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Food Webs. Food Chains vs. Food Webs. A food chain is one set of eating relationships. Food Chains vs. Food Webs. A food web is a network of food chains. NO food webs are complete . Producers. Use the sun’s energy to make food using photosynthesis
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Food Chains vs. Food Webs • A food chain is one set of eating relationships.
Food Chains vs. Food Webs • A food web is a network of food chains. • NO food webs are complete.
Producers • Use the sun’s energy to make food using photosynthesis http://www.wonderville.ca/asset/photosynthesis • During photosynthesis, plants use water, carbon dioxide, and sunlight to make sugar and oxygen. 6H20 + 6CO2 + sunlight ----> C6H12O6 + 6O2 (water) (carbon (glucose) (oxygen) dioxide)
Consumers • Primary Consumers • Herbivores • Only eat producers • Secondary Consumers • Carnivores, Omnivores • Eat producers and primary consumers • Tertiary Consumers • Carnivores, Omnivores • Eat producers, primary consumers, and secondary consumers
Consumers • Consumers use respiration to get energy from the food they eat. http://www.sumanasinc.com/webcontent/animations/content/cellularrespiration.html • During respiration, consumers break down glucose and oxygen to get the energy that is stored in them. C6H12O6 + 6O2 ----> 6H20 + 6CO2 + energy (glucose) (oxygen) (water) (carbon dioxide)
Energy in Food Webs • All energy starts with the sun. • The sun’s energy is stored in plants due to photosynthesis. • When plants break down their food, they get that energy so they can perform life functions (grow, repair, reproduce, etc.). • When plants are eaten by consumers, the stored energy moves into the consumer’s body due to respiration. Now consumers have energy to perform life functions. • When consumers eat consumers, the energy from one moves into the other.
Organizing Food Webs • Animals eat other organisms to get the energy from that organism. • Arrows point in the direction of energy flow (toward the “eater”). • Try to keep producers towards the bottom so arrows are mostly pointing upwards. • Try to place consumers in order (primary, secondary, tertiary) so arrows are mostly pointing upwards. • Decomposers should be drawn off to the side, as they eat everything once it dies. • All organisms must be labeled.
Sample Food Web Earthworm
Analyzing Food Webs • Any change to a food web (addition or removal of organisms) can affect ALL organisms in the web. • Look closely at this food web: If the grasshoppers died off, what would probably happen to … the birds? … the grass? … the rabbits? … the foxes?