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Layers of the Earth Geosphere The Earth as a System • Integrated system of rock, air, water, and living things. • This system is divided into four parts: – – – – atmosphere (air) hydrosphere (water) biosphere (living things) geosphere (rock) Geosphere • Solid part of the Earth’s crust that consists of all rock, and the soils and sediments on Earth’s surface. • Most located in Earth’s interior Earth’s Interior • Seismic Waves: the waves that travel through the Earth’s interior during an earthquake. • Altered by the type of material that it travels through. Seismologists • Scientists who measure changes in these waves to determine that the earth’s interior is made in layers. Composition of the Earth • Three layers: – crust – mantle – core • Density increases towards the center of the Earth Crust • Thin, outer layer. • Made up of light elements • less than 1% of Earth’s mass • 5-70km thick Mantle • Layer beneath the crust • 64% of mass of Earth • 2,900 km thick • Made of – lithosphere – asthenosphere – mesosphere Lithosphere • Outer layer • cool, rigid • divided up into huge tectonic plates Asthenosphere • 250 km thick • solid, plastic layer made of rock • flows very slowly and allows tectonic plates to move across Mesosphere • 2,250 km thick • “middle” sphere • lower part of mantle Core • 3,248 km radius • sphere of hot, dense nickel and iron • 4,000 - 5,000 °C • 1/3 of the Earth’s mass • Made of – Outer Core – Inner Core • Outer Core; 2,200 km thick, outer shell, made of liquid nickel and iron • Inner Core: 1,228 km radius; a sphere of solid iron and nickel First Life??? • First life may have first evolved deep in the crust and then migrated to the surface when conditions became favorable. • “extremophiles” • Hypothesized that the biomass below the surface far exceeds the biomass at the surface. • Be able to draw and label the three layers of the earth (crust, mantle, and core) as well as the 5 layers based on physical properties (lithosphere, asthenosphere, mesosphere, outer and inner core).