85-594: Eutheriodontia is a clade of therapsids which appear during the Middle Permian and which includes therocephalians and cynodonts , this latter group including mammals and related forms. With the dicynodonts , they form one of two lineages of therapsids that survived the End-Permian extinction and which diversified again during the Triassic , before the majority of them disappeared before or during
170-477: A gametangium , a specialized cell structure that becomes a fertile gamete -producing cell. The gametangium develops into a zygospore , a thick-walled spore formed by the union of gametes. When the zygospore germinates, it undergoes meiosis , generating new haploid hyphae, which may then form asexual sporangiospores . These sporangiospores allow the fungus to rapidly disperse and germinate into new genetically identical haploid fungal mycelia. The spores of most of
255-421: A monophyletic origin of fungi. The taxonomy of fungi is in a state of constant flux, especially due to research based on DNA comparisons. These current phylogenetic analyses often overturn classifications based on older and sometimes less discriminative methods based on morphological features and biological species concepts obtained from experimental matings . There is no unique generally accepted system at
340-479: A "ladder", with supposedly more "advanced" organisms at the top. Taxonomists have increasingly worked to make the taxonomic system reflect evolution. When it comes to naming , this principle is not always compatible with the traditional rank-based nomenclature (in which only taxa associated with a rank can be named) because not enough ranks exist to name a long series of nested clades. For these and other reasons, phylogenetic nomenclature has been developed; it
425-623: A clade can be described based on two different reference points, crown age and stem age. The crown age of a clade refers to the age of the most recent common ancestor of all of the species in the clade. The stem age of a clade refers to the time that the ancestral lineage of the clade diverged from its sister clade. A clade's stem age is either the same as or older than its crown age. Ages of clades cannot be directly observed. They are inferred, either from stratigraphy of fossils , or from molecular clock estimates. Viruses , and particularly RNA viruses form clades. These are useful in tracking
510-735: A cup-shaped fruit body that is often macroscopic and holds the hymenium , a layer of tissue containing the spore-bearing cells. The fruit bodies of the basidiomycetes ( basidiocarps ) and some ascomycetes can sometimes grow very large, and many are well known as mushrooms . The growth of fungi as hyphae on or in solid substrates or as single cells in aquatic environments is adapted for the efficient extraction of nutrients, because these growth forms have high surface area to volume ratios . Hyphae are specifically adapted for growth on solid surfaces, and to invade substrates and tissues. They can exert large penetrative mechanical forces; for example, many plant pathogens , including Magnaporthe grisea , form
595-650: A direct source of human food , in the form of mushrooms and truffles ; as a leavening agent for bread; and in the fermentation of various food products, such as wine , beer , and soy sauce . Since the 1940s, fungi have been used for the production of antibiotics , and, more recently, various enzymes produced by fungi are used industrially and in detergents . Fungi are also used as biological pesticides to control weeds, plant diseases, and insect pests. Many species produce bioactive compounds called mycotoxins , such as alkaloids and polyketides , that are toxic to animals, including humans. The fruiting structures of
680-615: A few species contain psychotropic compounds and are consumed recreationally or in traditional spiritual ceremonies . Fungi can break down manufactured materials and buildings, and become significant pathogens of humans and other animals. Losses of crops due to fungal diseases (e.g., rice blast disease ) or food spoilage can have a large impact on human food supplies and local economies. The fungus kingdom encompasses an enormous diversity of taxa with varied ecologies, life cycle strategies, and morphologies ranging from unicellular aquatic chytrids to large mushrooms. However, little
765-496: A fungal mycelium separates into pieces, and each component grows into a separate mycelium. Mycelial fragmentation and vegetative spores maintain clonal populations adapted to a specific niche , and allow more rapid dispersal than sexual reproduction. The "Fungi imperfecti" (fungi lacking the perfect or sexual stage) or Deuteromycota comprise all the species that lack an observable sexual cycle. Deuteromycota (alternatively known as Deuteromycetes, conidial fungi, or mitosporic fungi)
850-405: A high degree of metabolic versatility that allows them to use a diverse range of organic substrates for growth, including simple compounds such as nitrate , ammonia , acetate , or ethanol . In some species the pigment melanin may play a role in extracting energy from ionizing radiation , such as gamma radiation . This form of " radiotrophic " growth has been described for only a few species,
