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Is Human Evolution Finally Over?

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November 27 2002, 3:14 AM 

Author: Robin McKie
Filed: 9/28/2002, 9:09:04 PM
Source: The Observer

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.'



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Gene pioneer urges dream of human perfection

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November 27 2002, 3:16 AM 

Filed: 10/29/2002, 12:18:39 PM
Source: Globe and Mail
Saturday, October 26

James D. Watson, the grand duke of DNA, described one of his greatest fears yesterday to a packed auditorium: that society will be too scared to use genetics to make people as perfect as they can be.

Dr. Watson is one of the founding fathers of modern genetics. He was in Toronto for the respected Gairdner Foundation awards, which this year honoured the scientists who unravelled the human genome. He said the information will allow society to eradicate and prevent not only diseases but any other traits that might be deemed undesirable.

"Going for perfection was something I always thought you should do," said the 74-year-old Dr. Watson, peppering his radical perspectives with trademark humour. "You always want the perfect girl."

Would it be wonderful to turn the shy into extroverts? Calm down the hotheaded? Turn cold fish into warm human beings? As Dr. Watson sees it, the genetic revolution puts all these issues on the table.

"We'll be able to make correlations between genes and certain professions, genes for the undertaker — they really don't cry very much," he said, "or the sprinter.

"It will be an absolute flood that will start to explain everything ... even the cold fish."

Dr. Watson was younger than many of the students who came to hear him when, in 1953, he and Francis Crick discovered the molecular shape of deoxyribonucleic acid, known for short as DNA, at the famed Cavendish Laboratory at Cambridge University.

The double helix soon defined modern medicine, opened the field of molecular biology and transformed criminal justice with DNA fingerprinting that has convicted the guilty and exonerated the innocent, and that remains one of Dr. Watson's greatest prides.

But those are the field's obvious merits. The gangly, white-haired Dr. Watson, Nobel laureate, past Gairdner winner, author of seven books and recipient of 32 honorary degrees, was not at the University of Toronto's MacLeod Auditorium to rehash highlights or to reminisce.

He had come to talk about the future and the thorny issues facing society now that it has the human-genome map, which contains the precious instructions to build and operate us all: the fruit fly, the family pet, and even, Aunt Mary.

Dr. Watson took aim at scientists for not openly discussing where genetic progress may carry us.

"It's my impression that none of the genome-project leaders have gotten up and said, 'What we are going to do with this information; I think we should use it,'" he said. "Maybe they're afraid of offending people."

Never veering from controversy, Dr. Watson believes that women and their right to make reproductive choices could create the ideal future, where prenatal genetic screening keeps the sick or handicapped from ever being born and disease from being a serial killer.

In an interview earlier in the week, Dr. Watson mused that hang-gliding accidents might one day be the leading cause of death.

He is also a proponent of so-called human-germline engineering, in which doctors could add or delete elements from egg and sperm cells that will be passed down to future generations.

Perhaps adding genes that will turn slow learners into whiz kids, he said, or those to prevent smokers from ever developing lung cancer, or genes making people HIV-resistant, might be part of the future.

"But laws all over prevent DNA additives to the germlines," Dr. Watson lamented. "I'm sort of distressed when people say enhancement is bad -- the question, they wonder, is 'Who will we enhance?'"

Some of Dr. Watson's comments are unlikely to calm anyone with those thoughts, particularly when it comes to people's appearance. The Chicago-born scientist — a well-known admirer of attractive women (he titled one of his books Genes, Girls and Gamow) who keeps a 2002 calendar of tennis bombshell Anna Kournikova in his New York office — said nature can be cruel: "Who wants an ugly baby?"

Yet he admits people accuse him of wanting to use genetics "to produce pretty babies or perfect people.

"What's wrong with that?" he countered. "It's as if there's something wrong with enhancements."

Dr. Watson stressed his vision is not a bleak one. He too was haunted by the world portrayed in the 1997 film Gattaca, where genetically perfect members of an elite, conceived in labs, reign over the genetically "invalid," created naturally and condemned to society's lowest jobs.

The movie theme echoes concern that genetic enhancements will be available only to the wealthy, widening the gap between haves and have-nots. But Dr. Watson has more faith in the species: "Most humans are programmed by their genes to have compassion for their fellow man."

Dr. Watson's speech thrilled students in the audience: "It was the best lecture of the series," Seema Nagaraj, a biomedical-engineering student, said. "I appreciated his candour, that he was not afraid to state his views."


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porijeklo stanovnistva

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July 19 2012, 2:24 PM 

hvala dragana za izvrstan post podkrijepljen znanstvenim dokazima. moje je shvacanje postanka covjeka i njime rasa utemeljeno na
poznavanju pradavnih pocetaka koje je slavni kineski mudrac Lao Tse zapisao. po njegovoj teoriji je pocetak svega nista, sto znaci iz
tajne niceg je nastao cudez svega i to je objasnjeno u obliku kruga koji simbolizira puno i prazno. kinezi su krug razumijeli kao maternicu
ili neoplodjeno jajasce. tako je i radjanje jina i janga zapravo oplodjivanje maternice. znamo da covjek nastaje iz sjemena dakle usudio bih
se pritom razvoj covjeka usporediti za razvojem biljaka koje takodjer nastaju iz sjemena. kad sjeme biljke posadimo u zemlju najprije se pojave
dva mala listica, za njim opet nova dva dakle uvijek u paru. ona prva dva listica su roditelji drugih dvoje i tako redom dalje. zasto ne prihvatiti tezu
da se i covjek tako razvijao i tako su npr. najprije bili mama neandertal i papa neandertal. sad covjek ipak nije biljka pa treci i cetvrti listic nisu bas
odmah izrasli i za to je proteklo nekoliko godina mozda tisucljeca dok su se pojavili homo erectus i homo sapiens kojeg skoro vec mozemo smatrati
modernim covjekom sto je u prvo vrijeme znacilo da je on postao svjestan sebe i nije se vise bojao opake prirode. to je bio vjerojatno triumf koji je za
posljedice imao da se je covjek jednostavno 'rasuo' po tadasnjem svijetu i izolirano se razvijao. da se u jednom odredjenom trenutku taj zajednicki kromanjonski
substrakt kako ga izvrsno naziva dragana izdvojio na mediteranski i dinarski tip a ovaj dalje na nordijski raseljavanjem na sjever samo potvrdjuje tezu
da se 'svjestan' covjek muvao okolo, razmnozavao se i stvarao vlastita carstva. u jednom zanimljivom dokumentarcu objasnjeno je kroz prinzip 'uskog grla'
stvaranje i opstanak nekih rasa i propadanje drugih. usko grlo se moze shvatiti kroz potvrdjene i predpostavljene zemaljske katastrofe kojih nije bilo malo
i ciju je sudbinu prolazio i covjek kao njen stanovnik. nakon tih katastrofa mijenjao se i izgled zemlje i svih njenih stanovnika, biljaka, zivotinja i svijeta.
pojednostavljeno mozemo reci, da su se pojedini substrati probili a mnogi nisu, mozda jer su bili zaostali i preglupi za 'novi svijet'

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