https://humanorigins.si.edu/human-characteristics
Walking (video)
One Step at a Time. The earliest humans climbed trees and walked on the ground. This
flexibility helped them get around in diverse habitats and cope with changing climates.
Silhouette of Sahelanthropus tchandensis. Image courtesy of Karen Carr Studios From at least 6
to 3 million years ago, early humans combined apelike and humanlike ways of moving around.
Fossil bones like the ones you see here record a gradual transition from climbing trees to walking
upright on a regular basis.
7–6 million years ago
Sahelanthropus may have walked on two legs.
Becoming bipedal By 6 million years ago
The oldest evidence for walking on two legs comes from one of the earliest humans known,
Sahelanthropus. Walking upright may have helped this species survive in the diverse habitats
near where it lived—including forests and grasslands.
Leg support 6 million years ago
Silhouette of Orrorin tugenensis for femur. Image courtesy of Karen Carr Studio. The upper part
of this thigh bone is similar in size to those of other large apes. But the angled part more closely
resembles that of modern humans. It formed a strong bridge with the hip to support the body’s
weight, suggesting Orrorin tugenensis walked upright.
Strong knee 4.1 million years ago
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Every time you take a step, you briefly stand on one leg—putting stress on your leg bones. The
wide area of bone just below this the knee joint in Australopithecus anamensis is a result of that
stress. It provides strong evidence that this individual walked upright.
Mostly bipedal By 4 million years ago
Silhouette of Australopithicus afarensis with vertebrae Fossils from around this time period come
from early human species that lived near open areas and dense woods. Their bodies had evolved
in ways that enabled them to walk upright most of the time, but still climb trees. As a result, they
could take advantage of both habitats.
Curved spine 2.5 million years ago
The curve of your lower back absorbs shock when you walk. It is uniquely human. You can see a
similar curve in the spine of this early human, Australopithecus africanus, who walked upright in
a way very similar to modern humans.
Hip support 1.95 million years ago
The size and broad shape of the hip bones of Homo erectus are similar to a modern human’s,
showing that this early human species had given up climbing for walking.
Fully bipedal By 1.9 million years ago
Silhouette of Homo erectus pelvis. Image courtesy of Karen Carr Studios The pelvis and thigh
bones (outline to right) of Homo erectus are similar to modern humans, and show that this early
human was able to walk long distances. That ability was a big advantage during this time period.
East Africa’s environments were fluctuating widely between moist and dry, and open grasslands
were beginning to spread.
Long leg 1.89 million years ago
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The long thigh bones of Homo erectus enabled its owner to take long strides and therefore to
walk farther and faster than earlier humans.
Compare a Chimp with an Early and Modern Human
Modern chimpanzees occasionally walk upright, but their skeletons are not adapted for regular
walking on two legs. Early humans evolved skeletons that supported their bodies in an upright
position. Modern humans have bodies adapted for walking and running long distances on two
legs.
Skull
Drawings of skulls of a chimpanzee (left), early human (middle), and modern human (right).
Image courtesy of Karen Carr Studios The spine of a chimpanzee connects with the skull at the
back, holding the head at an angle.
The spine of early humans connected with the skull underneath, stabilizing the head when
walking upright.
Your spine connects with your skull underneath and near the center, holding your head firmly
upright.
Upper Leg Bone
Drawings of upper leg bones of a chimpanzee (left), early human (middle), and modern human
(right). Image courtesy of Karen Carr Studios Because the connection between the upper thigh
and hip bones is short in chimpanzees, the hip muscles cannot contract effectively to provide
support for upright walking.
The connection between the upper thigh and hip bones was longer in early humans than in
chimpanzees, and its base thicker. The hip muscles could provide support for walking.
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The connection between your upper leg and hip bones is long. Its base is strong and able to
withstand the stresses of walking and running.
Lower Knee
Drawings of lower knee bones of a chimpanzee (right), early human (middle), and modern human
(left). Image courtesy of Karen Carr Studios The chimpanzee knee joint is lightly built, so
chimpanzees cannot rest their weight on one leg at a time to walk for long periods.
The early human knee joint was strong, enabling this early human to regularly support its weight
on one leg at a time during walking.
Strong knee joints help support your body’s weight on one leg at a time while walking long
distances.