935-573: A motile zoospore , enabling them to propel themselves through water and enter their amphibian host. Other examples of aquatic fungi include those living in hydrothermal areas of the ocean. As of 2020, around 148,000 species of fungi have been described by taxonomists , but the global biodiversity of the fungus kingdom is not fully understood. A 2017 estimate suggests there may be between 2.2 and 3.8 million species. The number of new fungi species discovered yearly has increased from 1,000 to 1,500 per year about 10 years ago, to about 2,000 with
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#17327808643141020-402: A new haploid mycelium. Sexual reproduction in basidiomycetes is similar to that of the ascomycetes. Compatible haploid hyphae fuse to produce a dikaryotic mycelium. However, the dikaryotic phase is more extensive in the basidiomycetes, often also present in the vegetatively growing mycelium. A specialized anatomical structure, called a clamp connection , is formed at each hyphal septum. As with
1105-431: A peak of more than 2,500 species in 2016. In the year 2019, 1,882 new species of fungi were described, and it was estimated that more than 90% of fungi remain unknown. The following year, 2,905 new species were described—the highest annual record of new fungus names. In mycology, species have historically been distinguished by a variety of methods and concepts. Classification based on morphological characteristics, such as
1190-516: A process called branching , or occasionally growing hyphal tips fork, giving rise to two parallel-growing hyphae. Hyphae also sometimes fuse when they come into contact, a process called hyphal fusion (or anastomosis ). These growth processes lead to the development of a mycelium , an interconnected network of hyphae. Hyphae can be either septate or coenocytic . Septate hyphae are divided into compartments separated by cross walls (internal cell walls, called septa, that are formed at right angles to
1275-422: A revised taxonomy based on a concept strongly resembling clades, although the term clade itself would not be coined until 1957 by his grandson, Julian Huxley . German biologist Emil Hans Willi Hennig (1913–1976) is considered to be the founder of cladistics . He proposed a classification system that represented repeated branchings of the family tree, as opposed to the previous systems, which put organisms on
1360-567: A small drop of water (Buller's drop), which upon contact with the spore leads to its projectile release with an initial acceleration of more than 10,000 g ; the net result is that the spore is ejected 0.01–0.02 cm, sufficient distance for it to fall through the gills or pores into the air below. Other fungi, like the puffballs , rely on alternative mechanisms for spore release, such as external mechanical forces. The hydnoid fungi (tooth fungi) produce spores on pendant, tooth-like or spine-like projections. The bird's nest fungi use
1445-581: A structure called an appressorium that evolved to puncture plant tissues. The pressure generated by the appressorium, directed against the plant epidermis , can exceed 8 megapascals (1,200 psi). The filamentous fungus Paecilomyces lilacinus uses a similar structure to penetrate the eggs of nematodes . The mechanical pressure exerted by the appressorium is generated from physiological processes that increase intracellular turgor by producing osmolytes such as glycerol . Adaptations such as these are complemented by hydrolytic enzymes secreted into
1530-429: A suffix added should be e.g. "dracohortian". A clade is by definition monophyletic , meaning that it contains one ancestor which can be an organism, a population, or a species and all its descendants. The ancestor can be known or unknown; any and all members of a clade can be extant or extinct. The science that tries to reconstruct phylogenetic trees and thus discover clades is called phylogenetics or cladistics ,
1615-488: A terrestrial lifestyle necessitated a diversification of ecological strategies for obtaining nutrients, including parasitism , saprobism , and the development of mutualistic relationships such as mycorrhiza and lichenization. Studies suggest that the ancestral ecological state of the Ascomycota was saprobism, and that independent lichenization events have occurred multiple times. In May 2019, scientists reported
1700-668: A third of all fungi reproduce using more than one method of propagation; for example, reproduction may occur in two well-differentiated stages within the life cycle of a species, the teleomorph (sexual reproduction) and the anamorph (asexual reproduction). Environmental conditions trigger genetically determined developmental states that lead to the creation of specialized structures for sexual or asexual reproduction. These structures aid reproduction by efficiently dispersing spores or spore-containing propagules . Asexual reproduction occurs via vegetative spores ( conidia ) or through mycelial fragmentation . Mycelial fragmentation occurs when
