The history of the cell

From a lifeless planet to the first cells, oxygen, the cell that swallowed a bacterium and many-celled life, on a timeline of four and a half billion years.

1. 1 A planet without life
2. 2 The first cellslocked
3. 3 Two kinds of simple celllocked
4. 4 Oxygen changes everythinglocked
5. 5 The cell that swallowed a bacteriumlocked
6. 6 Many cellslocked
7. 7 The tree todaylocked