E3+Temperature+and+Species+Distribution

• The placement of biomes is dependent on temperature zones. • Temperature affects species distribution as well. o A species’s distribution is determined mostly by the temperature conditions that will make it a poor competitor. • The effects may be moderated by evolution. • Allen’s rule: Endothermic (animals that produce their own heat) from colder biomes have shorter body parts compared with warm weather animals because this will reduce the surface area: volume ratio which will result in less heat loss. • Bergmann’s rule: birds and mammals in cold areas will be larger that ones in warm climate to shrink their surface area:volume ratio. This is not a general rule; but can be true for specific species.

**Variations in the temperature profile of regions:**
• Latitudinal/seasonal: The tilting of the earth on its axis results in generalized zone with hotter temperatures. • Altitudinal: There is a one Celsius drop in temperature for every 100m in altitude. • Continentality: Land reflects less heat so it warms up faster than water. This gives the ocean a cooling effect. • Microclimate: There can be huge variations in temperature, especially between canopied forests and the soil. • Depth: Depth in soil or water can change temperature. These changes are always after surface fluctuations because of the distance. As soil is very thick and dense, it will not conduct heat as well as water does. • Diurnal: The radiation from the sun is rhythmical and therefore causes changes in temperature. A polar bear is an example of Bergmann's rule as its large mass reduces its surface area:volume ratio.

Similarly, a Capybara is an example of Allen's rule as mammals in tropical climates tend to be smaller as heat loss is not as much of a survival concern.