Evolution is complete: so where do we go from here?
Evolution could already be at an end, leaving the human race more uniform than ever, argues Steve Jones
http://www.telegraph.co.uk/earth/main.jhtml?xml=/earth/2008/10/07/scievolution107.xml
Things ain't what they used to be - but when were they? Not in 18th-century Japan, when the poet Ejima Kiseki wrote: "The shrewd observer of the modern scene will note that sons are altogether inferior to their fathers, and that the grandson rarely offers hope for improvement."
Plato felt much the same and Simon Heffer, the Plato de nos jours, agrees. Markets, crime, education; every day, in every way, things seem to get worse and worse. If the philosophers have it right, the human race is in decline - social, moral and, in the end, biological. Now science can test at least the last of those claims.
Because we understand how evolution happens, we can also guess where it will go next. It is, in Darwin's words, "descent with modification" - genetics plus time.
The process turns on differences: in genes themselve, and on natural selection - on inherited variation in the ability to copy them. Isolation helps changes to build up and, in time bears, Bushmen and Britons evolve from a common ancestor. Human diversity is so great that every sperm and egg ever made is unique.
It comes from inherited errors, or mutations. Will radiation, chemicals and the rest increase the rate and harm the future, as so many fear? In fact, the opposite is true.
The biggest source of mutation is not nuclear reactors, but the men who build them. Men never rest; we make sperm all the time (even while reading the Telegraph). Women, in contrast make their eggs only once, before birth, and release them at intervals. There are only 24 cell divisions between the egg that made a woman and the eggs she passes on; but that figure is far higher for sperm.
For a 28-year-old father it is around 300, but for a sixty year old it is several thousand. As a result, the rate of mutation goes up many times for old fathers compared to young ones. To forecast its future we need to know only how many elderly fathers there will be.
That figure is, in the West, in decline. Today's men start late, but stop early. In Cameroon, almost half the fathers are over 50, in Pakistan about a fifth, and in France only about one in twenty. Young dads mean that the rate of mutation is going down rather than up, and less, not more, of evolution's raw material is being made.
And what about natural selection? That, too, is on the way out. I depress my students with the statement that two out of three of them will die for reasons connected to the genes they carry. Then I cheer them up by pointing out that in Shakespeare's time, two out of three of them would be dead already.
Even in Darwin's day, about half of all British newborns died before they reached 21. In contrast, an English baby born today has a 99 per cent chance of surviving past then.
The Grim Reaper is taking a rest, and inherited differences in the ability to withstand cold, starvation or disease no longer power Darwin's machine. Those who die from such killers do so when they are so old that natural selection has lost interest.
The evolution exam has two papers. Most people pass the first, for they stay alive until they grow up. The second is harder, for candidates must reproduce. The more children they have, the higher their marks. Men can score higher than women, for females are limited in their success by the mechanics of pregnancy, while males are free to spread their sperm to a multitude, if they can find them.
Some societies still turn on that simple biological fact. Mohamed bin Laden, father of Osama of that ilk, had 22 wives and 53 children, while his famous son had, last time they were counted, five wives and 22 children. Plenty of his henchmen now have no chance of finding a mate and will die without issue.
The Irish were much the same. A fifth of the men of Donegal share the same Y chromosome - the mark of male descent - and trace ancestry from the same man. In Old Erin's glorious days, marital bliss was an exception.
Turlough O'Donnell, who died in 1423, had 18 sons. He descended from the High Kings of Ireland, who themselves sprang from a fifth-century bin Laden, a warlord called Niall of the Nine Hostages.
Niall's chromosome proves how, for centuries, just the mightiest passed on their genes. The weak and the powerful are now closer than they were. The important figure is how much inequality there is in the number of offspring.
Five centuries ago in Florence, the upper crust had twice as many children as did the peasantry, but now the Florentine poor have slightly more than the rich and in Britain it is the same story.
Differences in death rates and sexual success can be combined into a single figure. Across the world, it is in decline. India's cultures range from tribal hill-peoples to affluent urbanites, together with millions of peasants, who live as mediaeval Europeans once did. Natural selection has lost nine-tenths of its power among the Indian middle classes, compared to their tribal ancestors. The same is true when we compare modern Britain with our predecessors in Darwin's day.
As Darwin himself realised, evolution's third ingredient is isolation. Humans are 10,000 times more common than any other mammal of their size, and without modern technology the world's population would be half a million - about that of Glasgow.
People are dense, and on the move. No man (or woman) is an island nowadays, for the world is becoming a single genetic continent. History has always been made in bed, but the beds are getting closer together.
Once, we stayed close to where we were born and populations could build their own identity. Now, we no longer have to marry the girl or boy next door but can hop onto a plane and find a mate from miles away.
