Tuesday, July 29, 2008
Lichen is awesome.
Lichen (pictured above) is actually two organisms living in a symbiotic relationship. Fungus makes the body we can see and bears the name of the lichen, while the microscopic algal partner lives in the tissue of its fungal host. Fungi can't photosynthesize (they seem plant-like but are actually in an entirely different kingdom and are more closely related to you than plants are), they're heterotrophs that decompose organic matter to eat. The alga uses its host for the capture of water and minerals. The fungus benefits from the alga's ability to photosynthesize. The algal and fungal partners of some lichen have been separated and cultured in the lab, but out in the world, both rely on each other to grow and reproduce.
Lichen can survive in some pretty harsh natural conditions (many can enter a state of cryptobiosis-a sort of suspended animation-in response to dessication) but some are incredibly sensitive to man-made pollutants, and are widely used as pollution indicators.