ap bio: ch 52 figures

Global air circulation and precipitation patterns

-Intense solar radiation at equator initiates a global pattern of air circulation and precipitation. -High temps in the tropics evaporate water from earth's surface and cause warm, wet air masses to rise (blue arrows) and flow towards the poles. As the rising air masses expand and cool, they release much of their water content, creating abundant precipitation in tropics. -The high-altitude air masses, now dry, descend (tan arrows) toward Earth around 30 degrees N+S, absorbing moisture from the land and creating an arid climate (i.e. deserts)

How large bodies of water and mountains affect climate.

1. Cool air flows inland from shore, moderating temps near shore. 2. Air that encounters mountains flows upward, cools at higher altitudes, and releases water as precipitation. 3. Less moisture is left in air reaching leeward side, which therefore has little precipitation. This rain shadow can create desert on back side of mountain range.

Reciprocal effects of ecological and evolutionary change.

An ecological change, such as the expansion of a predator's range, can alter the selective pressures faced by prey populations. This could cause evolutionary change, such as an increase in the frequency of a new defensive mechanism in a prey population; that change, in turn, could alter the outcome of ecological interactions.

seasonal variation in sunlight intensity

Because Earth is tilted on its axis relative to its plane of orbit around the sun, the intensity of solar radiation varies seasonally. This variation is smallest in the tropics and increases toward the poles.

Latitudinal variation in sunlight intensity

Because sunlight strikes the tropics most directly, more heat per unit of surface area are delivered there. At higher altitudes, sunlight strikes earth at an oblique angle, and thus the light energy is more diffuse on earth's surface.

Seasonal turnover in lakes with winter ice cover.

Seasonal turnover causes the lake waters to be well oxygenated at all depths in spring and autumn; in winter and summer, when the lake is stratified by temperature, the oxygen concentration decreases with depth.

Global circulation of surface water in the oceans.

Water is warmed at the equator and flows north and south toward the poles, where it cools. Note the similarities between the direction of water circulation in the gyres and the direction of the trade winds in Figure 52.3.