When did the first hominids appear?

By John Pickrell

Five skulls belonging to some ancestors and relatives of modern humans. From left to right, the skulls are: Australopithecus africanus (3-1.8 mya); Homo habilis (or H. rudolfensis, 2.1-1.6 mya); Homo erectus (or H. ergaster, 1.8-0.3 mya, although the ergaster classification is generally recognised to mean the earlier part of this period); a modern human (Homo sapiens sapiens) from the Qafzeh site in Israel, which is around 92,000 years old; and a French Cro-Magnon human from around 22,000 years ago

(Image: Pascal Goetcheluck / SPL)

55 million years ago (MYA)

First primitive primates evolve

8 – 6 MYA

First gorillas evolve. Later, chimp and human lineages diverge

5.8 MYA

Orrorin tugenensis, oldest human ancestor thought to have walked on two legs

5.5 MYA

Ardipithecus, early “proto-human” shares traits with chimps and gorillas, and is forest-dwelling

4 MYA

Australopithecines appear. They have brains no larger than a chimpanzee’s – with a volume around 400 – 500 cm3 -, but walk upright on two legs. First human ancestors to live on the savannah

3.2 MYA

Lucy, famous specimen of Australopithecus afarensis, lives near what is now Hadar, Ethiopia

2.7 MYA

Paranthropus, lives in woods and grasslands, has massive jaws for chewing on roots and vegetation. Becomes extinct 1.2 MYA

2.5 MYA

Homo habilis appears. Its face protrudes less than earlier hominids, but still retains many ape features. Has a brain volume of around 600 cm3

Hominids start to use stone tools regularly, created by splitting pebbles – this starts Oldowan tradition of toolmaking, which last a million years

Some hominids develop meat-rich diets as scavengers, the extra energy may have favoured the evolution of larger brains

2 MYA

Evidence of Homo ergaster, with a brain volume of up to 850 cm3, in Africa

1.8 – 1.5 MYA

Homo erectus is found in Asia. First true hunter-gatherer ancestor, and also first to have migrated out of Africa in large numbers. It attains a brain size of around 1000 cm3

1.6 MYA

Possible first sporadic use of fire suggested by discoloured sediments in Koobi Fora, Kenya. More convincing evidence of charred wood and stone tools is found in Israel and dated to 780,000 years ago

More complex Acheulean stone tools start to be produced and are the dominant technology until 100,000 years ago

600,000 YA

Homo Heidelbergensis lives in Africa and Europe. Similar brain capacity to modern humans

500,000 YA

Earliest evidence of purpose-built shelters – wooden huts – are known from sites near Chichibu, Japan

400,000 YA

Early humans begin to hunt with spears

325,000 YA

Oldest surviving early human footprints are left by three people who scrambled down the slopes of a volcano in Italy

280,000 YA

First complex stone blades and grinding stones

230,000 YA

Neanderthals appear and are found across Europe, from Britain in the west to Iran in the east, until they become extinct with the advent of modern humans 28,000 years ago

195,000 YA

Our own species Homo sapiens appears on the scene – and shortly after begins to migrate across Asia and Europe. Oldest modern human remains are two skulls found in Ethiopia that date to this period. Average human brain volume is 1350 cm3

170,000 YA

Mitochondrial Eve, the direct ancestor to all living people today, may have been living in Africa

150,000 YA

Humans possibly capable of speech. 100,000-year-old shell jewellery suggests that that people develop complex speech and symbolism

140,000 YA

First evidence of long-distance trade

110,000 YA

Earliest beads – made from ostrich eggshells – and jewellery

50,000 YA

“Great leap forward”: human culture starts to change much more rapidly than before; people begin burying their dead ritually; create clothes from animal hides; and develop complex hunting techniques, such as pit-traps.

Colonisation of Australia by modern humans

33,000 YA

Oldest cave art. Later, Stone Age artisans create the spectacular murals at Lascaux and Chauvet in France

Homo erectus dies out in Asia – replaced by modern man

18,000 YA

Homo Floresiensis, “Hobbit” people, found on the Indonesian island of Flores. They stand just over 1 metre tall, and have brains similar in size to chimpanzees, yet have advanced stone tools

12,000 YA

Modern people reach the Americas

10,000 YA

Agriculture develops and spread. First villages. Possible domestication of dogs

5,500 YA

Stone Age ends and Bronze Age begins. Humans begin to smelt and work copper and tin, and use them in place of stone implements

5,000 YA

Earliest known writing

4,000 to 3,500 BC

The Sumerians of Mesopotamia develop the world’s first civilisation

A hominid is a family of primates that includes today's humans and their extinct direct ancestors. Before humans evolved into what they are today, several human-like species existed, some of which went extinct and some of which evolved into today's species—the only living species of hominids. Fossil discoveries suggest that the complete story of human evolution is still not fully known, although many of the major hominids species are documented.

