Eyes evolve
Compound eyes with thousands of lenses appear, and the world becomes visible to the things living in it.
- When
- Known to
- ± 5 million years
- Era
- Cambrian, Paleozoic
Cambrian arthropods carry sophisticated compound eyes — some Emu Bay specimens have more than 3,000 lenses and could resolve detail in dim water. Vision transforms ecology: predators can hunt at a distance and prey must hide, flee or armour themselves. The 'light switch' hypothesis holds that the arrival of image-forming eyes was itself a principal driver of the Cambrian explosion.