How the axe gave humans their hands: Discovery finds tool was key to our evolution
- Newly discovered bone helps to explain the evolution of human hands
- The 1.4 million-year-old bone - a third metacarpal - shows how hands changed between 1.7 million years ago and 800,000 years ago
- It runs across the palm joining the wrist and middle finger and keeps the wrist steady while a small object is held between the thumb and fingers
- People with this bone had an evolutionary advantage as they could use stone hand axes more effectively
A newly discovered fossil is helping to explain how human hands evolved into their current form.
Until recently, how our ancestors hand’s developed to be able to make full use of tools was a mystery.
However, the discovery of a new hand bone is helping to fill in the missing pieces in the evolutionary jigsaw.
The grass growing in flood plains would have attracted large herbivores such as horses, deer, rhino and beavers, which Stone Age man ate for protein and fat
WHAT DOES THE DISCOVERY TELL US?
The discovery of a 1.4 million-year-old third metacarpal bone fills a gap in the understanding of the evolution of the human hand.
It suggests that early man developed the bone as it enabled him to use tools and weapons more effectively meaning that he had an evolutionary advantage.
Before the hand evolved to include this bone, our ancestors had weak wrists that would not be strong enough to use a hand axe.
About 1.7 million years ago early humans created hand axes – some of the first stone tools – but how their hand’s developed to be able to use them effectively has remained a mystery until recently.
Prior to the development of stone axes, our ancestors had weak wrists which would not be able to grip small objects as powerfully as is necessary to use a hand axe.
However, New Scientist reports that a new hand bone has been discovered that helps to explain how human hands developed between 1.7 million years ago and 800,000 years ago.
In 2010, a team from the National Museums of Kenya discovered a new hand bone in Kenya.
Scientists at the University of Missouri identified the bone as a third metacarpal – the bone which runs across the palm linking the middle finger with the wrist.
The bone, which is thought to be about 1.4 million-years-old, keeps the wrist stable while a person is holding a small object between their thumb and fingers.
The scientists also said raw materials for making tools and fires were readily available in flood plains. Flint used for making hand axes (pictured) and scrapers could be found among river gravel
Hand bones of early Homo erectus are almost unknown, Richard Potts of the Smithsonian Institution in Washington told the New Scientist.
‘Having such a well-preserved specimen begins to answer questions about hand evolution,’ he said.
Dr Mary Marzke of Arizona State University explained to New Scientists that the bone proves that our ancestors’ hands were showing signs of evolution into their current form as much as 1.4 million years ago.
It is thought that all humans eventually developed this bone as those who had it initially were at an evolutionary advantage over those who did not.