- Protruding noses mean we’re not as good at air conditioning as primates
- Other ancient humans had flat noses like chimpanzees
- Our ancestors ventured out of Africa in spite of being nasally challenged
- Results show our nose wasn’t formed in response to changing climates
It was a key moment that allowed our species to spread around the world from humble beginnings in Africa.
But the migration of our ancestors from the African continent around 50,000 years ago was not helped by the evolution of our noses.
In fact, our protruding noses formed as a result of other changes in our face and did not help us adapt to new climates as was previously thought, new research suggests.
The researchers used a computer model to simulate the flow of air through human noses, pictured, compared to chimpanzees and macaques. In humans inhaled air is conditioned poorly in the nasal cavity in comparison with primates, such as chimpanzees and macaques, the results showed
We are flat-faced hominins with external noses that protrude from our faces.
We got this feature millions of years ago, when the faces of our Homo ancestors evolved to be flatter and a higher nasal cavity formed.
But our protruding noses mean that we are not as good at ‘air conditioning’ compared to primates like chimpanzees and macaques, a new study shows.
For the first time, Dr Takeshi Nishimura from Kyoto University and colleagues, carried out an investigation into nasal air conditioning in non-human hominoids based on what’s known as computational fluid dynamics.
This illustration shows evolution from Australopithecus with flat faces (left) to humans with protruding noses (right). Unlike the genus Homo, other hominins like australopithecines had flat nasal features and faculties that improved air conditioning
THE EVOLUTION OF MAN
55 million years ago – First primitive primates evolve
15 million years ago – Hominidae (great apes) evolve from the ancestors of the gibbon
8 million years ago – First gorillas evolve. Later, chimp and human lineages diverge
5.5 million years ago – Ardipithecus, early ‘proto-human’ shares traits with chimps and gorillas
4 million years ago – Ape like early humans, the Australopithecines appeared. They had brains no larger than a chimpanzee’s but other more human like features
3.9-2.9 million years ago – Australoipithecus afarensis lived in Africa.
3-2 million years ago – Australopithecus africanus lived
2.7 million years ago – Paranthropus, lived in woods and had massive jaws for chewing
2.3 million years ago – Homo habalis first thought to have appeared in Africa
1.85 million years ago – First ‘modern’ hand emerges
1.8 million years ago – Homo ergaster begins to appear in fossil record
1.6 million years ago – Hand axes become the first major technological innovation
800,000 years ago – Early humans control fire and create hearths. Brain size increases rapidly
400,000 years ago – Neanderthals first begin to appear and spread across Europe and Asia
200,000 years ago – Homo sapiens – modern humans – appear in Africa
40,0000 years ago – Modern humans reach Europe
Modern humans reach Europe around 40,000 years ago. Unlike our ancestors, the genus Homo, other hominins like australopithecines had flat nasal features and faculties that improved air conditioning
The researchers used a computer to simulate the flow of air through human noses, compared to chimps, left, and macaques, right. Our protruding noses mean we are not as good at air conditioning compared to these primates and our noses must have changed in response to something other than environmental changes
The researchers used a computer model to simulate the flow of air through human noses, compared to chimpanzees and macaques.
‘The CFD simulation showed a horizontal straight flow of inhaled air in chimpanzees and macaques, contrasting with the upward and curved flow in humans,’ the paper explained.
ISRAELI SKULL MAY EVIDENCE MIGRATION FROM AFRICA
Long ago, humans left their evolutionary cradle in Africa and passed through the Middle East on their way to Europe.
In January last year, scientists found the first fossil remains that appear to document that journey – a partial skull from an Israeli cave.
The skull dates from around 55,000 years ago, fitting into the period when scientists had thought the migrants inhabited the area.
And details of its anatomy resemble ancient skulls from Europe, Israel Hershkovitz of Tel Aviv University in Israel said.
The skull, which lacks facial features and its base, was found in Manot Cave in the Galilee region of northern Israel.
The migrants are called modern humans because of their anatomy. The earliest remains of modern humans in Europe date to about 45,000 years ago.
The study found that in humans inhaled air is conditioned poorly in the nasal cavity in comparison with primates.
Unlike our ancestors, the genus Homo, other hominins like australopithecines had flat nasal features and faculties that improved air conditioning.
This means our ancestors were not the most well-equipped when they ventured out of Africa.
‘The air-conditioning faculty in the nasal passages was probably impaired in early Homo members,’ continued the researchers.
‘Although they have survived successfully under the fluctuating climate of the Plio-Pleistocene, and then they moved out of Africa to explore the more severe climates of Eurasia.’
The Plio-Pleistocene period began around 5 million years ago and lasted until 12,000 years ago.
Insufficient conditioning can damage the tissues in the respiratory system and impair respiratory performance, undermining health and increasing the likelihood of death.
But the recent findings suggest the protruding nose had little effect on air conditioning, so the nasal anatomy of our ancestors was not very sensitive to the conditions in the atmosphere.
Instead, the researchers said, our protruding noses formed as a result of other changes in our faces and were not formed in response to a changing environment.
One of the differences between Australopithecus afarensis and Homo erectus was the face. Unlike our ancestors, the genus Homo, other hominins like australopithecines had flat nasal features and faculties that improved air conditioning
‘Even though the inhaled air is not adjusted well within the nasal cavity in humans, it can be fully conditioned subsequently in the pharyngeal cavity, which is lengthened in flat-faced Homo,’ the paper says.
This study highlights the importance of compensating human evolution, as well as adaptive evolution, the researchers said.
The diversification of Pleistocene hominins is a major evolutionary event in terms of understanding human evolution.
FIRST HUMANS LEFT AFRICA VIA THE SINAI PENINSULA
The first modern humans to arrive in Europe and Asia migrated north out of Egypt around 55,000 years ago, according to a study published in May last year.
The study answered a long standing question about the route early Homo sapiens took when spreading from the African continent.
It also showed most Europeans and Asians living today are more closely related genetically to people living in Egypt than in Ethiopia.
This suggests Egypt was the last stop for people migrating out of Africa 55,000 years ago rather than taking a more southerly route through Ethiopia.
Some scientists believed that humans may have travelled from Ethiopia across the Bab el Mandeb strait to the Arabian Peninsula.
However, the new research suggests a northern route from Egypt, through the Sinai peninsula and then out into Asia and Europe was the most likely route.
The findings also support evidence that these first humans to leave Africa came into contact with Neanderthals in the Levant at the time.
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