Chapter 43 The Biosphere (Sections 43.1 - 43.4)

1. Chapter 43The Biosphere(Sections 43.1 - 43.4)

2. 43.1 Effects of El Niño • El Niño is a recurring event in which equatorial waters of the eastern-central Pacific warm above their average temperature • During an El Niño, marine currents interact with the atmosphere to influence weather patterns worldwide – causing floods, droughts, and fires • Marine food webs along eastern Pacific coasts decline as warm water flow cuts off nutrient supplies to marine primary producers – in 1998, Galapagos sea lions starved to death

3. Effects on the Biosphere • The opposite of El Niño is La Niña, in which eastern Pacific waters become cooler than average – the west coast of the United States gets little rainfall and the likelihood of hurricanes in the Atlantic increases • El Niño/La Niña events are some of the factors that influence properties of the biosphere,which includes all places where we find life on Earth

4. Key Terms • El Niño • Periodic warming of equatorial Pacific waters and the associated shifts in global weather patterns • La Niña • Periodic cooling of equatorial Pacific waters and the associated shifts in global weather patterns • biosphere • All regions of Earth where organisms live

5. The Biosphere • Interactions among Earth’s oceans and atmosphere give rise to El Niño and other climate patterns

6. Effects of El Niño

7. Animation: Normal vs. El Niño Conditions

8. 43.2 Air Circulation Patterns • Climaterefers to average weather conditions (cloud cover, temperature, humidity, wind speed) over time • Regional climates are influenced by factors that affect winds and ocean currents (intensity of sunlight, distribution of land masses and seas, and elevation) • climate • Average weather conditions in a region over a long time period

9. Seasonal Effects • Seasonal changes in day length and temperature occur because Earth’s axis is tilted about 23 degrees: • In June, the Northern Hemisphere is tilted toward the sun, receives more intense sunlight, and has longer days than the Southern Hemisphere • In December, the Southern Hemisphere tilts sunward • In each hemisphere, the degree of seasonal change in day length increases with latitude

10. Earth’s Tilt and Yearly Rotation

11. Earth’s Tilt and Yearly Rotation D Spring equinox (March). Sun’s direct rays fall on equator; length of day equals length of night. A Summer solstice (June). Northern Hemisphere is most tilted toward sun; has its longest day. Sun C Winter solstice (December). Northern hemisphere is most tilted away from sun; has its shortest day. B Autumn equinox (September). Sun’s direct rays fall on equator; length of day equals length of night. Fig. 43.2, p. 724

12. D Spring equinox (March). Sun’s direct rays fall on equator; length of day equals length of night. A Summer solstice (June). Northern Hemisphere is most tilted toward sun; has its longest day. Sun C Winter solstice (December). Northern hemisphere is most tilted away from sun; has its shortest day. B Autumn equinox (September). Sun’s direct rays fall on equator; length of day equals length of night. Earth’s Tilt and Yearly Rotation Stepped Art Fig. 43.2, p. 724

13. Animation: Orbit Around the Sun

14. Air Circulation and Rainfall • Equatorial regions get more sun energy than higher latitudes • At high latitudes, sunlight is absorbed or reflected by more atmosphere, so less energy reaches the ground • Energy in an incoming parcel of sunlight is spread out over a larger surface area at higher latitudes • Variations in energy from sunlight causes surface warming, which drives global air circulation and rainfall patterns

15. Variation in Intensity of Solar Energy

16. Circulation and Rainfall (cont.) • Two important properties of air: • As air warms, it becomes less dense and rises • Warm air can hold more water than cooler air • Global air circulation and rainfall patterns: • At the equator, warm moist air rises and flows north and south, releasing rain that supports tropical rain forests • At 30° north or south, dry cool air sinks over deserts • At 60°, warm moist air rises again; then cool air sinks at the poles

17. Surface Wind Patterns • Air masses are not attached to Earth’s surface – the Earth spins beneath them, moving faster at the equator and slower at the poles • As a result, major winds seem to curve toward the right in the Northern Hemisphere; and toward the left in the Southern Hemisphere • The prevailing winds in the United States are westerlies

18. Circulation Patterns and Major Winds

19. Circulation Patterns and Major Winds Idealized Pattern of Air Circulation Major Winds Near Earth’s Surface Cooled, dry air descends D At the poles, cold air sinks and moves toward lower latitudes. E Major winds near Earth’s surface do not blow directly north and south because of the effects of Earth’s rotation. Winds deflect to the right of their original direction in the Northern Hemisphere and to the left in the Southern Hemisphere. easterlies (winds from the east) C Air rises again at 60° north and south, where air flowing poleward meets air coming from the poles. westerlies (winds from the west) B As the air flows toward higher latitudes, it cools and loses moisture as rain. At around 30° north and south latitude, the air sinks and flows north and south along Earth’s surface. northeast tradewinds (doldrums) southeast tradewinds westerlies A Warmed by energy from the sun, air at the equator picks up moisture and rises. It reaches a high altitude, and spreads north and south. easterlies Fig. 43.4, p. 725

