BIOMES: CLIMATE AND LIFE Different climates lead to different communities of organisms, especially vegetation. Biomes – large land regions with similar: Climate Soil Plants animals Each biome contains many ecosystems whose communities have adapted to differences in climate, soil, and other environmental factors.

Why are Biomes where they are? Latitude Solar Angles Ocean Current and Wind Distribute the extra heat energy at the equator towards the poles Water stores and transfers the heat (phase changes) P/E Ratio Precipitation to evaporation ratio Productivity Greater in low latitudes High sunlight, temperature, and moisture (photosynthesis) Declines as you approach the poles

P/E Ratio Abiotic Factors Influencing Biomes Insolation, precipitation, and temperature Increasing Temperature causes increasing evaporation Plants may be short of water even if it rains or snows a lot When the P/E ratio is 1 P=E Soil is rich and fertile More on productivity next week

Climate Change and biome Shift There is evidence that biomes are moving Examples: Woodlands becoming savannahs Tundra becoming shrubland Who cares? There are obstacles to migration Plants are slow Some places are in trouble

Precipitation determines the type of vegetation in each biome. Cold, dry air falls Cell 3 North Precipitation determines the type of vegetation in each biome. Moist air rises — rain Polar cap Cell 2 North Arctic tundra Evergreen coniferous forest 60° Cool, dry air falls Temperate deciduous forest and grassland 30° Desert Cell 1 North Tropical deciduous forest Moist air rises, cools, and releases Moisture as rain 0° Equator Tropical rain forest Tropical deciduous forest 30° Desert Figure 5.6 Natural capital: global air circulation and biomes. Heat and moisture are distributed over the earth’s surface by vertical currents, which form six giant convection cells at different latitudes. The resulting uneven distribution of heat and moisture over the planet’s surface leads to the forests, grasslands, and deserts that make up the earth’s biomes. Cell 1 South Temperate deciduous forest and grassland Cool, dry air falls 60° Cell 2 South Polar cap Cold, dry air falls Moist air rises — rain Cell 3 South Fig. 5-6, p. 103

BIOMES: CLIMATE AND LIFE ON LAND Ecotone: area between two biomes blending. Usually have more biodiversity.

BIOMES: CLIMATE AND LIFE ON LAND Parallel changes in vegetation type: equator to the poles lowlands to mountaintops Figure 5-11

Biome type is determined mostly by precipitation but also temperature and soil type Figure 5-10