Mushrooms are found all over the world and grow in a wide range of habitats. They can be found in extreme environments such as deserts or areas with high concentrations of salt or ionizing radiation, as well as in deep-sea sediments.
Some can survive intense UV and cosmic rays. Most fungi live in terrestrial environments, although some live partially or exclusively in aquatic systems.
The use of mushrooms by humans dates back to prehistory. Ancient peoples have used mushrooms as a food source, often unknowingly, for millennia in the preparation of leavened bread and fermented beverages. They were also used as kindling or for medicinal purposes. They are still used by humans in a very wide range.
They occur in all climatic zones, mainly on land, but also in water, both salty and fresh.
The actual number of mushroom species is very large. It is estimated that there are about 1-1.5 million species of them - four times as many as seed plants.
By 2020, about 148.000 species were described, but about 2000 new ones are described every year - about 90 percent of mushrooms remain unknown.
It was suggested that they had a limited ability to move, their type of growth, and their morphological differences from animals. This is still the case in popular consciousness, when, for example, when simplified lists of protected species are prepared, mushrooms are combined with plants. Mycology is also included in botany in the educational program, and the group of fungi inhabiting a given environment is called flora or mycoflora (recently also mycobiota or funga).
The separation of fungi from plants was first proposed in 1969 by the American botanist and climatologist, Robert Whittaker.
This was determined based on phylogeny (origin), biochemistry, and anatomy. Fungi are considered to be one of the developmental lines within the supergroup Opisthokonta, one of the six into which nucleobases (eukaryotes) are divided, which includes, among others, animals.
Like animals, fungi are heterotrophic and feed on organic nutrients in their environment, which they usually break down by releasing enzymes, making them soluble and available to them.
A common feature of fungi and animals is the production of the polysaccharide glycogen as a storage substance, while plants produce starch.
Although fungi, like plants, do not move, in the animal world, some individuals spend most of their lives in one place, such as sponges and hard corals.
Fungi do not perform photosynthesis, the cell walls of most fungi contain chitin, which does not occur in plants, but is characteristic of the exoskeleton of arthropods. Fungi also do not produce cellulose.
Each part of the fungi body is self-sufficient and there is no communication between them.
The hyphae branch and connect, which leads to the formation of mycelium, which is an interconnected network of hyphae. Many species of fungi develop specialized hyphal structures to extract nutrients from living hosts.
Mycelium can create more complex structures that perform specialized functions, e.g. rootstocks, mycelial cords, sclerotia, and fruiting bodies.
Fungi do not differentiate into tissues and organs.
Mycelia, grown on solid surfaces, are called colonies. Some individual colonies can reach extraordinary sizes and ages, as in the case of Armillaria ostoyae (a tree pathogenic fungus), which extends over an area of over 900 ha, with an estimated age of almost 9000 years.
In some species, the pigment melanin may play a role in extracting energy from ionizing radiation such as gamma radiation.
It is estimated that one-third of all fungi reproduce using more than one propagation method. Most of them can reproduce both sexually and asexually. In some species, asexual reproduction is not known at all.
The asexually reproducing form of the fungus is called anamorph, and the sexually reproducing form is called teleomorph. There are several methods of asexual reproduction (including fragmentation of the thallus, budding, spores) and several methods of sexual reproduction (spermatization, autogamy, parthenogamy, somatogamy, gametogamy, etc.).
Many species require small amounts of them to survive. They can be saprophytes feeding on dead organic matter, or parasites developing at the expense of other living organisms.
A characteristic feature of fungi is their cell wall made of chitin. A fungal cell may be mononucleate, binucleate, or multinucleate - a multinucleated cell is called a cellulose.
Fungi can breathe aerobically or anaerobically (yeast). Anaerobic respiration is called fermentation. As a result, ethyl alcohol and CO2 are produced.
Mycologists have developed several systems of classifying fungi.
A less official classification groups mushrooms according to:
They are the only organisms that can decompose lignin and are important in the decomposition of cellulose, thanks to a specific enzyme - cellulase.
Mushrooms can be a source of both inorganic matter, which are products of metabolism (CO2, H2O), and organic matter because they are food for many microorganisms. Fungi decompose branches and leaves - it is estimated that without this decomposition, 12 tons of cellulosic waste per hectare would be produced annually in tropical forests.
They form mycorrhiza with many plants (coexistence of roots or seeds of vascular plants with fungi) - it is estimated that the proper development of about 90 percent of plants depends on mycorrhizal fungi.
Many species of mushrooms are used in food production: bread, alcohol, and cheese. Some of them, such as brushes and aspergillus, contribute to its decomposition.
They are also used to produce medicines, mainly antibiotics (in the mid-20th century, 96 antibiotics of fungal origin were already known), organic compounds (citric acid), and enzymes on an industrial scale.
Edible mushrooms have culinary uses. For centuries, attempts have been made to introduce mushroom farming for industrial purposes. This was only achieved in 12 species. Their main source is still wild mushrooms.
An example of such a mushroom is the oyster mushroom. If it lacks protein, it hunts for nematodes by making loops from mycelial hyphae to catch them. After catching the nematodes, it releases enzymes on them to break them down and then takes in the missing nitrogen.
Cordyceps species are parasitic fungi that live on animals - insect larvae or spiders - using them as a source of protein. Ophiocordyceps unilateralis produces a substance that crosses the blood-brain barrier and paralyzes the ants' nervous system. These insects become helpless - zombie ants - and are completely controlled by the fungi.
This communication involves a multidirectional flow of information (in the form of chemical compounds and cellular structures) between fungal hyphae and other plants and trees.
Each mycelium has its own communication code.
It is called Pestalotiopsis microspora. Its polyurethane degradation activity was discovered only in 2010. This is the first species of fungus that is able to survive on polyurethane in anaerobic conditions.
This makes this fungus a potential candidate for bioremediation (biological land cleansing) projects involving large amounts of plastic.
His image appears on the back of the 2002 New Zealand $50 banknote.
It is a very rare mushroom, fully protected in Poland, it is placed on the Red List of Large-bearing Mushrooms with status E, i.e. "extinct".
The mushroom is inedible but extremely decorative.