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Desmarestiaceae
Desmarestiaceae is a family of brown algae, one of two families in the order Desmarestiales.Guiry, M. D. & G. M. Guiry. 2013Desmarestiales.AlgaeBase. National University of Ireland, Galway. Accessed 04 June 2013. The family gets its name from the genus ''Desmarestia'', which is named after the French zoologist Anselme Gaëtan Desmarest (1784-1838). There are three genera in this family. Two are monotypic, '' Himantothallus'' (species name '' Himantothallus grandifolius'') and '' Phaeurus'' (species name '' Phaeurus antarcticus''). These are both endemic to Antarctica.Peters, A. F., et al. (1997)Phylogeny and historical ecology of the Desmarestiaceae (Phaeophyceae) support a Southern Hemisphere origin.''J Phycol'' 33 294-309. The third genus, ''Desmarestia'', has 30Guiry, M. D. & G. M. Guiry. 2013''Desmarestia''.AlgaeBase. National University of Ireland, Galway. Accessed 04 June 2013. to 40 species. Most species have narrow, localized ranges, but some ''Desmarestia'', such as '' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Desmarestia Tropica
''Desmarestia tropica'', sometimes called tropical acidweed, is a species of seaweed in the family Desmarestiaceae. It is critically endangered, possibly extinct, and one of only fifteen protists evaluated by IUCN. Endemic to the Galápagos Islands, the specific epithet ''tropica'' alludes to its tropical habitat, rare for members of Desmarestiales. The common name ''acidweed'' applies to members of the genus ''Desmarestia'', generally characterized by fronds containing vacuoles of concentrated sulfuric acid, but it is unclear if this species also produces acid. History ''D. tropica'' was first collected by William Randolph Taylor on 19 January 1935, and twice more later that month. He published a description of the species ten years later in May 1945. The organism was last collected in 1972, and not seen since despite efforts to search the sighted locations and other possible habitats in the archipelago. Because of its preference for deep, cold water in a tropical loca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Desmarestiales
Desmarestiales is an order in the brown algae (Phaeophyceae). Members of this order have terete or ligulate (flat) pinnately branched thalli attached by discoid holdfasts. They have a sporphytic thallus usually aggregated to form a pseudo-parenchyma.Pound F.E. 1962 “The Biology of the Algae” Edward Arnold Ltd. The order gets its name from the genus '' Desmarestia'', which is named after the French zoologist Anselme Gaëtan Desmarest (1784–1838).Genaust, Helmut (1976). ''Etymologisches Wörterbuch der botanischen Pflanzennamen'' As the general name of the class suggests, their pigment A pigment is a colored material that is completely or nearly insoluble in water. In contrast, dyes are typically soluble, at least at some stage in their use. Generally dyes are often organic compounds whereas pigments are often inorganic comp ...ation is brown. References Further reading External links AlgaeBase Brown algae orders {{Phaeophyceae-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anselme Gaëtan Desmarest
Anselme Gaëtan Desmarest (6 March 1784 – 4 June 1838) was a French zoologist and author. He was the son of Nicolas Desmarest and father of Eugène Anselme Sébastien Léon Desmarest. Desmarest was a disciple of Georges Cuvier and Alexandre Brongniart, and in 1815, he succeeded Pierre André Latreille to the professorship of zoology at the '. He was elected to the American Philosophical Society in 1819 and to the Académie Nationale de Médecine in 1820. Desmarest published ' (1805), ' (1825), ' (1820) and ' (1816–30, with André Marie Constant Duméril). The brown algae ''Desmarestia'' is named in honour of Desmarest, as well as the family (Desmarestiaceae) — and in turn, the order (Desmarestiales) — of which the genus is the type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brown Algae
Brown algae (singular: alga), comprising the class Phaeophyceae, are a large group of multicellular algae, including many seaweeds located in colder waters within the Northern Hemisphere. Brown algae are the major seaweeds of the temperate and polar regions. They are dominant on rocky shores throughout cooler areas of the world. Most brown algae live in marine environments, where they play an important role both as food and as a potential habitat. For instance, '' Macrocystis'', a kelp of the order Laminariales, may reach in length and forms prominent underwater kelp forests. Kelp forests like these contain a high level of biodiversity. Another example is '' Sargassum'', which creates unique floating mats of seaweed in the tropical waters of the Sargasso Sea that serve as the habitats for many species. Many brown algae, such as members of the order Fucales, commonly grow along rocky seashores. Some members of the class, such as kelps, are used by humans as food. Between 1,5 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tropics
The tropics are the regions of Earth surrounding the Equator. They are defined in latitude by the Tropic of Cancer in the Northern Hemisphere at N and the Tropic of Capricorn in the Southern Hemisphere at S. The tropics are also referred to as the tropical zone and the torrid zone (see geographical zone). In terms of climate, the tropics receive sunlight that is more direct than the rest of Earth and are generally hotter and wetter as they aren't affected as much by the solar seasons. The word "tropical" sometimes refers to this sort of climate in the zone rather than to the geographical zone itself. The tropical zone includes deserts and snow-capped mountains, which are not tropical in the climatic sense. The tropics are distinguished from the other climatic and biomatic regions of Earth, which are the middle latitudes and the polar regions on either side of the equatorial zone. The tropics constitute 40% of Earth's surface area and contain 36% of Earth's landmass. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Extinction
