Climate and Terrestrial Biodiversity

Transcription

1 Climate and Terrestrial Biodiversity

2 Biodiversity and Climate Different climates lead to different communities of organisms, especially vegetation. As you move from the equator to the poles the amount of biodiversity decreases. Latitude

3 Biodiversity and Climate Weather is a local area s short-term physical conditions such as temperature and precipitation. Climate is a region s average weather conditions over a long time.

4 Earth s Current Climate Zones Figure 5-2

5 Climate An area's climate is determined mostly by: solar radiation, earth s rotation global patterns of air and water movement gases in the atmosphere earth s surface features.

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7 Solar Radiation Due to the tilt of the earth s axis, the earth is warmed unevenly making the tropics hot and the polar regions cold As the earth revolves around the sun the tilt also causes season changes in temperature and precipitation Figure 5-3

8 The Sun s rays strike the equator directly twice a year: 12 hours of daylight and 12 hours of darkness March Equinox March 20 th or 21 st September Equinox September 22 nd or 23 rd June Solstice June 20 th or 21 st Sun directly above the Tropic of Cancer (23.5 N latitude) the longest day in the northern hemisphere December Solstice December 21 st or 22 nd Sun directly over the Tropic of Capricorn (23.5 S latitude) the shortest day in the northern hemisphere

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10 Convection Currents Heat from the sun evaporates ocean water and transfers heat from the ocean to the atmosphere creating convection cells that move heat and water from one area to another (adiabatic cooling and heating) Figure 5-5

11 Convection Cells The result of the Coriolis effect is six giant convection cells at different latitudes forming large terrestrial regions characterized by similar climate, soil, plants and animals (Biomes) Figure 5-6

12 Fig. 7-8, p. 146

13 Polar Tundra Subpolar Coniferous forest Temperate Desert Hot Deciduous forest Chaparral Grassland Tropical Desert Rain forest Tropical seasonal forest Scrubland Savanna Fig. 7-10, p. 147

14 Earth s Rotation The largest input of solar energy occurs at the equator. As this air is heated it rises and moves toward the poles. However, the earth s rotation deflects the movement of the air over different parts of the earth. This creates global patterns of prevailing winds that help distribute heat and moisture in the atmosphere. Figure 5-4

15 The winds are deflected to the right in the northern hemisphere and to the left in the southern hemisphere in what is called the Coriolis effect.

16 Ocean Currents: Distributing Heat and Nutrients Heat and differences in water density create warm an cold ocean currents. Prevailing winds and irregularly shaped continents interrupt these currents and cause them to flow in roughly circular patterns between the continents Creates a connected loop of deep and shallow ocean currents which act like a giant conveyor belt and redistribute heat received by the sun (especially along the coast)

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18 Fig. 7-2, p. 142

19 Greenhouse Gases Warm the Lower Atmosphere Greenhouse gases H 2 O allow mostly visible light and some infra red CO 2 radiation and some UV radiation from the sun CH 4 to pass through the atmosphere N 2 O Greenhouse effect long wave length infra red radiation (heat) rises to the lower atmosphere

20 Flow of Energy to and from the Earth

21 The Earth s Surface Features Affect Local Climates Rain Shadow Effect Mountains-interrupt flow of prevailing winds and movement of storm

22 The Earth s Surface Features Affect Local Climates Heat Island Effect Cities- bricks, concrete, asphalt absorb and hold heat and buildings block wind flow. Causing higher temperatures and lower wind speeds

23 The Earth s Surface Features Affect Local Climates World s oceans and large lakes moderate weather and climate Heat is absorbed and released more slowly by water than by land. Creates land and sea breezes

24 ENSO A periodic (3-7 years) reversal in the surface (wind and water) currents in the tropical Pacific Ocean 1. Trade winds near South America weaken 2. Warm equatorial water from the western Pacific moves eastward to toward the west coast of South America 3. #2 suppresses upwelling of the coast of Peru (decreased productivity!) 4. Results in extremely rainy weather along the coast of South America and Southwestern US and extremely dry weather in Australia and SE Asia (affects most of the world)

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27 DESERT BIOMES Deserts are areas where evaporation exceeds precipitation. Deserts have little precipitation and little vegetation. Found in tropical, temperate and polar regions. Desert plants have adaptations that help them stay cool and get enough water.