Benefits and Costs of Walking
Scene illustrating a few of the benefits of upright walking. Image courtesy of Karen Carr Studios
Benefits
As environments changed, walking on two legs helped early humans survive by:

making it easier to pick fruits and other food from low-lying branches;

freeing hands for carrying food, tools, or babies;
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enabling early humans to appear larger and more intimidating;
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helping early humans cover wide, open landscapes quickly and efficiently.
Silhouette of a modern human with back pain Costs
Does your back ever hurt?
Back pain and other skeletal problems are relatively common in modern humans, an unfortunate
side effect of walking upright. Distributing all our weight on just two limbs can have painful
consequences, like lower back pain, slipped disks, arthritis in hips and knees, and collapsed foot
arches.
Try it!

Press your fingers beneath the top bones of both of your hips.

Now stand on one leg at a time.

Can you feel the muscles contract?
These are the muscles that support your body during walking. They attach to the areas that curve
inward above the hip socket
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New Tools, New Foods (video)
Stone core and flake from Lokalalei, Kenya, about 2.3 million years old
Dawn of technology By 2.6 million years ago
Early humans in East Africa used hammerstones to strike stone cores and produce sharp flakes.
For more than 2 million years, early humans used these tools to cut, pound, crush, and access
new foods—including meat from large animals.
How Do We Know This Zebra Was Food?
Scanning electron micrograph image of cut marks on fossil bone Stone tool marks on this zebra
bone look like those made during butchery experiments. Scientists have made experimental
stone tools and used them to butcher modern animals. There is a strong similarity between the
marks their tools made and the marks on fossil animal bones, indicating that early humans used
stone tools to butcher animals by at least 2.6 million years ago.
Handaxes came in handy Beginning 1.7 million years ago
Around this time, toolmakers began to strike huge flakes off stone cores. They shaped the large
flakes into handaxes by striking smaller flakes all around the edges. These multipurpose tools
dominated early human technology for more than a million years. Ancient handaxes have been
found in Africa, Asia, and Europe. Learn more about them and other Early Stone Age tools.
Handaxe Makers Cope with Catastrophe
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Handaxe from Bose, China, about 803,000 years old. Smithsonian scientists and their Chinese
colleagues found these handaxes in the same sediment layer with tektites, small rocks that
formed during a meteor impact 803,000 years ago.
Since the handaxes and tektites were in the same layer, both are the same age. Early humans
must have moved into the area right after the impact. They may have made the handaxes from
rocks that were exposed when forests burned.
A huge meteor impact occurred in the atmosphere near China 803,000 years ago and the shock
caused earth rocks to melt and explode, forming tektites. Widespread forest fires followed.
Shortly after, humans moved into the barren landscape and scavenged for resources.
What’s cooking? By 790,000 years ago
Control of fire provided a new tool with several uses—including cooking, which led to a
fundamental change in the early human diet. Cooking released nutrients in foods and made them
easier to digest. It also rid some plants of poisons.
The earliest hearths are at least 790,000 years old. Some researchers think cooking may reach
back more than 1.5 million years.
Wooden thrusting spear, Schöningen, Germany, about 400,000 years old.
Hunting Large Animals
By at least 500,000 years ago, early humans were making wooden spears and using them to kill
large animals.
Early humans butchered large animals as long as 2.6 million years ago. But they may have
scavenged the kills from lions and other predators. The early humans who made this spear were
hunting large animals, probably on a regular basis.
Reducing the risk
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Hunting large animals was a risky business. Long spears like this one were thrust into an animal,
enabling our ancestors to hunt from a somewhat safer distance than was possible with earlier
weapons. Three wooden spears like the 400,000-year-old one illustrated here were found at
Schöningen, Germany, along with stone tools and the butchered remains of more than 10 horses.
Oldest evidence of hunting
Horse shoulder blade or scapula from Boxgrove, England, about 500,000 years old The
semicircular wound on this fragment of a horse shoulder blade was made by a weapon such as a
spear, indicating it was killed by early humans. Other horse bones from the same site have
butchery marks from stone tools.
Explosion of technology By 100,000 years ago
Eventually new kinds of tools replaced stone handaxes. Some were small or made of several
parts. Some were made of bone, ivory, or antler. Over the past 100,000 years, as modern humans
spread around the world, the pace of technological change accelerated—leading to today’s
extraordinary diversity of specialized tools.
Bone needles from Xiaogushan, Liaoning Province, China, about 30,000–23,000
years old Making clothing
Awls and perforators were probably invented in Africa and carried to colder climates, where they
were used to pierce holes in clothing. Later, humans used bone and ivory needles to sew warm,
closely fitted garments.