The word hominid, which includes only human beings and their direct or immediate ancestors, should not be confused with the similar word hominoid. Hominoid includes both humans and apes, and therefore refers to a much larger and more diverse group of primates. All hominids are hominoids, but not all hominoids are hominids.

The first hominids are thought to have appeared on Earth about 3,000,000 to 4,000,000 years ago. The earliest known fossils have been discovered in southern and eastern Africa, and all appear to have three features in common: bipedalism or upright walking; an omnivorous diet (plant and animal); and an expansion of the brain. Eventually, over very long periods of time, these and other biological changes occurred and hominids became less and less apelike and more like today's modern humans. Many think that the first or earliest hominids came down from living in the trees and moved into the open fields or plains. Some think that a major climate shift brought this about since it is known that when hominids first appeared, the savannas were starting to replace forests. This is believed to have forced hominids to make a transition from being forest and tree dwellers to living in a more mixed habitat with woodland and open grasslands.

It is important to take note of the actual physical changes that would make hominids different from other primates. One obvious difference were different facial features. Hominids would lose much of their muzzle or protruding jaw, and the overall size of their faces would be reduced, especially their teeth and jaw. Their teeth would also develop thicker enamel and become less specialized. This is an indication that their diet was also less specialized and was probably omnivorous (both plant and meat eaters). Also reduced would be the bony ridges over their eyes, and the back of the skull would lose its crest or raised edge. The brain would also become larger in comparison to the rest of the body. At some point in their transition from trees to plains, hominids became bipedal, meaning that they could walk upright on two feet. This not only made them taller and able to see farther, but left their arms and hands free to carry things, to use tools, or otherwise do things that would further promote their survival. Bipedal walking resulted in significant changes to a hominid's lower spine, leg bones, and pelvis.

The oldest known hominid was found in South Africa and is called Australopithecus ramidus. Dated at about 4,400,000 years ago, this species walked on two legs but had a fairly small brain. There probably were even earlier types of hominids, but no one has yet found fossil remains. Paleoanthropologists (scientists who study the fossil remains of hominids) are not sure if Australopithecus is our direct ancestor or not. The first hominid to be considered human and therefore given the genus name Homo appeared probably about 2,000,000 years ago. Called Homo habilis meaning "handy man," it had a much larger brain than Australopithecus and is known to have used stone tools. Its skull and teeth were also different, and its face was smaller and more in proportion with the rest of its body. Between 1,500,000 and 500,000 years ago, Homo habilis was either replaced by or evolved into Homo erectus or "upright man." This is believed to be the first hominid to venture out of Africa and move into Asia and Europe. Significantly, its brain was even larger and it was able to use fire and make hand axes. About 300,000 years ago, the first Homo sapiens neanderthalensis, or Neanderthal man, appeared. Although it had a brain as large as humans are today, its head was still different, as its eye ridges were heavy, probably making it look fierce. Neanderthal man also made tools but unlike Homo habilis buried its dead in special graves.

About 40,000 years ago, humans similar to today's species first appeared. Called Homo sapiens sapiens ("wise man"), they may have interbred

LOUIS SEYMOUR BAZETT LEAKEY

British paleoanthropologist Louis Leakey (1903–1972) was a pioneer in the field of paleoanthropology, which is the study of the fossils of early humans and prehumans. He discovered the earliest known hominid (a family of primates that includes humans and the immediate ancestors of humans) and showed that humans were not only older than previously believed but that they may have first evolved in Africa.