28 DESERT BIOMES Variations in annual temperature (red) and precipitation (blue) in tropical, temperate and cold deserts. Figure 5-12

29 Tropical Desert Mean monthly temperature ( C) Freezing point Month Mean monthly precipitation (mm) Fig. 5-12a, p. 109

30 Temperate Desert Mean monthly temperature ( C) Freezing point Month Mean monthly precipitation (mm) Fig. 5-12b, p. 109

31 Polar Desert Mean monthly temperature ( C) Freezing point Month Mean monthly precipitation (mm) Fig. 5-12c, p. 109

32 DESERT BIOMES The flora and fauna in desert ecosystems adapt to their environment through their behavior and physiology. Figure 5-13

33 GRASSLANDS AND CHAPARRAL BIOMES Variations in annual temperature (red) and precipitation (blue). Figure 5-14

34 Tropical grassland (savanna) Mean monthly temperature ( C) Freezing point Month Mean monthly precipitation (mm) Fig. 5-14a, p. 112

35 Temperate grassland Mean monthly temperature ( C) Freezing point Month Mean monthly precipitation (mm) Fig. 5-14b, p. 112

36 Polar grassland (arctic tundra) Mean monthly temperature ( C) Freezing point Month Mean monthly precipitation (mm) Fig. 5-14c, p. 112

37 GRASSLANDS AND CHAPARRAL BIOMES Grasslands (prairies) occur in areas too moist for desert and too dry for forests. Savannas are tropical grasslands with scattered tree and herds of hoofed animals.

38 Temperate Grasslands Ø The cold winters and hot dry summers have deep and fertile soil that make them ideal for growing crops and grazing cattle. Figure 5-15

39 Temperate Grasslands Temperate tallgrass prairie ecosystem in North America. Figure 5-16

40 Polar Grasslands Ø Polar grasslands are covered with ice and snow except during a brief summer. Figure 5-17

41 Chaparral Chaparral has a moderate climate but its dense thickets of spiny shrubs are subject to periodic fires. Figure 5-18

42 FOREST BIOMES Variations in annual temperature (red) and precipitation (blue) in tropical, temperate, and polar forests. Figure 5-19

43 Tropical rain forest Mean monthly temperature ( C) Freezing point Month Mean monthly precipitation (mm) Fig. 5-19a, p. 116

44 Temperate deciduous forest Mean monthly temperature ( C) Freezing point Month Mean monthly precipitation (mm) Fig. 5-19b, p. 116

45 Polar evergreen coniferous forest (boreal forest, taiga) Mean monthly temperature ( C) Freezing point Month Mean monthly precipitation (mm) Fig. 5-19c, p. 116

46 FOREST BIOMES Forests have enough precipitation to support stands of trees and are found in tropical, temperate, and polar regions.

47 Tropical Rain Forest Tropical rain forests have heavy rainfall and a rich diversity of species. Found near the equator. Have year-round uniformity warm temperatures and high humidity. Figure 5-20

48 Tropical Rain Forest Filling such niches enables species to avoid or minimize competition and coexist Figure 5-21

49 Temperate Deciduous Forest Most of the trees survive winter by dropping their leaves, which decay and produce a nutrient-rich soil. Figure 5-22

50 Evergreen Coniferous Forests Consist mostly of cone-bearing evergreen trees that keep their needles yearround to help the trees survive long and cold winters. Figure 5-23

51 Temperate Rain Forests Coastal areas support huge conebearing evergreen trees such as redwoods and Douglas fir in a cool moist environment. Figure 5-24

52 MOUNTAIN BIOMES High-elevation islands of biodiversity Often have snowcovered peaks that reflect solar radiation and gradually release water to lowerelevation streams and ecosystems. Figure 5-25

53 HUMAN IMPACTS ON TERRESTRIAL BIOMES Human activities have damaged or disturbed more than half of the world s terrestrial ecosystems. Humans have had a number of specific harmful effects on the world s deserts, grasslands, forests, and mountains.

54 Natural Capital Degradation Desert Large desert cities Soil destruction by off-road vehicles Soil salinization from irrigation Depletion of groundwater Land disturbance and pollution from mineral extraction Fig. 5-26, p. 123

55 Natural Capital Degradation Grasslands Conversion to cropland Release of CO 2 to atmosphere from grassland burning Overgrazing by livestock Oil production and off-road vehicles in arctic tundra Fig. 5-27, p. 123

56 Natural Capital Degradation Forests Clearing for agriculture, livestock grazing, timber, and urban development Conversion of diverse forests to tree plantations Damage from off-road vehicles Pollution of forest streams Fig. 5-28, p. 124

57 Natural Capital Degradation Mountains Agriculture Timber extraction Mineral extraction Hydroelectric dams and reservoirs Increasing tourism Urban air pollution Increased ultraviolet radiation from ozone depletion Soil damage from off-road vehicles Fig. 5-29, p. 124