Hi. It's Mr. Andersen and in this podcast I'm going to talk about fungi.
Fungi is a pretty diverse group. It's things that you're familiar with like a mushroom.
But it's also things that are much smaller than that like a yeast which are going to
be single cell fungi. And they're also going to form sometimes symbiotic relationships.
So lichen for example is a symbiotic relationship between a fungi and then an algae. And so
not only do they breakdown and decompose material, but they're also going to serve another role.
Working symbiotically with both algae and then plants to allow them to function better.
And so basically if we look at their phylogeny. So this is the eukaryotes. So were going to
talk about things now that have a nucleus and have organelles. And you can find here
that here's our fungi. In other words when we try to classify all eukaryotes, we're going
to put them right here. If you look at animals, animals are going to be right here. And so
what does this mean? Well we're going to share more recent common ancestry with fungi than
we are with plants which are going to be way back here. Because we put green plants way
over on this side. And so we probably have more in common with a fungi, especially the
way we live our life than we do with green plants. But we're not directly related to
them. This is more in to the phylogeny of the actual fungi. And again we get this from
the tree of life project. And so you can see that we have this break off like this. And
there are monophyletic groups. In other words there's going to be some groups that you should
know because we know that these things all share common ancestry and they're one group.
And so there are going to be five of those. Chytridiomycota, zygomycota, glomeromycota,
ascomycota and then basidiomycota. And so these are ones that you do need to know because
they're monophyletic. And they're important when we're studying biology. But before we
get there let's get to the characteristics of fungi. Well they're eukaryotic. So they've
got a nuclei and organelles. They're heterotrophs. They originally were classified as plants
and you can see why. It almost looks like a plant. And they don't move. They don't run
around like animals. And they also have these root like structures that look like plant
roots. And so we used to classify them as plants, but they're not. They eat material.
And they're going to digest material. I'll show you some cool examples of that in just
a second. They have cell walls. So that separates them from us. Also the fact that they don't
move. And the cell walls are made of a polysaccharide called chitin. The exoskeleton of insects
are made from that similar structure. Most of the inside of the structure is actually
going to be filamentous. In other words it's made of filaments. And so this would be the
filaments in a mushroom. You can see these thin little filaments. You can see the cell
wall going around the outside of it. But they're not going to have any true tissues. In other
words they're not going to have, for example, a muscle tissue or nervous tissue. It's just
going to be a group of these hyphae they call these. That's what these filaments are called,
over and over and over again. And so even if we were to look in here to these fruiting
bodies of these mushrooms, we'd find that they're hyphae just packed together really,
really tightly. Or if we were to look at the roots of them, those are going to hyphae absorbing
nutrients. And so those are some of the characteristics shared by all fungi. They're all heterotrophic.
And so if you see one growing out of this tree or this rotting tree, they're digesting
the material inside there and they're eating. And you can see here that this mold, which
mold is kind of a term that just means fast growing fungi, you can see this mold is breaking
down this fruit. And if you've ever had athletes foot you've been infected by a fungus as well.
And so this right here is a fungus growing in between the toes. And it's hyphae will
actually grow into the tissues of the person's foot. It secretes an enzyme. Then it digests
that material inside. And it's really painful because it's starting to digest the nerves
on the outside of the foot. And one of my favorite fungi of all is this anthrobotrys.
Basically what they do is you can see the hyphae that they're growing here. But they'll
make these tiny little rings. And then when you have a worm like this. This is called
a nematode worm. Basically if the nematode worm starts to swim through this ring, it
will cinch tight on the nematode worm. It will grab a hold of it. And then it's going
to digest it from the outside in. And so this is an animal eating fungi. And so what could
be much cooler than that. How do they reproduce? Well they do reproduce a lot of the time asexually.
