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Pseudocentrotus Depressus
''Pseudocentrotus depressus'', commonly known as the pink sea urchin, is a species of sea urchin, one of only two species in the genus ''Pseudocentrotus''. It was first described in 1864 by the American marine zoologist Alexander Agassiz as ''Toxocidaris depressus'', having been collected during the North Pacific Exploring and Surveying Expedition undertaken by Captain Cadwalader Ringgold and later Captain John Rodgers. Description This sea urchin is distinctive in its shape, with the oral (lower) surface being flat and the aboral (upper) surface markedly depressed in the centre. The tubercles are numerous and even in size, and the spines are fine and short, their diameter being about a quarter of their length. The inter-ambulacral plates are broad and the pore pairs are arranged in slightly curved groups of six or seven pairs. Ecology As is the case with most other sea urchins, the sexes are separate in this species, and adults liberate eggs and sperm into the water column ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alexander Agassiz
Alexander Emmanuel Rodolphe Agassiz (December 17, 1835March 27, 1910), son of Louis Agassiz and stepson of Elizabeth Cabot Agassiz, was an American scientist and engineer. Biography Agassiz was born in Neuchâtel, Switzerland and immigrated to the United States with his parents, Louis and Cecile (Braun) Agassiz, in 1846. He graduated from Harvard University in 1855, subsequently studying engineering and chemistry, and taking the degree of Bachelor of Science at the Lawrence Scientific School of the same institution in 1857; in 1859 became an assistant in the United States Coast Survey. Thenceforward he became a specialist in marine ichthyology. Agassiz was elected a Fellow of the American Academy of Arts and Sciences in 1862. Up until the summer of 1866, Agassiz worked as assistant curator in the museum of natural history that his father founded at Harvard. E. J. Hulbert, a friend of Agassiz's brother-in-law, Quincy Adams Shaw, had discovered a rich copper lode known as the C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Species
In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. Other ways of defining species include their karyotype, DNA sequence, morphology, behaviour or ecological niche. In addition, paleontologists use the concept of the chronospecies since fossil reproduction cannot be examined. The most recent rigorous estimate for the total number of species of eukaryotes is between 8 and 8.7 million. However, only about 14% of these had been described by 2011. All species (except viruses) are given a two-part name, a "binomial". The first part of a binomial is the genus to which the species belongs. The second part is called the specific name or the specific epithet (in botanical nomenclature, also sometimes i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sea Urchin
Sea urchins () are spiny, globular echinoderms in the class Echinoidea. About 950 species of sea urchin live on the seabed of every ocean and inhabit every depth zone from the intertidal seashore down to . The spherical, hard shells (tests) of sea urchins are round and spiny, ranging in diameter from . Sea urchins move slowly, crawling with tube feet, and also propel themselves with their spines. Although algae are the primary diet, sea urchins also eat slow-moving (sessile) animals. Predators that eat sea urchins include a wide variety of fish, starfish, crabs, marine mammals. Sea urchins are also used as food especially in Japan. Adult sea urchins have fivefold symmetry, but their pluteus larvae feature bilateral (mirror) symmetry, indicating that the sea urchin belongs to the Bilateria group of animal phyla, which also comprises the chordates and the arthropods, the annelids and the molluscs, and are found in every ocean and in every climate, from the tropics to the pol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Species Description
A species description is a formal description of a newly discovered species, usually in the form of a scientific paper. Its purpose is to give a clear description of a new species of organism and explain how it differs from species that have been described previously or are related. In order for species to be validly described, they need to follow guidelines established over time. Zoological naming requires adherence to the ICZN code, plants, the ICN, viruses ICTV, and so on. The species description often contains photographs or other illustrations of type material along with a note on where they are deposited. The publication in which the species is described gives the new species a formal scientific name. Some 1.9 million species have been identified and described, out of some 8.7 million that may actually exist. Millions more have become extinct throughout the existence of life on Earth. Naming process A name of a new species becomes valid (available in zo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
North Pacific Exploring And Surveying Expedition
The North Pacific Exploring and Surveying Expedition, also known as the Rodgers-Ringgold Expedition was a United States scientific and exploring project from 1853 to 1856. Commander Cadwalader Ringgold (1802–1867) led the expedition until he was relieved of command in Hong Kong by a commission convened by Commodore Matthew Perry. Lt. John Rodgers (1812–1882) then commanded the expedition until its conclusion. The expedition under Ringgold Ringgold sailed on USS ''Porpoise'', a ship he had commanded during the U.S. Exploring Expedition years before. USS ''John Hancock'', commanded by Lt. John Rodgers and three other vessels including USS ''Vincennes'' would be the other vessels in the expedition. ''Porpoise'' joined the squadron at Hampton Roads, and with it, stood out to sea 11 June 1853. After stopping at Funchal, Madeira Islands; Porto Praya; and Simonstown, False Bay; the expedition arrived Batavia, Java, 12 December and in China in March 1854. Five months ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cadwalader Ringgold
