Modern humans, Homo sapiens: When, where and how did we evolve?

How old are Homo sapiens? Who are the first humans? It’s only natural to want to know where our species comes from.

Though these questions have been thought about for hundreds, if not thousands of years, there’s still a lot we don’t know about where humans come from. While the term human can be used by different scientists to mean different things, it’s often used to refer to members of the genus Homo, which includes our species and our closest relatives.

Finding more early Homo sapiens fossils will help scientists to better understand how our species evolved and when the first human lived.

What are Homo sapiens?

All humans alive today are Homo sapiens. You, your family, your friends and everyone you’ll ever meet is a member of this species.

Our species was named in 1758 by Carl Linnaeus, a Swedish naturalist. He chose the scientific name Homo sapiens, which means ‘wise man’ in Latin.

As this name can be singular or plural, it doesn’t need to be changed when referring to individuals or groups – Homo sapien, for example, would be incorrect.

While some scientists have historically placed living humans into subspecies, such as Homo sapiens sapiens, to distinguish us from our relatives, this has fallen out of favour. Instead, Homo sapiens is generally recognised as a species in its own right.

Homo sapiens characteristics

As the most widespread human species to ever live on Earth, Homo sapiens covers a huge range of diversity. Living people have a variety of different traits, including shapes, sizes and skin colours, but share certain characteristics that show we’re all members of one species.

Many of these characteristics can be found in our skeleton and are used by human evolution scientists, such as our expert Professor Chris Stringer, to identify archaic Homo sapiens remains.

“Our species has a number of diagnostic features that set us apart from other human species,” explains Chris. “The Homo sapiens skull, for instance, has a high and rounded braincase, only a small bony brow ridge above the eyes and a chin on the lower jaw, which our relatives don’t have.”

“Our body is also a different shape to our relatives, with relatively narrow shoulders, trunk and pelvis. CT scans of our body reveal further, less obvious differences, such as the structure of our inner ear and teeth.”

By examining the evolution of these characteristics, along with any preserved ancient DNA, scientists can begin to investigate where our species came from.

What was before Homo sapiens?

Ultimately, Homo sapiens evolution begins with the origin of the chimpanzee family.

Genetic evidence shows that the last common ancestor of all humans and modern chimpanzees is thought to have lived between six million and nine million years ago in Africa. A lack of fossil evidence, however, means very little is known about what this ancient Homo sapiens ancestor looked like.

This ancestor gave rise to a number of descendants, which may have included Sahelanthropus, Orrorin and Ardipithecus. Only a few fossils of these species have been found, meaning that it’s currently impossible to tell which of them might be part of the Homo sapiens lineage.

By about four million years ago, these early human relatives, also called hominins, eventually gave rise to Australopithecus. Unlike their predecessors, these animals could regularly walk upright, but probably not for long distances. It’s thought that they eventually gave rise to our genus, Homo, around 2.5 million years ago.

One of the longest lived members of this group is Homo erectus, an ancient human species that existed for more than 1.5 million years. It’s generally agreed that Homo erectus can be described as an ancestor of modern humans, though exactly how it’s related is strongly debated.

Until the 2010s, it was thought that Homo erectus was the ancestor of Homo heidelbergensis, which in turn was the common ancestor of both Homo sapiens and our closest relatives the Neanderthals. This view has now fallen out of favour following the re-dating of key fossils and further research, which suggest Homo heidelbergensis wasn’t a direct ancestor of our species.

While we don’t currently know what the last common ancestor of Homo sapiens and the Neanderthals is, we have some clues about when it lived. Genetic evidence, for example, suggests that it lived 500,000–700,000 years ago. However, research comparing teeth suggests our species split at least 800,000 years ago.

Chris has been involved in the analysis of a group of skulls from Yunxian, China, which complicate this picture further. The results suggest that the last common ancestor of Homo sapiens and other ancient species lived at least a million years ago.

