1. Chapter 20 and 21
The biosphere

2. Biosphere
The biosphere includes all places where organisms live on Earth

3. Biosphere The biosphere is divided into Biomes
Biomes are large areas distinctive in habitat conditions and community structure
Habitat conditions are shaped by
Climate
Topography
Soils

4. Biosphere Climate is the average weather conditions over time
Temperature, humidity, wind, precipitation, etc
Climates are created by several factors

5. Biosphere Climate Seasonal Effects
Daylength and temperature change due to the Earth’s tilted axis

6. Biosphere Climate Air Circulation Patterns
The equator gets more solar energy
Warms the air making it less dense
Causes evaporation from the ocean
Results in upward movement of warm moist air

7. Biosphere Climate Air Circulation Patterns Warm, moist air rises
Cools, releasing moisture as rain creating an area of high rainfall (rain forests)
Cooler air flows north and south
Cooled, dry air descends near 30°N and S latitudes
Creates an area of low rainfall (deserts)
The air cycles back towards the equator
Air warms and picks up moisture starting the cycle again
Several bands of circulating air encompass the globe

9. Biosphere Climate Surface Wind Patterns
Earth’s rotation curves the paths of the bands of air circulating the globe
Winds curve towards the right in the Northern Hemisphere
In the Southern Hemisphere the wind curves left
Creates the prevailing winds (westerlies and easterlies)
Doldrums occur where the winds are intermittent

10. Biosphere Climate Ocean Currents
More sunlight at the equator warms the water ultimately creating water currents through the ocean
Water temperatures contribute to regional differences in air temperature and rainfall

11. Figure Major climate zones correlated with surface currents and surface drifts of the world ocean. Warm surface currents start moving from the equator toward the poles, but prevailing winds, Earth’s rotation, gravity, the shape of ocean basins, and landforms influence the direction of flow. Water temperatures, which differ with latitude and depth, contribute to regional differences in air temperature and rainfall.
Fig. 43.5, p. 726

12. Biosphere Topography creates regional effects
Local topography affects climate
Proximity to oceans moderate climate
Elevation
Land masses: Rain Shadows
Warm moist air along the coast
Cools as the air rises over mountains (precipitation)
Dry air descends and warms as it flows down the leeward side

13. 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
moist habitats
1,000/25
1,000/ 85
15/ 25
Figure Rain shadow effect. On the side of mountains facing away from prevailing winds, rainfall is light. Black numbers signify annual precipitation, in centimeters, averaged on both sides of the Sierra Nevada, a mountain range. White numbers signify elevations, in meters.
Fig , p. 727

14. Biosphere
Soils
Types of soil directly impacts what plants can grow and their productivity
Soils differ in
Texture (ratio of sand, silt, and clay)
Structure (granular, blocky, etc) pH
Fertility (nutrient availability)

16. Questions What is the biosphere? What is a biome?
Warm air ______ (rises or lowers) and it holds ______ (more or less) water than cold air
Based on the air circulation patterns where would you expect deserts to form?
Based on the air circulation patterns where would you expect tropical rain forests to form?
T or F A rain shadow results from movement of air over a mountain range

17. Biomes Desert High temperature (cools at night) Low rainfall (0-10cm)
Vegetation: succulents, annuals
Areas which receive more rainfall have a greater variety of plants
Adapted to dry conditions
Animals: reptiles, insects, small nocturnal mammals
Air circulation patterns (30° latitude) and rain shadows create most deserts

18. Lowlands with lower rainfall
Uplands with a bit more rainfall

19. Mojave Desert after the rains: annual poppies sprout, flower, produce seeds, and die in the few short weeks while there is moisture

21. Fennec Fox
Jerboa

22. Biomes Grasslands Tropical to Temperate Rainfall 25-90 cm
Vegetation: grass, forbs (wild flowers), some trees
The amount of rain determines whether it is a short, tall, or savanna grassland
Adapted to strong winds, infrequent rain, drought
Animals: abundant diverse herbivores and their predators
Fires and grazing keeps shrubs and trees to a minimum

26. Fig b, p.763

27. Credit: © Joe McDonald/Visuals Unlimited
301213
Masai Ostrich on African savanna.

28. Credit: © Joe McDonald/Visuals Unlimited
300241
African Lioness (Panthera leo) and African Elephants, Masai Mara Game Reserve, Kenya.

29. Credit: © William J. Weber/Visuals Unlimited
228616
Black-Tailed Prairie Dog (Cynomys ludovicianus), head emerging from burrow.

30. Fig a, p.763