Carving and shaping
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Burins are specialized stone flakes with sharp, chisel-like tips. Humans used them to work bone,
antler, ivory, and wood and to carve designs and images on the surfaces of these materials.
Fishing
More than 70,000 years ago, humans in Central Africa used some of the earliest barbed points to
spear huge prehistoric catfish weighing as much as 68 kg (150 lbs.), enough to feed 80 people
for two days. Later, humans used harpoons to hunt large, fast marine mammals.
Hunting fast and dangerous prey
Spear-throwers provided leverage for hurling spears and darts greater distances with more speed
and accuracy and with less chance of injury from prey. Stone or bone points, attached to spears
or darts, enabled humans to exploit fast-moving prey like birds and large, dangerous prey like
mammoths.
Humans began making pottery for storage purposes Storing things
Early humans may have made bags from skin long ago. By around 26,000 years ago, they were
weaving plant fibers to make cords and perhaps baskets. About 20,000 years ago, in China, they
began making pottery.
Chimps Make Tools, Too
Chimpanzees in Guinea used this stone anvil and hammerstone to crack open oil palm nuts, an
energy-rich food. Nut cracking is one of the most sophisticated examples of chimpanzee tool
use.(Specimen courtesy of Professor Tetsuro Matsuzawa, Kyoto University Primate Research
Institute, Kyoto, Japan)
Chimpanzee stone anvil, hammerstone with palm nuts, ant-dipping tool, and spear Researchers
in Senegal observed a chimpanzee sharpen this stick and use it to spear bush babies sleeping
inside tree hollows—the first time chimpanzees were observed using tools to hunt. (Specimen
courtesy of Dr. Jill Pruetz, Iowa State University, Iowa)
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Chimpanzees in Guinea use specially prepared sticks like this to “fish” for ants, a high-protein
food. They make holes in the side of a nest, insert the stick, and pull it out—covered with ants.
(Specimen courtesy of Dr. Kathelijne Koops and Dr. William McGrew, Cambridge University,
England)
Benefits and Costs of Eating Meat
Illustrations of the benefits and costs of eating meat. Benefits
- Meat is a concentrated source of calories, protein, fat, and nutrients.
- Unlike many plants, most meat does not naturally contain toxic chemicals; so it was a relatively
safe food for early humans.
- Meat is more quickly digested than plants and does not require large guts, saving energy for
the brain and other organs.
Costs
- Hunting and scavenging large animals is risky and less predictable than gathering plants.
- Dangerous animals competed with early humans to obtain meat.
- Meat spoils quickly and can contain tapeworms and other parasites.
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Changing Body Shapes and Sizes
Short bodies, long guts By 6 million years ago
Australopithecus afarensis, "Lucy", reconstructed skeleton The earliest human species were small
in size and usually had long arms and short legs. Their plant-based diet required a large
digestive tract. A wide rib cage made room for the stomach, intestines, and other organs that
break down food.
Tall bodies, short guts By 1.9 million years ago
As some early humans adapted to hot climates, they evolved narrow bodies that helped them
stay cool. Long legs enabled them to travel longer distances. Eating meat and other foods that
could be digested quickly led to a smaller digestive tract, making more energy available for tall
bodies and large brains.
Compact bodies, short guts By 400,000 years ago
When early humans spread to colder climates, their body shapes evolved in ways that helped
them stay warm. Short, wide bodies conserved heat. Early humans continued to depend on
both raw meat and cooked food, both of which could be efficiently processed in a short digestive
tract.
Adapted to Hot Climates
This is the skeleton of an eight- to nine-year-old Homo erectus boy who lived in East Africa
about 1.6 million years ago. The pelvis shows he was male. His teeth tell his age. The boy was
1.6 m (5 ft 3 in) tall and weighed 48 kg (106 lb). If he had reached adulthood, he might have
grown to nearly 1.85 m (6 ft). His tall, lean body was well adapted to hot, dry environments.
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Narrow body
Notice the narrow pelvis of this species. The slender body shape helped keep the body cool, a big
advantage in hot climates.
Long legs
The lower legs of Homo erectus were long, a feature that helped dissipate heat.
This Homo erectus boy lived in a hot, dry part of East Africa near an ancient marsh. His species
was one of the first to spread beyond Africa, where it encountered a variety of environments.
