Lecture 3 - Ricklefs ch 3

Energy, Light, & Transformations - Ricklefs Ch 3

Leaf pigments: Cholorphyll - absorb green light spectra
Carotenoids (xanthophyll, carotene) - absorb yellow, orange spectra

absorption of light by water limits the depth at which photosynthesis can occur.
Euphotic zone = area near water surface in which photosynthesis can occur

Light intensity - referred to as radiant flux, expressed as W/m^2
Energy reaching Earth's atmosphere = 1,400 W/m^2 (aka Solar Constant)

Most of solar radiation absorbed by water,soil,plants, animals is converted to heat
Radiation =absorption/emission
How rapidly an object loses energy by radiation depends on the temperature of the radiating surface - it increases with the fourth power of absolute temperature. (i.e. warmer things radiate more rapidly than cooler things)

conduction = transfer of kinetic energy of heat from one substance to another thru contact. rate of transfer depends on its insulation (aka resistance to transfer)
convection = movement of heat in liquids and gases of different temperatures
evaporation = method to conduct heat
transpiration = evaporation of water form leaf surface
heat budget = all gains/losses of heat by an organism: change in heat content = metabolism - evaporation +/- radiation +/- conduction +/- convection

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