Summary:
- All of today’s camels are descended from the same camel ancestors.
- These ancestors lived in North America about a million years ago.
- Through natural selection, descendants of the original camel ancestors evolved the diversity they have today.
- The biogeography of islands yields some of the best evidence for evolution.
- Consider the birds called finches that Darwin studied on the Galápagos Islands (see Figure below).
- All of the finches probably descended from one bird that arrived on the islands from South America.
- The first bird was a seed eater.
- It evolved into many finch species.