YOU NEED YOUR TEXT BOOKS! JQ: How much energy does it take to produce a filet mignon?

Ecosystem Energy In ecosystems, energy moves through these niches: autotrophs - produce food by photosynthesis heterotrophs - consume autotrophs and other heterotrophs decomposers - rearrange organic materials into nutrients for autotrophs The amount of energy available to support life or the largest population that can be sustained by the available resources is called the carrying capacity.

Food chains represent the steps in transferring energy through the ecosystem. Complex and integrated food chains are called food webs. Energy can be represented by trophic pyramids that compare the number of organisms in a population, or the weight (biomass) of organisms, or the productivity (energy calories).

Generally, only 10% of the energy is passed on to the next higher level. Why does the amount of energy change if energy is never created or destroyed? 1. It can be converted into unusable forms such as heat or for an organisms’ respiration, metabolism, and predation. 2. Not all parts of an organism have food value or provide calories. ex: bones, scales USDA

The amount of energy available is calculated as net productivity or primary productivity. Primary productivity of the ocean is 22-28 billion tons of carbohydrates (mostly glucose). Gross productivity - respiration = net productivity given in units of g/m2/yr. Respiration is the amount of energy used at each level to maintain life (estimated at 90% of the available calories). If one trophic level has 100,000 calories available, only 10,000 can potentially be transferred to the next trophic level.

phytoplankton krill baleen whale The more levels in the ecosystem pyramid the less energy is available in a useable form at the next higher level. Shorter food chains are more efficient. The reason the ocean can support the tremendous expense of endothermic (warm-blooded) mammals is because they eat low on the food chain.