Chapter 4: The Kingdoms of the Protists and Fungi

The Grand Tour continues with the bizarre and intriguing protists and the wacky and wicked fungi.

Part 1: I See Something!

And if a man prevail against one, two shall withstand him: a threefold cord is not easily broken.

-Ecclesiastes 4:12, Douay-Rheims

Next stop on our Kingdom Grand Tour are two more rather mysterious realms. How can they not be when so many of their residents are invisible to us? When they have names like dog vomit slime mold and bleeding tooth mushrooms? When they look like plants (or maybe bacteria), and, yet, they’re not. These two mysterious realms are the Kingdom of the Protists and the Kingdom of Fungi. Fortunately, unlike the two tiny Kingdoms of Archaea and Bacteria, we can see many of these creatures if we search the woods and fields (and forgotten corners of refrigerators and pantries).

The most mystifying realm of them all is the Kingdom of the Protists. No joke: even scientists don’t really understand what is going on with these guys. Here’s how you can tell what is a protist: if something is not an animal, plant, fungus, bacteria, or archaea, then it is a protist. That’s like grouping together chocolate chip cookies, a hamburger, and iced tea because they are not Italian, Mexican, or Chinese food. Do you think those foods have much in common (besides being a pretty sweet lunch)? Not really, but if the only other option is “Other Foods,” then they would have to be grouped together. Same with the protists, its the “None of the Above” group of creation, but that just makes it all the more exciting to explore.

Flying over the Kingdom of the Protists, you would see much empty-looking soil and water, home to many thriving protists. You would also see oceans filled with towering green spires and fallen logs that are covered with disturbingly bright-colored goop.

Who would you like to visit first? Perhaps, I could interest you in the plant-like giant kelp forests that provide a home for many ocean creatures. If you are looking for something smaller, might I suggest the more animal-like amoebas, hunters of the microscopic world that can shift and transform their shape to envelope their prey. Looking for something a little bigger? Then step right on over to this deep-sea dwelling creature (a xenophyphorea, if you are brave); it has only one cell but is as large as a cereal bowl! If you are looking to stay a little more in your comfort zone, I highly recommend my favorite protist, the slime mold. These fluorescent yellow creatures seep an ooze over fallen trees and have even been known to solve mazes in their quest for food.

Once you are done exploring the epically bizarre Kingdom of the Protists, hop aboard your bird of choice and fly on over to the more familiar territory of the Kingdom of Fungi. As you fly overhead, you will see fallen logs, tree stumps, old apples, dried leaves, and all manner of dead things, each covered with gray or green fuzziness or perhaps some brightly colored mushrooms, with even more residents teeming around invisibly. What is up with all that dead stuff, you ask? You like tasty treats, don’t you? Oh, you don’t think stale bread sounds good? Fair enough, but one man’s trash is another fungi’s treasure. Fungi are one of the chief decomposers in many environments, breaking down dead creatures so that new creatures can take their place.

Now, I would bet that some of you think that fungi and mushrooms are the same thing. I can understand the confusion, after all mushrooms are the most charismatic of all fungi (the real fun guy in the group, you might say), but only about a sixth of the 75,000 known species of fungi have mushrooms.

Mushrooms come in an astonishing variety. Many mushrooms look like the typical white miniature umbrellas, but others are like shelves climbing up trees or tiny branches reaching for the sky or balls that explode in a cloud of dust when you touch them. They can be yellow, red, or orange and have evocative names like chicken of the woods or cauliflower mushrooms or lion’s mane. Many species of mushrooms are grown for us to eat, but others are extremely dangerous, so never eat a mushroom that you find – mushrooms are as beautiful and diverse as they can be dangerous.

In the Kingdom of the Fungi, there are also several types of creatures that are just one cell – yeasts, molds, and mildews. Yeasts have been our great help in the kitchen from the dawn of history, making breads light and fluffy, cheese blue and stinky, and the savory British spread Marmite...salty. Molds and mildews are decidedly less appetizing, such as when they are making fuzzy blue, red, or white colonies on our old bread or fruit.

