An article about food chains.
Feeding Relationships in Organisms
Food is important to all of us; it is the source of the energy that our bodies need to keep them working and enable us to move. It also gives us small quantities of important chemicals such as iron and vitamin C that our bodies need to work properly and the proteins that we need for growth.
Green plants are the world’s food factories. They range from the microscopic plants in sea plankton to giant oak trees. When the conditions are right these plants are all busy making food. Because green plants are the only things that make food, they are called producers. Using energy from the Sun, the plant makes food in the form of glucose, a form of sugar. The glucose is made from carbon dioxide and water. Once the plant has made glucose, it can convert it into other carbohydrates such as starch. Starch is the form in which plants store food. Potato plants store starch underground in tubers; other plants may store starch in the leaf, like cabbage, or in the stem, like celery.
You may not like cabbage, but slugs certainly do. They get their energy from the carbohydrates stores in the cabbage leaves. They also like to burrow their way into potato tubers that are underground. Slugs are examples of primary consumers, the first thing that eat the food produced by the plant. When humans eat the cabbage they are also primary consumers. The difference in feeding is that slugs are herbivores: they only eat plants. Many humans are omnivores: they eat animals as well as plants.
Many animals eat a variety of things and in turn are eaten by a variety of things. Humans eat a wide variety of producers, as well as primary and secondary consumers. An oak tree can support a large number of food chains, with several organisms appearing in more than one chain. In a habitat such as a tree, or a pong, the food chains can be put together to form a food web.