Has human evolution reached a standstill?
The changing story of life on earth is four billion years old. But some say we've come to a halt. Is technology changing the evolutionary rules?
'If you want to know what Utopia is like, just look around - this is it,' says Professor of Genetics, Steve Jones. So has the human species really reached its biological pinnacle? Is this as good as we get?
It was Charles Darwin who introduced the idea of evolution in his groundbreaking book 'The Origin of Species' in 1859. He claimed a common ancestry for all life, which then gradually evolved from simple into complex organisms.
His ideas had originally taken shape on a five-year voyage around the world on HMS Beagle in 1831, during which he saw evidence of animals adapting to their surroundings over time.
He found, for instance, that birds on one island had longer beaks than similar birds on a neighbouring island, because they had to fish for food through holes not present on the other island. Birds with short beaks would simply not survive there. While short-beaked birds struggled to survive, long-beaked birds were able to successfully reproduce, passing the crucial genetic trait to their offspring. He called this process 'natural selection,' and theorized that it applied to all living species.
But has the human species now stopped evolving? Professor Jones believes so. 'In Shakespeare's time, only about one English baby in three lived to the age of 21. All those deaths were raw material for natural selection; many of those kids died because of the genes they carried.
But now, about 99% of all babies make it to that age.'
The point is that these days everyone survives to reproduce, regardless of their genetic traits. Our technological advances so protect us from disease, hunger and cold that the principle of natural selection no longer applies.
It's possible that, without natural selection, humans may in fact slowly start getting weaker, as disadvantageous traits get passed on from parents to children.
The struggle for every species is to achieve the best mix of traits in the gene pool for their surroundings. Some say humans have achieved this now, and therefore evolution has ceased.
But Professor Chris Stringer, an anthropologist at the Natural History Museum, says we should assume nothing '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. 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?'
- 'Humans are still evolving emotionally, mentally, socially and spiritually.' Do you agree?
- Do humans need danger to evolve?
- Choose an environment on Earth and then design your own animal - what adaptations would it need to survive?
- As the world changes, natural selection might start applying to humans once again. How would we need to evolve in case of (for example) severe global warming, or intense air pollution? Draw a picture of how humans might look a million years from now.
Some People Say...
“Humans are the pinnacle of perfection.”
What do you think?
Q & A
- You mean evolution was still going on in Shakespeare's day?
- Yes. Evolution happens wherever some inheritable traits give a survival advantage over others. That only stopped being the case for humans very recently.
- Yet ancient pictures of humans look just like us!
- Evolution is slow and hard to discern for those living in the middle of it. It's taken over 4 billion years to get to now.
- So what drives evolution forward?
- Same as it's always been really. It's the generational cycle in which individuals select mates, mix their DNA and produce offspring. It's the 'natural selection' of who gets to mate that drives evolution.A Then you opt out of the evolutionary cycle and that's fine. Human evolution may increasingly be about choice rather than necessity.