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 thehuman family tree.
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
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
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 extinct
By 17,000 years ago
Extinction!
Homo floresiensis becomes extinct, leavingmodern humans (Homo sapiens) as the sole survivor in the once diverse human family tree
By 15,000 years ago
Modern humans reach the Americas
12,000 Years Ago
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
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
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
3,400 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
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.
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.
Changing the World:
Great Moments in Food Technology
1928 - Sliced bread1791 - 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.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.