Adapted to Cold Climates
Homo neanderthalensis; Skeleton An average adult male Neanderthal stood only about 1.63 m (5
ft 4 in) tall. That’s not much taller than the skeleton of the eight- to nine-year-old Homo
erectus boy at right. Neanderthals of Europe, who had evolved by about 200,000 years ago, had
to endure winter cold and even ice ages. Their short, broad bodies were well adapted to these
challenging climates.
Broad body
A short, broad body shape helps to retain heat, which is useful in cold environments like those
inhabited by Neanderthals.
Short legs
The lower leg bones in this Neanderthal skeleton are short compared to the upper leg bones, a
feature that reduced heat loss. Compare them with those of the Homo erectus skeleton at left.
This reconstructed skeleton includes parts of two Neanderthal individuals from different times
and places. One individual lived in western Europe 70,000 years ago. The other inhabited a cave
in what is now Israel 60,000 years ago. Both sites were cold and dry, like most of the places
where Neanderthals lived.
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Bodies Adapted to Diverse Climates and Diets
As early humans spread to different environments, they evolved body shapes that helped them
survive in hot and cold climates. Changing diets also led to changes in body shape.
The bodies of early humans were adapted to very active lifestyles. Their bones were thicker and
stronger than ours. Starting about 50,000 years ago, as a result of less physically demanding
lifestyles, humans evolved bones that were sleeker and weaker.
The Shrinking Human Gut
Early humans ate mainly plants, which take a longer time to digest than meat does. Long
digestive tracts helped process this food.
Modern humans eat a diet that includes meat and cooked foods. We can process these foods
efficiently with a shorter digestive tract.
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Bigger Brains: Complex Brains for a
Complex World
Endocasts of Homo erectus (left) and Homo sapiens (right) illustrate rapid increase in brain size.
As early humans faced new environmental challenges and evolved bigger bodies, they evolved
larger and more complex brains.
Large, complex brains can process and store a lot of information. That was a big advantage to
early humans in their social interactions and encounters with unfamiliar habitats.
Over the course of human evolution, brain size tripled. The modern human brain is the largest
and most complex of any primate.
Brain size increases slowly From 6–2 million years ago
During this time period, early humans began to walk upright and make simple tools. Brain size
increased, but only slightly.
Brain and body size increase From 2 million–800,000 years ago
During this time period early humans spread around the globe, encountering many new
environments on different continents. These challenges, along with an increase in body size, led
to an increase in brain size.
Brain size increases rapidly From 800,000–200,000 years ago
Human brain size evolved most rapidly during a time of dramatic climate change. Larger, more
complex brains enabled early humans of this time period to interact with each other and with
their surroundings in new and different ways. As the environment became more unpredictable,
bigger brains helped our ancestors survive.
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Why the sudden increase in brain size?
Graphs showing changes in climate and changes in braincase volume. Courtesty of Karen Carr
Studios The top graph shows how Earth’s climate has fluctuated over the past 3 million years.
Notice how much the fluctuations increased between 800,000 and 200,000 years ago. To
construct this graph, scientists studied fossils of tiny organisms found in ocean sediment cores.
The bottom graph shows how brain size increased over the past 3 million years—especially
between 800,000 and 200,000 years ago. A large brain capable of processing new information
was a big advantage during times of dramatic climate change. To construct this graph, scientists
measured the brain cavities of more than 160 early human skulls.
Evidence of ancient brains
Endocasts are replicas of the insides of early and modern human braincases. They represent the
size and shape of the brains that once occupied the braincases.
How are endocasts made?
Brains do not fossilize. They deteriorate, leaving a cavity inside the braincase.
Sometimes sediments fill the cavity and harden, making a natural endocast. Scientists also make
artificial endocasts to study, like the ones above.
To obtain an accurate measure of brain size, scientists remove an endocast from the braincase
and record its volume, or use CT scanning to measure the inside of the braincase.
Compare Your Brain with a Chimpanzee’s
Humans are primates, and chimpanzees are our closest living relatives.
The brains of the earliest humans were similar in size to those of chimpanzees. But over time,
human and chimpanzee brains evolved in several different and important ways.
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Speed of Growth
Chimpanzee brains grow rapidly before birth. Growth levels off very soon after birth. Image
courtesy of Karen Carr Studio.
Human brains grow rapidly before birth through the first year and into childhood. Image courtesy
of Karen Carr Studios
Connections
A chimpanzee’s temporal cortex has less white matter, reflecting fewer connections between
nerve cells.
