Island Biogeography Part 1

Biogeography Exam 5

Typical Islands

small land masses isolated from other land masses by water

Continental Islands

An island which was once part of the adjacent continent. At some point it had the same biota as the as the continent.

Continental islands connection was via: 

continental shelf, possibly united during Pleistocene glaciations OR broke away from the rest of the continent 

Continental islands were once _____ with the _______ during Pleistocene, via ____ or _____.

Continental islands were once connected with the mainland during Pleistocene, via land or ice.

Examples of continental islands

These permanently separated from the mainland:

• Greater Antilles: Cuba (80 MYA)

• New Zealand (80-90 MYA)

• Madagascar (100 MYA)

• Seychelles (65 MYA)

Oceanic Island

an island that arose from the ocean floor and has never been connected to a continent

On oceanic islands, all ____ came via ______

On oceanic islands, all biota came via long distance dispersal; usually originating from the nearest land 

Oceanic islands arose as distant ______ from ______.

• ______ formed near ______

• Formed at a ______ or along ______

• Formed at ________

Oceanic islands arose as distant volcanoes from ocean floor. 

• Volcanoes formed near mid-ocean trench

• Formed at a hotspot or along fracture zones

• Formed at mid-ocean ridge

Oceanic islands that formed at/near a trench:

• ______

• ______

• ______

• Aleutians 

• Lesser Antilles 

• Lesser Sunda Islands

Oceanic islands that formed at hot spot or fracture zone:

• ______

• ______

• Hawaiian Islands (hotspot)

• Galapagos Islands (fracture zone)

Oceanic islands that formed at mid-ocean ridge:

• ______

• Azores 

In some cases, when we’re not sure of the origin we look at ______

direction of plate movement

Some distant islands have _____, probably started as _____, but very long _____ and ______ give it many features of _______

Some distant islands have continental rocks, probably started as continental, but very long time and distant isolations give it many features of oceanic islands 

New Caledonia = 

continental island and a coral reef 

Coral islands = 

oceanic island