Fungi can live in a variety of habitats that are classified as either marine or terrestrial: in the soil, in water, and on plants and animals. Evidence suggests that some fungi have evolved closely with their partnered plant or animal to develop a productive symbiotic relationship. Fungi, which include yeast, mushrooms and mold, are classified separately from plants, animals and bacteria.
Fungi function as decomposers, and are capable of breaking down even toxic substances. When fungi are taking nutrients from an organism that is still living, the fungi can be considered a parasite. Because fungi are so extremely adaptable, they thrive in very different environments across the globe. Some fungi live in deserts, others in hydrothermal vents deep below the ocean’s surface. Mycorrhizal fungi are present in the soil and gain nutrients from the roots of plants or the remains of decomposing plants. Other fungi found in soil (known as ruderals) collect their nutrients from rainwater. Some fungi, like molds, thrive best in dark, damp places and can be a constant irritant to humans (especially in forms like black bread mold). On the other hand, mushrooms—which are actually the fruit of certain types of fungi—can be a tasty addition to a meal.