environmental science

A classic example of mutualistic symbiosis between a fungus and a photosynthetic alga is lichen. Lichen is a type of composite organism in which a symbiotic relationship exists between algae, which photosynthesize energy from light, and a fungus, which provides protection and access to essential minerals for the alga, such as nitrogen and phosphorus. The alga is able to use the energy it captures in the photosynthesis process to provide nutrients and energy to the fungus, while the fungus, in turn, helps protect the alga from environmental stresses and makes mineral resources available to the alga. This type of symbiosis can be found in almost every ecosystem on the planet and is an integral part of many of the Earth's biological systems.