“Our research into the skull shape of ancient humans suggests that the Yunxian fossils are on a very old branch of our family tree,” Chris says. “They may lie close to the common ancestor of Homo sapiens, the Neanderthals and the group containing the Denisovans and Homo longi, otherwise known as Dragon Man.”

“As to where that common ancestor lived and why the species split apart, it’s very uncertain. There are just so many possibilities.”

Taken together, the variety of conflicting evidence means that the earliest Homo sapiens could have emerged anywhere within a period covering half a million years.

When did Homo sapiens first appear?

Narrowing down exactly how long ago Homo sapiens emerged is difficult without fossils from when our species first appeared between 500,000 and one million years ago. No fossils of this age have been identified so far, but they should exist.

Looking for the remains of these individuals is more difficult than it first appears. It may be difficult to identify early members of a species, especially when key parts of the Homo sapiens definition didn’t all evolve at the same time.

“Diagnostic features of our species, such as our chins and narrow hips, would have taken a long time to evolve,” explains Chris. “As a result, early members of the Homo sapiens lineage are unlikely to have all, or even most, of the characteristics we have today.”

The oldest known remains of Homo sapiens are found in Jebel Irhoud, Morocco. These approximately 300,000-year-old fossils have a mix of ancient traits, such as a strong brow ridge, and more modern characteristics, such as thinner jawbones.

Other early fossils have been found in Eliye Springs in Kenya and at Florisbad in South Africa where a partial skull has been dated to be around 260,000 years old. Later fossils from sites in Ethiopia, including Omo Kibish and Herto, show that a more globular braincase had developed by about 200,000 years ago.

While these fossils are recognisably Homo sapiens, they have a slightly different mix of ancient and modern features. This has led to some scientists naming human subspecies such as Homo sapiens idaltu, but this practice is not widely supported.

Instead, many scientists now believe that the mixture of characteristics means that Homo sapiens don’t have one origin, but several.

Where did Homo sapiens come from?

Nearly all of the evidence suggests that Homo sapiens came from Africa. The DNA of all living people can be traced back to the continent and the oldest fossils of our species have all been found there.

For a long time, it was thought that our species began in a single south or east African population, which then spread across the continent. However, fossil and genetic evidence now suggests we’re descended from several different populations across Africa.

“The Pan-African model suggests that our species formed from multiple lineages of closely related hominins, which eventually came together to make the Homo sapiens we know today,” says Chris.

“Rather than having a direct line from our ancestors to today, it seems that isolated populations of our species evolved in different pockets of Africa. They developed distinctive qualities, including a wide range of facial features and skull shapes, to survive in their region. They were able to pass these traits on if and when they bred with other populations.”

The differences between these populations can also be seen in the tools they made. Tools found at Morocco’s Jebel Irhoud are some of the earliest evidence of the Middle Stone Age, when ancient humans began to pre-shape their hand tools. These techniques are collectively known as prepared core technologies.

While this change in culture is seen spreading across the continent, different populations responded to it in different ways. Later on, northern African populations made arrowheads or spearheads with features known as tangs – tapered ends that would slot into the split wooden shaft which probably helped to connect the two together.

Central African groups, meanwhile, were making tools such as heavy axes and picks instead. These differences suggest that these Homo sapiens populations were isolated from each other for long periods, perhaps due to barriers such as deserts, forests and rivers, and were adapting to different conditions.

Taken together, this evidence suggests that modern human origins can’t be traced back to a single point in time. Instead, it seems the traits and cultures of different ancestral populations combined over thousands of years, giving us what we now know as Homo sapiens.

While this process took place in Africa, some early modern humans were already beginning to venture out of the continent. Though many of these pioneering groups wouldn’t survive, they were paving the way for Homo sapiens’ next great challenge – spreading around the world.

This article includes information from the book Our Human Story by our scientists Dr Louise Humphrey and Professor Chris Stringer.