Louis Leakey's parents were missionaries who were trying to convert African natives to Christianity. Leakey was, therefore, born in Kabete, Kenya, which was then part of the British Empire. He was raised among the Kikuyu tribe, a group of Africans who lived in the area where the mission was located. The young Leakey was able to speak the Kikuyu language as well as his own English, and although he had a governess who instructed him, he spent most of his time with other Kikuyu children exploring the countryside. This would remain with him all his life, and it is said that Leakey always thought of himself as an African instead of an Englishman. When Leakey was finally sent to England at age sixteen to begin his formal education, he found he could not get along with the typical English schoolboy with whom he had nothing in common. Although he got along better at Cambridge University, he was forced to take a year out of school when he suffered a head injury when kicked twice in a rugby match. This absence from school enabled him to join a fossil-hunting expedition to Tanganyika (now Tanzania), an experience that showed him what he really wanted to do in life.

After Leakey obtained his degree from Cambridge in 1926, he decided to devote his career to studying the origins of humanity, which he believed would be found in Africa. At this time, most scientists believed that Asia and not Africa was the original center of human evolution (the process by which humans changed over generations). Leakey began his work at two African fossil sites, one at Lake Victoria and the other at Olduvai Gorge, now in Tanzania. Olduvai was a 350-mile (217.36 kilometers) ravine that contained a great deal of evidence, like primitive stone tools, that some forms of humans had lived there very long ago.

During the mid-1930s, Leakey divorced his wife and married one of his students, Mary Douglas Nicol (1913–1996). Together, they would spend more than thirty years at Olduvai searching for the fossil remains of the creatures who had made and used those tools. The Leakeys were very determined scientists and put up with a great deal of hardships at Olduvai. They seldom had enough financial support and the remoteness of the site made their supplies and equipment scarce and difficult to haul. Finally, in 1959 while Leakey himself was in his tent sick with malaria, Mary discovered the fossil they had been looking for. She located the skull fragments of a hominid with a small brain and near-human teeth that they named Zinjan thropus boisei and later renamed Australopithecus boisei. This was the first more or less complete skull of its kind, and it was also the first to be accurately dated. Potassium-argon testing showed that it was about 1,800,000 years old. Although Leakey argued it was probably an evolutionary deadend and not a direct ancestor of modern humans, it nonetheless added considerably to the knowledge of human origins and showed that humans are older than previously thought.

The following year, Leakey's son, Jonathan, discovered the fossil remains of the larger-brained Homo habilis, or "handy man," which Leakey claimed was the direct ancestor of modern Homo. For this claim, Leakey received a great deal of criticism, and it must be said that he often would overstate his claims and overpublicize himself and his work. Leakey was an ambitious man who recognized the value of publicity in terms of obtaining financial support for his work. Despite his sometimes overblown claims, his significance resides in the fact that he did change the views concerning human development and pushed back the date when humans first appeared to a time much earlier than scientists had originally thought. He also showed that human evolution began in Africa rather than in Asia, which was also an early belief. As recently as 1977, five years after his death, his wife Mary discovered a set of footprints that were dated to about 4,000,000 years ago. After Mary died in 1996, the Leakey's son, Richard, continued their work.

with Neanderthals, or Neanderthals may have simply died out. This newest species began using its brain in ways not seen before, made better tools, began cultivating crops, and created sculptures and cave paintings. They developed language, music, built cities, and eventually created civilizations. All of these and other activities are suggested when we say that humans developed culture. Since today's particular species burst on the scene some 40,000 years ago, too little time has passed for us to notice any real biological changes, and any evolution that humans have made since then has been primarily cultural rather than biological.

[See alsoFossils; Homo sapiens neanderthalensis; Human Evolution ]

Human Evolution , The history of how the human species , Homo sapiens sapiens, evolved is reconstructed by evidence gathered by paleontologists, anthropologists, arche… Human Population , Modern humans (Homo sapiens ) are grouped with the mammals (class Mammalia) in the subphylum Vertebrata. Within the mammals, humans are assigned by t… Anthropocentrism , Anthropocentrism A “-centrism” is a worldview or way of looking at things that places some particular value or group at the center. Anthropocentrism… Human , human •Alabaman, Amman, Ammon, Drammen, gammon, Mammon, salmon •Bradman, Caedmon, madman, madmen •flagman, flagmen •trackman, trackmen •hangman, hang… Primate , The mammals (warm-blooded animals) called primates include the lower primates (lemurs, lorises, and tarsiers) and the higher primates (monkeys, apes,… Australopithecus , Australopithecus (ôstrā´lōpĬth´əkəs, –pəthē´kəs), an extinct genus of the hominid family found in Africa between about 4 and 1 million years ago. At…

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