Presentation on theme: "1. Review- Energy is said to flow in a “one-way stream” through an ecosystem. In your own words, describe what that means Form a Hypothesis- Explain what."— Presentation transcript:
11. Review- Energy is said to flow in a “one-way stream” through an ecosystem. In your own words, describe what that means Form a Hypothesis- Explain what you think might happen to the food chain on pg 65 if there were a sudden decrease in the number of crayfish 2. Review- On average, what proportion of the energy in an ecosystem is transferred from on trophic level to the next, where does that energy go Calculate- Draw an energy pyramid for a five step food chain. If 100% of the energy is available at the first trophic level, what percent is available at the highest trophic level
23.3 Energy Flow in Ecosystems Ch 3 The Biosphere3.3 Energy Flow in Ecosystems
3What happens to energy stored in body tissues when one organism eats another Energy moves from the “eaten” to the “eater.” Where it goes from there depends on who eats whom.
4Food Chain Diagrams that shows what eats what Arrows point from food source to what eats itArrow shows flow of energySeries of steps in which organisms transfer energy by eating and being eaten.
5Food Web Combination of all the food chains in the community Arrows point from food source to who eats it.
7Decomposers and Detritivores Most producers die without being eatenDecomposers convert that dead material to detritus, which is eaten by detritivoresDecomposition process releases nutrients.
8Food Webs and Disturbance All of the animals in this food web depend directly or indirectly on krill- zooplanktonIn recent years, krill populations have dropped substantially.
9Trophic Levels and Ecological Pyramids Energy PyramidsShow the relative amount of energy available at each trophic levelBiomass PyramidsIllustrates the relative amount of living organic matter at each trophic levelNumbers PyramidsShows the relative number of individual organisms at each trophic level in an ecosystem.
10Trophic Levels Each step in a food chain or food web Primary producers always make up the first trophic levelVarious consumers occupy every other level.
11Pyramids of Energy Each level passes on roughly only 10% of the energy Organisms expend much of the energy they acquire on life processes, such as respiration, movement, growth, and reproduction10 Percent RuleOnly 10% of the energy at any given level is available for use by organisms in the next higher levelWhat do you like to eatWhat would be the best for humans to eat.
13Pyramids of Biomass and Numbers Total amount of living tissue within a given trophic levelUsually greatest biomass and numbers are at the base of the pyramidSize of pyramid depends on amount of energy available.