1. I. Changes in the Environment

2. A. The Lithosphere
1. Tectonic plates- large movable parts of the lithosphere.
a. Fifteen different ones on our planet
2. We sit on the North American plate

4. 3. Collisions of plates cause. earthquakes, volcanoes, and mountains
3. Collisions of plates cause earthquakes, volcanoes, and mountains to form

8. 4. Always moving; about 10 cm per year
5. Lithosphere also changes by weathering
a. Breaking o f rocks by water and wind
b. Pieces are carried away by erosion

9. B. Pangea 1. Many years ago there was one continent called Pangea
a. Guy who proved it cut out continents on paper and put’em together like a puzzle

11. 2. If continents move at 10 cm per year
2. If continents move at 10 cm per year and South America is 3075 km from Africa, how many years ago should Pangea have existed?
a km= 307,500,000cm
b. Years=307,500,000 cm / 10 cm per year
c. Years = 30,750,000 ago