Humans have far more white matter in the temporal cortex, reflecting more connections between
nerve cells and a greater ability to process information.
Size
Average weight of adult chimpanzee brain: 384 g (0.85 lb)
Average weight of modern human brain: 1,352 g (2.98 lb)
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Benefits and Costs of a Big Brain
Brain weight versus energy requirements. Image courtesy of Karen Carr Studios
Benefits
The modern human brain can:
- store many decades worth of information;
- collect and process information, then deliver output, in split seconds;
- solve problems and create abstract ideas and images.
It can also do much more.
Costs
- A big brain gobbles up energy. Your brain is 2 percent of your body’s weight but uses 20
percent of your oxygen supply and gets 20 percent of your blood flow.
- Large brains mean large heads, making childbirth more difficult and painful for human mothers
than for other primates.
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Social Life (video)
Group Survival
Social bonds helped ensure humans' survival.
Sharing food, caring for infants, and building social networks helped our ancestors meet the daily
challenges of their environments.
Over time, early humans began to gather at hearths and shelters to eat and socialize. As brains
became larger and more complex, growing up took longer—requiring more parental care and the
protective environment of a home. Expanding social networks led, eventually, to the complex
social lives of modern humans.
Sharing resources Beginning 2.6–1.8 million years ago
Some groups of early humans began collecting tools and food from a variety of places and
bringing them to favored resting and eating spots. Sharing vital resources with other members of
the group led to stronger social bonds and enhanced the group’s chances of survival.
Evidence from Kanjera, Kenya
About 2 million years ago, early humans transported stone up to 12 km (7 mi) to a site at
Kanjera, Kenya. There they made stone tools for butchering animals. Smithsonian scientists,
working at Kanjera with colleagues from Kenya and the United States, have excavated stone tools
and butchered animal bones.
How Do We Know Tools Were Transported?
Different rock types have different chemical compositions. Stone tools excavated from Kanjera
chemically match rocks found at natural sources up to 12 km (7 mi) away. Early humans carried
the tools from these distant places, probably stopping and using them along the way.
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Burned flint from the 790,000 year old site of Gesher Benot Ya'aquov, Israel.
Gathering at the hearth Beginning 800,000 years ago
During this time period, at Gesher Benot Ya’aqov in Israel, early humans gathered around
campfires that they made and controlled. Why did they come together at these early hearths? Perhaps to socialize, to find comfort and warmth, to share food and information, and to find
safety from predators.
A close look at the tiny pieces of flint in this photograph reveals that the flint has been deformed
by fire—evidence of fire-making at Gesher Benot Ya’aqov 790,000 years ago.
How Do We Know These Were Hearths?
Scientists found debris from stone tool-making that had been scorched by fire at Gesher BenotYa’aqov. Close by were concentrations of burned seeds and wood, marking the location of early
hearths. More than a dozen hearths, dating back 790,000 years, have been found at the
excavation site.
More time to grow Beginning 500,000–160,000 years ago
By this time, early humans had evolved much larger brains. Infants were born with small brains,
enabling the head to pass through the birth canal. The brain continued to grow throughout a
long childhood. During adolescence, youngsters continued to prepare for the challenges of
adulthood.
Two Roads to Adulthood
Humans are unique among primates in having long, distinct periods of childhood and
adolescence. These stages enable us to learn, play, socialize, and absorb important experiences
prior to adulthood.
During childhood, human children depend on adults for food and care. During adolescence, a
growth spurt occurs, and male and female body features develop.
How Do We Know How Long It Took to Grow Up?
As teeth develop, new enamel layers form daily. Scientists used CT-scanning to count the enamel
layers on teeth of a Homo sapiens child who lived in northern Africa 160,000 years ago.
The layers show that the teeth were growing and erupting at the same rate as those of seven- to
eight-year-old children today, telling us that this fossil human child was growing at the same
rate as living humans.
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A microscope photo showed scientists the enamel layers on one of the teeth. By counting them,
they calculated the length of this individual’s childhood.
Explore one of the Earliest-known Human Shelters
Reconstruction illustration of 400,000-year-old shelter from Terra Amata, France This 400,000year-old shelter at Terra Amata, France, provided protection for an early human family or social
group. Scientists found post holes and other evidence of multiple shelters at this site. Some
shelters were as long as 14.9 m (49 ft.).
Scientists also found fossil human feces here. They contain pollen from plants that blossom in
late spring and early summer, indicating when humans occupied the shelters.
