Lichens are organisms that consists of fungus and algae. Together they are able to live in places where neither of them could live alone. The hyphae of the fungus protects the algae and supplies it with water and minerals. The algae produce its own food through photosynthesis — it eats sunshine to make carbohydrates — which it then shares with its fungus partner.
We know of more than 20,000 different fungi which live — in symbiosis with alga — as lichens, and different types of lichen cover about seven percent of the earth’s total surface.
It was Swiss botanist Simon Schwendener who, in 1867, first declared that lichens are a composite of fungus and algae. 10 years later, German mycologist Albert Bernhard Frank termed the word symbiotism to describe this mutualistic relationship, but it was his fellow countryman and fellow mycologist Heinrich Anton de Bary who further tweaked the word and came up with symbiosis, which is the one that stuck in our lingos.
Almost simultaneously Belgian zoologist and paleontologist Pierre-Joseph van Beneden coined the word mutualism to describe “mutual aid among species,” in other words a symbiosis that is beneficial to both of the involved organisms. (There are other types of symbiosis, too: commensalism, parasitism, competition, …)
Mutualism drives evolution. I think about humanity’s relationship to corn … how the domestication of corn sparked agriculture and had massive impact on how human culture developed. But not only that: it also had a massive impact on how corn developed. In fact corn wouldn’t even exist without the help of humans, since it developed only after generations of selective breeding of a wild grass called teosinte. Teosinte’s symbiotic relationship with another species, humans, impacted the evolution of a new crop. And it was a symbiosis that was also of great benefit for humans.
Bibliography
- Crombie, James M. and Vernon Herbert Blackman. “Lichens” in Encyclopædia Britannica. 11th. ed. vol. 16. Cambridge: Cambridge University Press. 1910-1911.
- Kropotkin, Peter. Mutual Aid: A Factor of Evolution. New York: McClure, Phillips & Co., 1902.
- McKean, Erin. The New Oxford American Dictionary. 2nd ed. New York: Oxford University Press, 2005.
- Sheldrake, Merlin. Entangled Life: How Fungi Make Our Worlds, Change Our minds & Shape Our Futures. New York: Random House, 2021.