The Biosphere Chapter 49 We have talked about predation, competition and species interactions and how they affect the structure of populations, communities and ecosystems. This chapter considers the physical forces shaping the biosphere itself… Biogeography — the study of the distribution of organisms, past and present, and of diverse processes that underlie their distribution patterns.

Climate Climate refers to the average weather conditions. Climate includes: Temperature Humidity Wind velocity Cloud cover Rainfall

Climate Climate is shaped by four factors: (1) Variations in the amount of incoming solar radiation (2) The earth’s daily rotation and path around the sun (3) The world distribution of continents and oceans (4) The elevation of land masses These all interact to produce prevailing winds and ocean currents that influence the global patterns of climate

Ocean Currents are affected by: 1) Latitudinal and seasonal variations in solar heating, creating variations in temperature of ocean waters on a vast scale 2) Earth’s rotation / wind friction Clockwise rotation - Northern hemisphere Counterclockwise - Southern hemisphere 3) Position of land masses and shape of ocean basins

Climate zones correlated with surface currents & drifts dry tropical warm temperate cool temperate cold subpolar polar (ice) warm surface currentcold surface current

Rain Shadow Effect Rain shadow effect, a reduction of rainfall on the side of high mountains facing away from prevailing winds (aka leeward side). Only plants adapted to arid or semiarid conditions grow in rain shadows.

Biome and Ecoregions Biome is a large region of land characterized by habitat conditions and by its community structure. Biome distribution corresponds w/ climate, topography and soil type The form of the dominant plant tells us something of the weather conditions