1785-438: Is a stub . You can help Misplaced Pages by expanding it . Clade In biological phylogenetics , a clade (from Ancient Greek κλάδος (kládos) 'branch'), also known as a monophyletic group or natural group , is a grouping of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree . In the taxonomical literature, sometimes
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#17327808643141870-581: Is also strongly supported by molecular phylogenetics . This fungal group is distinct from the structurally similar myxomycetes (slime molds) and oomycetes (water molds). The discipline of biology devoted to the study of fungi is known as mycology (from the Greek μύκης mykes , mushroom). In the past, mycology was regarded as a branch of botany , although it is now known that fungi are genetically more closely related to animals than to plants. Abundant worldwide, most fungi are inconspicuous because of
1955-499: Is also used with a similar meaning in other fields besides biology, such as historical linguistics ; see Cladistics § In disciplines other than biology . The term "clade" was coined in 1957 by the biologist Julian Huxley to refer to the result of cladogenesis , the evolutionary splitting of a parent species into two distinct species, a concept Huxley borrowed from Bernhard Rensch . Many commonly named groups – rodents and insects , for example – are clades because, in each case,
2040-404: Is considered to be the publication of Pier Antonio Micheli 's 1729 work Nova plantarum genera . Micheli not only observed spores but also showed that, under the proper conditions, they could be induced into growing into the same species of fungi from which they originated. Extending the use of the binomial system of nomenclature introduced by Carl Linnaeus in his Species plantarum (1753),
2125-476: Is in turn included in the mammal, vertebrate and animal clades. The idea of a clade did not exist in pre- Darwinian Linnaean taxonomy , which was based by necessity only on internal or external morphological similarities between organisms. Many of the better known animal groups in Linnaeus's original Systema Naturae (mostly vertebrate groups) do represent clades. The phenomenon of convergent evolution
2210-625: Is known of the true biodiversity of the fungus kingdom, which has been estimated at 2.2 million to 3.8 million species. Of these, only about 148,000 have been described, with over 8,000 species known to be detrimental to plants and at least 300 that can be pathogenic to humans. Ever since the pioneering 18th and 19th century taxonomical works of Carl Linnaeus , Christiaan Hendrik Persoon , and Elias Magnus Fries , fungi have been classified according to their morphology (e.g., characteristics such as spore color or microscopic features) or physiology . Advances in molecular genetics have opened
2295-645: Is not an accepted taxonomic clade and is now taken to mean simply fungi that lack a known sexual stage. Sexual reproduction with meiosis has been directly observed in all fungal phyla except Glomeromycota (genetic analysis suggests meiosis in Glomeromycota as well). It differs in many aspects from sexual reproduction in animals or plants. Differences also exist between fungal groups and can be used to discriminate species by morphological differences in sexual structures and reproductive strategies. Mating experiments between fungal isolates may identify species on
2380-515: Is responsible for many cases of misleading similarities in the morphology of groups that evolved from different lineages. With the increasing realization in the first half of the 19th century that species had changed and split through the ages, classification increasingly came to be seen as branches on the evolutionary tree of life . The publication of Darwin's theory of evolution in 1859 gave this view increasing weight. In 1876 Thomas Henry Huxley , an early advocate of evolutionary theory, proposed
2465-489: Is still controversial. As an example, see the full current classification of Anas platyrhynchos (the mallard duck) with 40 clades from Eukaryota down by following this Wikispecies link and clicking on "Expand". The name of a clade is conventionally a plural, where the singular refers to each member individually. A unique exception is the reptile clade Dracohors , which was made by haplology from Latin "draco" and "cohors", i.e. "the dragon cohort "; its form with
2550-537: Is the result of a large-scale collaborative research effort involving dozens of mycologists and other scientists working on fungal taxonomy. It recognizes seven phyla , two of which—the Ascomycota and the Basidiomycota—are contained within a branch representing subkingdom Dikarya , the most species rich and familiar group, including all the mushrooms, most food-spoilage molds, most plant pathogenic fungi, and
2635-473: Is their means of mobility , except for spores (a few of which are flagellated ), which may travel through the air or water. Fungi are the principal decomposers in ecological systems. These and other differences place fungi in a single group of related organisms, named the Eumycota ( true fungi or Eumycetes ), that share a common ancestor (i.e. they form a monophyletic group ), an interpretation that
