Your turn
Each lab is one step from the video. Tap, drag and slide to test the evidence yourself.
Each lab isolates one line of evidence. Dates are approximate; see the notes.
Tap the buttons and slide the sliders.
Lay a chimp foot, then your own foot, over the 3.6-million-year-old Laetoli print. Which one matches?
Compare the big-toe position and heel with a chimpanzee foot and a human foot. The prints were most likely made by Australopithecus afarensis.
Tap a foot. Does it fit the old footprint?
Drag the time marker back. When do the chimp branch and our branch meet?
Rewind both lineages. They meet in a shared ancestral population about 6–7 million years ago (genetic estimates 6–9).
Slide back, back, back. Where do the two branches meet?
The tree is simplified: two branches only.
Tap a bone. Which ones say "walker" and which say "climber"?
The pelvis and knee show upright walking; the skull, long arms and curved fingers do not look like ours.
Tap a bone on Lucy!
Pick a species. How big was its brain compared with yours?
Brain volume ranges in cm³ for Australopithecus afarensis, Homo erectus, Neanderthals and modern humans.
Tap a name. Whose brain is the biggest?
Ranges are typical values from fossil skulls.
Slide through 7 million years. How many kinds of humans were alive at once?
Sweep the cursor and count overlapping species. Dates are approximate and the links between species are debated.
Slide the time. How many kinds of people lived together?
The time axis is squeezed so recent species fit. Links between species are still debated.
Send people out of Africa, one route at a time.
Early Homo sapiens fossils span Africa; later dispersals reached Australia within ~60,000 years and the Americas within ~30,000.
Tap a place. Walk there!
Routes are simplified.
People did not appear all at once. Over a very, very long time, our family slowly changed. It started in Africa.
Long ago, someone walked on soft volcano ash in Tanzania and left footprints. The big toe sits in line with the other toes, just like yours!
We did not come from chimps. Chimps are our cousins. Far back, we shared the same family. It split into two branches: one led to chimps and one led to us.
Our family learned to walk on two legs first. A skeleton called Lucy could walk, but her brain was small and she could still climb trees. Big brains came much later.
People made sharp stone tools, learned to use fire to keep warm and cook, and some walked out of Africa.
Our family is not a line. It is like a bush with many branches. Long ago, different kinds of people lived at the same time. Today only one kind is left: us!
Humans evolved gradually from apelike ancestors in Africa over roughly six to seven million years.18 One of the first big changes was walking upright. Much later came stone tools, bigger brains and the use of fire. Our own species, Homo sapiens, appeared in Africa about 300,000 years ago and later spread across the planet.515
Two things surprise most people. First, we didn't evolve from chimpanzees. We share a common ancestor with them. Second, the story isn't a ladder. It's a bushy family tree, with many human species, several of them alive at the same time.917
Human evolution is the long process of change by which people came from apelike ancestors.1 Evolution doesn't change any single animal during its life. It changes populations over many generations. Small changes in DNA are passed from parents to children, and the ones that help with survival and having children slowly become more common.1
Scientists who study this are called paleoanthropologists. Their evidence includes fossil bones, footprints, stone tools, the remains of old campfires, butchery marks on animal bones and, more and more, ancient DNA.1
We evolved from apelike ancestors, but not from any ape alive today. Humans and the African great apes (chimpanzees, bonobos and gorillas) share ancestors, and our line split from the chimpanzee line roughly six to seven million years ago in Africa.19 Genetic estimates put the split between six and nine million years ago.8
Chimps are our closest living relatives. Our DNA sequences differ by only about 1%.17 Think of chimps as cousins, not grandparents: they have been evolving for exactly as long as we have. Monkeys are more distant cousins still.
Dates are approximate and get updated as new fossils are found. "Mya" means million years ago.
| When | What happened | Key evidence |
|---|---|---|
| 7–6 Mya | Earliest possible members of our branch | Sahelanthropus skull, Chad; Orrorin leg bones, Kenya79 |
| 4.4 Mya | Possibly walked upright, also climbed; woodland | Ardipithecus ramidus, Ethiopia7 |
| 3.85–2.95 Mya | Upright walking, small brains | Australopithecus afarensis ("Lucy", 3.2 Mya)310 |
| 3.66 Mya | Oldest known human footprints | Laetoli, Tanzania216 |
| 3.3 Mya | Oldest known stone tools | Lomekwi 3, Kenya14 |
| 2.4–1.5 Mya | Early Homo, bigger brains, tools | Homo habilis, "handy man"20 |
| ≈1.9 Mya | Human-like body; first known to leave Africa; hand axes and hearths later in its time | Homo erectus; Dmanisi, Georgia, 1.8 Mya411 |
| ≈400,000–40,000 years ago | Neanderthals in Europe and Asia | Fossils, tools and DNA12 |
| ≈300,000 years ago | Earliest Homo sapiens | Jebel Irhoud, Morocco15 |
| Within ≈60,000 years | Modern humans reach Australia; later the Americas | Archaeology and DNA1 |
| Within 12,000 years | Farming begins; cities come later | Archaeology15 |
In 1978, Mary Leakey's team in Laetoli, Tanzania, uncovered a trail of about 70 footprints, around 27 metres long, pressed into damp volcanic ash about 3.6 million years ago.2 The big toe lines up with the other toes, and each step lands heel first and pushes off with the toes, the way you walk. A chimp's big toe sticks out to the side for gripping.2 The prints were most likely made by Australopithecus afarensis, whose fossils are found in the same layer.2 (A second trail nearby suggests that another kind of upright walker may have lived there too.16)