Before we leave these two kingdoms, we must visit a creature that is neither here nor there, so to speak. It is a nomad that roams among the kingdoms: the lichen. Lichens grow on trees or rocks, looking kind of like flat leaves or short green branches or even orange dust. These creatures are made up of a fungus and a bacteria or an algae (a kind of protist) living together as one creature. The two working together are stronger than each on its own, allowing them to live in harsh environments like the Arctic or deserts. The protist or bacteria make food for the fungus, and the fungus provides water and protection. These little creatures are surely a wonder of creation.

Check out Chapter 4A Podcast Episode!

Check the gills on these (fun)gis. Image by Andreas from Pixabay

Part 2: These are Fun Guys: Fungi and Fungus-Like Protists

‘One side will make you grow taller, and the other side will make you grow shorter.’ ‘One side of what? The other side of what?’ thought Alice to herself . ‘Of the mushroom,’ said the Caterpillar, just as if she had asked it aloud.

-Alice’s Adventures in Wonderland by Lewis Carroll

As we have been visiting the Kingdoms of the Protists and Fungi, you might not have noticed since we have been looking at bigger creatures, but these guys are not prokaryotes like the archaea and bacteria (creatures without a nucleus in their cells). Instead, they are eukaryotes (they have a nucleus in their cells which holds the DNA). Scientists even use these cell differences to split all creatures into three domains: Bacteria, Archaea, and Eukaryotes (including protists, fungi, plants, and animals).

You might be saying to yourself, but why do bacteria and archaea get their own groups while we’re lumped in with athlete’s foot? Well, among eukaryotes you can find some surprising similarities. Animals have melanin in their skin which gives it color, while some fungi use melanin to produce food in radioactive environments. Insects and mushrooms both use chitin (a special kind of carbohydrate) to give themselves strength and structure. Protists share so much in common with other eukaryotes that they are actually described as being either animal-like, plant-like, or fungus-like. The fungus-like ones, such as slime molds, primarily vary from true fungus because of their lack of chitin. Fungus-like protists’ cells are more similar to plants, but they are generally decomposers like fungi, making them both heterotrophs. We’ll come back to visit the animal-like and plant-like protists after we have met their respective counterparts.

We talked about the many different types of mushrooms, but what exactly is a mushroom? A mushroom is actually the fruit of the fungus, like an apple on a tree, so picking a mushroom hurts the fungus no more than picking that apple hurts the tree. The main part of the fungus is actually under the ground, in the log, on the tree, or anywhere else the mushroom happened to be growing. If you go out in the forest and turn over a log, you might see a bunch of white tendrils all criss-crossing each other. That is the main part of the fungus known as the mycellium (my-see-lee-um). Mycellia (plural of mycellium) do amazing things in the environment, including helping trees talk to each other and helping crops get nitrogen, as we will discuss more later.

The largest creature in the world is one fungus that lives in Oregon, with its mycellium covering over 2000 acres (that’s an area as big as 1500 American football fields) and likely weighing at least 10,000 tons (or as much as about 65 blue whales). Pretty much all you will ever see of it, though, are its mushrooms that appear like magic here and there throughout the forest. Scientists think that this mushroom is not only enormous but also ancient – maybe even alive when the pyramids were being built in Egypt.

What makes mushrooms grow? When the conditions are right (such as after it rains or after a forest fire), the mycellium will produce a mushroom. A typical mushroom has a tall stalk with a cap on top of it. The caps can be many different shapes, from the typical flat or conical shapes to a v-shape with a deep cleft in the middle. Under the cap, the mushroom might have gills (thin sheets like teeth on a comb), pores (little holes), ridges or teeth that hold the spores (kind of like seeds) of the fungus. As the mushroom ages, it spreads the spores so that more of the fungus can grow. Fungi can also grow by spreading out their mycellia.

1We’ll come back to the comparisons between the plant-like and animal-like protists and other creatures in later chapters.

Check out Chapter 4B Podcast Episode!

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