Energy Transfer And Productivity

1-3%

• over 90% of the sun’s energy is reflected back into space or absorbed by the atmosphere • not all wavelengths of light can be absorbed and used for photosynthesis • light may not fall on chlorophyll molecule • factors such as low CO2 levels may limit the rate of photosynthesis

• the total quantity of energy that the plants in a given area in a given time • convert to organic matter • is called gross production

• some energy is left to be stored in plants, as some energy is used for respiration • the chemical energy store that is left is known as net production

Net production = gross production - respiratory losses

• some parts of the organism is not eaten • some parts are not eaten but cannot be digested and are therefore lost in faeces • some of the energy is lost in excretory materials, such as urine • some energy losses occur as heat from respiration and directly from the body to the environment

• limits 4/5 organisms because insufficient energy is available to support a large enough breeding population at trophic levels higher than these • total mass of organisms in a particular place (biomass) is less higher at trophic levels • total amount of energy stored is less at each level as one moves up a food chain

• energy lost to environment through respiration as heat • energy lost to environment during egestion (production of faeces)

N = I - (F + R)

• keeping animals indoors keeping them warm - reducing energy transferred to surroundings • predators removed so there is less energy wasted escaping • feeding can be controlled, reduced wastage • restricted movement reduces energy usage in muscle contraction

Energy transfer = (energy available after the transfer / energy available before the transfer) x 100