Eutheriodontia - Misplaced Pages Continue
2720-427: Is unclear and may be lower than other sexual processes. It is known to play a role in intraspecific hybridization and is likely required for hybridization between species, which has been associated with major events in fungal evolution. In contrast to plants and animals , the early fossil record of the fungi is meager. Factors that likely contribute to the under-representation of fungal species among fossils include
2805-612: The Cambrian (542–488.3 Ma), also long before land plants. Fossilized hyphae and spores recovered from the Ordovician of Wisconsin (460 Ma) resemble modern-day Glomerales , and existed at a time when the land flora likely consisted of only non-vascular bryophyte -like plants. Prototaxites , which was probably a fungus or lichen, would have been the tallest organism of the late Silurian and early Devonian . Fungal fossils do not become common and uncontroversial until
2890-647: The Latin fungus (mushroom), used in the writings of Horace and Pliny . This in turn is derived from the Greek word sphongos (σφόγγος 'sponge'), which refers to the macroscopic structures and morphology of mushrooms and molds; the root is also used in other languages, such as the German Schwamm ('sponge') and Schimmel ('mold'). The word mycology is derived from the Greek mykes (μύκης 'mushroom') and logos (λόγος 'discourse'). It denotes
2975-599: The Latin form cladus (plural cladi ) is used rather than the English form. Clades are the fundamental unit of cladistics , a modern approach to taxonomy adopted by most biological fields. The common ancestor may be an individual, a population , or a species ( extinct or extant ). Clades are nested, one in another, as each branch in turn splits into smaller branches. These splits reflect evolutionary history as populations diverged and evolved independently. Clades are termed monophyletic (Greek: "one clan") groups. Over
3060-746: The Triassic–Jurassic extinction , except for a lineage of cynodonts that later gave rise to mammals. The clade was named in 1986 by James Allen Hopson and Herbert Richard Barghusen , the name meaning the "true Theriodontia". Within Hopson's system, the Eutheriodontia are the sister group of the Gorgonopsia within the Theriodontia . A close relationship between therocephalians and cynodonts had been recognized for many years. In 2001
3145-545: The ascomycete genus Cochliobolus , and the ascomycete Pneumocystis jirovecii . The earliest mode of sexual reproduction among eukaryotes was likely homothallism, that is, self-fertile unisexual reproduction . Besides regular sexual reproduction with meiosis, certain fungi, such as those in the genera Penicillium and Aspergillus , may exchange genetic material via parasexual processes, initiated by anastomosis between hyphae and plasmogamy of fungal cells. The frequency and relative importance of parasexual events
3230-440: The biopolymer chitin. Fungal mycelia can become visible to the naked eye, for example, on various surfaces and substrates , such as damp walls and spoiled food, where they are commonly called molds . Mycelia grown on solid agar media in laboratory petri dishes are usually referred to as colonies . These colonies can exhibit growth shapes and colors (due to spores or pigmentation ) that can be used as diagnostic features in
3315-455: The roots of plants. As eukaryotes, fungi possess a biosynthetic pathway for producing terpenes that uses mevalonic acid and pyrophosphate as chemical building blocks . Plants and some other organisms have an additional terpene biosynthesis pathway in their chloroplasts, a structure that fungi and animals do not have. Fungi produce several secondary metabolites that are similar or identical in structure to those made by plants. Many of
3400-601: The Dutch Christiaan Hendrik Persoon (1761–1836) established the first classification of mushrooms with such skill as to be considered a founder of modern mycology. Later, Elias Magnus Fries (1794–1878) further elaborated the classification of fungi, using spore color and microscopic characteristics, methods still used by taxonomists today. Other notable early contributors to mycology in the 17th–19th and early 20th centuries include Miles Joseph Berkeley , August Carl Joseph Corda , Anton de Bary ,
3485-417: The Eutheriodontia were defined as the least inclusive clade including Mammalia and Bauria . Even today, the taxon has a strong recognition among paleontologists and is regularly cited in several studies concerning therapsids . The therocephalians and cynodonts are thought to have diverged in the Middle Permian , and each group independently evolved mammal-like features, including a secondary palate and
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3570-718: The Homobasidiomycetes (a taxon roughly equivalent to the mushroom-producing species of the Agaricomycetes ). Two amber -preserved specimens provide evidence that the earliest known mushroom-forming fungi (the extinct species Archaeomarasmius leggetti ) appeared during the late Cretaceous , 90 Ma. Some time after the Permian–Triassic extinction event (251.4 Ma), a fungal spike (originally thought to be an extraordinary abundance of fungal spores in sediments ) formed, suggesting that fungi were
