#Things to consider
- The story of atoms, molecules and their interactions is called chemistry.
- The story of organisms is called biology.
- Three important revolutions shaped the course of history: the Cognitive Revolution kick-started history about 70,000 years ago. The Agricultural Revolution sped it up about 12,000 years ago. The Scientific Revolution, which got under way only 500 years ago, may well end history and start something completely different.
- Horses and donkeys have a recent common ancestor and share many physical traits. But they show little sexual interest in one another. They will mate if induced to do so – but their offspring, called mules, are sterile.
- Species that evolved from a common ancestor are bunched together under the heading ‘genus’ (plural genera).