Building Social NetworkS Beginning 130,000 years ago
Over time, humans began interacting with social groups located far from their own. By 130,000
years ago, groups who lived 300 km (186 mi) apart were exchanging resources. Social networks
continued to expand and become more complex. Today, people from around the globe rely on
one another for information and goods.
How many groups do you belong to?
Modern humans are part of many communities that encourage sharing and cooperation,
sometimes among people who have never even met. These alliances enrich our lives and enable
us to share expertise and the risks of survival. They can also pose serious conflicts among people
of different communities.
Nassarius gibbosulus/ shell beads found at Grotte des Pigeons, Taforalt,
Morocco, about 82,000 years old, transported more than 40 km (25 mi). Early
Trade Routes?
These and other shells and shell beads were discovered far from the seas where they originated.
By 40,000 years ago, humans were transporting decorative shells—and perhaps trading them—
over areas of more than 500 km (310 mi).
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Through expanded social networks like these, humans increased their access to resources and
thus their ability to survive.
Growing Up
These two young children, born about 3 million years apart, grew up at very different rates.
As childhood lengthened, parents devoted more time and energy to caring for the young.
Australopithecus afarensis; Dikika 1, skull and partial skeleton
Three-year-
old Australopithecus afarensis 3.3 million years old
A CT-scan showed small canine teeth forming in the skull, telling us this individual was female.
Her baby teeth had erupted in a pattern similar to a three-year-old chimpanzee’s. But her brain
size indicates that a human growth rate was evolving.
Two-year-old Neanderthal 70,000-50,000 years old
The leg bones of this child are about the same length as those of a modern two-year-old,
indicating that this young Neanderthal was growing at a modern human rate, with a long
childhood.
Scientists found this skeleton of a two-year-old Neanderthal lying on its back in a deep burial pit
inside a cave, with a slab of limestone at the top of the head.
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Language and symbols (video)
Humans Express Themselves
From pigments to printing presses, symbols changed the way humans lived and provided new
ways to cope with an unpredictable world.
Modern humans used color, words, and sound to produce the artifacts you see here. The ability
to plan, record information, and communicate helped humans survive as climates fluctuated
strongly.
Ultimately, words and symbols led to language and the richness of modern human life.
Communicating with color By 350,000 years ago
With ocher and manganese, our ancestors marked objects and possibly their own skin. Colors
were symbols by which they identified themselves and their group.
Humans may have first used ocher either as an adhesive or a pigment, and later to make artistic
drawings and paintings.
Flattened areas on these pieces of pigment are signs of grinding or rubbing, telling us that they
were held and used roughly like chunky crayons.
Illustration of an ancient child burial. Image courtesy of Karen Carr Studio.
Ancient Burials By 100,000 years ago
Our ancestors often buried the dead together with beads and other symbolic objects. Burial
rituals heightened the group’s memory of the deceased person. These rituals may imply a belief
that a person’s identity extends beyond death.
Child burial 24,000 years ago
At Sunghir, Russia, a twelve- to thirteen-year-old boy and a nine- to ten-year-old girl were
buried together, head-to-head, flanked by two huge mammoth tusks. Members of their
community covered them with red ocher and ornamented them with beaded caps, carved
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pendants, and
more than 10,000 ivory beads.
Expressing identity
Ishango bone (top left), carved reindeer antler with tally marks (top right), and engraved ocher
plaque (bottom). Images courtesy of Chip Clark, James Di Loreto, and Donald H. Hurlbert,
Smithsonian Institution.
By 100,000 years ago
What do you wear to define who you are?
Our ancestors used jewelry and other personal adornments to reflect their identity. These
adornments may have represented membership in a particular group or someone’s age, sex, and
social status.
Recording information By 77,000 years ago
All of these objects have marks that may have been used to count or store information.
Researchers are debating exactly what the marks represent.
From simple beginnings like these came our ability to store enormous amounts of information.
Information or decoration?
A close-up look at these objects shows that in all three the markings are clearly organized. This
systematic pattern suggests to some researchers that the markings represent information rather
than decoration.
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Engraved Stone, Berekhat Ram, Golan Heights, Middle East, about 280,000-250,000 years old.
Image courtesy of the Smithsonian Institution.
Creating paintings and figurines By 40,000 years ago
By this time, humans were creating two- and three-dimensional images of the world around
them. By 17,000 years ago, they had developed all the major representational techniques
including painting, drawing, engraving, sculpture, ceramics, and stenciling. Working on stone,
ivory, antler, and occasionally clay, they created imaginative and highly complex works of art.