How far was your birthplace from that of your partner and how far apart were your mother and father, and your grandmother and grandfather on each side, born? In almost every case the distance has increased and continues to do so (my wife and I first saw the light 3,000 miles apart, my mother and father ten; and, as my students say, it shows).
Everywhere, the biological frontiers are getting leakier. A grand averaging is slowing evolution's power. One British marriage in fifty is between partners from different ethnic groups and many more cohabit.
Afro-Caribbean males are half as likely again to marry a white female than are black women to find a white husband, while among Chinese those preferences are reversed. Britain is among the most sexually open nations in the world.
People choose mates almost as much by level of education as by skin colour. Other countries are going the same way and Homo sapiens will soon be a lot more uniform than it was.
Health, birth control and the healing power of lust all conspire to tell us that, at least in the developed world, and at least for the time being, evolution is over. So, if you are worried about what Utopia is going to be like, cheer up - you are living in it now.
Leading geneticist Steve Jones says human evolution is over
Julia Belluz
http://www.timesonline.co.uk/tol/news/uk/science/article4894696.eceHuman evolution is grinding to a halt because of a shortage of older fathers in the West, according to a leading genetics expert.
Fathers over the age of 35 are more likely to pass on mutations, according to Professor Steve Jones, of University College London.
Speaking today at a UCL lecture entitled “Human evolution is over” Professor Jones will argue that there were three components to evolution – natural selection, mutation and random change. “Quite unexpectedly, we have dropped the human mutation rate because of a change in reproductive patterns,” Professor Jones told The Times.
“Human social change often changes our genetic future,” he said, citing marriage patterns and contraception as examples. Although chemicals and radioactive pollution could alter genetics, one of the most important mutation triggers is advanced age in men.
This is because cell divisions in males increase with age. “Every time there is a cell division, there is a chance of a mistake, a mutation, an error,” he said. “For a 29-year old father [the mean age of reproduction in the West] there are around 300 divisions between the sperm that made him and the one he passes on – each one with an opportunity to make mistakes.
“For a 50-year-old father, the figure is well over a thousand. A drop in the number of older fathers will thus have a major effect on the rate of mutation.”
Professor Jones added: “In the old days, you would find one powerful man having hundreds of children.” He cites the fecund Moulay Ismail of Morocco, who died in the 18th century, and is reputed to have fathered 888 children. To achieve this feat, Ismail is thought to have copulated with an average of about 1.2 women a day over 60 years.
Another factor is the weakening of natural selection. “In ancient times half our children would have died by the age of 20. Now, in the Western world, 98 per cent of them are surviving to 21.”
Decreasing randomness is another contributing factor. “Humans are 10,000 times more common than we should be, according to the rules of the animal kingdom, and we have agriculture to thank for that. Without farming, the world population would probably have reached half a million by now – about the size of the population of Glasgow.
“Small populations which are isolated can evolve at random as genes are accidentally lost. World-wide, all populations are becoming connected and the opportunity for random change is dwindling. History is made in bed, but nowadays the beds are getting closer together. We are mixing into a global mass, and the future is brown.”
Why the Halt of Evolution is a Good Thing
Tim Dowling
http://www.guardian.co.uk/science/2008/oct/08/evolutionAccording to the geneticist Professor Steve Jones, we have stopped evolving. A decrease in the level of mutation and the reduced influence of natural selection means that as far as humans are concerned the future looks like more of the same - no wings, no scissorhands, no third hypno-eye. This has generally been treated as disappointing news, but there are many upsides to the halt of evolution. Well, there are four.
1. We're not going backwards. If we're standing still then at least we're not backsliding down the evolutionary ladder, despite whatever anecdotal evidence to the contrary you may have gathered. This is good news. If de-evolution were suddenly to start accelerating rapidly we could all end up as hairy little hominids standing around on all fours in the lobbies of buildings waiting for someone tall enough to come along and push the lift button.
2. This will give chimps a chance to catch up. Without wishing to imply that chimps are somehow insufficiently "evolved", they'll be a lot more use when they can finally read a shopping list. Eventually, an entire servant class of primates could be forced to do our bidding, just like in Escape From the Planet of the Apes. And we all know how well that worked out.
3. If we ever visit the future, we'll fit right in. Should time travel become plausible, we know that the first volunteers will be able to walk among the humans of tomorrow without someone grabbing them out of a crowd and shouting, "Hey pointy! Where's your other face?"
4. We can quit while we're ahead. When dolphins get together to mull over their existence on earth so far, how long do you think it is before one of them squeaks the dolphin equivalent of "If I could do it all over again, I'm not so sure I would return to the water this time"? Even if they don't say so out loud, they must be dimly aware that they made, in evolutionary terms, a fairly dramatic wrong turn. We've been comparatively lucky so far, and now we know we'll get to stay just exactly as we are until we've finished reducing this planet to a smouldering cinder.
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