Energy Flow in an Ecosystem A. Source of energy for most all living things The Sun

B . Who Eats What 1. producers or autotrophs – make their own food by photosynthesis (ex: plants) or chemosynthesis (ex: deep sea vent autotrophs)

2. consumers or heterotrophs – get energy by eating other organisms Herbivores – eat producers (eat plants) Carnivores – eat other consumers (eat meat) Scavengers – eat meat that is already dead Omnivores – eat both producers and consumers Decomposers – break down dead organisms and return nutrients to the soil (examples: bacteria and fungi)

CFU 1. If you have a salad made with lettuce, carrots, and cucumbers for lunch, what level (type) of heterotroph would you be at that time? 2. If you put some grilled chicken on your salad, what level of heterotroph would you be? 3. What two groups of organisms are responsible for recycling organic material?

3. Energy Transfer Food Chain - shows the one way flow of energy in an ecosystem Food Web – interconnected food chains

4. Trophic Levels Trophic Level- Each step in the food chain or web is a different trophic level

Energy Flow and Trophic Levels

Rule of Ten Only about 10% of the energy available within one trophic level is transferred to organisms at the next trophic level. About 90% is used by the organism for its own metabolic activities.

5. Biomass Biomass- total amount of living matter within a given trophic level

CFU – Write your answers in your notebook.  1)Show the following as a food chain: snake, hawk, oats, mouse 2)Draw an energy pyramid for the four step food chain in question 1. If 1000 kilo joules of energy are available at the first trophic level, how much is available at each other levels? (Write your answers on each trophic level of your pyramid.)