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74-560: See text Marchantia is a genus of liverworts in the family Marchantiaceae and the order Marchantiales . The genus was named by French botanist Jean Marchant after his father. The thallus of Marchantia shows differentiation into two layers: an upper photosynthetic layer with a well-defined upper epidermis with pores and a lower storage layer. The thallus features tiny cup-like structures called gemma cups, containing gemmae , small packets of tissue that are used for asexual reproduction. The combination of barrel-shaped pores and

148-498: A model organism ). Free-living ciliates are usually the top heterotrophs and predators in microbial food webs, feeding on bacteria and smaller eukaryotes, present in a variety of ecosystems, although a few species are kleptoplastic . Others are parasitic of numerous animals. Ciliates have a basal position in the evolution of alveolates, together with a few species of heterotrophic flagellates with two cilia collectively known as colponemids . The remaining alveolates are grouped under

222-853: A polyphyletic grouping of several independent clades that evolved from the last eukaryotic common ancestor . Protists were historically regarded as a separate taxonomic kingdom known as Protista or Protoctista . With the advent of phylogenetic analysis and electron microscopy studies, the use of Protista as a formal taxon was gradually abandoned. In modern classifications, protists are spread across several eukaryotic clades called supergroups , such as Archaeplastida ( photoautotrophs that includes land plants), SAR , Obazoa (which includes fungi and animals), Amoebozoa and Excavata . Protists represent an extremely large genetic and ecological diversity in all environments, including extreme habitats. Their diversity, larger than for all other eukaryotes, has only been discovered in recent decades through

296-421: A big portion of the oxygen produced worldwide, and comprising much of the marine phytoplankton ; the brown algae , filamentous or 'truly' multicellular (with differentiated tissues) macroalgae that constitute the basis of many temperate and cold marine ecosystems, such as kelp forests ; and the golden algae , unicellular or colonial flagellates that are mostly present in freshwater habitats. Inside Gyrista,

370-454: A collection of amoebae, flagellates and amoeboflagellates with complex life cycles, among which are some slime molds ( acrasids ). The two clades Euglenozoa and Percolozoa are sister taxa, united under the name Discicristata , in reference to their mitochondrial cristae shaped like discs. The species Tsukubamonas globosa is a free-living flagellate whose precise position within Discoba

444-407: A genus is determined by taxonomists . The standards for genus classification are not strictly codified, so different authorities often produce different classifications for genera. There are some general practices used, however, including the idea that a newly defined genus should fulfill these three criteria to be descriptively useful: Moreover, genera should be composed of phylogenetic units of

518-651: A later homonym of a validly published name is a nomen illegitimum or nom. illeg. ; for a full list refer to the International Code of Nomenclature for algae, fungi, and plants and the work cited above by Hawksworth, 2010. In place of the "valid taxon" in zoology, the nearest equivalent in botany is " correct name " or "current name" which can, again, differ or change with alternative taxonomic treatments or new information that results in previously accepted genera being combined or split. Prokaryote and virus codes of nomenclature also exist which serve as

592-628: A long time and redescribed as new by a range of subsequent workers, or if a range of genera previously considered separate taxa have subsequently been consolidated into one. For example, the World Register of Marine Species presently lists 8 genus-level synonyms for the sperm whale genus Physeter Linnaeus, 1758, and 13 for the bivalve genus Pecten O.F. Müller, 1776. Within the same kingdom, one generic name can apply to one genus only. However, many names have been assigned (usually unintentionally) to two or more different genera. For example,

666-601: A major cause of harmful algal blooms due to their toxicity; some live as symbionts of corals, allowing the creation of coral reefs. Dinoflagellates exhibit a diversity of cellular structures, such as complex eyelike ocelli, specialized vacuoles, bioluminescent organelles, and a wall surrounding the cell known as the theca . Rhizaria is a lineage of morphologically diverse organisms, composed almost entirely of unicellular heterotrophic amoebae, flagellates and amoeboflagellates, commonly with reticulose (net-like) or filose (thread-like) pseudopodia for feeding and locomotion. It

740-409: A reference for designating currently accepted genus names as opposed to others which may be either reduced to synonymy, or, in the case of prokaryotes, relegated to a status of "names without standing in prokaryotic nomenclature". An available (zoological) or validly published (botanical) name that has been historically applied to a genus but is not regarded as the accepted (current/valid) name for

