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Protists and Fungi

August 18, 2019


Captions on! Click CC to turn off. Over time, we’ve gotten some comments asking
about our channel name like…why we picked amoebas and what is an amoeba anyway? Well, it turns out amoebas are easy to draw,
and we are sisters so our channel name seemed…practical. Kind of. Now, we don’t really resemble real life
amoebas with our eyes, stars on our heads…heads. None of those things are very amoeba like. If you’d like to see some real life amoeba
footage, we have a great channel recommendation in the video details. Part of it is that we happen to really love
amoebas and other protists. It just turns out that sometimes people forget
about protists. I mean, they’re not exactly easy to see. Most protists are microscopic. Most are unicellular- which means they are
made up of one cell- although there are some multicellular protists. Protists are eukaryotes, which means that
unlike prokaryotes, they do have a nucleus and other membrane-bound organelles. Many protists can move and so if you’re
curious about how they do their locomotion, they might have flagella or cilia or in our
case as an amoeba—they might move around by extending their pseudopods. Some protist cells are animal-like where they
won’t typically have cell walls while others are plant or fungus like, where you will see
a cell wall. Protists are such a diverse group because
it’s a category many organisms are put into when they don’t quite meet the requirements
for a plant, animal, or fungus. If you wanted to find a protist, where would
you look? Well, that really depends on what kind of
protist you are looking for. Protists can be found in the water—both
saltwater and freshwater, in the soil, or in other animals. Just some examples. If you were trying to find a protist, you
would likely want to consider what it eats. Protists can be autotrophs or heterotrophs. Recall that autotrophs make their own food,
and in the case of protists, it’s common to see photosynthetic autotrophs. This can include diatoms and euglena as some
example autotrophs. Although euglena is tricky because euglena
can actually act as a heterotroph too. Heterotroph protists eat other things. So amoebas are one. So are paramecia. And slime molds. That’s a confusing type because many times
when you see the word “mold” you think of fungi, which we’ll get to later. But slime molds are protists. Protist reproduction is actually very complex,
and we’d need another video to cover it. Some do binary fission, a simple asexual process
of just splitting that we also talked about in our bacteria video. But many do sexual reproduction too. Some protist life cycles include lengthy haploid
and diploid stages, especially in some of the parasitic types of protists. So, again, another video. So you may wonder, how does a protist really
affect me? Well, protists do a lot of good in the world. Photosynthetic protists in aquatic environments
act as important producers—producing oxygen and also being a part of the food chain. Many types of protists, like the fascinating
slime molds are decomposers. Many organisms have relationships with protists
that they depend on. Examples? Many coral species depend on a certain types
of protist to fix carbon for them; some types of insects require protists in their gut to
help them digest certain types of plant matter. But there are some problematic protists. One example for humans is that they can cause
disease. Many people think mosquitoes are the sole
cause of malaria, which is a potentially deadly disease. But actually, mosquitoes are a carrier for
the disease. Because malaria is actually caused by a type
of parasitic protist that lives in a specific type of mosquito’s gut and can reproduce
in the human body. By working on mosquito control in areas where
malaria is found, it can help prevent the protist from spreading. Also, there are medications for malaria that
can keep the protist from being able to reproduce in the human body. We should point out, there are also dangerous
types of amoeba. Most amoeba species are harmless to humans,
but there is a species of amoeba that can be lethal to humans if it is able to enter
the human body. While cases of this infection are very rare,
it has a high mortality rate. It’s important that research continues to
look for ways to treat it. And the Irish Potato Famine in the 1800’s,
which caused so much destruction of potato crops, was caused by a type of protist that
resembles a fungus but is actually a protist. Learn more about this in the video details. So, we covered a lot about protists now. What about fungi? They’re far more fun than one may realize. Overdone? Perhaps. Fungi, like protists, are also eukaryotes. Most fungi have cells walls made of carbohydrate
called chitin. You can also find chitin as part of the exoskeletons
of insects- kind of cool. So if you were looking for fungi, where would
you look? Many people automatically think of areas that
are dark with moisture, which sure you can find fungi there, but you can actually find
fungi in all kinds of places: in the soil, in your house, in aquatic environments, on
you… When you see fungi, they might remind you
of something like a plant, but if considering molecular genetics, fungi are actually more
related to animals than they are plants. Fungi don’t require light for photosynthesis
like plants do because fungi don’t do photosynthesis. Unlike the classification of protists, which
as we mentioned can include autotrophs, fungi are heterotrophs and therefore consume organic
matter. Most fungi are multicellular, but there are
unicellular fungi too. Many types of fungi can do both sexual and
asexual reproduction. Both of these forms of reproduction often
involve the use of spores—think way smaller than plant seeds—and these can be spread
far away from the parent fungus by wind or by animals or another method. Like the protists, fungi reproduction can
be very complex and we’d need another video to cover it. When people think of fungi, they often think
of something gross. Or not good. Now it is true that fungi can be problematic. For example- yeast infections, ringworm, thrush,
athlete’s foot- these are all examples of fungal infections that can affect humans. Fungi can also be parasites of many organisms,
like this nematode. Although many species of nematodes are also
parasitic too so sometimes it’s a parasite on a parasite. Fungi can also attack plants and therefore
cause destruction to crops. But fungi do a lot of good. They are excellent decomposers which is very
important for ecosystems. Many types of fungi make up food sources for
other organisms. Many fungi are involved in some of the foods
humans eat: like producing some types of cheese. Or helping bread rise by using yeast. Yeast is a fungus. Or mushrooms—mushrooms themselves are a
fungus. Many types of fungi have symbiotic mutual
relationships with other organisms. For example, fungi can help increase the surface
area of plant roots for so many species of plants and help the plant access more water
and minerals. In return, the fungus gets some products of
the plant’s photosynthesis. Or there is lichen, which is a symbiotic relationship
of a fungus and typically an algae. We mention lichen in our ecological succession
video where you can see its role as a pioneer species—and lichen is also a food and habitat
source for organisms. In medicine, we should mention that many antibiotics
are derived from fungus. In fact, the first antibiotic – Penicillin
– was accidentally discovered from a mold. A fungus. So, overall, fungi and protists continue to
fascinate us. And scientists still learn more about them
all the time. Did you know there has been research on the
potential use of phytoplankton as a source of biofuel? Or that some types of fungi are used as biocontrol
agents against pest insects as an alternative to chemical pesticides? Or that yeasts have roles in biotechnology,
like recombinant DNA technology? You can learn more about these from some further
reading suggestions in the video details. Maybe one day you will be part of discovering
more about what these amazing and sometimes overlooked organisms can do. Well, that’s it for the Amoeba Sisters and,
we remind you to stay curious!

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