evolution - this is it?

February 3, 2002

http://www.observer.co.uk/international/story/0,6903,644002,00.html

Is human evolution finally over?

Scientists are split over the theory that natural selection has come to

a standstill in the West. Robin McKie reports

Sunday February 3, 2002

The Observer

For those who dream of a better life, science has bad news: this is the

best it is going to get. Our species has reached its biological pinnacle

and is no longer capable of changing.

That is the stark, controversial view of a group of biologists who

believe a Western lifestyle now protects humanity from the forces that

used to shape Homo sapiens.

'If you want to know what Utopia is like, just look around - this is

it,' said Professor Steve Jones, of University College London, who is to

present his argument at a Royal Society Edinburgh debate, 'Is Evolution

Over?', next week. 'Things have simply stopped getting better, or worse,

for our species.'

This view is controversial, however. Other scientists argue that mankind

is still being influenced by the evolutionary forces that created the

myriad species which have inhabited Earth over the past three billion

years.

'If you had looked at Stone Age people in Europe a mere 50,000 years

ago, you would assume the trend was for people to get bigger and

stronger all the time,' said Prof Chris Stringer, of the Natural History

Museum, London. 'Then, quite abruptly, these people were replaced by

light, tall, highly intelligent people who arrived from Africa and took

over the world. You simply cannot predict evolutionary events like this.

Who knows where we are headed?'

Some scientists believe humans are becoming less brainy and more

neurotic; others see signs of growing intelligence and decreasing

robustness, while some, like Jones, see evidence of us having reached a

standstill. All base their arguments on the same tenets of natural

selection.

According to Darwin's theory, individual animals best suited to their

environments live longer and have more children, and so spread their

genes through populations. This produces evolutionary changes. For

example, hoofed animals with longer necks could reach the juiciest

leaves on tall trees and therefore tended to eat well, live longer, and

have more offspring. Eventually, they evolved into giraffes. Those with

shorter necks died out.

Similar processes led to the evolution of mankind, but this has now

stopped because virtually everybody's genes are making it to the next

generation, not only those who are best adapted to their environments.

'Until recently, there were massive differences between individuals'

lifespans and fecundity,' said Jones. 'In London, the death rate

outstripped the birth rate for most of the city's history. If you look

at graveyards from ancient to Victorian times, you can see that a half

of all children died before adolescence, probably because they lacked

genetic protection against disease. Now, children's chances of reaching

the age of 25 have reached 98 per cent. Nothing is changing. We have

reached stagnation.'

In addition, human populations are now being constantly mixed, again

producing a blending that blocks evolutionary change. This increased

mixing can be gauged by calculating the number of miles between a

person's birthplace and his or her partner's, then between their

parents' birthplaces, and finally, between their grandparents'.

In virtually every case, you will find that the number of miles drops

dramatically the more that you head back into the past. Now people are

going to universities and colleges where they meet and marry people from

other continents. A generation ago, men and women rarely mated with

anyone from a different town or city. Hence, the blending of our genes

which will soon produce a uniformly brown-skinned population. Apart from

that, there will be little change in the species.

However, such arguments affect only the Western world - where food,

hygiene and medical advances are keeping virtually every member of

society alive and able to pass on their genes. In the developing world,

no such protection exists.

'Just consider Aids, and then look at chimpanzees,' says Jones. 'You

find they all carry a version of HIV but are unaffected by it.

'But a few thousand years ago, when the first chimps became infected,

things would have been very different. Millions of chimps probably died

as the virus spread through them, and only a small number, which

possessed genes that conferred immunity, survived to become the

ancestors of all chimps today.

'Something very similar could soon happen to humans. In a thousand

years, Africa will be populated only by the descendants of those few

individuals who are currently immune to the Aids virus. They will carry

the virus but will be unaffected by it. So yes, there will be change

there all right - but only where the forces of evolution are not being

suppressed.'

However, other scientists believe evolutionary pressures are still

taking their toll on humanity, despite the protection afforded by

Western life. For example, the biologist Christopher Wills, of the

University of California, San Diego, argues that ideas are now driving

our evolution. 'There is a premium on sharpness of mind and the ability

to accumulate money. Such people tend to have more children and have a

better chance of survival,' he says. In other words, intellect - the

defining characteristic of our species - is still driving our evolution.

This view is countered by Peter Ward, of the University of Washington in

Seattle. In his book, Future Evolution, recently published in the US by

Henry Holt, Ward also argues that modern Western life protects people

from the effects of evolution. 'I don't think we are going to see any

changes - apart from ones we deliberately introduce ourselves, when we

start to bio-engineer people, by introducing genes into their bodies, so

they live longer or are stronger and healthier.'

If people start to live to 150, and are capable of producing children

for more than 100 of those years, the effects could be dramatic, he

says. 'People will start to produce dozens of children in their

lifetimes, and that will certainly start to skew our evolution. These

people will also have more chance to accumulate wealth as well. So we

will have created a new race of fecund, productive individuals and that

could have dramatic consequences.

'However, that will only come about when we directly intervene in our

own evolution, using cloning and gene therapy. Without that, nothing

will happen.'

Stringer disagrees, however. 'Evolution goes on all the time. You don't

have to intervene. It is just that it is highly unpredictable. For

example, brain size has decreased over the past 10,000 years. A similar

reduction has also affected our physiques. We are punier and

smaller-brained compared with our ancestors only a few millennia ago. So

even though we might be influenced by evolution, that does not

automatically mean an improvement in our lot.'

robin.mckie

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February 3, 2002

Dear Desert Rat,

You can not use what has been happening in the New World for

what has been the tick of a geological second as an example of where

evolution is headed. We have been expanding into a virtual vacuum.

However when the population of the USA reaches a billion, which will

probably happen maybe by 2100, there will be a definate tendancy

toward decreased stature, more compliant social skills (which means

my line will die down), strong instincts to have babies (now that it

has become voluntary which also means that I am on the ash heap of

evolution), but most importantly for the theme of this discussion

group, a tendancy toward more efficient digesting and coping with

junk food (and maybe an instinct not to eat it).

So maybe you had better teach your grandchildren how to grow

celery in the back yard. Then they will have a little less of a

chance of being clipped 100 years from now. By the time their

grandchildren live with two billion in 2150 the coal and oil will

have run out so even celery may not help them. But every century they

can keep going is something and at least they will have hybrid vigor

and lots of genes to select from.

Sincerely, Charles Weber

February 4, 2002

Dear Charles Webber :

Well said but don't give me credit for the article. Like the razzed

comedian said " I don't write the jokes folks, I just tell them " .

At any rate my own feelings are that the people who actually own and

control what happens in the world will see to it that the population

does not reach the proportions of which you speak.

Poisoning young men and women during Desert Storm and flouridating water

supplies, vaccinations at birth (Elaine's previous post) could be just

warm-ups for their declared objectives to reduce the population of the

world.

No joke,

Ron

Charles Webber wrote :