814-473: A small group (3 species) of freshwater or marine suspension-feeding bacterivorous flagellates with typical excavate appearance, closely resembling Jakobida and some metamonads but not phylogenetically close to either in most analyses. Diaphoretickes includes nearly all photosynthetic eukaryotes. Within this clade, the TSAR supergroup gathers a colossal diversity of protists. The most basal branching member of

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888-427: A taxon; however, the names published in suppressed works are made unavailable via the relevant Opinion dealing with the work in question. In botany, similar concepts exist but with different labels. The botanical equivalent of zoology's "available name" is a validly published name . An invalidly published name is a nomen invalidum or nom. inval. ; a rejected name is a nomen rejiciendum or nom. rej. ;

962-529: A top special gametophore stalks called antheridiophores and archegoniophores, respectively. These are borne on separate thalli and thus the plants are dioicous . Once fertilized, the ovum is called a zygote and develops into a small sporophyte plant, which remains attached to the larger gametophyte plant. The sporophyte produces spores which develop into free-living male and female gametophyte plants. Asexual reproduction occurs by means of gemmae , discoid clumps of cells which are genetically identical to

1036-455: A total of c. 520,000 published names (including synonyms) as at end 2019, increasing at some 2,500 published generic names per year. "Official" registers of taxon names at all ranks, including genera, exist for a few groups only such as viruses and prokaryotes, while for others there are compendia with no "official" standing such as Index Fungorum for fungi, Index Nominum Algarum and AlgaeBase for algae, Index Nominum Genericorum and

1110-474: A variety of algae. In addition, two smaller groups, Haptista and Cryptista , also belong to Diaphoretickes. The Stramenopiles, also known as Heterokonta, are characterized by the presence of two cilia, one of which bears many short, straw-like hairs ( mastigonemes ). They include one clade of phototrophs and numerous clades of heterotrophs, present in virtually all habitats. Stramenopiles include two usually well-supported clades, Bigyra and Gyrista , although

1184-420: A wide variety of animals – which act as secondary or intermediate host – but can undergo sexual reproduction only in the primary or definitive host (for example: felids such as domestic cats in this case). Some species, for example Plasmodium falciparum , have extremely complex life cycles that involve multiple forms of the organism, some of which reproduce sexually and others asexually. However, it

1258-571: Is paraphyletic , with some analyses placing the root of the eukaryote tree within Metamonada. Discoba includes three major groups: Jakobida , Euglenozoa and Percolozoa . Jakobida are a small group (~20 species) of free-living heterotrophic flagellates, with two cilia, that primarily eat bacteria through suspension feeding; most are aquatic aerobes, with some anaerobic species, found in marine, brackish or fresh water. They are best known for their bacterial-like mitochondrial genomes. Euglenozoa

1332-440: Is a rich (>2,000 species) group of flagellates with very different lifestyles, including: the free-living heterotrophic (both osmo- and phagotrophic) and photosynthetic euglenids (e.g., the euglenophytes , with chloroplasts originated from green algae); the free-living and parasitic kinetoplastids (such as the trypanosomes ); the deep-sea anaerobic symbiontids ; and the elusive diplonemids . Percolozoa (~150 species) are

1406-612: Is discouraged by both the International Code of Zoological Nomenclature and the International Code of Nomenclature for algae, fungi, and plants , there are some five thousand such names in use in more than one kingdom. For instance, A list of generic homonyms (with their authorities), including both available (validly published) and selected unavailable names, has been compiled by the Interim Register of Marine and Nonmarine Genera (IRMNG). The type genus forms

1480-445: Is not yet settled, but is probably more closely related to Discicristata than to Jakobida. The metamonads (Metamonada) are a phylum of completely anaerobic or microaerophilic protozoa, primarily flagellates . Some are gut symbionts of animals such as termites , others are free-living, and others are parasitic. They include three main clades: Fornicata , Parabasalia and Preaxostyla . Fornicata (>140 species) encompasses

1554-460: Is somewhat arbitrary. Although all species within a genus are supposed to be "similar", there are no objective criteria for grouping species into genera. There is much debate among zoologists about whether enormous, species-rich genera should be maintained, as it is extremely difficult to come up with identification keys or even character sets that distinguish all species. Hence, many taxonomists argue in favor of breaking down large genera. For instance,

