...

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Steve Jones was interviewed on the radio this morning. It fleshes things out somewhat and is worth a listen.

http://news.bbc.co.uk/today/hi/today/ne ... 656220.stm

As I understand it he is arguing that with respect to

(i) mutation - there is less of this than before because it is related to the age of men when they have children - there are fewer old fathers nowadays - variation comes from men because they produce sperm throughout their lives whereas women do not

(ii) natural selection - is less of a factor because (a) variation in the gene pool no longer leads to early deaths i.e. selection is no longer permitted to operate in this way (b) people are having fewer children therefore there is less variation out there and so less material for natural selection to work on

(iii) environmental changes - these are almost negligible because we have created our own environment but these cannot be ruled out especially those factors producing global epidemics.

I get the impression he is making a case based on inferences from known facts e.g. mutation is positively related to aging and older men no longer have children (or so many as before). And of course he is generalising. His arguments seem good to me although I take your point about men previously dying out before reaching old age.

You know what, Ish? I recall something about that.

"Uncontacted tribes" being photographed from planes or helicopters from a distance.

Except..... don't you just wonder what those "uncontacted tribes" think of the sudden appearance of planes or helicopters? I mean...no one is suggesting that they are blind. They must have seen them.

I take your point about men previously dying out before reaching old age.

Then there is the V_iagra/C_ialis factor which has been introduced!

Minimalist wrote:You know what, Ish? I recall something about that.

"Uncontacted tribes" being photographed from planes or helicopters from a distance.

Except..... don't you just wonder what those "uncontacted tribes" think of the sudden appearance of planes or helicopters? I mean...no one is suggesting that they are blind. They must have seen them.

Good point. If they have been counted, they have been discovered - just at a distance, I guess.

I mean how do they know that they're uncontacted unless they've contacted them in some way?


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Yeah, uncontacted does not mean "undiscovered." Except if I recall correctly the point of the article was that mining or foresting operations were beginning to encroach on their lands which mean that "contact" is going to come.

Would be good if we could warn those people to shoot the miners and loggers full of arrows....and to keep their distance when they do so.

Wasn't that helicopter discovery photograph a hoax?

variation comes from men because they produce sperm throughout their lives whereas women do not

Did I say that? Er...like women produce one batch for eggs for life whereas men make sperm forever...er, that's OK...maybe...I'm going to bed, good night.