A food chain is a set of organisms where one organism eats another along the chain. Food chains contain three or more organisms. They describe the patterns of eating behavior in ecosystems. An ecosystem is the interrelationship between plants, animals and environment in any given area. Food chains can be found in every ecosystem.
Food Chain Organisms
A food chain always begins with plants or other organisms that derive their energy from the sun. According to The University of Michigan, these are called producers. The next organism in the food chain is a plant eater, such as a deer or a snail. Organisms that eat producers are called primary consumers. These are eaten by the next organism in the chain. This could either be a carnivore, which is an animal that only eats meat, or an omnivore, which eats both plants and other animals. Organisms that eat primary consumers are called secondary consumers.
Food Chains That Include Humans
Human beings are omnivores, although some choose to eat only plants and plant products. Humans are at the top of any food chain because we eat other animals, but no other animal has humans as part of its normal diet. The animals humans eat are usually plant eaters, such as chickens, or other omnivores, such as pigs. Two examples of food chains of three organisms that include humans are: grass – cow – human; and seaweed – crab – human.
A more accurate description of organism eating associations is a food web. Food chains show a limited picture of the diets of organisms within an ecosystem. Cows do not only eat grass. They eat many different plants and cattle feed. Humans do not only eat cows. We have a wide variety of foods in our diet, including many plants. A food web shows a group of organisms and the connections between producers and consumers in that system.
Food Webs That Include Humans
Human beings eat food that comes from many different ecosystems around the world, because we are able to grow our own food and transport it to distant places. There are also ecosystems where humans are part of the local food web. One example of this is in the Arctic. Primary producers in this system are the algae and phytoplankton in the ocean. Fish and plankton eat these. Fish also eat plankton, and other fish. Seals, walruses, birds and whales eat fish. Polar bears and humans eat these, and also fish. The relationships are complex.