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1628-500: Is termed protistology . Protists are a diverse group of eukaryotes (organisms whose cells possess a nucleus ) that are primarily single-celled and microscopic but exhibit a wide variety of shapes and life strategies. They have different life cycles , trophic levels , modes of locomotion , and cellular structures . Although most protists are unicellular , there is a considerable range of multicellularity amongst them; some form colonies or multicellular structures visible to

1702-474: Is the type species , and the generic name is permanently associated with the type specimen of its type species. Should the specimen turn out to be assignable to another genus, the generic name linked to it becomes a junior synonym and the remaining taxa in the former genus need to be reassessed. In zoological usage, taxonomic names, including those of genera, are classified as "available" or "unavailable". Available names are those published in accordance with

1776-402: Is unclear how frequently sexual reproduction causes genetic exchange between different strains of Plasmodium in nature and most populations of parasitic protists may be clonal lines that rarely exchange genes with other members of their species. The pathogenic parasitic protists of the genus Leishmania have been shown to be capable of a sexual cycle in the invertebrate vector, likened to

1850-408: Is widespread among multicellular eukaryotes, it seemed unlikely until recently, that sex could be a primordial and fundamental characteristic of eukaryotes. The main reason for this view was that sex appeared to be lacking in certain pathogenic protists whose ancestors branched off early from the eukaryotic family tree. However, several of these "early-branching" protists that were thought to predate

1924-621: The International Code of Zoological Nomenclature ; the earliest such name for any taxon (for example, a genus) should then be selected as the " valid " (i.e., current or accepted) name for the taxon in question. Consequently, there will be more available names than valid names at any point in time; which names are currently in use depending on the judgement of taxonomists in either combining taxa described under multiple names, or splitting taxa which may bring available names previously treated as synonyms back into use. "Unavailable" names in zoology comprise names that either were not published according to

1998-824: The International Plant Names Index for plants in general, and ferns through angiosperms, respectively, and Nomenclator Zoologicus and the Index to Organism Names for zoological names. Totals for both "all names" and estimates for "accepted names" as held in the Interim Register of Marine and Nonmarine Genera (IRMNG) are broken down further in the publication by Rees et al., 2020 cited above. The accepted names estimates are as follows, broken down by kingdom: The cited ranges of uncertainty arise because IRMNG lists "uncertain" names (not researched therein) in addition to known "accepted" names;

2072-499: The bicosoecids , phagotrophic flagellates that consume bacteria, and the closely related Placidozoa , which consists of several groups of heterotrophic flagellates (e.g., the deep-sea halophilic Placididea ) as well as the intestinal commensals known as Opalinata (e.g., the human parasite Blastocystis , and the highly unusual opalinids , composed of giant cells with numerous nuclei and cilia, originally misclassified as ciliates). The alveolates (Alveolata) are characterized by

2146-729: The bigyromonads , a group of bacterivorous or eukaryovorous phagotrophs. A small group of heliozoan-like heterotrophic amoebae, Actinophryida , has an uncertain position, either within or as the sister taxon of Ochrophyta. The little studied phylum Bigyra is an assemblage of exclusively heterotrophic organisms, most of which are free-living. It includes the Labyrinthulomycetes , among which are single-celled amoeboid phagotrophs, mixotrophs, and fungus-like filamentous heterotrophs that create slime networks to move and absorb nutrients, as well as some parasites. Also included in Bigyra are

2220-547: The diplomonads , with two nuclei (e.g., Giardia , genus of well-known parasites of humans), and several smaller groups of free-living, commensal and parasitic protists (e.g., Carpediemonas , retortamonads ). Parabasalia (>460 species) is a varied group of anaerobic, mostly endobiotic organisms, ranging from small parasites (like Trichomonas vaginalis , another human pathogen) to giant intestinal symbionts with numerous flagella and nuclei found in wood-eating termites and cockroaches . Preaxostyla (~140 species) includes

2294-532: The heterotrophic protists, known as protozoa , were considered part of the animal kingdom , while the phototrophic ones, called algae , were studied as part of the plant kingdom . Even after the creation of a separate protist kingdom, some minuscule animals (the myxozoans ) and 'lower' fungi (namely the aphelids , rozellids and microsporidians , collectively known as Opisthosporidia ) were studied as protists, and some algae (particularly red and green algae ) remained classified as plants. According to

