Discuss what would happen if an organism no longer existed. Have one student in one group drop their yarn, and have the next student drop theirs, and so on. The oxygen released as a by-product is atmospheric oxygen, vital to respiration in plants and animals. Photosynthesis, in general, is the reverse of respiration, in which carbohydrates are broken down to release energy. These are also known as autotrophs, since they make their own food.
Producers are able to harness the energy of the sun to make food.
They make up the bulk of the food chain or web. In short, consumers are every organism that eats something else. Primary consumers are the herbivores, and are the second largest biomass in an ecosystem. This continues with tertiary consumers, etc. These are mainly bacteria and fungi that convert dead matter into gases such as carbon and nitrogen to be released back into the air, soil, or water.