Chapter 2 A Living Planet

1. Chapter 2A 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