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2368-431: The monophyly of Bigyra is being questioned. Branching outside both Bigyra and Gyrista is a single species of enigmatic heterotrophic flagellates, Platysulcus tardus . Much of the diversity of heterotrophic stramenopiles is still uncharacterized, known almost entirely from lineages of genetic sequences known as MASTs (MArine STramenopiles), of which only a few species have been described. The phylum Gyrista includes

2442-419: The nomenclature codes , which allow each species a single unique name that, for animals (including protists ), plants (also including algae and fungi ) and prokaryotes ( bacteria and archaea ), is Latin and binomial in form; this contrasts with common or vernacular names , which are non-standardized, can be non-unique, and typically also vary by country and language of usage. Except for viruses ,

2516-404: The platypus belongs to the genus Ornithorhynchus although George Shaw named it Platypus in 1799 (these two names are thus synonyms ) . However, the name Platypus had already been given to a group of ambrosia beetles by Johann Friedrich Wilhelm Herbst in 1793. A name that means two different things is a homonym . Since beetles and platypuses are both members of the kingdom Animalia,

2590-480: The sequencing of entire genomes and transcriptomes , and electron microscopy studies of the flagellar apparatus and cytoskeleton . New major lineages of protists and novel biodiversity continue to be discovered, resulting in dramatic changes to the eukaryotic tree of life. The newest classification systems of eukaryotes do not recognize the formal taxonomic ranks (kingdom, phylum, class, order...) and instead only recognize clades of related organisms, making

2664-576: The TSAR clade is Telonemia , a small (7 species) phylum of obscure phagotrophic predatory flagellates, found in marine and freshwater environments. They share some cellular similarities with the remaining three clades: Rhizaria , Alveolata and Stramenopiles , collectively known as the SAR supergroup . Another highly diverse clade within Diaphoretickes is Archaeplastida , which houses land plants and

2738-477: The anaerobic and endobiotic oxymonads , with modified mitochondria , and two genera of free-living microaerophilic bacterivorous flagellates Trimastix and Paratrimastix , with typical excavate morphology. Two genera of anaerobic flagellates of recent description and unique cell architecture, Barthelona and Skoliomonas , are closely related to the Fornicata. The malawimonads (Malawimonadida) are

2812-501: The apicomplexans ( Apicomplexa ) are a large (>6,000 species) and highly specialized group of obligate parasites who have all secondarily lost their photosynthetic ability (e.g., Plasmodium falciparum , cause of malaria ). Their adult stages absorb nutrients from the host through the cell membrane, and they reproduce between hosts via sporozoites, which exhibit an organelle complex (the apicoplast ) evolved from non-photosynthetic chloroplasts. The other branch of Myzozoa contains

2886-442: The base for higher taxonomic ranks, such as the family name Canidae ("Canids") based on Canis . However, this does not typically ascend more than one or two levels: the order to which dogs and wolves belong is Carnivora ("Carnivores"). The numbers of either accepted, or all published genus names is not known precisely; Rees et al., 2020 estimate that approximately 310,000 accepted names (valid taxa) may exist, out of

2960-450: The botanical ( ICN ) and the zoological ( ICZN ) codes of nomenclature . Protists display a wide range of distinct morphologies that have been used to classify them for practical purposes, although most of these categories do not represent evolutionary cohesive lineages or clades and have instead evolved independently several times. The most recognizable types are: In general, protists are typical eukaryotic cells that follow

3034-453: The circular shape of the gemma cups are diagnostic of the genus. Multicellular purple colored scales with single cell thickness and unicellular rhizoids are present on the ventral surface of the thallus. Marchantia can reproduce both sexually and asexually . Sexual reproduction involves sperm from antheridia on the male plant fertilizing an ovum (egg cell) in the archegonium of a female plant. The antheridia and archegonia are borne

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3108-399: The clade Myzozoa , whose common ancestor acquired chloroplasts through a secondary endosymbiosis from a red alga. One branch of Myzozoa contains the apicomplexans and their closest relatives, a small clade of flagellates known as Chrompodellida where phototrophic and heterotrophic flagellates, called chromerids and colpodellids respectively, are evolutionarily intermingled. In contrast,

3182-477: The classification more stable in the long term and easier to update. In this new cladistic scheme, the protists are divided into various branches informally named supergroups . Most photosynthetic eukaryotes fall under the Diaphoretickes clade, which contains the supergroups Archaeplastida (which includes plants) and TSAR (including Telonemia , Stramenopiles , Alveolata and Rhizaria ), as well as

