LS1_LECTURE_21

animal diversity also tends to be low migration why

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Unformatted text preview: rbaceous plants. !  Low plant species diversity, low productivity, and low aboveground biomass. !  Animal diversity also tends to be low. migration Why Are the Tropics Wet? !  Areas along the equator receive the most moisture; locations at about 30º N and 30º S latitude are among the driest on Earth. as warm air rises and cools=, is dropped over the=ropid,/xl9 !  A major cycle in global air circulation, called a Hadley cell, is responsible for this pattern. Why Are the Tropics Warm and the Poles Cold? !  Areas of the world are warm if they receive a large amount of sunlight per unit area; they are cold if they receive a small amount of sunlight per unit area. !  Earth s spherical shape dictates that regions at or near the equator receive more sunlight per unit area than regions that are closer to the poles, due to the angle at which the solar radiation hits the Earth. What Causes Seasonality in Weather? !  Seasons—regular, annual fluctuations in temperature, precipitation, or both —result from Earth s 23.5º tilt on its axis. !  In June, the Northern Hemisphere is tilted toward the Sun, so it faces the Sun most directly and receives the largest amount of solar radiation per unit area. !  In December, the Southern Hemispher...
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