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Cavalier-Smith
Thomas (Tom) Cavalier-Smith, FRS, FRSC, NERC Professorial Fellow (21 October 1942 – 19 March 2021), was a professor of evolutionary biology in the Department of Zoology, at the University of Oxford. His research has led to discovery of a number of unicellular organisms (protists) and advocated for a variety of major taxonomic groups, such as the Chromista, Chromalveolata, Opisthokonta, Rhizaria, and Excavata. He was known for his systems of classification of all organisms. Life and career Cavalier-Smith was born on 21 October 1942 in London. His parents were Mary Maude (née Bratt) and Alan Hailes Spencer Cavalier Smith. He was educated at Norwich School, Gonville and Caius College, Cambridge (MA) and King's College London (PhD). He was under the supervision of Sir John Randall for his PhD thesis between 1964 and 1967; his thesis was entitled "''Organelle Development in'' Chlamydomonas reinhardii". From 1967 to 1969, Cavalier-Smith was a guest investigato ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cavalier-Smith's System Of Classification
The biological classification system of life introduced by British zoologist Thomas Cavalier-Smith involves systematic arrangements of all life forms on earth. Following and improving the classification systems introduced by Carl Linnaeus, Ernst Haeckel, Robert Whittaker, and Carl Woese, Cavalier-Smith's classification attempts to incorporate the latest developments in taxonomy. His classification has been a major foundation in modern taxonomy, particularly with revisions and reorganisations of kingdoms and phyla. Cavalier-Smith has published extensively on the classification of protists. One of his major contributions to biology was his proposal of a new kingdom of life: the Chromista, although the usefulness of the grouping is questionable given that it is generally agreed to be an arbitrary (polyphyletic) grouping of taxa. He also proposed that all chromista and alveolata share the same common ancestor, a claim later refuted by studies of morphological and molecular evidence b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chromista
Chromista is a biological kingdom consisting of single-celled and multicellular eukaryotic species that share similar features in their photosynthetic organelles (plastids). It includes all protists whose plastids contain chlorophyll ''c'', such as some algae, diatoms, oomycetes, and protozoans. It is probably a polyphyletic group whose members independently arose as a separate evolutionary group from the common ancestor of all eukaryotes. As it is assumed the last common ancestor already possessed chloroplasts of red algal origin, the non-photosynthetic forms evolved from ancestors able to perform photosynthesis. Their plastids are surrounded by four membranes, and are believed to have been acquired from some red algae. Chromista as a biological kingdom was created by British biologist Thomas Cavalier-Smith in 1981 to differentiate some protists from typical protozoans and plants. According to Cavalier-Smith, the kingdom originally included only algae, but his later analysis in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Excavata
Excavata is a major supergroup of unicellular organisms belonging to the domain Eukaryota. It was first suggested by Simpson and Patterson in 1999 and introduced by Thomas Cavalier-Smith in 2002 as a formal taxon. It contains a variety of free-living and symbiotic forms, and also includes some important parasites of humans, including ''Giardia'' and ''Trichomonas''. Excavates were formerly considered to be included in the now obsolete Protista kingdom. They are classified based on their flagellar structures, and they are considered to be the most basal flagellate lineage. Phylogenomic analyses split the members of Excavata into three different and not all closely related groups: Discobids, Metamonads and Malawimonads. Except for Euglenozoa, they are all non-photosynthetic. Characteristics Most excavates are unicellular, heterotrophic flagellates. Only the Euglenozoa are photosynthetic. In some (particularly anaerobic intestinal parasites), the mitochondria have been greatly ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhizaria
The Rhizaria are an ill-defined but species-rich supergroup of mostly unicellular eukaryotes. Except for the Chlorarachniophytes and three species in the genus Paulinella in the phylum Cercozoa, they are all non-photosynthethic, but many foraminifera and radiolaria have a symbiotic relationship with unicellular algae. A multicellular form, ''Guttulinopsis vulgaris'', a cellular slime mold, has also been described. This group was used by Cavalier-Smith in 2002, although the term "Rhizaria" had been long used for clades within the currently recognized taxon. Being described mainly from rDNA sequences, they vary considerably in form, having no clear morphological distinctive characters (synapomorphies), but for the most part they are amoeboids with filose, reticulose, or microtubule-supported pseudopods. In the absence of an apomorphy, the group is ill-defined, and its composition has been very fluid. Some Rhizaria possess mineral exoskeleton (thecae or loricas), which is in differ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Opisthokont
The opisthokonts () are a broad group of eukaryotes, including both the animal and fungus kingdoms. The opisthokonts, previously called the "Fungi/Metazoa group", are generally recognized as a clade. Opisthokonts together with Apusomonadida and Breviata comprise the larger clade Obazoa. Flagella and other characteristics A common characteristic of opisthokonts is that flagellate cells, such as the sperm of most animals and the spores of the chytrid fungi, propel themselves with a single ''posterior'' flagellum. It is this feature that gives the group its name. In contrast, flagellate cells in other eukaryote groups propel themselves with one or more ''anterior'' flagella. However, in some opisthokont groups, including most of the fungi, flagellate cells have been lost. Opisthokont characteristics include synthesis of extracellular chitin in exoskeleton, cyst/spore wall, or cell wall of filamentous growth and hyphae; the extracellular digestion of substrates with osmotrophic a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protist
