Mycology is a branch of biology
concerned with the study of fungi.
It may not sound like the most interesting thing to make a video about.
But fungi are some of the most incredible
and important organisms on the planet
and have been throughout the history of earth,
possibly having been around for up to one billion years.
Distinct from both plants and animals,
fungi are their own separate ‘kingdom’,
with literally millions of species
coming in all shapes and sizes.
One fungus to the next can be as different
as the snake and giraffe,
or chicken and the dung beetle.
Although we might tend to think of mushrooms
when we think of fungi,
this is actually only the fruiting body of the fungus
with much more going on below the surface.
Some fungi are microscopic and invisible to the naked eye.
While one fungus, the “Humongous Fungus”,
is believed to be the single largest organism that exists by area,
covering 2,200 acres in the US state of Oregon.
For some people,
the word “fungus” might stir up negative connotations,
and of course, some fungi can cause infections or diseases,
while others are poisonous.
And that furry stuff growing on your strawberries,
that’s a fungus too.
However, while the bad is often visible and obvious,
fungi are very much a force for good as well.
We just don’t notice it.
Fungi are not something we tend to think about often.
But they are and especially have been
immensely important to the ecosystem of this planet.
In fact, it’s no understatement to say
the life as we know it, would not be possible without fungi.
To understand how, we need to go back a few years,
well, a few billion years.
Life in the form of single-cell organisms
had already been around for a long time in the oceans.
But as far as we know
the land was largely rocky and barren of life.
Things started to change when some early bacteria developed the ability of “photosynthesis”,
the process of converting the sun’s light into nutrients.
Over time, the byproduct of this,
more oxygen in the atmosphere,
led to the acceleration of more complex organisms
in what is known as the ‘Cambrian explosion’,
about 540 million years ago.
But again this was effectively confined to the water.
The transition of more complex life forms to land was made possible
because of fungi and their unique ability.
Fungi can eat rocks,
breaking them down and turning them into soil.
This is achieved by secreting digestive enzymes,
as well as through mechanical pressure.
Fungi were able to access nutrients
that were otherwise unavailable to any other organism at the time.
It was commonly thought that
a short 60 million years or so after the Cambrian explosion,
fungi began to move onto land.
They would’ve most likely benefited from
access to more than two billion years of bacteria on the shore to feed on.
Of course, the fossil records from this period
have quite significant gaps,
so there’s plenty of uncertainty
with actually the possibility that fungi had already been on land
for a full 500 million years earlier.
However long fungi had been on land beforehand,
we are fairly certain that
they were eventually followed by small proto-plants,
simple organisms that could photosynthesise.
Fungi had minerals and plants had photosynthesis,
but they both needed what the other had to survive.
Fungi and plants began to cooperate
in a process known as symbiosis,
forming a mutually beneficial relationship.
As the fungi and plants began to spread, colonising the land
they began to turn the Earth green.
The soil became more suitable for
many other types of plants that had yet to evolve,
eventually allowing for some to become independent of the fungi.
With ecosystems becoming more complex,
new dynamic balances were established.
The increase in oxygen produced by plants
was balanced out by a growing population of organisms
that needed the oxygen to live.
Likewise, the organic matter that started to build up after things would die
needed to be recycled
so it could continue to be used.
This is where fungi come in.
To put it simply, fungi “eat death”.
By breaking down dead things,
they allow the nutrients to be used again by living things.
This set up another important cycle,
that is fundamental to sustaining all life on Earth,
with fungi serving as one of the final building blocks
for the world we know and love today.
Of course, while new cycles were being established and developed
into what would guide our modern ecosystems,
older relationships continued to thrive.
In particular the symbiosis between plants and fungi,
has continued to change and evolve even to this day,
allowing more complex partnerships to form.
There are two types of Mycorrhizae,
in which the fungus wraps itself
around the roots of the plant,
in which the fungus will actually penetrate the cell wall of the plant,
entwining itself around the cell membrane.
But as invasive as this sounds,
this can actually make it even easier for the plant to benefit.
