Biology 2601A/B Lecture Notes - Encelia Farinosa, Quercus Rubra, Ectotherm
25 Nov 2012
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Document Summary
An ectotherm does not generate internal heat and a poikilotherm has its body temperature determined by equilibration with the thermal conditions of the environment. We will explore ways in which this statement is irrelevant. Encelia farinosa is a species of plant that grows in extremely hot, arid environments and therefore must be white to increase its albedo (the capacity to reflect solar radiation). The black pearl pepper on the other hand, absorbs far more radiation because of its low albedo. In general, leaf colour alters provides a long-term adaptive response to altering the amount of solar radiation absorbed by a plant. Most plants don"t change their colour and utilize short term strategies for maintaining body temperature. With regards to convection (the heat exchange with air molecules that brings organisms closer to air temperature), plants will often manipulate the shape of their leaves in order to exploit convection currents for their benefit.
