Despite being a closer relative to animals than plants, fungi behave more like plants to our human observations. They do not move around like animals and do not possess sensory organs the way animals do. Fungi and animals may have traveled together along the eukaryote evolutionary highway, but they still got off at different exits.
Despite these differences, all three of the main eukaryote branches—plants, fungi, and animals—fill essential niches in our ecosystem, with each one benefiting from the other in some way.
What Separates Animals from Plants?
Plants and animals both cover an extremely diverse range of things in their own respective arenas that highlighting superficial differences would be a futile task. Therefore, we need to take things down to a fundamental level. In this case, that means the cells that make up plants and animals.
At a cellular level, plants and animals are completely different, and that fundamental difference changes the way each lifeform operates on a macro scale. Granted, the cells can look very similar when you consider what they consist of. This is because they are both from the same distant brach in the tree of life. The cells that make plants, animals, and fungi are all called eukaryotic cells, while the cells that form bacteria are called prokaryotic. But despite this fundamental similarity, the cells of plants and animals work in very different ways.
Looking from the outside in, the first significant difference you might notice is the cell walls, which are much more rigid in plants than they are in animals. Indeed, animals are not rigid at all, owing to the fact that they don’t have walls but membranes. The next thing is the organelles, which are the components inside the cell. Plant cells contain chloroplasts, which are the component that allows them to convert sunlight into energy, and is absent in animal cells. Another difference is vacuoles. These can be thought of as water-balloon-like organelles that are present in some animal cells but not in the relative size that they are in plant cells. These fill up with water to “inflate” the cell, which keeps the plant sturdy. When you see flowers wilting as they die, that wilting is a direct result of the vacuoles losing their water.
Pulling back to a more macro observation, plants breath in carbon dioxide and breath out oxygen, which is the opposite of what animals do. This should help to illustrate the importance of plants to animals. More than just the basis of our food chain, they are responsible for the very air we breathe.
One final significant difference between plants and animals is the lack of a nervous system in plants. Animals typically have some kind of governing system—such as a brain and accompanying nervous system—that governs their behavior. This is absent in plants, though they do exhibit behavioral patterns through other means.
What do Animals and Fungi Have in Common?
The most significant commonality that fungi and animals share is a lack of chlorophyll, which would allow them to process sunlight for energy. Despite behaving more like a plant in the way they grow and propagate, the lack of this essential plant-like trait makes them more similar to animals in the way they obtain their energy.
Another similarity with animals—albeit not all animals—is the presence of chitin. This substance makes up the cell walls of fungi and is also present in certain animals, particularly those with exoskeletons.
The final similarity we are going to highlight is the cellular structure. Like animals—and plants, for that matter—fungi cells are eukaryote. Along with protists, these four classifications of life on Earth all come from the same common ancestor.
Do Fungi Have More in Common with Plants or Animals?
From a purely scientific perspective, fungi are more closely related to animals than plants due to their lack of chlorophyll and the fact that they need to consume nutrition from organic substances, unlike plants, which are synthesizing in nature. These differences may seem smaller than some of the more obvious similarities, but from a scientific point of view, these speak to a more fundamental difference between plants and fungi that stretches back to first the branching off of plants from this evolutionary line. Plants are widely thought to be the first of the three—plants, fungi, and animals—to branch away from the common ancestor, meaning they have spent more time diverging than animals and fungi have.
Of course, to the untrained eye, fungus often bears much more of a similarity to plants in the sense that it grows in a similar way to plants and does not behave like an animal.
What are the Five Groups of Fungi?
There many thousands of different species of fungi, each with their own unique properties. However, they can all be broken down into five distinct families, each with quite different places in our ecosystem.
Chytridiomycota
Informally known as chytrids, this group of fungi can be a little difficult to classify owed to the significant variation that can be found within the group. Chytrids are aquatic fungi, though they can also thrive on land in capillary networks around soil and are considered terrestrial in those cases.
Chytrids have been found in a huge variety of habitats, from bogs to rivers, from spings to ditches, and, of course, in soils where there is sufficient water content, as we mentioned above. Despite this apparent ubiquity, you will likely never see them due to their microscopic size. The exception to this is chytridiomycosis, an infectious disease that affects amphibians and has been linked to some quite dramatic population declines in those animals and even extinctions. They also have a tendency to infect algae and certain microbes, though they may also affect plants.
Chytrids play an important role in the decomposition of materials like cellulose, pollen, keratin, and chitin. Pollen, in particular, can be subjected to substantial colonization by chytrids, as a lot of pollen accumulates in bodies of water.
Zygomycota
Moving on to a more visible example of fungi, Zygomycota—also known as zygote fungi—is a mostly a terrestrial fungus that is known to have over a thousand different species under its umbrella. The most well-recognized example of zygote fungi is sporangium, which features a long, thin stem with a bulbous, ball-like cap.
Zygote fungi is mostly a parasite of plants and animals, including insects, though it can also form symbiotic relationships with some plants. They are able to grow in a broad range of environments, with the optimum temperature a little above average room temperature. One of the more useful features of zygote fungi is that many species of them can be used in industrial processes, such as leather making and food production.
One of the most widely seen examples of zygote fungi is as one of the many types of mold that can form on bread that has been left too long.
Glomeromycota
Glomeromycota—which unfortunately does not have an easy to pronounce alternative name—boasts around two hundred and thirty species under its fungal umbrella. This type of fungus is very dependant on plantlife—vascular land plants in particular—for carbon and energy, although some evidence shows that certain species of Glomeromycota may be able to exist independently.
It is estimated that around half of all fungi found in soil is one of the Glomeromycota species, with a staggering eighty to ninety percent of all land plants thought to be in a symbiotic relationship with fungi. In this relationship, the fungi extract sugars from the plant in exchange for dissolving minerals in the soil, which then provide the plant with nutrients.
