Paleobiogeography

Biogeography (ENVR333)Fall 2007

5 October 2006

PaleoBiogeography

• Time Scale• Theory of Continental Drift and

Plate Tectonics• The Breakup of Pangea• Biogeographic Implications of a

Dynamic Geography

Geologic Time Scale

(Fig 7.1 MacDonald 2003)

Theory of Continental Drift

• Alfred Wegener (1880-1930)

• 1915 The Origin of Continents and Oceans

• Pangea = supercontinent

Evidence for Continental Drift

Matching shapes

Similar rock types and structures

Continuity of plant and animal fossils

Glacial deposits

Plate Tectonics

Fig 7.5 MacDonald 2003)

Plate Tectonics

Pangea

200 million km2 or 40% of earth’s surface

connectivity

Break up of Pangea

Laurasia

Gondwanaland

Tethyan Seaway

Break up of Pangea

Cenozoic ChangesIndia rafts into Asia (45 mya)

Africa and Europe rejoin (17 mya)

Stepping Stone Islands created (15 mya)

Central American Landbridge (6mya)

Epicontinental seas disappear

http://www.clearlight.com/%7Emhieb/WVFossils/continents.html

Biogeographic ImplicationsSpeciation

Biogeographic Implications

Corridors and Barriers

Great American Interchange

Biogeographic Implications

Corridors and Barriers

12,000 ybp

today

Beringia

Biogeographic ImplicationsMarine-Climate effects