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
4 CLIMATE: A BRIEF INTRODUCTION 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 5.2Natural 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 PLAYANIMATION
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.
9 Corilois Effect Solar energy Cold desertsAir cools and descends at lower latitudes.WesterliesForests30°NNortheast tradesHot desertsWarm air rises and moves toward the poles.Forests0°Solar energyEquatorAir cools and descends at lower latitudes.Southeast tradesHot deserts30°SThe highest solar energy input is at the equator.Figure 7.3Global 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.WesterliesForestsCold deserts60°SFig. 7-3, p. 142
10 Convection CurrentsGlobal air circulation is affected by the properties of air water, and land.Figure 7-4
11 Global Air Circulation, Ocean Currents, and Biomes Fig 7.611
12 Animation: Air Circulation and Climate PLAYANIMATION
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 sunlightpenetrate the loweratmosphere andwarm the earth'ssurface.(b) The earth's surface absorbsmuch of the incoming solar radiationand degrades it to longer-wavelengthinfrared (IR) radiation, which risesinto the lower atmosphere. Some of thisIR radiation escapes into space as heat,and some is absorbed by molecules ofgreenhouse gases and emitted as evenlonger-wavelength IR radiation, whichwarms the lower atmosphere.(c) As concentrations ofgreenhouse gases rise,their molecules absorband emit more infraredradiation, which addsmore heat to the loweratmosphere.Figure 5.7Natural 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 7-515
16 Rain Shadow Effect On the leeward side of the mountain range, air descends, warms, andReleases little moisture.Prevailing windspick up moisturefrom an ocean.On the windwardside of a mountain range,air rises, cools, andreleases moisture.Dry habitatsMoist habitatsFigure 5.8Natural 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
18 BIOMES: CLIMATE AND LIFE ON LAND 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 ofCapricornTemperate grasslandFigure 5.9Natural 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)ChaparralConiferous forestTemperate deciduous forestTropical forestDesertFig. 7-8
20 BIOMES: CLIMATE AND LIFE ON LAND Biome type is determined by precipitation, temperature and soil typeFigure 7-10
21 BIOMES: CLIMATE AND LIFE ON LAND 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 BIOMESDeserts 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 BIOMESVariations in annual temperature (red) and precipitation (blue) in tropical, temperate and cold deserts.Figure 7-11
24 DESERT BIOMESThe flora and fauna in desert ecosystems adapt to their environment through their behavior and physiology.
25 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.
26 Climate Graphs of Tropical, Temperate, and Cold Grasslands Fig 7-1226
27 Temperate GrasslandsTemperate tall-grass prairie ecosystem in North America.
28 ChaparralFigure 7.14Chaparral vegetation in the U.S. state of Utah and a typical climate graph.Stepped ArtFig. 7-14, p. 152
29 FOREST BIOMESForests 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 7-1530
31 Tropical Rain ForestTropical 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 7-1732
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 7-2035