By 6 million years ago:
Early humans had evolved upright posture and the ability to walk upright on short legs. Male canine teeth were about equal in size to females’, which indicates a significant shift in social life.
By 4.1 million years ago:
Broad knee joints indicate clear adaptation to regular bipedal walking.
By 3.6 million years ago:
Oldest definite early human footprint trails, with footprints of other animals and environmental evidence.
By 2.6 million years ago:
Early humans made basic tools and ate meat obtained from large animals.
By 2.5 million years ago:
Clear evidence of a double-curved spine, which indicates a shock-absorbing system associated with bipedal walking.
By 1.9 million years ago:
Robust hip bone and lengthened thigh bone indicate that human ancestors could walk farther, faster and more easily.
By 1.8 million years ago:
Early humans dispersed from Africa to Asia.
By 1.6 million years ago:
First major technological innovation. Hand axes are made. Hand-axe technology persists for more than 1.2 million years.
By 800,000 years ago:
Early humans had control of fire and created hearths.
At 800,000 years ago:
Beginning of the most rapid increase in early human brain size (relative to body size). The fastest pace of brain enlargement took place between 800,000 and 200,000 years ago.
By 500,000 years ago:
Evidence of brain enlargement implies considerably prolonged maturation of the young. Early humans hunted large animals.
By 400,000 years ago:
Early humans made shelters. Early humans invented wooden thrusting spears.
250,000 years ago:
Early humans began to communicate with symbols—with evidence of the oldest known “crayons” (faceted sticks and chunks of pigment).
200,000 years ago:
Modern humans (Homo sapiens) evolved in Africa; they gathered and hunted food, like earlier human species. The date of 200,000 years is based on the oldest known H. sapiens crania and the estimated age of convergence (back in time) of all the mitochondrial DNA diversity recorded in living human populations. Three species of early humans overlapped in time with H. sapiens. The other three species became extinct between about 70,000 and 17,000 years ago.
By 164,000 years ago:
Modern humans collected and cooked shellfish.
By 160,000 years ago:
Modern humans had evolved prolonged periods of childhood growth, as found in people today.
Between 135,000-100,000 years ago:
Modern humans temporarily spread beyond Africa. Modern humans made shell beads, the oldest known jewelry.
By 130,000 years ago:
Modern humans exchanged resources over long distances.
By 104,000 years ago:
Modern humans became capable of capturing fast and dangerous prey.
By 100,000 years ago:
Earliest recorded purposeful burial.
Between 100,000-32,000 years ago:
Neanderthals (H. neanderthalensis) created rare carved plaques and pendants.
By 90,000 years ago:
Modern humans made special tools for fishing.
By 77,000 years ago:
Modern humans recorded information on objects. Modern humans became capable of making clothing by perforating hide.
About 74,000 years ago:
Near-extinction of H. sapiens. Greatly reduced population, with numbers estimated at about 10,000 adults of reproductive age to as few as 600. Timing correlates with repeated, large-scale droughts in portions of Africa.
By 70,000 years ago:
Homo erectus became extinct.
By 60,000 years ago:
Modern humans began a series of permanent worldwide migrations.
By 60,000–40,000 years ago:
Modern humans created permanent drawings.
By 50,000 years ago:
Modern humans reached Australia.
By 40,000 years ago:
Modern humans reached Europe.
By 40,000-35,000 years ago:
Modern humans created paintings and figurines.
By 35,000 years ago:
Modern humans created musical instruments.
By 30,000–24,000 years ago:
Modern humans became capable of making well-fitted clothing using bone needles.
By 28,000 years ago:
Neanderthals (H. neanderthalensis) became extinct.
By 26,000 years ago:
Modern humans made baskets.
By 17,000 years ago:
H. floresiensis became extinct, leaving modern humans (H. sapiens) as the sole survivors of the once diverse human evolutionary tree.
By 15,000 years ago:
Modern humans reached the Americas (by at least this date).
Beginning 12,000 years ago:
Humans become a “turning point” in the history of life as they control the growth and breeding of certain plants and animals. Farming and herding ensue, which transformed natural landscapes—first locally, then globally. Food production led to settlement (villages, towns, cities) and population growth.
By 10,500 years ago:
First domestication of plants and animals.
By 8,000 years ago:
Modern humans use symbols to represent words and concepts.
Between 1959 and 1999:
Human population doubled from 3 billion to 6 billion people in just 40 years.
At least 83 percent of Earth’s land surface had been directly affected by humans.
More humans live in cities than in rural areas.
Human population is expected to reach about 7 billion.