The most famous member of that species is Lucy, found in Ethiopia on 24 November 1974. Her skeleton is about 40% complete.10 She lived about 3.2 million years ago.9 Lucy's hips and legs show she walked upright, but her brain was small, usually under 500 cm³ in her species, or about a third the size of ours. Her long arms and curved fingers were still good for climbing trees.3 Lucy showed that upright walking came long before big brains.10 Walking on two legs may have helped early humans spot predators, and it left their hands free to carry food and tools.10
The oldest known stone tools, from Lomekwi in Kenya, are about 3.3 million years old. That's older than the oldest known fossils of our genus, Homo.14 Knocking one stone against another gives a sharp flake for cutting. Homo habilis, "handy man", lived from about 2.4 to 1.5 million years ago. It had a larger brain than Lucy's species, and its fossils are found with simple stone tools.20
Homo erectus appeared about 1.9 million years ago. It was the first species with human-like body proportions: long legs and shorter arms.411 It made large hand axes by about 1.76 million years ago, and the earliest known hearths (campfires) date from its time, used for warmth, protection and cooking.4 It was also the first human we know of to leave Africa, reaching Dmanisi in Georgia by about 1.8 million years ago and later China and Java.11
| Species | Typical brain size |
|---|---|
| Australopithecus afarensis (Lucy's species) | about 385–550 cm³10 |
| Homo erectus | about 550–1,250 cm³11 |
| Neanderthals | at least 1,200–1,750 cm³12 |
| Homo sapiens today | about 1,300 cm³ on average5 |
You've probably seen a drawing of apes turning into a person, step by step, in a line. Scientists say that picture is misleading. Britannica calls our family tree a "family bush".18 The Natural History Museum describes it as a story that is "not one of neat, linear progression".9
Most scientists recognize about 15 to 20 species of early humans, and most of them left no living descendants.1 Often, several lived at once. Around two million years ago, big-jawed Paranthropus shared East Africa with early Homo.22 Even 50,000 years ago, our species shared the planet with Neanderthals in Europe and western Asia,12 Denisovans in Asia,21 and the tiny Homo floresiensis on the island of Flores in Indonesia, who stood about 1.06 m tall.6 By about 25,000 years ago, only Homo sapiens was left.17
What's still debated? Plenty. Scientists don't agree on exactly how the species are related or which ones were our direct ancestors.1 Nobody knows for sure which species was the last common ancestor of us and Neanderthals. Homo heidelbergensis used to be the favourite, but that view has fallen out of favour.8 New finds keep surprising experts. Homo naledi, a small-brained species from South Africa, turned out to be only about 236,000 to 335,000 years old.19
All early human fossils from 6 to 2 million years ago come from Africa, and our species began there too.1 The oldest Homo sapiens fossils, about 300,000 years old, come from Jebel Irhoud in Morocco. Other early fossils from Florisbad in South Africa (260,000 years) and Omo in Ethiopia (about 195,000 years, maybe older) suggest our species took shape across the whole continent, not in one spot.158 Modern humans have a high, rounded braincase, a small brow ridge and a chin.8
Later, groups spread out of Africa. People reached Australia probably within the past 60,000 years and the Americas within roughly the past 30,000 years.1 On the way they met other humans. Modern humans spreading into Asia around 60,000 years ago had children with Neanderthals, so most people with recent roots outside Africa carry about 2% Neanderthal DNA.13 Some people in Oceania, including Papua New Guinea and Australia, also carry DNA from Denisovans.21 Farming began only within the last 12,000 years, and cities came later.1
So when people ask "how did humans get on Earth?", the scientific answer is this story: we weren't dropped in all at once, we grew as one twig on a very old tree. The Smithsonian notes that many people have come to reconcile their beliefs with this scientific evidence.1 To learn how bones and footprints survive for millions of years, see how fossils are formed.
Over about 6 to 7 million years, populations of apes in Africa slowly changed. One branch began walking upright, later made stone tools, grew bigger brains and used fire. Many related species appeared and most died out. Our own species, Homo sapiens, appeared in Africa about 300,000 years ago and later spread around the world.
No. Humans and chimpanzees share a common ancestor that lived roughly 6 to 7 million years ago. Since then both lines have kept evolving. Chimps are our closest living cousins, not our ancestors, and monkeys are more distant relatives still.
According to the scientific evidence, humans were not placed on Earth suddenly. Our species evolved from earlier human species in Africa about 300,000 years ago. Those species evolved from older apelike ancestors. Fossils, footprints, stone tools and DNA all record the steps.
About 6 to 7 million years from the split with the chimpanzee line to today. Upright walking was in place by about 4 million years ago, stone tools by 3.3 million, Homo erectus by about 2 million, and Homo sapiens by about 300,000 years ago.
Scientists treat it as extremely well supported. Thousands of fossils, dated rock layers, ancient tools and DNA from living and extinct humans all fit together. The details of how each species is related are still debated, and new finds keep refining the picture.
Lists of '7 stages' are a simplification. Commonly named members include Sahelanthropus, Ardipithecus and Australopithecus (groups of species), Homo habilis, Homo erectus, Homo heidelbergensis and Homo sapiens. But they were not neat steps on a ladder. They are branches on a bushy tree, and some lived at the same time.
Yes. When modern humans spread out of Africa they met Neanderthals and interbred. As a result, most people with recent ancestry outside Africa carry about 2% Neanderthal DNA. Some people, especially in Oceania, also carry DNA from Denisovans.