3256-446: The common characteristic of a ventral groove in the cell used for suspension feeding , which is considered to be an ancestral trait present in the last eukaryotic common ancestor . The Excavata is composed of three clades: Discoba , Metamonada and Malawimonadida , each including 'typical excavates' that are free-living phagotrophic flagellates with the characteristic ventral groove. According to most phylogenetic analyses, this group

3330-499: The current consensus, the term 'protist' specifically excludes animals, embryophytes (land plants) —meaning that all algae fall under this category— and all fungi, although lower fungi are often studied by protistologists and mycologists alike. The names of some protists (called ambiregnal protists), because of their mixture of traits similar to both animals and plants or fungi (e.g. slime molds and flagellated algae like euglenids ), have been published under either or both of

3404-761: The dinoflagellates and their closest relatives, the perkinsids ( Perkinsozoa ), a small group (26 species) of aquatic intracellular parasites which have lost their photosynthetic ability similarly to apicomplexans. They reproduce through flagellated spores that infect dinoflagellates, molluscs and fish . In contrast, the dinoflagellates ( Dinoflagellata ) are a highly diversified (~4,500 species) group of aquatic algae that have mostly retained their chloroplasts, although many lineages have lost their own and instead either live as heterotrophs or reacquire new chloroplasts from other sources, including tertiary endosymbiosis and kleptoplasty . Most dinoflagellates are free-living and compose an important portion of phytoplankton, as well as

3478-451: The emergence of meiosis and sex (such as Giardia lamblia and Trichomonas vaginalis ) are now known to descend from ancestors capable of meiosis and meiotic recombination , because they have a set core of meiotic genes that are present in sexual eukaryotes. Most of these meiotic genes were likely present in the common ancestor of all eukaryotes , which was likely capable of facultative (non-obligate) sexual reproduction. This view

3552-446: The form "author, year" in zoology, and "standard abbreviated author name" in botany. Thus in the examples above, the genus Canis would be cited in full as " Canis Linnaeus, 1758" (zoological usage), while Hibiscus , also first established by Linnaeus but in 1753, is simply " Hibiscus L." (botanical usage). Each genus should have a designated type , although in practice there is a backlog of older names without one. In zoology, this

3626-737: The generic name (or its abbreviated form) still forms the leading portion of the scientific name, for example, Canis lupus lupus for the Eurasian wolf subspecies, or as a botanical example, Hibiscus arnottianus ssp. immaculatus . Also, as visible in the above examples, the Latinised portions of the scientific names of genera and their included species (and infraspecies, where applicable) are, by convention, written in italics . The scientific names of virus species are descriptive, not binomial in form, and may or may not incorporate an indication of their containing genus; for example,

3700-633: The largest component, with 23,236 ± 5,379 accepted genus names, of which 20,845 ± 4,494 are angiosperms (superclass Angiospermae). By comparison, the 2018 annual edition of the Catalogue of Life (estimated >90% complete, for extant species in the main) contains currently 175,363 "accepted" genus names for 1,744,204 living and 59,284 extinct species, also including genus names only (no species) for some groups. The number of species in genera varies considerably among taxonomic groups. For instance, among (non-avian) reptiles , which have about 1180 genera,

3774-411: The lizard genus Anolis has been suggested to be broken down into 8 or so different genera which would bring its ~400 species to smaller, more manageable subsets. Protist A protist ( / ˈ p r oʊ t ɪ s t / PROH -tist ) or protoctist is any eukaryotic organism that is not an animal , land plant , or fungus . Protists do not form a natural group, or clade , but are

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3848-535: The meiosis undertaken in the trypanosomes. The species diversity of protists is severely underestimated by traditional methods that differentiate species based on morphological characteristics. The number of described protist species is very low (ranging from 26,000 to 74,400 as of 2012) in comparison to the diversity of plants, animals and fungi, which are historically and biologically well-known and studied. The predicted number of species also varies greatly, ranging from 1.4×10 to 1.6×10 , and in several groups

3922-403: The most (>300) have only 1 species, ~360 have between 2 and 4 species, 260 have 5–10 species, ~200 have 11–50 species, and only 27 genera have more than 50 species. However, some insect genera such as the bee genera Lasioglossum and Andrena have over 1000 species each. The largest flowering plant genus, Astragalus , contains over 3,000 species. Which species are assigned to a genus