3655-487: The air over long distances. Specialized mechanical and physiological mechanisms, as well as spore surface structures (such as hydrophobins ), enable efficient spore ejection. For example, the structure of the spore-bearing cells in some ascomycete species is such that the buildup of substances affecting cell volume and fluid balance enables the explosive discharge of spores into the air. The forcible discharge of single spores termed ballistospores involves formation of
3740-645: The apex) as in the case of some endophytic fungi, or growth by volume expansion during the development of mushroom stipes and other large organs. Growth of fungi as multicellular structures consisting of somatic and reproductive cells—a feature independently evolved in animals and plants —has several functions, including the development of fruit bodies for dissemination of sexual spores (see above) and biofilms for substrate colonization and intercellular communication . Fungi are traditionally considered heterotrophs , organisms that rely solely on carbon fixed by other organisms for metabolism . Fungi have evolved
3825-414: The basis of biological species concepts. The major fungal groupings have initially been delineated based on the morphology of their sexual structures and spores; for example, the spore-containing structures, asci and basidia , can be used in the identification of ascomycetes and basidiomycetes, respectively. Fungi employ two mating systems : heterothallic species allow mating only between individuals of
3910-497: The basis of comparisons of the rate of evolution in closely related groups. The oldest fossilizied mycelium to be identified from its molecular composition is between 715 and 810 million years old. For much of the Paleozoic Era (542–251 Ma), the fungi appear to have been aquatic and consisted of organisms similar to the extant chytrids in having flagellum-bearing spores. The evolutionary adaptation from an aquatic to
3995-692: The brothers Louis René and Charles Tulasne , Arthur H. R. Buller , Curtis G. Lloyd , and Pier Andrea Saccardo . In the 20th and 21st centuries, advances in biochemistry , genetics , molecular biology , biotechnology , DNA sequencing , and phylogenetic analysis have provided new insights into fungal relationships and biodiversity , and have challenged traditional morphology-based groupings in fungal taxonomy . Most fungi grow as hyphae , which are cylindrical, thread-like structures 2–10 μm in diameter and up to several centimeters in length. Hyphae grow at their tips (apices); new hyphae are typically formed by emergence of new tips along existing hyphae by
4080-621: The cell wall giving the hypha its shape), with each compartment containing one or more nuclei; coenocytic hyphae are not compartmentalized. Septa have pores that allow cytoplasm , organelles , and sometimes nuclei to pass through; an example is the dolipore septum in fungi of the phylum Basidiomycota. Coenocytic hyphae are in essence multinucleate supercells. Many species have developed specialized hyphal structures for nutrient uptake from living hosts; examples include haustoria in plant-parasitic species of most fungal phyla, and arbuscules of several mycorrhizal fungi, which penetrate into
4165-525: The discovery of a fossilized fungus, named Ourasphaira giraldae , in the Canadian Arctic , that may have grown on land a billion years ago, well before plants were living on land. Pyritized fungus-like microfossils preserved in the basal Ediacaran Doushantuo Formation (~635 Ma) have been reported in South China. Earlier, it had been presumed that the fungi colonized the land during
4250-602: The dominant life form at this time, representing nearly 100% of the available fossil record for this period. However, the relative proportion of fungal spores relative to spores formed by algal species is difficult to assess, the spike did not appear worldwide, and in many places it did not fall on the Permian–Triassic boundary. Sixty-five million years ago, immediately after the Cretaceous–Paleogene extinction event that famously killed off most dinosaurs, there
4335-547: The early Devonian (416–359.2 Ma), when they occur abundantly in the Rhynie chert , mostly as Zygomycota and Chytridiomycota . At about this same time, approximately 400 Ma, the Ascomycota and Basidiomycota diverged, and all modern classes of fungi were present by the Late Carboniferous ( Pennsylvanian , 318.1–299 Ma). Lichens formed a component of the early terrestrial ecosystems, and
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#17327808643144420-412: The effects on growth rates are small, and the underlying biophysical and biochemical processes are not well known. This process might bear similarity to CO 2 fixation via visible light , but instead uses ionizing radiation as a source of energy. Fungal reproduction is complex, reflecting the differences in lifestyles and genetic makeup within this diverse kingdom of organisms. It is estimated that