A protist () is any eukaryotic organism (that is, an organism whose cells contain a cell nucleus) that is not an animal, plant, or fungus. While it is likely that protists share a common ancestor (the last eukaryotic common ancestor), the exclusion of other eukaryotes means that protists do not form a natural group, or clade. Therefore, some protists may be more closely related to animals, plants, or fungi than they are to other protists. However, like the groups ''algae'', ''invertebrates'', and '' protozoans'', the biological category ''protist'' is used for convenience. Others classify any unicellular eukaryotic microorganism as a protist. The study of protists is termed protistology. History The classification of a third kingdom separate from animals and plants was first proposed by John Hogg in 1860 as the kingdom Protoctista; in 1866 Ernst Haeckel also proposed a third kingdom Protista as "the kingdom of primitive forms". Originally these also included prokaryotes, b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chromalveolata
Chromalveolata was a eukaryote supergroup present in a major classification of 2005, then regarded as one of the six major groups within the eukaryotes. It was a refinement of the kingdom Chromista, first proposed by Thomas Cavalier-Smith in 1981. Chromalveolata was proposed to represent the organisms descended from a single secondary endosymbiosis involving a red alga and a bikont. The plastids in these organisms are those that contain chlorophyll c. However, the monophyly of the Chromalveolata has been rejected. Thus, two papers published in 2008 have phylogenetic trees in which the chromalveolates are split up, and recent studies continue to support this view. Groups and classification Historically, many chromalveolates were considered plants, because of their cell walls, photosynthetic ability, and in some cases their morphological resemblance to the land plants (Embryophyta). However, when the five-kingdom system (proposed in 1969) took prevalence over the animal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
International Prize For Biology
The is an annual award for "outstanding contribution to the advancement of research in fundamental biology." The Prize, although it is not always awarded to a biologist, is one of the most prestigious honours a natural scientist can receive. There are no restrictions on the nationality of the recipient. Past laureates include John B. Gurdon, Motoo Kimura, Edward O. Wilson, Ernst Mayr, Thomas Cavalier-Smith, Yoshinori Ohsumi and many other great biologists in the world. Information The International Prize of Biology was created in 1985 to commemorate the 60-year reign of Emperor Shōwa of Japan and his longtime interest in and support of "Biology." The selection and award of the prize is managed by the Japan Society for the Promotion of Science. The laureate is awarded a beautiful medal, 10 million yen, and an international symposium on the scientist's area of research is held in Tokyo. The prize ceremony is held in the presence of Emperor of Japan. The first International Pri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Linnean Medal
The Linnean Medal of the Linnean Society of London was established in 1888, and is awarded annually to alternately a botanist or a zoologist or (as has been common since 1958) to one of each in the same year. The medal was of gold until 1976, and is for the preceding years often referred to as "the Gold Medal of the Linnean Society", not to be confused with the official Linnean Gold Medal which is seldom awarded. The engraver of the medal was Charles Anderson Ferrier of Dundee, a Fellow of the Linnean Society from 1882. On the obverse of the medal is the head of Linnaeus in profile and the words Carl Linnaeus, "Carolus Linnaeus", on the reverse are the arms of the society and the legend ''"Societas Linnaeana optime merenti"''; an oval space is reserved for the recipient's name.Gage A.T. and Stearn W.T. (1988) ''A Bicentenary History of the Linnean Society of London'', Linnean Society of London, p. 80 Linnean medallists 19th century *1888: Joseph Dalton Hooker, Sir Joseph D. Hoo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Norwich School (educational Institution)
Norwich School (formally King Edward VI Grammar School, Norwich) is a selective English independent day school in the close of Norwich Cathedral, Norwich. Among the oldest schools in the United Kingdom, it has a traceable history to 1096 as an episcopal grammar school established by Herbert de Losinga, first Bishop of Norwich. In the 16th century the school came under the control of the city of Norwich and moved to Blackfriars' Hall following a successful petition to Henry VIII. The school was refounded in 1547 in a royal charter granted by Edward VI and moved to its current site beside the cathedral in 1551. In the 19th century it became independent of the city and its classical curriculum was broadened in response to the declining demand for classical education following the Industrial Revolution. Early statutes declared the school was to instruct 90 sons of Norwich citizens, though it has since grown to a total enrolment of approximately 1,020 pupils. For most of its his ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frink Medal
The Frink Medal for British Zoologists is awarded by the Zoological Society of London "For significant and original contributions by a professional zoologist to the development of zoology." It consists of a bronze plaque (76 by 83 millimetres), depicting a bison and carved by British sculptor Elisabeth Frink. The Frink Medal was instituted in 1973 and first presented in 1974. commissioned by The Zoological Society of London (Elisabeth Frink Estate) Recipients SourcZSL See also * |
Phylogeny
A phylogenetic tree (also phylogeny or evolutionary tree Felsenstein J. (2004). ''Inferring Phylogenies'' Sinauer Associates: Sunderland, MA.) is a branching diagram or a tree showing the evolutionary relationships among various biological species or other entities based upon similarities and differences in their physical or genetic characteristics. All life on Earth is part of a single phylogenetic tree, indicating common ancestry. In a ''rooted'' phylogenetic tree, each node with descendants represents the inferred most recent common ancestor of those descendants, and the edge lengths in some trees may be interpreted as time estimates. Each node is called a taxonomic unit. Internal nodes are generally called hypothetical taxonomic units, as they cannot be directly observed. Trees are useful in fields of biology such as bioinformatics, systematics, and phylogenetics. ''Unrooted'' trees illustrate only the relatedness of the leaf nodes and do not require the ancestral root to be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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