Today’s Factismal: Mushroom spores are covered by chitin, which is the same substance that makes up lobster shells.
“Mushroom” is one of those “I know it when I see it” words that biologists avoid like the plague (which is another one of those words). The English word mushroom comes from the Latin word for mushroom (mussirio) via the French word for, you guessed it, mushroom. Throughout the long trek from Latin to English, the mushroom has also been called a toadstool, frogstool, panther cap, and puffball by people who either hunted them for their delicate flavor or tried to eradicate them for what they did to the lawn. But scientists have just one word for mushrooms; they call them fungi (or “funguses” when they want to sound less erudite) and consider them one of the greatest boons to life on Earth.
Fungi are related to plants, as you might expect. What you might not expect is that they are more closely related to animals. Where plant cells are surrounded by walls of cellulose, the cell walls of most fungi are surrounded by chitin, which is the same material that forms the shells of lobsters, crabs, and shrimp. And a few fungi have no cell walls at all! On the genetic level, fungi have even more similarities to animals than they do to plants. In one sense, they are among our most distant relatives.
And what good relatives they are! Fungi are saprotrophs that live by eating dead organic material, such as leaves, bark, meat, and used food. They turn the detritus into food for themselves and then, when they die, into nutrients that animals and plants use to grow. Without fungi, the Earth would be covered in piles of dead wood and heaps of feces. Fungi are essential to life on Earth.
Of course, being essential means that they are also widespread. Fungi are found on every continent and in every clime. There are fungi that live in Antarctica, feeding on penguin guano and dead mosses. There are fungi that live in the Amazon, eating the dead rubber trees and sloth feces. And there are fungi that live in your home, eating the untreated wood and bits of hair and dead skin cells that every human sheds. Though they can do some harm if allowed to grow where they shouldn’t (say, on your new wooden fence),fungi also do a lot of good. More than $850 million worth of mushrooms were sold in the US alone, for purposes ranging from food (mushroom pizza – yum!) to medicine. Mushrooms have already added a potent new antibiotic to the doctor’s little black bag, and may also add new pain-relievers and powerful cancer-fighting drugs.
If you’d like to contribute to the science of fungi or just start looking for your own mushrooms, then head on over to the Mushroom Observer: