Biogeography provides evidence of evolution by showing that closely related species are usually found in geographically close areas, while Darwin observed unique species had evolved in isolation on the Galapagos Islands, related to ancestral species from the nearest continent. His hypotheses were that only certain organisms could cross the ocean to colonize the islands, limiting what species were present, and over time in isolation the species would evolve divergently from their ancestors.

1. Evidence of Evolution:
Biogeography
Harriet was a tortoise that Darwin took with him
when he left the Galapagos Islands in 1835. She
spent most of her life in an Australian zoo until
she died in 2006 at the age of 175 years old.

2. Biogeography
The study of the geographic distribution of organisms.

3. Biogeography
Closely related species are usually found in areas
that are geographically close to each other

4. Biogeography

5. Biogeography
The behaviour of different species depends on their
environment also. For example, those with no
natural predators will not avoid humans.

6. Biogeography
While researching at the Galapagos Islands, Darwin
developed several hypotheses for a remote island:

7. Biogeography
1) Only birds, plants, and some reptiles can
cross the ocean to get to the island.

8. Biogeography
2) Animals unable to cross the ocean would not
be found on the island.

9. Biogeography
3) Over time the ancestral species would evolve
and diversify in isolation.

10. Biogeography
4) These uniquely evolved species are related
to a species on the nearest continent.
These treecreepers are
actually 2 different
species. Can you see the
differences?

11. How is Biogeography Evidence of
Evolution?