What do you think is the largest organism in the world?
An elephant or a whale? If not those, then it must be a tree, then, surely. But what
if I told you that the largest organism in the world is actually a fungus? In the
Blue Mountains of Oregon, the honey mushroom quietly thrives above and beneath the soil,
with underground filaments spanning across four square miles, or a whopping 1,665 football fields.
Another massive organism is the giant kelp, which is a protist. A single individual can
reach lengths of 175 feet, providing shelter and nutrients that support an entire ecosystem.
In today's lesson, we'll be diving into the kingdoms of these two giants as we describe
the key characteristics of both fungi and protists, identify examples of each,
and explain how they are important to humans and the environment. Let's get into it!
In our last few lessons, we learned about the plant and animal kingdoms. Today,
we'll be taking a look at the final two kingdoms of Eukarya: Fungi and Protists.
Starting with Fungi. Fungi get a bad rap because they're often associated with molds and spoiled
food. However, fungi are incredibly diverse and include millions of different species
outside of the ones growing in your spoiled leftovers. So, what exactly is a fungus,
and how do scientists identify them? Well, like plants and animals, fungi
are eukaryotic, which means they store their DNA in a nucleus. Like plants, fungi reproduce using
spores, but unlike their leafy cousins, they can't perform photosynthesis. No photosynthesis
means they can't make their own food. Instead, they feed off organic matter to obtain energy.
In this way, they share mixed traits of both plants and animals. Some examples
include mushrooms, yeasts, and molds. Fungi serve many useful purposes. By
eating decaying matter, they recycle organic materials and keep resources flowing through
the environment. Additionally, penicillin, the first antibiotic to fight bacterial infections,
was derived from a fungus. Fungi are helpful in the kitchen as well. If you recall from
a previous lesson, yeasts are responsible for making bread rise when baked in the oven using
a process called fermentation. Many mushrooms are edible and considered delicacies around the world,
and molds are actually an important component in some kinds of cheeses. So, whether you're enjoying
fine dining, good health, or nature in general, there's a lot to appreciate about this group.
This brings us to the weirdest kingdom in the domain Eukarya: Protists. You can think of these
guys as the Island of Misfit Eukaryotes. It's where scientists put organisms that don't quite
fit into any other categories. Simply put, a protist is a eukaryote that is not a plant,
animal, or fungus. Other than that, there simply aren't any defining characteristics.
Most of them are motile or capable of movement, but from here things get a lot fuzzier.
Some protists are unicellular, while some are multicellular. Some make their own food,
and some eat other things to survive. And some have cell walls, and some don't.
Some examples of protists include algae, which behave a lot like plants; amoebas,
which are very similar to animals; and slime molds, which are easily mistaken for fungi.
Despite their strange qualities, there are a lot of reasons to be thankful that protists exist.
Algae, in particular, are one of the most important organisms on Earth, comprising
the backbone of all marine ecosystems in the world and providing over half of the Earth's oxygen via
photosynthesis. That's more than trees produce. So, the next time you take a breath of fresh air,
thank the protists, because that's where most of the oxygen is coming from.
And with that, we have wrapped up our unit on the diversity of life. In today's lesson, we learned
that Fungi and Protista are both kingdoms within the domain Eukarya. Fungi are spore-producing
organisms that feed off organic matter, and some examples include mushrooms, yeasts, and molds.
Protists are all eukaryotic organisms that are not plants, animals, or fungi,
and include organisms such as algae, amoebas, and slime molds.
In our next unit, we'll explore how all of our planet's diverse organisms interact
together as we dive into the incredible scientific field of ecology. Until then,
I'm Tony, and remember, life is full of wonders, so keep learning, and don't ever stop wondering.