Ascomycota
Commonly known as sac fungi, this is the largest phylum of fungi, being made up of over sixty-four thousand different species. Ninety-eight percent of lichens feature this kind of fungi, and it is also the fungi present in yeast, which is used in a wide range of food products from beer to bread. That being said, they are also responsible for a range of plant diseases, including Dutch elm disease. One type of Ascomycota—Aspergillus fumigatus—is the most common cause of fungal infections in human lungs, typically affecting people who are immune-compromised.
It is not all bad, however. This branch of the fungal kingdom is also responsible for penicillin and a number of fungal delicacies.
Basidiomycota
Though sac fungi have the largest number of species, and Glomeromycota makes up almost half of the fungi found in our soils, it is Basidiomycota that you will most likely recognize more than any other kind of fungus. This is the type of fungi that is responsible for the traditional mushrooms that we are familiar with, from toadstools to clamshells. If you’ve ever picked mushrooms, it will have been from this family of fungi.
The visible mushroom that we pick and eat is the fruiting body of the fungi, and only sprouts when the mycelium from which it grew is ready to spread its spores. Once the spores have been shed, the mushroom then dies, and the process repeats.
What are the Beneficial Functions of Fungi in Nature?
The exact roles that any given fungi plays in nature are down to that specific fungi’s properties and behaviors, but there are some common traits across many mushroom species that can be used to illustrate the beneficial functions of fungi as a whole.
We’ve picked out a few of the more significant benefits that fungi bring to the table for a little more of an in-depth look.
Food
For those mushrooms that are edible, the fungus is an invaluable source of nutrients for humans and animals alike. Granted, not every fungus is safe for consumption, but many of the edible variants are packed full of essential ingredients that can help keep the eater healthy.
This has led to certain mushroom species being cultivated worldwide as a food source. Despite this, mushrooms represent a relatively small portion of our overall food intake, but they are also used in the production of other foods and drinks in less direct ways, such as a part of a cultivation process.
When picking mushrooms yourself, it is crucial that you are properly educated in what you are picking since not all mushrooms are edible, and some are poisonous. In the case of some mushrooms—such as the aptly named death cap—the poisonous mushroom closely resembles other perfectly edible mushrooms, further complicating the issue.
Recycling
Decomposition is often an underappreciated part of nature. Without decomposition, the materials in dead plants, animals, and other living things would not be returned to nature, where their nutrients can help to fuel the growth of other living things.
Along with bacteria, fungi are responsible for most of the recycling that happens in nature, returning dead materials into the soil from whence they came. Without fungi, the rate of decomposition in our ecosystem would be severely reduced, which in turn would mean a smaller capacity for life on this planet. It is a large planet, but the natural resources we benefit from are still finite. If those valuable nutrients and minerals were finding their way back into the Earth at a slower rate, it would eventually become a limiting factor in how much new life could grow.
Plant Growth
As we mentioned earlier in the post, certain types of fungi are found in between eighty and ninety percent of land plants, where they form a symbiotic relationship that benefits the plant as much as it does the fungi.
As plants are close to the base of most food chains—including our own—it doesn’t take a scientist to see why this is beneficial to us. Indeed, to every living thing.
Naturally, there are exceptions to every rule, and some types of fungi do far more harm than good to plant life, but on the whole, fungi’s impact on the world of plants is a beneficial one.
Medicinal
There are many folk remedies that center around certain types of mushrooms, and these may well be considered very beneficial as more research is done into the purported effects they can have on our health. That being said, fungi form the basis of one of the most revolutionary medicines we have—penicillin, which led to the discovery of antibiotics and a quantum leap forward in our ability to treat a range of medical problems.
Controlled Harm
Humans have made use of certain parasitic fungi as a means to control the population of things like caterpillars that eat crops. There are other pests that can be controlled through the use of certain fungi as a kind of natural pesticide.
How do Fungi Benefit Humans?
There are several ways in which fungi benefit humans, many of which we have touched on in this post already. Perhaps the most significant direct benefit that fungi have had on humanity is the discovery of penicillin, which has dramatically extended the life expectancy of the average person thanks to a way of fighting infections that is lightyears ahead of anything that came before it. There is also a range of purported health benefits from consuming certain types of mushroom, with folk medicine, in particular, having plenty of uses for fungi.
On a more indirect front, the symbiotic relationship between plants and certain types of fungi is undoubtedly crucial to humans. Whether you are a meat-eater, a vegetarian, a vegan, or anything in between, plants form a vital part of your food chain, even if you yourself aren’t eating them.
Beyond that, there are the instances we touched on in the last section, where humans use certain parasitic species of fungi to control pests in crop-growing scenarios.
And, of course, there is the vital service of decomposition that fungi carry out on a mass scale across the globe. This process allows the circle of life to continue, as dead plants and animals can shed their nutrients back into the Earth for the living to consume. Without this, not only would there be less of a capacity for healthy, living things in our world, but we would be wading through inches deep of dead plants and animals all the time.
Perhaps that last part is an exaggeration, but you get the idea.
Final Thoughts
Despite appearances, fungi are closer to animals than they are plants in a number of ways, many of which are not obvious to human observation. Despite this fact, fungi are very much their own lifeform and are entirely separate from animals, just as they are from plants.
Of course, we share this ecosystem with lifeforms that are even further removed from plants, fungi, and animals. These three are grouped together under the umbrella of eukaryote life, but there are other types of life that branched away at different times to the eukaryote branch, and, compared to those other types of life, plants, animals, and fungi are essentially one single umbrella of life that is considerably more different than anything from their own branch.