4505-427: The environment to digest large organic molecules—such as polysaccharides , proteins , and lipids —into smaller molecules that may then be absorbed as nutrients. The vast majority of filamentous fungi grow in a polar fashion (extending in one direction) by elongation at the tip (apex) of the hypha. Other forms of fungal growth include intercalary extension (longitudinal expansion of hyphal compartments that are below
4590-535: The estimated age of the oldest terrestrial lichen fossil is 415 Ma; this date roughly corresponds to the age of the oldest known sporocarp fossil, a Paleopyrenomycites species found in the Rhynie Chert. The oldest fossil with microscopic features resembling modern-day basidiomycetes is Palaeoancistrus , found permineralized with a fern from the Pennsylvanian. Rare in the fossil record are
4675-535: The force of falling water drops to liberate the spores from cup-shaped fruiting bodies. Another strategy is seen in the stinkhorns , a group of fungi with lively colors and putrid odor that attract insects to disperse their spores. In homothallic sexual reproduction , two haploid nuclei derived from the same individual fuse to form a zygote that can then undergo meiosis . Homothallic fungi include species with an Aspergillus -like asexual stage (anamorphs) occurring in numerous different genera, several species of
4760-417: The formation of the hook ensures proper distribution of the newly divided nuclei into the apical and basal hyphal compartments. An ascus (plural asci ) is then formed, in which karyogamy (nuclear fusion) occurs. Asci are embedded in an ascocarp , or fruiting body. Karyogamy in the asci is followed immediately by meiosis and the production of ascospores . After dispersal, the ascospores may germinate and form
4845-414: The general public due to their historical classification, as well as several similarities. Like plants, fungi often grow in soil and, in the case of mushrooms , form conspicuous fruit bodies , which sometimes resemble plants such as mosses . The fungi are now considered a separate kingdom, distinct from both plants and animals, from which they appear to have diverged around one billion years ago (around
4930-546: The group consists of a common ancestor with all its descendant branches. Rodents, for example, are a branch of mammals that split off after the end of the period when the clade Dinosauria stopped being the dominant terrestrial vertebrates 66 million years ago. The original population and all its descendants are a clade. The rodent clade corresponds to the order Rodentia, and insects to the class Insecta. These clades include smaller clades, such as chipmunk or ant , each of which consists of even smaller clades. The clade "rodent"
5015-777: The higher taxonomic levels and there are frequent name changes at every level, from species upwards. Efforts among researchers are now underway to establish and encourage usage of a unified and more consistent nomenclature . Until relatively recent (2012) changes to the International Code of Nomenclature for algae, fungi and plants , fungal species could also have multiple scientific names depending on their life cycle and mode (sexual or asexual) of reproduction. Web sites such as Index Fungorum and MycoBank are officially recognized nomenclatural repositories and list current names of fungal species (with cross-references to older synonyms ). The 2007 classification of Kingdom Fungi
5100-408: The host cells to consume nutrients. Although fungi are opisthokonts —a grouping of evolutionarily related organisms broadly characterized by a single posterior flagellum —all phyla except for the chytrids have lost their posterior flagella. Fungi are unusual among the eukaryotes in having a cell wall that, in addition to glucans (e.g., β-1,3-glucan ) and other typical components, also contains
5185-411: The identification of species or groups. Some individual fungal colonies can reach extraordinary dimensions and ages as in the case of a clonal colony of Armillaria solidipes , which extends over an area of more than 900 ha (3.5 square miles), with an estimated age of nearly 9,000 years. The apothecium —a specialized structure important in sexual reproduction in the ascomycetes—is
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#17327808643145270-416: The intense UV and cosmic radiation encountered during space travel. Most grow in terrestrial environments, though several species live partly or solely in aquatic habitats, such as the chytrid fungi Batrachochytrium dendrobatidis and B. salamandrivorans , parasites that have been responsible for a worldwide decline in amphibian populations. These organisms spend part of their life cycle as
5355-590: The last few decades, the cladistic approach has revolutionized biological classification and revealed surprising evolutionary relationships among organisms. Increasingly, taxonomists try to avoid naming taxa that are not clades; that is, taxa that are not monophyletic . Some of the relationships between organisms that the molecular biology arm of cladistics has revealed include that fungi are closer relatives to animals than they are to plants, archaea are now considered different from bacteria , and multicellular organisms may have evolved from archaea. The term "clade"