3996-403: The naked eye. The term 'protist' is defined as a paraphyletic group of all eukaryotes that are not animals , plants or fungi . Because of this definition by exclusion, protists encompass almost all of the broad spectrum of biological characteristics expected in eukaryotes. The distinction between protists and the other three eukaryotic kingdoms has been difficult to settle. Historically,

4070-428: The name could not be used for both. Johann Friedrich Blumenbach published the replacement name Ornithorhynchus in 1800. However, a genus in one kingdom is allowed to bear a scientific name that is in use as a generic name (or the name of a taxon in another rank) in a kingdom that is governed by a different nomenclature code. Names with the same form but applying to different taxa are called "homonyms". Although this

4144-860: The number of predicted species is arbitrarily doubled. Most of these predictions are highly subjective. Molecular techniques such as environmental DNA barcoding have revealed a vast diversity of undescribed protists that accounts for the majority of eukaryotic sequences or operational taxonomic units (OTUs), dwarfing those from plants, animals and fungi. As such, it is considered that protists dominate eukaryotic diversity. Stramenopiles Alveolata Rhizaria Telonemia Haptista Microhelida Cryptista Archaeplastida Provora Hemimastigophora Meteora sporadica Discoba Metamonada Ancyromonadida Malawimonadida CRuMs Amoebozoa Breviatea Apusomonadida Opisthokonta The evolutionary relationships of protists have been explained through molecular phylogenetics ,

4218-430: The parent and contained in cup-like structures on the upper surface of the plant. These are dispersed when rain splashes into the cups and develop into new plants. Asexual reproduction can also occur when older parts of the plant die and the surviving newer branches develop into separate plants. This bryophyte -related article is a stub . You can help Misplaced Pages by expanding it . Genus The composition of

4292-442: The photosynthetic Ochrophyta or Heterokontophyta (>23,000 species), which contain chloroplasts originated from a red alga . Among these are many lineages of algae that encompass a wide range of structures and morphologies. The three most diverse ochrophyte classes are: the diatoms , unicellular or colonial organisms encased in silica cell walls ( frustules ) that exhibit widely different shapes and ornamentations, responsible for

4366-583: The phyla Cryptista and Haptista . The animals and fungi fall into the Amorphea supergroup, which contains the phylum Amoebozoa and several other protist lineages. Various groups of eukaryotes with primitive cell architecture are collectively known as the Excavata . Excavata is a group that encompasses diverse protists, mostly flagellates, ranging from aerobic and anaerobic predators to phototrophs and heterotrophs. The common name 'excavate' refers to

4440-539: The presence of cortical alveoli , cytoplasmic sacs underlying the cell membrane of unknown physiological function. Among them are three of the most well-known groups of protists: apicomplexans, dinoflagellates and ciliates. The ciliates ( Ciliophora ) are a highly diverse (>8,000 species) and probably the most thoroughly studied group of protists. They are mostly free-living microbes characterized by large cells covered in rows of cilia and containing two kinds of nuclei, micronucleus and macronucleus (e.g., Paramecium ,

4514-541: The provisions of the ICZN Code, e.g., incorrect original or subsequent spellings, names published only in a thesis, and generic names published after 1930 with no type species indicated. According to "Glossary" section of the zoological Code, suppressed names (per published "Opinions" of the International Commission of Zoological Nomenclature) remain available but cannot be used as the valid name for

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4588-475: The remaining eukaryotes. Protists generally reproduce asexually under favorable environmental conditions, but tend to reproduce sexually under stressful conditions, such as starvation or heat shock. Oxidative stress , which leads to DNA damage , also appears to be an important factor in the induction of sex in protists. Eukaryotes emerged in evolution more than 1.5 billion years ago. The earliest eukaryotes were protists. Although sexual reproduction

4662-470: The same kind as other (analogous) genera. The term "genus" comes from Latin genus , a noun form cognate with gignere ('to bear; to give birth to'). The Swedish taxonomist Carl Linnaeus popularized its use in his 1753 Species Plantarum , but the French botanist Joseph Pitton de Tournefort (1656–1708) is considered "the founder of the modern concept of genera". The scientific name (or

