Key concepts: ecological systems vary over space and time, solar energy input and topography shape earth"s physical environments (climate) More heat at equator than poles because there sun rays are diffused at poles, more direct solar radiation at equator: latitudinal variation in heating. Hotter temps around equator, as you move away cooler temps: global temp patterns, tilt of the earth. Cooler when hemisphere tilt is away from sun. Heat energy is redistributed: atmospheric circulation, hadley cells, coriolis effect, ocean circulation. Atmospheric circulation is driven by: latitudinal variation in heating of earth, hadley cell. 1: warm air rises, warm air expands, warm air cools, clouds form, air cools and descends, warm air rises. Atmospheric circulation: hadley cell, temperate zones, equator, expansion and uplift of equatorial cell, warm air, polar cell, at polar zones. Subsidence of cold air converging air at the poles.