Mushrooms are kind of like weird plants. They grow out of the soil, they don’t really move around, you can put them in a salad. However, not only do fungi have their own classification separate from plants and animals, they might actually be more like animals than plants. Even weirder than that, some people think fungi descended from extraterrestrial life. I’m not sure we can prove that in a scientific fashion at the moment, but it makes for an interesting discussion. After my brother and sister-in-law gave me a log that sprouts glow-in-the dark mushrooms for my birthday (non-psychedelic, mind you), I became interested in what fungi are exactly, and why they seem so strange.
So, what are fungi? What’s cool about them, and why do some people think they are from outer space?
Fungus is a broad category of life that is distinct from plants, animals or bacteria (For more on this, see Seth’s post about taxonomy, and this Wikipedia entry on how life is organized). Typical characteristics of a fungus are cell walls made of chitin, it doesn’t produce its own food like a plant does, and it grows and behaves much like vegetation. The most conspicuous fungi - mushrooms and toadstools - are just the fruiting bodies of an organism that is mostly underground. Due to their knack for existing underground, fungi are relatively poorly studied and the fossil record doesn’t have much to offer either. Other fungi include yeast, truffles, mildew and mold. To us, fungi are foods, molds on our foods, parasites, diseases, cures for diseases, hallucinogenic drugs, and gnome accoutrements.
What’s cool about fungi
Fungi are extremely diverse and their differences from more familiar organisms are quite interesting.
- Fungus reproduction is quite different from plant or animal reproduction. Some species have males and females, others have both male and female parts on each individual, some can do either, some have more than two sexes, even thousands of sexes. Although this list is a gross oversimplification and represents an animal-centric viewpoint, I’m not sure fungal reproduction can even be compared to animal reproduction. For more on this, check out this very cool blog.
- Even though they seem more like plants, on a genetic level, the latest studies show that fungus are more like animals. Animals and fungus may share an ancient ancestor, which was likely a one-celled organism kind of like a tiny fungus-y animal. Although it may sound crazy, the idea may not be too hard to get used to; both animals and fungi eat other stuff instead of making their own food like plants do.
- The largest organism on Earth might be a fungus. In Oregon, a fungus exists that covers an area the size of 1,665 football fields and you wouldn’t even notice it.
- Fungal diseases can do some interesting things. See Kenny’s post on fungi as it relates to zombies. White nose-syndrome, the cause of decline in bats in North America, is a rather unpleasant fungus. Then there's athlete's foot and more.
- The coolest thing, and what I think is the source of their strangeness, is that they are very difficult to observe. This difficulty is because they are often underground, they can grow and shrink rapidly (imagine the bread that you just bought yesterday that is suddenly being consumed by mold), and their soft bodies are not preserved well. Yet they are everywhere, they are critical components of the ecosystem as decomposers, and they are an enormous and diverse group of organisms.
Check out this video for fungus doing some serious decomposition, and killing for nutrition.
Could fungi be the descendants of alien organisms?
This theory may not stand up well against new genetic and molecular research into the evolution of fungus, but the belief that fungi are the descendants of an extraterrestrial immigrant to Earth comes from:
- The ability of fungal spores and even growing fungus to withstand the extreme conditions of outer space Example 1, Example 2
- The perceived weirdness of fungi compared to other organisms
- The compatibility of this theory with the very old theory that life exists throughout the universe, and Earth was “seeded” with some type of organism via meteor or other vessel. See Kenny's post, which discusses this theory and microbes in space.
So that's just a quick look into the world of fungus. Keep an eye out for future posts delving into more detail, and share your fungus fun facts and questions!