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Chapter 7 Climate and Terrestrial Biodiversity. 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. 7-1 What Factors Influence Climate? .
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Core Case StudyBlowing 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
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.
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.
Animation: Climate and Ocean Currents Map PLAY ANIMATION
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.
Video: Seasonal Variation PLAY VIDEO
Corilois Effect 60°N Cold deserts Air cools and descends at lower latitudes. Westerlies Forests 30°N Hot deserts Northeast trades Warm air rises and moves toward the poles. Forests Solar energy 0° Equator Air cools and descends at lower latitudes. Southeast trades Hot deserts 30°S The highest solar energy input is at the equator. Westerlies Forests Cold deserts 60°S Fig. 7-3, p. 142
Convection Currents • Global air circulation is affected by the properties of air water, and land. Figure 7-4
Animation: Air Circulation and Climate PLAY ANIMATION
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.
(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.
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 Fig. 7-7
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.
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.
Tropic of Cancer Equator High mountains Polar ice Polar grassland (arctic tundra) Tropic of Capricorn Temperate grassland Tropical grassland (savanna) Chaparral Coniferous forest Temperate deciduous forest Tropical forest Desert Fig. 7-8
BIOMES: CLIMATE AND LIFE ON LAND • Biome type is determined by precipitation, temperature and soil type Figure 7-10
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
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.
DESERT BIOMES • Variations in annual temperature (red) and precipitation (blue) in tropical, temperate and cold deserts. Figure 7-11
DESERT BIOMES • The flora and fauna in desert ecosystems adapt to their environment through their behavior and physiology.
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.
Climate Graphs of Tropical, Temperate, and Cold Grasslands Fig 7-12
Temperate Grasslands • Temperate tall-grass prairie ecosystem in North America.
Chaparral Stepped Art Fig. 7-14, p. 152
FOREST BIOMES • Forests have enough precipitation to support stands of trees and are found in tropical, temperate, and polar regions.
Climate Graphs of Tropical, Temperate, and Cold Forests Fig 7-15
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
Stratification of Specialized Plant and Animal Niches in a Tropical Rain Forest Fig 7-17
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.
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.