5440-518: The latter term coined by Ernst Mayr (1965), derived from "clade". The results of phylogenetic/cladistic analyses are tree-shaped diagrams called cladograms ; they, and all their branches, are phylogenetic hypotheses. Three methods of defining clades are featured in phylogenetic nomenclature : node-, stem-, and apomorphy-based (see Phylogenetic nomenclature§Phylogenetic definitions of clade names for detailed definitions). The relationship between clades can be described in several ways: The age of
5525-521: The loss of a postorbital bar (these features were retained in mammals, which are considered a derived group of cynodonts). Mammalian features that both groups inherited from a common ancestor include the loss of teeth on the palate , the expansion of the epipterygoid bone at the base of the skull (an area called the alisphenoid in mammals), and the narrowing of the skull roof to a narrow sagittal crest running between large temporal openings . [REDACTED] This therapsid -related article
5610-546: The more familiar mushrooms . These organisms are classified as one of the traditional eukaryotic kingdoms , along with Animalia , Plantae , and either Protista or Protozoa and Chromista . A characteristic that places fungi in a different kingdom from plants , bacteria , and some protists is chitin in their cell walls . Fungi, like animals, are heterotrophs ; they acquire their food by absorbing dissolved molecules, typically by secreting digestive enzymes into their environment. Fungi do not photosynthesize . Growth
5695-607: The nature of fungal fruiting bodies , which are soft, fleshy, and easily degradable tissues, and the microscopic dimensions of most fungal structures, which therefore are not readily evident. Fungal fossils are difficult to distinguish from those of other microbes, and are most easily identified when they resemble extant fungi. Often recovered from a permineralized plant or animal host, these samples are typically studied by making thin-section preparations that can be examined with light microscopy or transmission electron microscopy . Researchers study compression fossils by dissolving
5780-401: The opposite mating type , whereas homothallic species can mate, and sexually reproduce, with any other individual or itself. Most fungi have both a haploid and a diploid stage in their life cycles. In sexually reproducing fungi, compatible individuals may combine by fusing their hyphae together into an interconnected network; this process, anastomosis , is required for the initiation of
5865-445: The phrase fauna and flora be replaced by fauna, flora, and funga . Before the introduction of molecular methods for phylogenetic analysis, taxonomists considered fungi to be members of the plant kingdom because of similarities in lifestyle: both fungi and plants are mainly immobile , and have similarities in general morphology and growth habitat. Although inaccurate, the common misconception that fungi are plants persists among
5950-468: The plant and fungal enzymes that make these compounds differ from each other in sequence and other characteristics, which indicates separate origins and convergent evolution of these enzymes in the fungi and plants. Fungi have a worldwide distribution, and grow in a wide range of habitats, including extreme environments such as deserts or areas with high salt concentrations or ionizing radiation , as well as in deep sea sediments. Some can survive
6035-417: The preparation of leavened bread and fermented juices. Some of the oldest written records contain references to the destruction of crops that were probably caused by pathogenic fungi. Mycology became a systematic science after the development of the microscope in the 17th century. Although fungal spores were first observed by Giambattista della Porta in 1588, the seminal work in the development of mycology
6120-451: The researched species of fungi are transported by wind. Such species often produce dry or hydrophobic spores that do not absorb water and are readily scattered by raindrops, for example. In other species, both asexual and sexual spores or sporangiospores are often actively dispersed by forcible ejection from their reproductive structures. This ejection ensures exit of the spores from the reproductive structures as well as traveling through
6205-466: The resolution and added robustness to estimates of genetic diversity within various taxonomic groups. Mycology is the branch of biology concerned with the systematic study of fungi, including their genetic and biochemical properties, their taxonomy, and their use to humans as a source of medicine, food, and psychotropic substances consumed for religious purposes, as well as their dangers, such as poisoning or infection. The field of phytopathology ,
6290-405: The scientific study of fungi. The Latin adjectival form of "mycology" ( mycologicæ ) appeared as early as 1796 in a book on the subject by Christiaan Hendrik Persoon . The word appeared in English as early as 1824 in a book by Robert Kaye Greville . In 1836 the English naturalist Miles Joseph Berkeley 's publication The English Flora of Sir James Edward Smith, Vol. 5. also refers to mycology as
