Geographic Template Environmental variables exhibit non- random patterns Patterns of spatial variation comprise the geographic template, forms the foundation of all biogeographic patterns Biota and interactions of biota form gradients in response to geographic template

Geographic Template Energy driving spatial and temporal dynamics –Earth’s core and gravity –Sun – heat transfer, angle and seasons

Local to Global Effects (S-facing slopes in N. Hemisphere (opp in S. Hem.

Elevational Effects Why glaciers at tropics? Properties of Air Density and pressure of air decreases with elevation Air moving up a mountain loses heat due to reducing density Loses heat energy (adiabatic cooling) as molecules move apart

Greenhouse Effect Water vapor and carbon dioxide (as well as methylated metals) trap longer energy wavelengths Holds heat Moist environments – limited diel temp fluctuation Dry environments – diel temp flux

Wind and Rainfall Climatic cells – differential heating Coriolis effect – wind patterns Surface winds create ocean currents

Temperature + Winds + Ocean Currents = global pattern of precipitation Predictable general trends Rainy season in tropics tied to equinox Horse latitudes (30 – 35° N and S) – descending air absorbs moisture Mediterranean climate – west side of continents – hot, dry summer; mild, wet winter

Rain Shadow

Climate and Scale Climate scales down to millimeters Creates patchy distribution Inhospitable environment can contain hospitable meso- and microclimates

Soils Distinct pedogenic regimes Close correlation with global climate cycles (compare Figures 3.7 and 3.12) Soil types can range from limited (Great Plains) to complex mosaic (mountains) Tell story of temporal development of global geographic template (and a time-travelling map)

Aquatic Environments Main points to get are diversity of space and time Patchiness (clinal zones in lakes, intertidal to abyssal in oceans)