Microorganisms are very tiny one-celled organisms, viruses, fungi, and bacteria, and are found everywhere in the world. They are found in all living things, plants and animal. There are more microorganisms on and inside your body than there are cells that make up your entire body. Microorganisms can live in the air, on land, and in fresh or salt water environments. Some of them, pathogens, can be harmful and causes diseases, but there are some microorganisms that are needed for living things to survive.
All of the living things, plant and animal, in earthâ€™s environmental communities of forests, deserts, tundra, water, air, and all of the rest depend on the cryptobiotic crust or microbiotic layer in the soil. This is the layer of soil that most microbes live in. These microbe communities are made up of fungi, cyanobacteria and lichens. They look like a grayish cover on the ground when they are first forming, but do form in clumps of lichen that look like little hills after about 50 years of growth.
Microorganisms also are responsible for building fertile soil for plants to grow in. Microbes stick to the roots of plants and decompose dead organic matter into food for the plant to absorb. The plants that live and grow because of the microorganisms that live on them make a home for other animals to live in. Some microorganisms make people, animals, and plants sick, but others make people well and kill the bacteria on plants that make them sick. Drug companies that make medicines use hundreds of different microorganisms to make medicines that will help cure diseases. Human waste products are broken down into safer particles by some microorganism. Scientists are always looking for new ways to use microbes.