5-1-5 Biogeograpy: Separation and Divergence Flashcards
Define biogeography
The study of how plants and animals are distributed across the globe.
Why are similar species found in different parts of the world?
A plant or animal that evolves in one place may spread to other accessible areas of the world.
Geographical barriers can affect the evolution of population. Give an example.
Darwin observed that there were many finch species on the Galapagos Islands, but not on the mainland. This indicated that bodies of water acted as barriers, and the finches do not travel from one island to another, so they evolve separately in each island. There were no barriers in the continent to isolate the finches and cause them to evolve separately.
Another example:
Camels and llamas are close relatives, but they are found in two separate continents. Why?
Fossil records indicate that camel evolved in North America and later migrated to South America and also across the Bering Strait into Asia and then into Africa. Camels became extinct in North America. Once separated, the groups in Asia and Africa evolved separately from those in South America.
Placement of continents can also affect the spread of species. Give an example.
Marsupials arose when South America, Antarctica, and Australia were all joined as a single land mass. Australia split off before the evolution of placental mammals such as dogs, cats, and horses. Before humans arrived, Australia had only marsupial mammals.
What is comparative anatomy?
The study of body structures of different species to find similarities that may point to a common ancestor.
What are homologous structures?
Body structures from different species that are similar.
An example of a homologous structure.
The forelimbs of vertebrates are organized in much the same way.
What can affect the spread of species?
Placement of continents and geographical barriers
