Energy Flow in Ecosystems Chapter 3 3 How
- Slides: 17
Energy Flow in Ecosystems Chapter 3. 3
How does energy flow through ecosystems? Energy flows through an ecosystem in a one-way stream, from primary producers to various consumers. Energy moves from “eaten” to “eater”.
Food Chain Food chain = a series of steps in which organisms transfer energy by eating and being eaten. Ex.
Food chains can vary in length.
Food Web In most ecosystems, feeding interaction are much more complicated than a simple chain. Animals eat more than one type of food. Food Web = complex network of feeding interactions among organisms of an ecosystem.
Decomposers & Detritivores Why are they so important? Most primary producers (plants) die without being eaten. Decomposers convert that dead material to detritus → which is eaten by detritivores Decomposition releases nutrients that can be used by primary producers. Without decomposers- nutrients would be locked within dead organisms.
Food Webs and Disturbance • Changes in one level will drastically affect other levels.
What would happen if algae populations decreased drastically?
Trophic Levels Each step in a food chain or food web = trophic level Primary producers make up the first trophic level. Consumers occupy every other level.
Ecological Pyramids Ecological pyramids show relative amount of energy or matter contained within each trophic level. - Energy - Biomass - Numbers
Energy Pyramids of energy show the relative amount of energy available at each trophic level of a food chain or food web. Only a small portion of energy in a trophic level is ultimately stored in the bodies of organisms at the next level. Most of energy is expended by the organisms – movement, respiration, growth, reproduction, or lost as heat.
Energy Pyramid About 10% of energy is transferred to the next trophic level.
Biomass Pyramid Biomass = total amount of living tissue within a trophic level Pyramid of biomass illustrates the relative amount of living organic matter available at each trophic level.
Pyramid of Numbers Pyramid of numbers shows the relative number of individual organisms at each trophic level in an ecosystem.
Pyramid of Numbers In some cases consumers are far less massive than the organism they feed on. May result in an inverted pyramid of numbers. Biomass usually is normal pyramid.