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Chapter 7 Climate and Terrestrial Biodiversity

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1 Chapter 7 Climate and Terrestrial Biodiversity

2 Core Case Study Blowing in the Wind: A Story of Connections
Wind connects most life on earth. Keeps tropics from being unbearably hot. Prevents rest of world from freezing. Figure 7-1

3 7-1 What Factors Influence Climate?
Concept 7-1 An area's climate is determined mostly by solar radiation, the earth’s rotation, global patterns of air and water movement, gases in the atmosphere, and the earth’s surface features. 3

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. Latitude and elevation help determine climate.

5 Figure 5.2 Natural capital: generalized map of the earth’s current climate zones, showing the major contributing ocean currents and drifts and upwelling areas. Fig. 7-2

6 Animation: Climate and Ocean Currents Map

7 Solar Energy and Global Air Circulation: Distributing Heat
Global air circulation is affected by the uneven heating of the earth’s surface by solar energy, seasonal changes in temperature and precipitation.

8 Video: Seasonal Variation

9 Corilois Effect Solar energy
Cold deserts Air cools and descends at lower latitudes. Westerlies Forests 30°N Northeast trades Hot deserts Warm air rises and moves toward the poles. Forests Solar energy Equator Air cools and descends at lower latitudes. Southeast trades Hot deserts 30°S The highest solar energy input is at the equator. Figure 7.3 Global air circulation. 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. Westerlies Forests Cold deserts 60°S Fig. 7-3, p. 142

10 Convection Currents Global air circulation is affected by the properties of air water, and land. Figure 7-4

11 Global Air Circulation, Ocean Currents, and Biomes
Fig 7.6 11

12 Animation: Air Circulation and Climate

13 Ocean Currents: Distributing Heat and Nutrients
Global warming: Considerable scientific evidence and climate models indicate that large inputs of greenhouse gases from anthropogenic activities into the troposphere can enhance the natural greenhouse effect and change the earth’s climate in your lifetime.

14 (b) The earth's surface absorbs much of the incoming solar radiation
(a) Rays of sunlight penetrate the lower atmosphere and warm the earth's surface. (b) The earth's surface absorbs much of the incoming solar radiation and degrades it to longer-wavelength infrared (IR) radiation, which rises into the lower atmosphere. Some of this IR radiation escapes into space as heat, and some is absorbed by molecules of greenhouse gases and emitted as even longer-wavelength IR radiation, which warms the lower atmosphere. (c) As concentrations of greenhouse gases rise, their molecules absorb and emit more infrared radiation, which adds more heat to the lower atmosphere. Figure 5.7 Natural capital: the natural greenhouse effect. When concentrations of greenhouse gases in the atmosphere rise, the average temperature of the troposphere rises. (Modified by permission from Cecie Starr, Biology: Concepts and Applications, 4th ed., Pacific Grove, Calif.: Brooks/Cole, 2000)

15 Connected Deep and Shallow Ocean Currents
Fig 7-5 15

16 Rain Shadow Effect On the leeward side of the mountain range, air
descends, warms, and Releases little moisture. Prevailing winds pick up moisture from an ocean. On the windward side of a mountain range, air rises, cools, and releases moisture. Dry habitats Moist habitats Figure 5.8 Natural capital: The rain shadow effect is a reduction of rainfall on the sides of mountains facing away from prevailing surface winds. Warm, moist air in prevailing onshore winds loses most of its moisture as rain and snow on the windward (wind-facing) slopes of a mountain range. This leads to semiarid and arid conditions on the leeward side of the mountain range and the land beyond. The Mojave Desert in the U.S. state of California and Asia’s Gobi Desert were both created by this effect. Fig. 7-7

17 7-2 How Does Climate Affect the Nature and Locations of Biomes?
Concept 7-2 Differences in average annual precipitation and temperature lead to the formation of tropical, temperate, and cold deserts, grasslands, and forests, and largely determine their locations. 17

Different climates lead to different communities of organisms, especially vegetation. Biomes – large terrestrial regions characterized by similar climate, soil, plants, and animals. Each biome contains many ecosystems whose communities have adapted to differences in climate, soil, and other environmental factors.

19 Tropic of Cancer Equator Tropic of Capricorn High mountains Polar ice
Polar grassland (arctic tundra) Tropic of Capricorn Temperate grassland Figure 5.9 Natural capital: the earth’s major biomes—the main types of natural vegetation in various undisturbed land areas—result primarily from differences in climate. Each biome contains many ecosystems whose communities have adapted to differences in climate, soil, and other environmental factors. Human ecological footprints (Figures 3 and 4 on pp. S12–S15 in Supplement 4) have removed or altered much of the natural vegetation in some areas for farming, livestock grazing, lumber and fuelwood, mining, and construction. Tropical grassland (savanna) Chaparral Coniferous forest Temperate deciduous forest Tropical forest Desert Fig. 7-8

Biome type is determined by precipitation, temperature and soil type Figure 7-10

Parallel changes occur in vegetation type occur when we travel from the equator to the poles or from lowlands to mountaintops. Figure 7-9

22 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.

23 DESERT BIOMES Variations in annual temperature (red) and precipitation (blue) in tropical, temperate and cold deserts. Figure 7-11

24 DESERT BIOMES The flora and fauna in desert ecosystems adapt to their environment through their behavior and physiology.

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.

26 Climate Graphs of Tropical, Temperate, and Cold Grasslands
Fig 7-12 26

27 Temperate Grasslands Temperate tall-grass prairie ecosystem in North America.

28 Chaparral Figure 7.14 Chaparral vegetation in the U.S. state of Utah and a typical climate graph. Stepped Art Fig. 7-14, p. 152

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

30 Climate Graphs of Tropical, Temperate, and Cold Forests
Fig 7-15 30

31 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 7-16

32 Stratification of Specialized Plant and Animal Niches in a Tropical Rain Forest
Fig 7-17 32

33 Evergreen Coniferous Forests
Consist mostly of cone-bearing evergreen trees that keep their needles year-round to help the trees survive long and cold winters.

34 7-3 How Have We Affected the Word’s Terrestrial Ecosystems?
Concept 7-3 In many areas, human activities are impairing ecological and economic services provided by the earth’s deserts, grasslands, forests, and mountains. 34

35 Major Human Impacts on Terrestrial Ecosystems
Fig 7-20 35

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