

 All organisms need energy – without energy there are no life functions!  Producers are the first producers of energy- rich compounds that other organisms need to survive  AKA autotrophs

PhotosynthesisChemosynthesis

 Many animals, bacteria and fungi cannot capture energy directly from the environment  Consumers aka heterotrophs must get energy from other organisms by consuming them

 Energy passes through an ecosystem in a series of steps called a food chain.  But it’s not always that simple….why?

 Primary producer = producer in food chain  Primary consumer = first consumer (an herbivore) in the food chain  Secondary consumer = second consumer in the food chain  Tertiary consumer = third consumer in the food chain Who is who in the food chain below?

 Organisms typically do not only consume one source of food.  Ecologists describe a network of feeding interactions as a food web.

 Each step in a food chain or web is called a trophic level  Ecological pyramids show the relative amount of energy or matter within each tropic level of an ecosystem.  3 Types of Ecological Pyramids o Energy o Biomass o Numbers

 Shows that each level of the pyramid stores only a portion of energy from the previous level. Only about 10% of energy moves to the level above

 If the first level of the energy pyramid has 1000 units of energy, how much would the top level have?  Hint: Only 0.1% of the energy will be left!  Solution: 1000 units X = 1 unit

 Shows the total amount (in weight – grams) of living tissue within a trophic level, called biomass

 Shows the relative number of organisms at each trophic level