Plate Tectonics

The evolution of species on the land is linked to and driven by various climatological and geological changes that operated on the land surface of the earth.

As we will discuss later, the earth currently has significant climate variations on a timescale of 100,000 years. In addition, over the last 200-250 million years the earth is experiencing an era go global tectonic motion which makes the land surface a Dangerous Place to Live:

Plate Tectonics means that the crust of the earth is divided into large connected units, all of which are moving relative to one another and colliding with one another in various ways. The idea of Plate Tectonics was first published by the German geologist, Alfred Wegener in 1915 but this theory was largely ridiculed until magnetic mapping of the ocean floor was done in the late 50's. This history of the acceptance of this theory is summarized here .

Summary of Evidence for Plate Tectonics:

Now it is recognized that the surface of the earth can be divided up into roughly 10--12 large scale plates and perhaps a number of smaller ones as in the case of the Pacific Northwest

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