A collection of images shows the diversity of eyes found in the natural world, and it's explained how eyes are a product of natural selection that evolved for best use. It is explained how these diverse eyes work; from the simple collection of light-sensitive cells in an earthworm, to the indented cells in a nautilus and onto eyes that possess lenses. The differences are clearly shown using practical models, including the pinhole camera at the Greenwich Observatory.

This clip is from:
First broadcast:
18 November 2008

Students could explain in their own words how the physiology and effectiveness of eyes of an earthworm and a nautilus differ. They could then be asked to explain how the lens might have evolved.