Fungi

Although often inconspicuous, fungi occur in every environment on earth and play very important roles in most ecosystems.

Along with bacteria, fungi are the major decomposers of dead organic matter in most terrestrial (and some aquatic) ecosystems, and therefore play an important role in nutrient cycles and in many food webs.

Fungi are also used extensively by humans: yeasts are responsible for fermentation of beer and bread, and mushroom farming and gathering is a large industry in many countries.

A fungus of the species Armillaria ostoyae may be the largest organism on the planet!