THE ORIGIN OF MAN IS NOT ONE, BUT MANY DIFFERENT

by  Judith Jorge July 11, 2018

Website  ABC mosaic fossils, artifacts and environments throughout Africa

It indicates that our species came from interactions

between a set of populations whose connectivity

It changed over time.

Yasmine Gateau

Max Planck Institute

for the Science of Human History
 

Scientists suggest that Homo sapiens

not from a single ancestral population

in a region of Africa,

as often it stated ...

The  history of human evolution  is far from linear.

It is an intricate mosaic of species, crosses and migration which is not easy to put every little piece. The new findings shed light on the labyrinth of our origins, but instead to simplify it more and more entangled.

A good example is the latest research by an international team of scientists. 

So far, many had assumed that early humans originated in Africa as a single relatively large ancestral population, but the new scientific consortium believes that the beginnings were much more diverse, with ancestors scattered across the spaced temporarily different habitats continent such as forests or deserts.

Milenios separation resulted in an astounding variety of human forms, which mixture finally gave rise to Homo sapiens.

cultural artifacts from the Stone Age

North and South Africa.

Eleanor Scerri / Francesco d'Errico / Christopher Henshilwood
 

While it is widely accepted that our species was born in Africa, it is unclear how we evolved within the continent.

In an article ( Did our Species Evolve in subdivided Populations across Africa, and Why Does It Matter ? ) Published this week in the journal Trends in Ecology and Evolution ', the team puts into question the idea that there was a single population interchanged genes and technologies such as stone tools of a more or less random. 

From the study of bones, stones, genes and something much less common such as new and more detailed reconstructions of climates and habitats of Africa in the last 300,000 years, researchers have come to their own conclusions, much more complex.

"The stone tools and other artifacts, generally known as material culture, have distributions significantly clustered in space and time , " says lead study author Eleanor Scerri , of the University of Oxford in the UK and the Max Institute Planck Science of Human History in Germany.

"While there is a continental trend towards more sophisticated material culture, this 'modernization' clearly does not originate in a region or place in a given period".

Evolutionary changes the shape of the braincase

from an elongate shape to a globular shape.

The latter evolves within the lineage of Homo sapiens

through an expansion of the cerebellum and parietal bulge.

Philipp Gunz, Max Planck Institute for Evolutionary Anthropology

Human fossils tell a similar story.

"When we look at the morphology of human bones in the last 300,000 years, we see a complex combination of archaic and modern at different places and at different times traits," says Chris Stringer, a researcher at the Museum of Natural History in London and co-author in the study .

"As with material culture, if we see a continental trend towards modern human form, but different modern features appear in different places at different times, and some archaic features are present until very recently."

Isolation cycles

Genes agree.

"It is difficult to reconcile genetic patterns we see in living African and DNA extracted from the bones of Africans who lived in the last 10,000 years, with the existence of an ancestral human population," says Professor Mark Thomas, geneticist University College London and co-author of the study.

"We see signs of a deep reduced connectivity in the past, some very old and levels of overall genetic diversity than a single population would cost you to keep bloodlines."

To understand why human populations were so divided, and how these divisions changed over time, researchers looked past climates and environments of Africa, which give a picture of the habitable zones changing and often isolated.

Many of the most inhospitable regions of Africa today, as the Sahara, were one wet and green again, with interlocking networks of lakes and rivers, and abundant wildlife.

Similarly, some tropical regions are humid and arid green today were one time.These changing environments influenced human populations, which have gone through many cycles of isolation.

This lead to local adaptation and development of a material culture and unique biological composition, followed by genetic and cultural mixture.

"The evolution of human populations in Africa was multiregional. Our descent was multiethnic. And the evolution of our material culture was multicultural," said Scerri.

"We have to look at all regions of Africa to understand human evolution.