Do you see a human head and body on the engraved stone to the right? Scientific studies show
that humans deepened the natural grooves on this stone and smoothed planes and curves to
create an image. It may be one of the earliest representations of a human figure.
When Did Humans Start Writing?
By around 8,000 years ago, humans were using symbols to represent words and concepts. True
forms of writing developed over the next few thousand years.
●Cylinder seals were rolled across wet clay tablets to produce raised designs.
●Cuneiform symbols stood for concepts and later for sounds or syllables.
When Did Humans Start Talking?
Scientists are not sure. Spoken language does not fossilize, and there are few clues about when
our ancestors began to use complex language to communicate.
However, making and using some of the objects here, which date back 350,000 years, involved
complex behaviors that probably required language.
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Spoken language became possible when the voice box dropped lower in the throat. Image
courtesy of Karen Carr Studio.
Benefits and Costs of Talking
Benefits
Spoken language is essential to modern human cultures. We use language to communicate in a
complex, ever changing world.
As our bodies evolved for speech, the voice box dropped lower in the throat. The area above the
vocal chords lengthened, enabling us to make a wide variety of sounds.
Costs
When the voice box dropped to make speech possible, it became impossible to swallow and
breathe at the same time. Food could get stuck in the larynx and cause choking.
Because human babies do not have a lowered voice box, they can breathe while nursing like
other mammal infants.
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Humans change the world
For millions of years all humans, early and modern alike, had to find their own food. They spent a
large part of each day gathering plants and hunting or scavenging animals. Then, within just the
past 12,000 years, our species, Homo sapiens, made the transition to producing food and
changing our surroundings. We have been so successful that we have inadvertently created a
turning point in the history of life on Earth.
200,000 Years Ago
Modern Humans Evolve in Africa
During a time of dramatic climate change, modern humans (Homo sapiens) evolved in Africa. Like
early humans, modern humans gathered and hunted food. They evolved behaviors that helped
them respond to the challenges of survival.
The first modern humans shared the planet with at least three species of early humans. Over
time, as modern humans spread around the world, the other three species became extinct. We
became the sole survivors in the
human family tree.
Modern humans exchange resources over long distances. Image courtesy of Karen Carr Studio. By
164,000 years ago
Modern humans collect and cook shellfish. By 130,000 years ago
Modern humans exchange resources over long distances. By 90,000 years ago
Modern humans make special tools for fishing. Between 80,000 and 60,000 years ago
Modern humans spread to Asia. By 77,000 years ago
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Modern humans almost become extinct. Image courtesy of Karen Carr Studio.
Modern humans record information on objects. About 74,000 years ago
Near-extinction!
Modern humans almost become extinct; as a result of extreme climate changes, the population
may have been reduced to about 10,000 adults of reproductive age. By 70,000 years ago
Extinction!
Homo erectus becomes extinct By 60,000–40,000 years ago
Modern humans create permanent drawings
Homo neanderthalensis becomes extinct. Image courtesy of Karen Carr Studio. By 50,000 years
ago
Modern humans reach Australia By 40,000 years ago
Modern humans reach Europe By 28,000 years ago
Extinction!
Neanderthals (Homo neanderthalensis) become extinctBy 17,000 years ago
Extinction!
Homo floresiensis becomes extinct, leaving modern humans (Homo sapiens) as the sole survivor
in the once diverse human family tree By 15,000 years ago
Modern humans reach the AmericasHumans grow their own food. Image courtesy of Karen Carr
Studio. 12,000 Years Ago
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The Turning Point
Eventually, humans found they could control the growth and breeding of certain plants and
animals. This discovery led to farming and herding animals, activities that transformed Earth’s
natural landscapes—first locally, then globally.
As humans invested more time in producing food, they settled down. Villages became towns, and
towns became cities. With more food available, the human population began to increase
dramatically.
11,200 years ago
Figs cultivated in Lower Jordan Valley, Middle East
11,000 years ago
Jericho, West Bank, begins to grow into a city
9,500 years ago.
