Lichen-covered Branch
This close-up view shows lichen covering every inch of a small tree branch in the southern Turkish city of Adana. Lichen is a composite organism—a fungus and a photosynthetic organism (usually algae) living together in a symbiotic relationship.
Photograph by Nurlan Tahirli, MyShot
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Energy Flow Through an Ecosystem
Trophic levels provide a structure for understanding food chains and how energy flows through an ecosystem. At the base of the pyramid are the producers, who use photosynthesis or chemosynthesis to make their own food. Herbivores or primary consumers, make up the second level. Secondary and tertiary consumers, omnivores and carnivores, follow in the subsequent sections of the pyramid. At each step up the food chain, only 10 percent of the energy is passed on to the next level, while approximately 90 percent of the energy is lost as heat. Teach your students how energy is transferred through an ecosystem with these resources.
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Energy Flow Through an Ecosystem
Trophic levels provide a structure for understanding food chains and how energy flows through an ecosystem. At the base of the pyramid are the producers, who use photosynthesis or chemosynthesis to make their own food. Herbivores or primary consumers, make up the second level. Secondary and tertiary consumers, omnivores and carnivores, follow in the subsequent sections of the pyramid. At each step up the food chain, only 10 percent of the energy is passed on to the next level, while approximately 90 percent of the energy is lost as heat. Teach your students how energy is transferred through an ecosystem with these resources.