Land bridge

From Wikipedia, the free encyclopedia
Jump to navigation Jump to search

A land bridge is a term in biogeography. It is a narrow land connection between otherwise separate areas, sometimes called an isthmus.

Its significance is that animals and plants may cross over it when the sea level is lower. They cannot easily cross when the sea level is higher, and water covers the land bridge. The separation of a once connected population often leads to speciation, the splitting of one species into two and the two species change over time to be different but have distant similarities.

There are several causes which affect whether a land bridge is above or below the water. Plate tectonics amay cause the rise or lowering of land. The causes of general sea level changes are not fully understood, but when sea levels fall, shallow sections of continental shelf may get exposed. Sometimes the sea floor rises due to "post-glacial rebound" after an ice age.

Notable examples[change | change source]