The plant will happily let another organism literally live inside it,
because the fungus helps the plant derive more nutrients.
Today, the vast majority of plants
benefit from a symbiotic relationship with various different species of fungi.
Some numbers have suggested
as high as 90 % of plants in the world.
Some plants, after millions of years of evolution alongside fungi
still rely entirely on them for survival.
The orchid plant family, for example,
has virtually no independent energy reserve
during its germination stage,
that is, while it’s growing from a seed
into… well, a plant.
Now, many orchids engage in a symbiotic relationship with fungi
that is not mutually beneficial.
Many of these species are actually a parasite to certain fungi,
in which the plant will effectively suck the energy out of the fungus,
in this case referred to as the “host”.
At the same time,
the fungus may also be involved
in a symbiotic relationship with another plant.
So the orchid indirectly
gets its energy through photosynthesis,
even though many of these species
actually lost the ability to photosynthesise themselves.
Parasitism can also work the other way around of course
with a fungus that is a parasite to a plant.
As well as the exchange of nutrients between fungi and plants,
fungi can actually help the plants
exchange nutrients among themselves.
For example, a small tree in a forest
with limited access to sunlight
could be fed more nutrients to help it
thus growing tall enough to be able to photosynthesise on its own.
These more complex types of interactions
between a fungus and potentially many different plants
from the smallest flowers to the tallest trees
are known as “common mycorrhizal networks”.
Fungi are capable of connecting entire forests,
which can sort of be thought of as “Nature’s Internet”,
or somewhat more comically, the “Wood Wide Web”.
Fungi are able to facilitate communication between plants,
which can be especially strong
if the plants are of the same spicies.
Now, obviously plants aren’t literally
having a conversation with each other,
They’re not sentient.
However, the communication they are capable of
is still pretty impressive.
While plants are able to communicate via the air as well,
via the fungi is much more effective.
Signals and cues are transferred between plants
which can influence behaviour.
For example, fungi can mediate
the transfer of chemicals that plants produce
to stunt the growth of their neighbouring, rival plants,
such as by depriving them of nutrients
or inhibiting their photosynthesis.
These so-called “allelochemicals”
may also be used against herbivores,
such as insects, that might want to eat the plant.
Alternatively, fungi can also facilitate
the warning signals that affected plants send to unaffected plants,
triggering the plants’ defensive response.
Such a response could come in the form of a chemical
that acts as a repellent to the attacker,
which could be a pathogen, something that can give plants diseases,
or again, a herbivore.
Of course, this isn’t just the fungus being altruistic.
It’s just in the best interest
of the fungus that the plant survives,
allowing the continuation of their mutually beneficial symbiotic relationship.
Fungi have played a key role in the development of the world as we know it.
They may not always be visible,
and they are not usually something we think of
as being all that important.
But fungi are an unseen cornerstone of the ecosystems.
Silently pulling strings behind the scenes,
forging relationships with many other organisms,
both alive and dead.
Of course, it’s not just plants that fungi interact with,
us humans also have a long history with fungi as well.
Whether it be as a food source,
or the yeast we need for our beer and bread,
their medicinal purposes, pest control and so many other uses,
fungi have always been there.
Always there as an influential part
of not just the history of our planet,
but of human history as well,
both for good and bad.
The topic of fungi has proven to be
one of the most surprisingly interesting topics I’ve made a video about.
This video was actually inspired
by a very compelling documentary I watched
called The Kingdom: How Fungi Made Our World.
The documentary is available on CuriosityStream,
which is the sponsor of this video.
The documentary takes a much deeper look
into the history of fungi
and their symbiosis with plants,
as well as how fungi have revolutionised medicine,
their many other uses
and also the dangers posed by some fungi.
This video was barely able to scratch the surface.
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and enter the promo-code “wonderwhy” during the sign-up process.
A big thank you to CuriosityStream for sponsoring this video,
and for letting me use parts of the documentary in this video.
And as always, thanks for watching, I’ll see you next time.
Mycology is a branch of biology