Homo

Meaning

Homo (from Latin homō 'human') is a genus of great ape (family Hominidae). It came from an early hominin called Australopithecus.

Living Species

Today, the Homo genus has one living species: Homo sapiens, which are modern humans.

Ancient Relatives

There were several extinct species in the Homo genus. These include Homo erectus and Homo neanderthalensis, known as archaic humans. They were closely related to us and lived millions of years ago.

Early Members

The oldest known member of the Homo genus is Homo habilis. Its fossils are over 2 million years old. Homo erectus appeared around the same time. They lived in Africa and Eurasia for more than a million years.

Modern Humans

Anatomically modern humans, early H. sapiens, first appeared in Africa between 300,000 to 200,000 years ago. Around the same time, Homo neanderthalensis lived in Europe and Western Asia. H. sapiens left Africa in waves, possibly as early as 250,000 years ago. By 50,000 years ago, they had reached Eurasia and Oceania. They met and mixed with archaic humans during these travels.

Names and taxonomy

Main articles: Human taxonomy, Names for the human species, and Homininae

The word "Homo" comes from Latin and means "human being" or "man." The scientific name for modern humans, Homo sapiens, was given by Carl Linnaeus in 1758. Other human-like species were named later, such as Homo neanderthalensis in 1864 and Homo erectus in 1892.

The group Homo has not always had clear rules for which species belong to it. When scientists first named Homo, they only thought of modern humans. But when they discovered Neanderthals, they added another species. Over time, many fossils were found, and scientists debated which ones belonged to Homo. What ties them together is that they could walk on two legs like us and made tools.

Many old names for early human-like species have now been grouped under Homo. For example, names like Pithecanthropus and Sinanthropus are now considered part of Homo erectus. Scientists still argue about how to sort these species, especially when new fossils are found. Today, it seems that only Homo sapiens modern humans have been alive since the end of the last ice age.

Evolution

Main article: Human evolution

Further information: Timeline of human evolution, Hominini, and Chimpanzee–human last common ancestor

Australopithecus and the appearance of Homo

Further information: Australopithecus

Some early species, like Australopithecus garhi, Australopithecus sediba, Australopithecus africanus, and Australopithecus afarensis, might be related to the start of the Homo group. These species share some features with Homo, but scientists are not sure which one was the true ancestor.

Since the 2010s, it has become harder to know exactly when Homo began. Traditionally, it was thought to start when early humans first used stone tools. But in 2010, scientists found evidence that Australopithecus afarensis might have used stone tools around 3.3 million years ago, much earlier than Homo appeared. A fossil found in 2013 in Afar, Ethiopia, called LD 350-1, shows a mix of older and newer features. Some scientists now think Homo might have started as early as 3.3 million years ago, while others believe it was later, around 1.9 million years ago.

One big change from earlier species to Homo is the increase in brain size, from about 460 cm³ in A. garhi to 660 cm³ in H. habilis, and even larger in later species.

Homo habilis

Homo habilis appeared about 2.1 million years ago. Before 2010, some scientists thought H. habilis should not be part of Homo, but in Australopithecus. One reason to put it in Homo was that it used tools, but we now know that some Australopithecus species used tools even earlier. Also, H. habilis and H. erectus lived at the same time, meaning H. erectus might not have come directly from H. habilis. Instead, they might have shared a common ancestor.

Homo erectus

Homo erectus is often thought to have developed from H. habilis about 2 million years ago. Fossils found in the Caucasus showed traits between H. habilis and H. erectus, like a bigger brain size, growing from about 575 cm³ in H. habilis to around 850 cm³ in H. erectus. Early H. erectus fossils were found outside Africa, making some think H. erectus developed in Eurasia and later moved back to Africa. Studies also suggest that H. habilis might have lived at the same time as H. erectus for about half a million years.

Phylogeny

The group Homo belongs to the family of great apes. It includes modern humans, called Homo sapiens, and several older species like Homo erectus and Homo neanderthalensis. These older species are closely related to us and are sometimes called archaic humans.

Homo and another group named Paranthropus are thought to come from a common ancestor, a species named Australopithecus africanus. Scientists are still studying the exact family tree and when these groups separated. Some ancient Homo species, such as Homo erectus, may have mixed with other early human groups, leaving signs of their DNA in people today.

List of lineages

See also: List of human evolution fossils

Scientists are still learning about some early human-like species, such as H. rudolfensis, H. ergaster, H. georgicus, H. antecessor, H. cepranensis, H. rhodesiensis, H. neanderthalensis, Denisova hominin, and H. floresiensis.

Some scientists think there were only three main species of early humans: H. habilis, H. erectus, and Homo sapiens. But scientists do not always agree on how to group these species, so this is a tricky subject. These early humans could sometimes breed with each other, even after they began to evolve in different ways.