Learning path · Intermediate
The Story of Life
Four billion years in eight lessons: the first cells, the code of DNA, evolution, the microbes that run the world, mass extinctions and the webs that link living things.
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- 1
Life & Biology
The Origin of Life
Around four billion years ago, on a hot young planet, chemistry became biology. Nobody knows exactly how, but the clues are piling up.
4 min read 4-question quiz
- 2
Life & Biology
What Is Life? The Cell
Everything alive is made of cells, tiny bags of chemistry that eat, grow, copy themselves and die. You are a cooperative of about 37 trillion of them.
4 min read 4-question quiz
- 3
Life & Biology
DNA and Genes
Inside every one of your cells is a two-metre-long molecule carrying the complete instructions to build and run you. Here is how the code works.
4 min read 4-question quiz
- 4
Life & Biology
Evolution
Every species alive, including ours, descends from earlier ones, shaped over millions of years by a simple process Darwin called natural selection. Here is how it works and how we know.
4 min read 4-question quiz
- 5
Life & Biology
Bacteria and Viruses
The smallest living things outnumber everything else combined and run the planet's chemistry. Most are harmless; some keep you alive; a few can kill you.
4 min read 4-question quiz
- 6
Life & Biology
Dinosaurs and Mass Extinctions
For 165 million years dinosaurs ruled the land, then nearly all of them vanished in a single catastrophe. Their story is also the story of how life nearly ended five times.
3 min read 4-question quiz
- 7
Life & Biology
Ecosystems and Food Webs
No living thing lives alone. Energy from the Sun flows through plants, grazers and predators, and the whole web can unravel when one thread is pulled.
4 min read 4-question quiz
- 8
Plants & Fungi
Photosynthesis: How Plants Eat Light
Every leaf is a solar panel that turns sunlight, water and air into sugar and oxygen. It is the chemical reaction that feeds almost everything alive.
3 min read 4-question quiz