10,000 years ago
Cows domesticated in Africa and Middle East
Squash cultivated in Central America
9,500 years ago
Wheat cultivated in Middle East
Çatalhöyük, Turkey, begins to grow into a city
9,000 years ago
Sheep domesticated in Middle East
Rice cultivated in China
Corn cultivated in North America
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4,400 years ago. Image courtesy of Karen Carr Studio.8,000 years ago
Chickens domesticated in Southeast Asia
7,000 years ago
Potatoes cultivated in South America
Bananas cultivated in Southeast Asia
5,600 years ago
Horses domesticated in Eurasia
4,400 years ago
Caral, Peru, begins to grow into a city
3,600 years ago
Cacao (chocolate) cultivated in Central America
3,100 years ago. Image courtesy of Karen Carr Studio.
3,400 years ago
Athens, Greece, begins to grow into a city
3,100 years ago
Xi’an, China, begins to grow into a city
2,760 years ago
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Rome, Italy, begins to grow into a city
2,000 years ago
Tea cultivated in China
165-180
Smallpox kills millions of citizens in ancient Rome
500
Coffee cultivated in Africa
540-542
Bubonic plague kills up to 10,000 people a day in Europe, North Africa, and the Near East
1345-1400
Bubonic plague (“The Plague”) kills at least a third of Europe’s population
1918-1919
Influenza kills up to 40 million people worldwide, about 5% of the entire human population.
Humans Change the World: Today
Modern humans have spread to every continent and grown to huge numbers. Producing our own
food, rather than tracking it down daily, has freed us to enrich our lives in many ways—to
become artists, inventors, scientists, politicians, and more.
We have altered the world in ways that benefit us greatly. But this transformation has unintended
consequences for other species as well as for ourselves, creating new survival challenges.
By 1995, at least 83% of Earth’s land surface had been directly affected by humans.
In 2004, the International Union for Conservation of Nature (IUCN) reported that current bird,
mammal, and amphibian extinction rates were at least 48 times greater than natural extinction
rates—possibly 1,024 times higher.
As of 2005, humans had built so many dams that nearly six times as much water was held in
storage as flowed freely in rivers.
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World population growth. Image courtesy of Karen Carr Studio.
Benefits and Costs of Our Success
Benefits
By settling down and producing our own food, we created:
●enough food to feed billions of people and respond to catastrophes;
●buildings that protect us from extreme weather;
●technologies that enable us to extend our lives, communicate worldwide, and venture into
space;
●time to think, create, play, socialize, and much more.
Costs
By settling down and producing our own food, we created:
●piles of waste that form natural breeding grounds for contagious diseases;
●large concentrations of people, enabling diseases to spread and become epidemics;
●domesticated landscapes that displace wild habitats;
●loss of wild species that depend on natural habitats.
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Technologies enabling plant and animal domestication, as seen in by these stone sickle blades
from Dynastic Egypt and Ali Kosh, Iran, represent a turning point of human interaction with the
environment. Image courtesy of Chip Clark, Smithsonian Institution.
Changing the World:
Great Moments in Food Technology
1928 - Sliced bread
1791 - Artificial teeth
63 BCE - Water-powered grist mill
500 BCE - Iron plow
9500 BCE - Grain storehouse
Changing the World:
Animal Domestication
FACT: From 1961 to 2004, the population of cattle, pigs, sheep, and goats increased from 2.7 to
4.1 billion. The number of domesticated fowl
grew from 3 to 16 billion.
FACT: Of the estimated 15,000 species of mammals and birds, only about 30–40 have been used
for food.
FACT: Fewer than 14 species of animals account for 90% of global livestock production today.
Changing the World:
Agriculture
FACT: About a quarter of Earth’s surface is used to grow crops.
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FACT: Fewer than 20 plant species produce most of the world’s food.
FACT: Most of the world’s population is dependent on 4 main crops: wheat, corn, rice, and
potatoes.
Changing the World:
Growing Numbers of People
FACT: Between 1959 and 1999, just 40 years, the human population doubled from 3 billion to 6
billion people.
FACT: Today the population continues to grow by over 90 million people a year.
FACT: By 2042, the world population may reach 9 billion, an increase of 50% in 43 years.
Changing the World:
Unintended Consequences
FACT: A cholera pandemic that began in 1961 is still ongoing in Asia, Africa, and the Americas.
The number of cases reported in 2006 was 79% more than in 2005.
FACT: Every year between 3 and 5 million people get “the flu,” and between 250,000 and
500,000 people die from it.
FACT: A child dies of malaria every 30 seconds. About 40% of the world’s population is at risk of
malaria.
FACT: Every second someone in the world is infected with tuberculosis. One-third of the world’s
population is infected.
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