**1. Introduction**

Diastrophism includes both tectonic movements and plate tectonics. Together with changes in climate, they largely explain the high number of endemic species and biodiversity of both plants and animals on the North American continent. Each continent has had a different climatic and geological history, which explains why each continent differs in its biota from the others, although there are considerable similarities in the evolution of the biota. Thus in Europe, there are relatively few endemic species of plants (Birks, 2008) in contrast to 70% endemic vascular plants in the North American Tundra and Boreal Forest of the western Cordillera of Canada (Harris, 2008), and close to 100% endemic species in some groups of insects. This chapter provides an outline of the evolution of the biota of North America from the time that it was part of the massive continent (Pangaea) occupying the area around the South Pole, until the present day.