4736-423: The same principles of physiology and biochemistry described for those cells within the "higher" eukaryotes (animals, fungi or plants): they are aerobic organisms that consume oxygen to produce energy through mitochondria , and those with chloroplasts perform carbon fixation through photosynthesis in chloroplasts . However, many have evolved a variety of unique physiological adaptations that do not appear in

4810-408: The scientific epithet) of a genus is also called the generic name ; in modern style guides and science, it is always capitalised. It plays a fundamental role in binomial nomenclature , the system of naming organisms , where it is combined with the scientific name of a species : see Botanical name and Specific name (zoology) . The rules for the scientific names of organisms are laid down in

4884-488: The sister clade to Ochrophyta are the predominantly osmotrophic and filamentous Pseudofungi (>1,200 species), which include three distinct lineages: the parasitic oomycetes or water moulds (e.g., Phytophthora infestans , the agent behind the Irish Potato Famine ), which encompass most of the pseudofungi species; the less diverse non-parasitic hyphochytrids that maintain a fungus-like lifestyle; and

4958-497: The specific name particular to the wolf. A botanical example would be Hibiscus arnottianus , a particular species of the genus Hibiscus native to Hawaii. The specific name is written in lower-case and may be followed by subspecies names in zoology or a variety of infraspecific names in botany . When the generic name is already known from context, it may be shortened to its initial letter, for example, C. lupus in place of Canis lupus . Where species are further subdivided,

5032-412: The standard format for a species name comprises the generic name, indicating the genus to which the species belongs, followed by the specific epithet, which (within that genus) is unique to the species. For example, the gray wolf 's scientific name is Canis lupus , with Canis ( Latin for 'dog') being the generic name shared by the wolf's close relatives and lupus (Latin for 'wolf') being

5106-717: The study of environmental DNA and is still in the process of being fully described. They are present in all ecosystems as important components of the biogeochemical cycles and trophic webs . They exist abundantly and ubiquitously in a variety of forms that evolved multiple times independently, such as free-living algae , amoebae and slime moulds , or as important parasites . Together, they compose an amount of biomass that doubles that of animals. They exhibit varied types of nutrition (such as phototrophy , phagotrophy or osmotrophy ), sometimes combining them (in mixotrophy ). They present unique adaptations not present in multicellular animals, fungi or land plants. The study of protists

5180-403: The taxon is termed a synonym ; some authors also include unavailable names in lists of synonyms as well as available names, such as misspellings, names previously published without fulfilling all of the requirements of the relevant nomenclatural code, and rejected or suppressed names. A particular genus name may have zero to many synonyms, the latter case generally if the genus has been known for

5254-576: The values quoted are the mean of "accepted" names alone (all "uncertain" names treated as unaccepted) and "accepted + uncertain" names (all "uncertain" names treated as accepted), with the associated range of uncertainty indicating these two extremes. Within Animalia, the largest phylum is Arthropoda , with 151,697 ± 33,160 accepted genus names, of which 114,387 ± 27,654 are insects (class Insecta). Within Plantae, Tracheophyta (vascular plants) make up

5328-429: The virus species " Salmonid herpesvirus 1 ", " Salmonid herpesvirus 2 " and " Salmonid herpesvirus 3 " are all within the genus Salmonivirus ; however, the genus to which the species with the formal names " Everglades virus " and " Ross River virus " are assigned is Alphavirus . As with scientific names at other ranks, in all groups other than viruses, names of genera may be cited with their authorities, typically in

5402-580: Was further supported by a 2011 study on amoebae . Amoebae have been regarded as asexual organisms , but the study describes evidence that most amoeboid lineages are ancestrally sexual, and that the majority of asexual groups likely arose recently and independently. Even in the early 20th century, some researchers interpreted phenomena related to chromidia ( chromatin granules free in the cytoplasm ) in amoebae as sexual reproduction. Some commonly found protist pathogens such as Toxoplasma gondii are capable of infecting and undergoing asexual reproduction in

5476-480: Was the last supergroup to be described, because it lacks any defining characteristic and was discovered exclusively through molecular phylogenetics . Three major clades are included, namely the phyla Cercozoa , Endomyxa and Retaria . Retaria contains the most familiar rhizarians: forams and radiolarians , two groups of large free-living marine amoebae with pseudopodia supported by microtubules , many of which are macroscopic. The radiolarians (Radiolaria) are

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