Science finds human evolution is speeding up
Will humans ever stop evolving? For years, academics believed Homo sapiens had reached their final form. But now stunning new research suggests the human body is changing faster than ever.
At a hospital in the year 3000, a mother waits nervously as the doctor examines her newborn child.
Staring at the baby’s squashed face and knobbly feet, the doctor glances over to his chart. So far, so good. Just beneath the surface of the skin, huge arteries pump blood to curiously large hands.
Then, examination complete, the doctor darts across the room on his hoverboard and hands the child to her excited mother. “She’s perfect”, he declares.
Nobody knows exactly what future humans will look like. Indeed, predictions range from the mundane – slightly bluer eyes or darker skin – to the completely bizarre.
Humans could one day grow beaks, making trips to the dentist a thing of the past, predicted biologist Dr Gareth Fraser in 2013. In the same year, neuroscientist Dean Burnett argued that rigid human fingers could slowly evolve into tentacles as touch screens take over the world.
Today, these predictions sound more like science fiction than reality. But while tentacles and beaks may be a long way off, a new study by Australian scientists suggests that more subtle changes in human anatomy may be emerging faster than ever.
The group’s research shows that many babies born today look different to those born only 150 years ago. They have shorter faces, new bones in their feet and legs and an extra artery in their arms.
And their wisdom teeth, once used by ancient humans to chew foliage, are missing.
The scientists call these changes microevolution. “A lot of people thought humans have stopped evolving. But our study shows we are still evolving – faster than at any point in the past 250 years”, says Dr Teghan Lucas, one of the scientists involved in the study.
Dr Lucas and her colleagues believe the changes are occurring because modern humans live in a favourable environment. “We have advanced as a species to the point where natural selection no longer removes the outliers in the gene pool.”
When Charles Darwin proposed the theory of evolution in 1859, only half of British children survived to celebrate their 21st birthday. Today, that figure stands at an astonishing 99%.
Indeed, due to early death or infertility, many ancient humans were not able to reproduce. Now, modern medicine means more people have the chance to pass on their genes.
The result is a series of unexpected changes in the human body – from extra arteries to smaller jaws.
For a long time, scientists thought that evolution was slowing and humans had nearly reached their final form. Then, in 2007, shock research quashed that conventional wisdom.
Humans and chimpanzees separated 6 million years ago. But when American academics analysed DNA samples from the two species, they found fewer differences than they were expecting, indicating that human evolution was slower in the distant past.
In fact, the scientists concluded that over the past 10,000 years, humans have evolved up to 100 times faster than ever before.
Now, a decade later, Dr Lucas believes that the process is accelerating once again.
So, will humans ever stop evolving?
Definitely, say some. Most evolutionary changes happen in small or isolated populations where significant mutations can become established in the gene pool, points out anthropologist Ian Tattersall. Today, mass movement of the human population makes meaningful evolution unlikely. And there is yet another, more terrifying force which may stop human evolution in its tracks – mass extinction.
The opposite is true, say others. The results of the scientific research are clear. Human evolution has sped up, not stopped. In the 1880s, only 10% of babies born retained the extra artery in their arm throughout their life. Today, the figure is 30% and scientists predict that by 2100, a majority will have the blood vessel. As long as humans remain wandering the Earth, evolution will continue.
- Is the human body perfect in its current form?
- How would the world be different if other human species, such as Neanderthals, had not become extinct?
- Draw a picture of what you think humans will look like in the year 3000.
- Write a short story about a present day human who travels thousands of years into the future to meet their descendants.
Some People Say...
“Evolution tells us where we came from, not where we can go.”Jerry Coyne, American biologist and author
What do you think?
Q & A
- What do we know?
- Today, it is generally agreed that modern humans evolved from apelike ancestors in Africa, and that every person alive today can trace their genetic ancestry to that continent. The theory of evolution itself was first proposed in the 19th century by Charles Darwin, who suggested that species gradually change over time due to the process of natural selection. The idea contradicted the commonly held Christian belief at the time that God created all of the animals and plants that live on Earth.
- What do we not know?
- One main area of debate surrounds how humans might evolve in the future. Some academics believe technological innovations might make the most difference to human life. Professor Braden Allenby, an environmental engineer, argues that artificial intelligence and gene editing technology means that the human body is already a design space. Others, like geneticist Gerald Crabtree of Stanford University, worry that humans may already have reached an intellectual peak more than 2,000 years ago.
- Extra artery
- The blood vessel in the forearm, which supplies blood to the hand in the womb, previously disappeared after birth but is now increasingly prevalent in adults. It is not harmful – and can actually help by boosting blood supply.
- Natural selection
- The process whereby organisms better adapted to their environment survive, produce more offsprings and pass on their genes.
- Charles Darwin
- An English naturalist who came up with the theory of evolution by natural selection after observing how animals had adapted to survive in the remote Galapágos Islands.
- Rejected or declared invalid. The word is derived from the Latin word “cassus” meaning null or void.
- Deoxyribonucleic acid is the molecule that carries the genetic code of all organisms. If evolution had been proceeding at its current rate since the species split, there should be 160 times more differences between humans and chimpanzees.
- Ian Tattersall
- Tattersall is a curator at the American Museum of Natural History in New York. As well as on human evolution, he has also worked with lemurs.