Extinction is the termination of a kind of organism or of a group of kinds ( taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and recover may have been lost before this point. Because a species' potential range may be very large, determining this moment is difficult, and is usually done retrospectively. This difficulty leads to phenomena such as Lazarus taxa, where a species presumed extinct abruptly "reappears" (typically in the fossil record) after a period of apparent absence. More than 99% of all species that ever lived on Earth, amounting to over five billion species, are estimated to have died out. It is estimated that there are currently around 8.7 million species of eukaryote globally, and possibly many times more if microorganisms, like bacteria, are included. Notable extinct animal species include non-avian dinosaurs, saber-toothed cats, dod ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Galápagos Islands
The Galápagos Islands ( es, Islas Galápagos) are an archipelago of volcanic islands in the Eastern Pacific, located around the Equator west of the mainland of South America. They form the Galápagos Province of the Republic of Ecuador, with a population of slightly over 33,000 (2020). The province is divided into the Cantons of Ecuador, cantons of San Cristóbal Island, San Cristóbal, Santa Cruz Island (Galápagos), Santa Cruz, and Isabela Island (Galápagos), Isabela, the three most populated islands in the chain. The Galápagos are famous for their large number of Endemism, endemic species, which were studied by Charles Darwin in the 1830s and inception of Darwin's theory, inspired his theory of evolution by means of natural selection. All of these islands are protected as part of Ecuador's Galápagos National Park and Galápagos Marine Reserve, Marine Reserve. Thus far, there is no firm evidence that Polynesian expansion, Polynesians or the indigenous peoples of South Am ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gamete
A gamete (; , ultimately ) is a haploid cell that fuses with another haploid cell during fertilization in organisms that reproduce sexually. Gametes are an organism's reproductive cells, also referred to as sex cells. In species that produce two morphologically distinct types of gametes, and in which each individual produces only one type, a female is any individual that produces the larger type of gamete—called an ovum— and a male produces the smaller type—called a sperm. Sperm cells or spermatozoa are small and motile due to the flagellum, a tail-shaped structure that allows the cell to propel and move. In contrast, each egg cell or ovum is relatively large and non-motile. In short a gamete is an egg cell (female gamete) or a sperm (male gamete). In animals, ova mature in the ovaries of females and sperm develop in the testes of males. During fertilization, a spermatozoon and ovum unite to form a new diploid organism. Gametes carry half the genetic information of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Desmarestia Ligulata
''Desmarestia ligulata'' is a species of brown algae found worldwide. Its common names include color changer, Desmarest's flattened weed, and sea sorrel, though the last name can also refer to other species of '' Desmarestia''. Habitat This species is found between the low intertidal to subtidal zones on open coasts. It is the most abundant marine algae associated with giant kelp forests. Acid accumulation ''Desmarestia ligulata'' is known for its ability to accumulate high levels of sulfuric acid in its vacuole A vacuole () is a membrane-bound organelle which is present in plant and fungal cells and some protist, animal, and bacterial cells. Vacuoles are essentially enclosed compartments which are filled with water containing inorganic and organic mo ...s. This accumulation appears to be active and permanent, occurring during cell growth and division while unaffected by light regimes or external nutrient profiles. It has been suggested that this acid accumulation is an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thallus
Thallus (plural: thalli), from Latinized Greek (), meaning "a green shoot" or " twig", is the vegetative tissue of some organisms in diverse groups such as algae, fungi, some liverworts, lichens, and the Myxogastria. Many of these organisms were previously known as the thallophytes, a polyphyletic group of distantly related organisms. An organism or structure resembling a thallus is called thalloid, thallodal, thalliform, thalline, or thallose. A thallus usually names the entire body of a multicellular non-moving organism in which there is no organization of the tissues into organs. Even though thalli do not have organized and distinct parts ( leaves, roots, and stems) as do the vascular plants, they may have analogous structures that resemble their vascular "equivalents". The analogous structures have similar function or macroscopic structure, but different microscopic structure; for example, no thallus has vascular tissue. In exceptional cases such as the Lemnoid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oogamy
Oogamy is an extreme form of anisogamy where the gametes differ in both size and form. In oogamy the large female gamete (also known as ovum) is immobile, while the small male gamete (also known as sperm) is mobile. Oogamy is a common form of anisogamy, with almost all animals and land plants being oogamous. Occurrence Oogamy is found in most species that reproduce sexually, all higher species being oogamous. Oogamy is found in all land plants, and in some red algae, brown algae and green algae. Oogamy is favored in plants because only one gamete has to travel through harsh environments outside the plant. Oogamy is also present in oomycetes. Almost all animals are oogamous. There are exceptions, such as the opiliones that have immobile sperm. Etymology The term oogamy was first used in the year 1888. Evolution It is generally accepted that isogamy is the ancestral state and that oogamy evolves from isogamy through anisogamy. However, transitions do exist betwe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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