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
