The lichens
Lichens represent an example of symbiosis between two species, one autotrophic (represented by an alga, more rarely by cyanophytic bacteria) and one heterotrophic (in this case a fungus). The characteristics of both the appearance and functioning of the individual that is generated are completely different from the two starting individuals. In this association, the fungus obtains from the algae the substances with which to feed, while the alga is able, thanks to the fungus, to live in hostile environments, especially for lack of water.