Last updated on October 23rd, 2023 at 08:55 pm
The answer is far from being as obvious as it seems: fungi have in turn been classified as a separate kingdom in the organization of life, when their lineages are also related to both plants and animals.
They grow like plants, but feed on external organic components, like animals. Fungi are definitely not plants like the others… And in fact, they are not. Since 1969, it has been admitted that fungi constitute a separate kingdom.
Fungi could be more like animals than plants
In the beginning, plants and animals were mainly classified in separate categories because of their different mobility and apparent sensitivity – because in reality plants react to their environment, according to criteria like temperature, humidity or simply gravity. Fungi, according to these criteria, have logically been classified with plants. However, microscopic and biochemical studies show that fungi differ greatly from plants. First, they do not have chlorophyll for photosynthesis and feed – like animals – on organic matter contained in their environment. Like plants, the cells of fungi have a wall, but it is not made of cellulose, but of chitin, which is also found in the carapaces of insects and crustaceans. Moreover, mushrooms do not have stems, leaves, or even roots, replaced by filaments called mycelium. Finally, they do not store their energy in the form of starch, like plants, but glucose, like animals.
In 1969, fungi became a separate kingdom
It was not until the work of Robert Whittaker in 1969 that fungi became a separate kingdom, called “fungi”, among five. Thus, there were plants, animals, fungi, prokaryotes (cells without nuclei such as bacteria) and protists (unicellular cells with nuclei, such as amoebas). Since 2015, a new classification proposes to divide living organisms into seven kingdoms, grouped into two “super kingdoms”.
Mushrooms are often mistaken for plants because they are attached to the ground. But they have no roots, no stems, no leaves. Moreover, they are never green, because they have no chlorophyll. This proves that, unlike plants, fungi do not photosynthesize and cannot make their own food. They find it by associating with another living being or by parasitizing it. They can also digest dead plants or animals. Fungi therefore belong to a separate kingdom, neither plant nor animal: the fungal kingdom.