And so when you have mushrooms just continuing to grow out and out and out and out. And they
can grow relatively quick, that's going to be asexual. But then they can also have a
sexual phase as well. And so the spores that come out of a puff ball like this are usually
going to be asexual spores that can spread to an area where there's a little bit of water,
some food and they can start growing. But there's also sexual portions. So these were
formed through a sexual process. If we look at this mushroom right here, basically what
you get are, this would be a basidiomycetes. Basically you're going to have spores that
fall down. You get the growth of a new mushroom, but then we can have sexual reproduction producing
more spores. And so there's a variety of ways they reproduce. Like I mentioned at the beginning,
there are five important phyla that you have to know when it comes to studying fungi. And
I classified them from A to Z. This is just a quick way that I remember it. So we've got
A, B, C and we've got Z over here. So we go from A to Z. A, B, C and then we've got G
in the middle and the G can stand for um, Golly, aren't those fungi cool? Because these
ones are going to be really cool in just a second. And so let's go from A to Z. So the
first ones are the ascomycota. Ascomycota, the asco or the ascus, that's what ascus means.
It means cups. So ascus means cup fungi. Or sac fungi. And you can see right here this
is that sac. And then the spores are going to form on the inside of that. And that's
why we call it the ascomycota. Why are these important? Well this is my favorite fungi
of all. This is the morel. We like to go hunting them in the spring. They taste delicious but
they're really hard to find. You're looking right here at the sexual portion of that.
But you can see these sacs on the inside. Or the sac right here. But ascomycota are
also important. So penicillin is a fungus or an ascomycota that is going to make a lot
of the antibiotics that we have. And so they're important for that. If we look at basidiomycota
is the next one. And so that's the B. Basidio comes from the word basidium, which means
club. And you can see that on the underside of a mushroom they're going to have these
little gills. But if we zoom in closer we're going to find these club like structures.
And each of those club like structures is going to form spores. We'll have four spores
that are found on this basidium. And that's where the name basidiomycota comes from. It's
club fungi. And so what are the big ones? These are going to be the mushrooms that we
think of when we think of fungi. Those are going to be basidiomycota. If we look at these
two together sometimes we would say these two share common ancestry, ascomycota and
basidiomycota. And we sometimes call these the higher fungi. What's next? Next is the
C. So that's going to be chytridiomycota. And these are going to be sometimes referred
to as the chytrids. These used to classified as protists. And the reason why is that they
have a flagellated stage where they'll actually swim around. We now know that they're true
fungi. You've read about these in the news because we've seen on the planet huge increases
in deaths of frogs. And a lot of those are related to chytrid fungi that are infecting
the frogs. Alright, let's go to the G then. So the G stands for the glomeromycota. Glomeromycota
are very important because what they'll do is they form a symbiotic relationship with
plants or a plant symbiosis. So what we have are these mycorrhizal relationships. And so
this right here is the root of a plant. But you can see the fungi growing inside it. And
almost all plants, in other words every plant that we look for has these relationships between
the glomeromycota and their roots. What does that give them? Well that gives them increased
surface area and it allows them to take in more water. And then they give these fungi
a place to live. And so it's a great relationship for both the fungi and for the plant. And
then the last one is going to be the zygomycota. Zygomycota, its name comes from the zygosporangia
which is going to be this resistant structure where the spores are actually formed. It will
rupture and then we get this hiss as the spores are spread out. If you look at that, a bunch
of them together look like that. And a whole bunch of them together are going to look like
this. So this is a bread mold, zygosporangia that you're familiar with. And so basically
what happens if you leave some bread out, one of these spores is going to land on it
and were going to get the growth of this fungus. What's the fungus eating? It's eating the
bread because that's what they do. They're heterotrophs. And so can you remember those
five important phyla of fungi? Ascomycota. Basidiomycota. Chytridiomycota. Glomeromycota.
And zygomycota. And they're all just different types of fungi. And fungi serve a huge roll
on our planet. They breakdown material when it's dead and dying. They recycle those nutrients,
but they also form these symbiotic relationships with plants and algae. And I hope that all
is helpful.