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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 locatio ... [...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 compo ...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 Zoology, 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 botany, type species. References French zoologists French taxonomists 1784 births 1838 deaths French carcinologists French mammalogists French ornithologists 18th-century French zoologists 19th-century French ... [...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 1,500 and ... [...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. , the ... [...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, dodos, m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Galápagos Islands
The Galápagos Islands (Spanish: , , ) are an archipelago of volcanic islands. They are distributed on each side of the equator in the Pacific Ocean, surrounding the centre of the Western Hemisphere, and are part of the Republic of Ecuador. Located west of continental Ecuador, the islands are known for their large number of endemic species that were studied by Charles Darwin during the second voyage of HMS ''Beagle''. His observations and collections contributed to the inception of Darwin's theory of evolution by means of natural selection. The Galápagos Islands and their surrounding waters form the Galápagos Province of Ecuador, the Galápagos National Park, and the Galápagos Marine Reserve. The principal language on the islands is Spanish. The islands have a population of slightly over 25,000. The first recorded visit to the islands happened by chance in 1535, when Fray Tomás de Berlanga, the Bishop of Panamá, was surprised to find this undiscovered land on a vo ... [...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 an ... [...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 vacuoles. This accumulation appears to be active Active may refer to: Music * ''Active'' (album), a 1992 album by Casiopea * Active Records, a record label Ships * ''Active'' (ship), several commercial ships by that name * HMS ''Active'', the name of various ships of the British Royal ... 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 evo ... [...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 Lemnoideae, where ... [...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 between ani ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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