Energy Transfers
A food chain is a linear sequence of links in a food web starting from a species that are called producers in the web and ends at a species that called decomposers species in the web. A food chain also shows how the organisms are related with each other by the food they eat. A food chain differs from a food web, because a food web follows a complex network of eating relations based on trophic levels that has many outcomes. A food chain follows a one way path of eating relations. A trophic level is the position that an organism occupies in a food chain; where it lies on the food chain depends on what it eats and what eats it. All food chains start with energy from the sun. About ten percent of the energy from the sun is transferred to available energy by producers.
Producers are organisms that make their own food (autotrophs). They preform photosynthesis to convert the energy from the sun to make sugar for food, carbon dioxide, and water. Consumers feed on producers or other consumers. First levels consumers are organisms
that eat producers for food; first consumers get their energy from producers. Second level consumers are organisms that eat first level consumers; they get their energy from first level consumers. Third level consumers are organisms that eat second level consumers; they get their energy from second level consumers. Energy is lost at each level. At each level, only about ten percent of the energy of the lower level is converted to usable energy; as illustrated in the picture. Decomposers are organisms that break down dead or decaying organisms, and in doing so carry out the natural process of decomposition. Examples of decomposers include bacteria, worms, and mushrooms. The organisms of a chain are classified into these levels on the basis of their feeding behavior. The first and lowest level contains the producers, green plants. The plants or their products are consumed by the second-level organisms—the herbivores, or plant eaters. At the third level, primary carnivores, or meat eaters, eat the herbivores; and at the fourth level, secondary carnivores eat the primary carnivores. These categories are not strictly defined, as many organisms feed on several trophic levels.
that eat producers for food; first consumers get their energy from producers. Second level consumers are organisms that eat first level consumers; they get their energy from first level consumers. Third level consumers are organisms that eat second level consumers; they get their energy from second level consumers. Energy is lost at each level. At each level, only about ten percent of the energy of the lower level is converted to usable energy; as illustrated in the picture. Decomposers are organisms that break down dead or decaying organisms, and in doing so carry out the natural process of decomposition. Examples of decomposers include bacteria, worms, and mushrooms. The organisms of a chain are classified into these levels on the basis of their feeding behavior. The first and lowest level contains the producers, green plants. The plants or their products are consumed by the second-level organisms—the herbivores, or plant eaters. At the third level, primary carnivores, or meat eaters, eat the herbivores; and at the fourth level, secondary carnivores eat the primary carnivores. These categories are not strictly defined, as many organisms feed on several trophic levels.