In 1887 the British mycologist William Hay commented that he who studied fungi “must boldly face a good deal of scorn … and is actually regarded as a sort of idiot among the lower orders”. Even the father of modern taxonomy, Carl Linnaeus avoided classifying individual species of fungi. Linnaeus categorised fungi as “cryptogamia” because he couldn’t find their sexual organs - “crypto” meaning hidden.
So, what are fungi?
With modern science and DNA sequencing, we know that fungi are not really plants at all. In fact, fungi are more closely related to animals. Their cell walls are made from the same material that makes insects exoskeletons – chiten and they don’t make food from photosynthesis like plants but instead, spit out enzymes from their roots (hyphae) and digest the surrounding matter into small enough morsels for their cells to engulf - somewhat like what goes on inside our stomachs when we digest food. Fungi are so different to plants and animals that they could be considered a kingdom of their own. Indeed there are many people advocating that we give fungi a kingdom of their own: Flora, Fauna and Funga, has a certain ring to it.
In fact, the very earth we live on may owe itself to the work of fungal hyphae. A combination of the chemicals that fungi exude and the strength of force its hyphae have allow for the breakdown of rock into soil. Fungi have been breaking down matter like this for around 1.5 billion years.
Somewhere along their evolutionary journey they joined forces with primitive algae or cyanobacteria and created one of nature’s most amazing symbioses - lichen. That’s right, you heard me, lichen are really a partnership between fungi and algae. Algae and cyanobacteria give fungi the power of photosynthesis and in return, they give back the gift of protection from the elements and stability which helps with water absorption. The symbiosis is so rooted in evolution that it has evolved several times in different species and can be recreated easily under laboratory conditions.
The question of “what is a fungi” is different depending on what species you look at. They can be single celled organisms, as in yeast, or multi-cellular. They reproduce clonally (by mitosis) or sexually through meiosis and in many cases, both. Sexual reproduction is itself a minefield, worthy of an entire blog but as our friend Carl Linnaeus found, fungi do not have male and female organs like animals or plants, that is to say, their reproductive cells (gametes) look too similar to distinguish (known as isogamy). So how do they reproduce sexually? Gametes within a fungal hypha or perhaps between different species of fungal hyphae sense that they are of the same species but different enough – scientists call these “mating types” often labelled + or – instead of male and female – and they reproduce by meiosis, forming the cells of the next generation.
In many cases, these cells are born on a mushroom. The mushroom is the fruiting body of a fungi that holds the spores, filled with cells of the next generation, ready to be carried on the wind until they land on the perfect substrate and start to spread their hyphae once again, breaking down the world around them. Did you know we breathe between 1-10 fungal spores with every breathe we take?
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