Long before the modern humans known as Homo sapiens originated on the same continent, the first humans initially appeared in Africa about two million years ago.
Anthropologists
still have a lot to learn about how various human populations interacted and interbred
during this extensive prehistoric period. They're beginning to fill in some of
the gaps now that additional archaeological and genealogical research has been
conducted.
Introduction to Human evolution
Ø The First Human
Priorities
first any member of the Homo (Latin for "man") genus is referred to
as a "human." Although they have found some of the first humans,
scientists are still unsure of when or how the first ones evolved.
Homo
habilis, sometimes known as the "handy man," was one of the first
known humans and lived in Eastern and Southern Africa between 2.4 million and
1.4 million years ago. Others include Homo rudolfensis, who lived in Eastern
Africa between 1.9 and 1.8 million years ago (its name comes from its discovery
in East Rudolph, Kenya), and Homo erectus, the "upright man," who
lived between 1.89 million and 110,000 years ago and spread from Southern
Africa to modern-day China and Indonesia.
Researchers
have discovered evidence of these primitive humans as well as a mysterious
"superarchaic" population that split off from other humans in Africa
some two million years ago. According to a report published in Science Advances
in February 2020, these superarchaic humans interbred with the descendants of
Neanderthals and Denisovans. This is the earliest recorded occurrence of human
groups mating together, however we know this occurred far more frequently in
the past.
Introduction to Human evolution
Ø Neanderthals,
Denisovans, and Early Humans All Mixed Together
The archaic
humans—Neanderthals, Denisovans, and other extinct human groups—came after the
superarchaic ones.
Neanderthals,
or Homo neanderthalensis, have been studied by archaeologists since the 19th
century, while Denisovans were only discovered in 2008 (the population is so
recent that it lacks a scientific name yet). Since then, scientists have
learned that Neanderthals and Denisovans not only interbred with one another but also with contemporary humans.
Alan R.
Rogers, professor of anthropology and biology at the University of Utah, is the
lead author of the Science Advances paper. "When the Max Plank Institute
[for Evolutionary Anthropology] began getting nuclear DNA sequenced data from
Neanderthals, then it became very clear very quickly that modern humans carried
some Neanderthal DNA," he says. "That really was a turning moment...
Very immediately after that, it was widely accepted.
We know much
less about Denisovans than we do about Neanderthals because they were a more
recently found population. But there is evidence that they coexisted alongside
Neanderthals for about 100,000 years in Siberia, according to archaeologists.
The most recent find of a 13-year-old girl who lived in a cave approximately
90,000 years ago provides the strongest proof of this. Her father was a
Denisovan, according to DNA testing, while her mother was a Neanderthal.
Introduction to Human evolution
Ø A Messy Human
Evolution
Researchers
are still trying to determine when all of this intergroup mating occurred.
Around 70,000 years ago, modern humans made their way from Africa to Europe and
Asia, where they may have interbred with Neanderthals. According to studies,
there were apparently more than one interactions between Neanderthals and
contemporary humans.
Less is
known about the Denisovans and their travels, but research indicates that
between 50,000 and 15,000 years ago, modern humans interbred with them in Asia
and Australia.
Because
their ancestors didn't migrate out of Africa to encounter the Neanderthals in
Europe and Asia, several experts believed until recently that individuals of
African origin didn't have Neanderthal ancestry. However, a publication
published in Cell in January 2020 upended that narrative by revealing that
current people all over Africa also include a sizable percentage of Neanderthal
DNA. This, according to researchers, may have been brought about by modern
humans returning to Africa over the previous 20,000 years after mating with
Neanderthals in Europe and Asia.
According to
Andrew C. Sorensen, a postdoctoral researcher in archaeology at Leiden
University in the Netherlands, it may be preferable to think of human evolution
as a "braided stream" as opposed to a "traditional tree of
evolution" given these kinds of discoveries. Although Neanderthal and Deniosovan
DNA only makes up a small portion of our genes, the majority of modern humans'
DNA still comes from a group that originated in Africa. However, recent
research on inter-group mating has confounded our understanding of human
evolution.
The more DNA
evidence we have, it seems like five new questions arise for every one that is
resolved. So it's kind of like playing whack-a-mole with evolution.
Introduction to Human evolution
Ø Ancestors of
Early Humans Had Common Skills
When human
tribes came into contact, it's likely that more than simply genes were exchanged.
According to a 2018 Nature publication on which Sorensen was the lead author,
Neanderthals living in modern-day France some 50,000 years ago knew how to
ignite a fire. The ability to ignite a fire is a crucial talent that various
human populations may have learned from one another; some modern humans may
have even learned how to start a fire from Neanderthals.
According to
Sorensen, "These early human groups, they really got around." It's
incredibly challenging to piece together these relationships with these people
since they move around so frequently.
Introduction to Human evolution Introduction to Human evolution