6375-420: The sexual cycle. Many ascomycetes and basidiomycetes go through a dikaryotic stage, in which the nuclei inherited from the two parents do not combine immediately after cell fusion, but remain separate in the hyphal cells (see heterokaryosis ). In ascomycetes, dikaryotic hyphae of the hymenium (the spore-bearing tissue layer) form a characteristic hook (crozier) at the hyphal septum. During cell division ,
6460-508: The size and shape of spores or fruiting structures, has traditionally dominated fungal taxonomy. Species may also be distinguished by their biochemical and physiological characteristics, such as their ability to metabolize certain biochemicals, or their reaction to chemical tests . The biological species concept discriminates species based on their ability to mate . The application of molecular tools, such as DNA sequencing and phylogenetic analysis, to study diversity has greatly enhanced
6545-434: The small size of their structures, and their cryptic lifestyles in soil or on dead matter. Fungi include symbionts of plants, animals, or other fungi and also parasites . They may become noticeable when fruiting , either as mushrooms or as molds. Fungi perform an essential role in the decomposition of organic matter and have fundamental roles in nutrient cycling and exchange in the environment. They have long been used as
6630-546: The spread of viral infections . HIV , for example, has clades called subtypes, which vary in geographical prevalence. HIV subtype (clade) B, for example is predominant in Europe, the Americas and Japan, whereas subtype A is more common in east Africa. Fungi A fungus ( pl. : fungi or funguses ) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds , as well as
6715-598: The start of the Neoproterozoic Era). Some morphological, biochemical, and genetic features are shared with other organisms, while others are unique to the fungi, clearly separating them from the other kingdoms: Shared features: Unique features: Most fungi lack an efficient system for the long-distance transport of water and nutrients, such as the xylem and phloem in many plants. To overcome this limitation, some fungi, such as Armillaria , form rhizomorphs , which resemble and perform functions similar to
6800-609: The structurally similar hook in the ascomycetes, the clamp connection in the basidiomycetes is required for controlled transfer of nuclei during cell division, to maintain the dikaryotic stage with two genetically different nuclei in each hyphal compartment. A basidiocarp is formed in which club-like structures known as basidia generate haploid basidiospores after karyogamy and meiosis. The most commonly known basidiocarps are mushrooms, but they may also take other forms (see Morphology section). In fungi formerly classified as Zygomycota , haploid hyphae of two individuals fuse, forming
6885-594: The study of fungi. A group of all the fungi present in a particular region is known as mycobiota (plural noun, no singular). The term mycota is often used for this purpose, but many authors use it as a synonym of Fungi. The word funga has been proposed as a less ambiguous term morphologically similar to fauna and flora . The Species Survival Commission (SSC) of the International Union for Conservation of Nature (IUCN) in August 2021 asked that
6970-616: The study of plant diseases, is closely related because many plant pathogens are fungi. The use of fungi by humans dates back to prehistory; Ötzi the Iceman , a well-preserved mummy of a 5,300-year-old Neolithic man found frozen in the Austrian Alps, carried two species of polypore mushrooms that may have been used as tinder ( Fomes fomentarius ), or for medicinal purposes ( Piptoporus betulinus ). Ancient peoples have used fungi as food sources—often unknowingly—for millennia, in
7055-511: The surrounding matrix with acid and then using light or scanning electron microscopy to examine surface details. The earliest fossils possessing features typical of fungi date to the Paleoproterozoic era, some 2,400 million years ago ( Ma ); these multicellular benthic organisms had filamentous structures capable of anastomosis . Other studies (2009) estimate the arrival of fungal organisms at about 760–1060 Ma on
7140-420: The way for DNA analysis to be incorporated into taxonomy, which has sometimes challenged the historical groupings based on morphology and other traits. Phylogenetic studies published in the first decade of the 21st century have helped reshape the classification within the fungi kingdom, which is divided into one subkingdom , seven phyla , and ten subphyla . The English word fungus is directly adopted from
7225-410: Was a dramatic increase in evidence of fungi; apparently the death of most plant and animal species led to a huge fungal bloom like "a massive compost heap". Although commonly included in botany curricula and textbooks, fungi are more closely related to animals than to plants and are placed with the animals in the monophyletic group of opisthokonts . Analyses using molecular phylogenetics support
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