VI. Energy in the Ecosystem

A. Energy and Food 1. Biomass- the total amount of organic matter at a trophic level 2. Majority of world’s biomass comes from producers a. Only use 30% of total sun that reaches the Earth b. Produce 170 billion metric tons of food per year

c. Most of the food produced is used by the plant for self- sustaining organism 3. Only energy converted to biomass can be made into food 4. 10% law- only ten percent of energy can be passed up trophic levels

a. Applies to biomass as well b. Why can a food web only support a max of 5 levels?

.1% 1% 10% 100%

B. Ecological Pyramids 1. Ecological pyramid- diagram shows the relative amount of energy in different trophic levels 2. Can show biomass or even number of organisms a. Ten percent rule applies