The theory that the planet's continents are in motion was first proposed in 1912, but it was not fully accepted until the late 1900's. The concept in time became linked with the theory of plate tectonics. In addition to providing, for the first time, an understanding of why earthquakes and volcanoes are distributed the way they are, the theory explains some of the environmental changes that occurred over the past 20 million years. Some anthropologists believe the collision of the African continent with Eurasia, which took place at that time, produced profound environmental changes in east Africa and south Africa and may have led to the appearance of the human line. More information: |
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