Andes Mountains, South America

6. Andes Mountains, South America

9. Evidence of Continental Drift Fossils • Similar fossils of several different animals and plants that once lived on land had been found on widely separated continents. • The ages of different fossils predated Wegener’s time frame for the breakup of Pangaea.

10. Fossils • Fossils of Glossopteris, a seed fern that resembled low shrubs, have been found on many continents, indicating that the areas had a single climate that was close to the equator.

12. Earth’s Layers

13. Layers of the Earth • There are two ways that scientists label the layers of the Earth. • Composition layers • Physical layers

14. Composition (What it is made of) • Crust • Mantle • Core

15. How are the earth’s layers similar to an egg? Shell=crust Egg white=mantle Yolk=core Earth’s Layers

16. Outer layer 5-100 km thick Thinnest layer 2 types of crust Oceanic (very dense, made of basalt) Continental (less dense, made of granite) The Crust

17. Oceanic and Continental Crust

18. Middle layer Very thick layer Roughly 2800 km thick No one has ever drilled to the mantle It is VERY hot composed of silicate rocks that are rich in iron and magnesium Even though its solid it can flow The Mantle

19. Convection Currents Convection Currents Cause the Tectonic Plates to move Movement of these plates Cause: Earth Quakes Mountains Volcanoes Rift valleys Tsunamis

20. Tectonic Plates • Earth’s crust is broken into about 19 pieces • These plates move on top of the asthenosphere

21. The Core • Made mostly of Iron and Nickel • 1/3 of the earth’s mass • Very hot • The core’s diameter is about the size of Mars (6856 km )

22. Physical Layers • The less familiar layers are the physical layers. • They are based on how the layer looks or acts.

23. Physical Structure of the Earth • Lithosphere (Crust) - (15-300 km) rigid outer layer • The tectonic Plates • A combination of crust and the upper region of the mantle • Cold and brittle (easily broken)

24. Physical Layers • Asthenosphere • weak sphere” (250 km) • Hard rock that acts like warm tar or honey • Ductile and highly Viscous • involved in plate tectonic movements

25. Mesosphere • Layer found between the asthenosphere and the outer core

26. Physical Layers Continued • Outer Core- (2200 km) • liquid layer • Inner Core-(diameter= 2456 km) • Solid, dense core of the planet • Densest layer of the planet

27. Side by side comparison

28. The “spheres” • Atmosphere • Least dense layer of the Earth • Made of mostly oxygen and nitrogen • Surrounds the Earth • Filters out harmful radiation

29. Biosphere • Layer that all life is in • Not a specific location, just anywhere life is found

30. Hydrosphere • Density= ~1.0 g/mL • Describes the combined mass of water found on, under, and over the surface of a planet. • Approximately 75% of the Earth's surface, an area of some 361 million square kilometres (is covered by ocean.

31. Interesting fact… • Did you know?... • The center of the Earth’s core is hotter than the surface of the sun. The temperature of Earth’s inner core reaches 6000 °C whereas the surface of the sun is roughly 5500 °C. • The sun’s core, however, is 15,000,000 °C