20. Circulation Patterns and Major Winds Fig. 43.4, p. 725

21. Animation: Global Air Circulation Patterns To play movie you must be in Slide Show Mode PC Users: Please wait for content to load, then click to play Mac Users: CLICK HERE

22. Key Concepts • Air Circulation Patterns • Air circulation starts with latitudinal differences in energy inputs from the sun • Movement of air from the equator toward poles is affected by Earth’s rotation and gives rise to major surface winds and latitudinal patterns in rainfall

23. Animation: Air Circulation and Climate I To play movie you must be in Slide Show Mode PC Users: Please wait for content to load, then click to play Mac Users: CLICK HERE

24. Animation: Air Circulation and Climate II To play movie you must be in Slide Show Mode PC Users: Please wait for content to load, then click to play Mac Users: CLICK HERE

25. 43.3 Ocean, Landforms, and Climates • The ocean is a continuous body of water that covers more than 71% of Earth’s surface • Its water moves in currents that distribute nutrients through marine ecosystems • Warm and cold surface currents affect coastal climates

26. Ocean Currents • As in air, sunlight affects ocean temperature and sets major currents moving away from the equator • The direction of surface currents is determined by the force of major winds, Earth’s rotation, and topography • Clockwise in the Northern Hemisphere • Counterclockwise in the Southern Hemisphere • Deep, narrow currents flow away from the equator along the eastern coast of continents; shallow, wide currents flow toward the equator on western coasts

27. Climate and Major Surface Currents

28. Regional Effects • Mountains, valleys, and other land features affect climate • High mountain ranges (such as the Rockies) that parallel the coast block moist air from moving inland, causing a rain shadow on their leeward side • rain shadow • Dry region downwind of a coastal mountain range

29. Rain Shadow Effect

30. Rain Shadow Effect Fig. 43.6.1, p. 727

31. Rain Shadow Effect A Prevailing winds move moisture inland from the Pacific Ocean. B Clouds pile up and rain forms on side of mountain range facing prevailing winds. moist habitats C Rain shadow on side facing away from the prevailing winds makes arid conditions. 4,000/ 75 3,000/ 85 2,000/25 1,800/ 125 1,000/25 moist habitats 1,000/ 85 15/ 25 Fig. 43.6.1, p. 727

32. Rain Shadow Effect Fig. 43.6.2, p. 727

33. Rain Shadow Effect Fig. 43.6.3, p. 727

34. Coastal Breezes

35. Coastal Breezes A In afternoon; the land is warmer than the sea, so the breeze blows onto shore. cool air warm air Fig. 43.7a, p. 727

36. Coastal Breezes B In the evening, the sea is warmer than the land; the breeze blows out to sea. Fig. 43.7b, p. 727

37. A In afternoon; the land is warmer than the sea, so the breeze blows onto shore. cool air warm air B In the evening, the sea is warmer than the land; the breeze blows out to sea. Coastal Breezes Stepped Art Fig. 43.7, p. 727

38. Monsoons • Differential heating of water and land also causes monsoons • Example: In the summer, hot air rises over Asia, drawing in moist air from the Indian Ocean; in the winter, cool air sinks and a dry wind blows toward the coast • monsoon • Wind that reverses direction seasonally

39. Key Concepts • Ocean Circulation Patterns • Heating of the tropics also sets ocean waters in motion • As water circulates, it carries and releases heat, and so affects the climate on land • Interactions between oceans, air, and land affect coastal climates

40. Animation: Major Climate Zones and Ocean Currents To play movie you must be in Slide Show Mode PC Users: Please wait for content to load, then click to play Mac Users: CLICK HERE

41. 43.4 Biomes • Biomes are communities with similar climates and vegetation that evolve in widely separated regions as a result of similar environmental factors • biome • Discontinuous region characterized by its climate and dominant vegetation

42. Differences Between Biomes • Rainfall and temperature are the main determinants of the type of biome in a given region • Soils also influence biome distribution • Properties of soils vary depending on the types, proportions, and compaction of mineral particles and varying amounts of humus • Climate and soils affect primary production, so primary production varies among biomes

43. Major Biomes and Marine Ecoregions

44. Major Biomes and Marine Ecoregions

45. Primary Productivity

46. Similarities Within a Biome • Unrelated species in widely separated parts of a biome may have similar body structures that arose by morphological convergence • Example: Cactuses with water-storing stems live in North American deserts, and euphorbs with water-storing stems live in African deserts, but cactuses and euphorbs do not share a common ancestor with a water-storing stem

47. Animation: Rain Shadow Effect To play movie you must be in Slide Show Mode PC Users: Please wait for content to load, then click to play Mac Users: CLICK HERE

48. Animation: Major Biomes To play movie you must be in Slide Show Mode PC Users: Please wait for content to load, then click to play Mac Users: CLICK HERE