1. Chapter 2 A Living Planet

2. The Solar System  Consists of the sun and nine planets and other celestial bodies –Comets: spheres of ice and dust –Asteroids: large chunks of rocky material

3. The Structure of the Earth  Earth has 3 layers –Core: iron and nickel –Mantle: magma –Crust: thin layer of rock

4. The Structure of the Earth  Atmosphere: layer of gases  Lithosphere: includes crust and upper mantle –Forms ocean floor –Forms 7 continents: Asia, Africa, North America, South America, Europe, Australia, Antartica  Hydrosphere: water elements of earth  Biosphere: where plants and animals live

5. The Structure of the Earth  Continental Drift Theory –Earth was once a supercontinent that divided and slowly drifted apart over millions of years

6. Bodies of Water  Oceans and Seas –Covers 71% of earth –Pacific Ocean, Atlantic Ocean, Indian Ocean, Artic Ocean –Circulates through 3 basic motions  Currents: like rivers in ocean  Waves: swells or ridges produced by wind  Tides: created by gravitational pull of moon or sun

7. Bodies of Water  Hydrologic Cycle –The continuous circulation of water between the atmosphere, the oceans, and the earth

8. Bodies of Water  Lakes –Hold more than 95% of earth’s fresh water supply –Salt water lakes  Rivers and streams –Flow through channels and move water to or from larger bodies of water –Drainage basin: are drained by major river

9. Bodies of Water  Ground Water –Water held in pores of rock –Water table: level at which rock is saturated  Can change depending on amount of precipitation

10. Landforms  Naturally formed features on the surface of the earth –Volcano-Plateau-Cataract –Strait-Mesa-Glacier –Island-Prairie-Cliff –Delta-Steppe-Mountain –Marsh-Valley-Butte –Oasis-Canyon-Swamp –Flood plain-River mouth-Cape –Bay-Harbor-Sea level

11. Landforms  Oceanic landforms: –Continental shelf: earth’s surface from edge of a continent to deep part of the ocean –Ridges: places where new crust is being formed on edges of tectonic plates –Islands: formed by volcanic action, deposits of sand, or deposits of coral skeletons

12. Landforms  Continental landforms –Relief: the difference in elevation of a landform from its lowest point to its highest point  Mountains, hills, plains, plateaus –Topography: the combination of the surface shape and composition of the landforms and their distribution in a region

13. Internal Forces Shaping the Earth  Plate tectonics  Earthquakes  Volcanoes

14. Plate Tectonics  Tectonic Plates: enormous moving pieces of the earth’s lithosphere –Move in 1 of 4 ways  Spreading or moving apart  Subduction or diving under another plate  Collision or crashing into one another  Sliding past each other in a shearing movement

16. Plate Tectonics  3 types of boundaries mark plate movement –Divergent boundary: move apart horizontally –Convergent boundary: plates collide; one goes under the other or both plates crumble –Transform boundary: plates slide past one another –Fault: fracture in the earth’s crust

17. Volcanoes  Crack in earth’s surface where magma, gases, and water from the lower part of the mantle pour out  Lava: magma that has reached earth’s surface

18. Volcanoes  Ring of Fire –Zone around rim of the Pacific Ocean –Eight major plates meet here –Volcanic action and earthquakes often occur –Hot springs and geysers

19. Earthquakes  Violent movement of the earth  Occurs when plates slide past each other at a fault  Seismograph: detects earthquakes

20. Earthquakes  Location –Focus: where earthquake begins –Epicenter: directly above focus on the earth’s surface  Damage –Richter Scale: relative strength of earthquake  Tsunami –Giant wave in ocean

22. External Forces Shaping the Earth  Weathering  Erosion  Building soil

23. Weathering  Physical and chemical processes that change the characteristics of rock on or near the earth’s surface  Creates sediment; smaller pieces of rock –Mud, sand, silt

24. Weathering  Mechanical weathering: processes that break rock into smaller pieces –Does not change composition of rock –Frost, plant roots, human activity

25. Weathering  Chemical weathering: rock is changed into a new substance as a result of interaction between elements in the air or water and minerals in the rock –Iron rusting, acid rain –Occurs more in warm, moist climates

26. Erosion  Occurs when weathered material is moved by the action of wind, water, ice or gravity  Transporting agent must be present

27. Erosion  Water erosion –Water flows in streams or rivers  Erode vertically and horizontally  Delta: fan-like landform that occurs when a river enters the ocean –Wave action along coastline  Can reduce or increase beaches

28. Erosion  Wind erosion –Transports and deposits material in other locations –New landforms may be produced  Sand dunes –Loess  Wind blown silt and clay sediment that produce very fertile soil

29. Erosion  Glacial erosion –Glacier: large, long-lasting mass of ice that moves because of gravity –Glaciation: the changing of landforms by slowly moving glaciers –Moraine: when rocks left behind by a glacier form a ridge or hill

30. Building Soil  Soil: loose mixture of weathered rock, organic matter (humus), air and water  Soil factors –Parent material –Relief –Organisms –Climate –Time