Cadwalader Ringgold (August 20, 1802 – April 29, 1867) was an officer in the United States Navy who served in the United States Exploring Expedition, later headed an expedition to the Northwest and, after initially retiring, returned to service during the Civil War. Life and early career Cadwalader Ringgold was born August 20, 1802, in Washington County, Maryland, at Fountain Rock, the family estate. His mother was Maria Cadwalader (1776–1811), daughter of John Cadwalader (1742–1786), who was a general during the American Revolutionary War. Some sources spell his first name with two "l"s. His father was Samuel Ringgold, a Maryland politician who later served in the U.S. House of Representatives. He had an older brother, Samuel Ringgold, an army officer called "the father of modern artillery" and who died in the Battle of Palo Alto. Cadwalader was the sixth of 11 children, the youngest child of his mother, who then died. His father remarried and had five more children by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
John Rodgers (American Civil War Naval Officer)
John Rodgers (August 8, 1812 – May 5, 1882) was an admiral in the United States Navy. He began his naval career as a commander in the American Civil War and during his Postbellum service became an admiral. Early life and career Rodgers, a son of the famous Commodore John Rodgers, was born near Havre de Grace, Maryland. He received his appointment as a midshipman in the Navy on April 18, 1828. Service in the Mediterranean on board and opened his long career of distinguished service, and he commanded an expedition of Naval Infantry and Marines in Florida during the Seminole Wars. In the mid-1850s he succeeded Commander Ringgold in command of the North Pacific Exploring and Surveying Expedition, which added greatly to the knowledge of far eastern and northern waters. Following his promotion to commander in 1855, he married and settled to work in the Navy's Japan Office in Washington, D.C., where he was serving when the Civil War broke out. Civil War service Commander Ro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Water Column
A water column is a conceptual column of water from the surface of a sea, river or lake to the bottom sediment.Munson, B.H., Axler, R., Hagley C., Host G., Merrick G., Richards C. (2004).Glossary. ''Water on the Web''. University of Minnesota-Duluth. Retrieved 27 May 2014. Descriptively, the deep sea water column is divided into five parts—'' pelagic zones'' (from Greek πέλαγος (pélagos), 'open sea')—from the surface to below the floor, as follows: ''epipelagic'', from the surface to 200 meters below the surface; ''mesopelagic'', from 200 to 1000 meters below the surface; '' bathypelagic'', from 1000 to 4000 meters below the surface; ''abyssopelagic'', from 4000 meters below the surface to the level sea floor; ''hadopelagic'', depressions and crevices below the level sea floor. The concept of water column is useful since many aquatic phenomena are explained by the incomplete vertical mixing of waters with discrete chemical, physical or biological characteristics. Fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Larva
A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle. The larva's appearance is generally very different from the adult form (''e.g.'' caterpillars and butterflies) including different unique structures and organs that do not occur in the adult form. Their diet may also be considerably different. Larvae are frequently adapted to different environments than adults. For example, some larvae such as tadpoles live almost exclusively in aquatic environments, but can live outside water as adult frogs. By living in a distinct environment, larvae may be given shelter from predators and reduce competition for resources with the adult population. Animals in the larval stage will consume food to fuel their transition into the adult form. In some organisms like polychaetes and barnacles, adults are immobil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plankton
Plankton are the diverse collection of organisms found in Hydrosphere, water (or atmosphere, air) that are unable to propel themselves against a Ocean current, current (or wind). The individual organisms constituting plankton are called plankters. In the ocean, they provide a crucial source of food to many small and large aquatic organisms, such as bivalves, fish and whales. Marine plankton include bacteria, archaea, algae, protozoa and drifting or floating animals that inhabit the saltwater of oceans and the brackish waters of estuaries. Freshwater plankton are similar to marine plankton, but are found in the freshwaters of lakes and rivers. Plankton are usually thought of as inhabiting water, but there are also airborne versions, the aeroplankton, that live part of their lives drifting in the atmosphere. These include plant spores, pollen and wind-scattered seeds, as well as microorganisms swept into the air from terrestrial dust storms and oceanic plankton swept into the air ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metamorphosis
Metamorphosis is a biological process by which an animal physically develops including birth or hatching, involving a conspicuous and relatively abrupt change in the animal's body structure through cell growth and differentiation. Some insects, fish, amphibians, mollusks, crustaceans, cnidarians, echinoderms, and tunicates undergo metamorphosis, which is often accompanied by a change of nutrition source or behavior. Animals can be divided into species that undergo complete metamorphosis (" holometaboly"), incomplete metamorphosis ("hemimetaboly"), or no metamorphosis (" ametaboly"). Scientific usage of the term is technically precise, and it is not applied to general aspects of cell growth, including rapid growth spurts. Generally organisms with a larva stage undergo metamorphosis, and during metamorphosis the organism loses larval characteristics. References to "metamorphosis" in mammals are imprecise and only colloquial, but historically idealist ideas of transformation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Elsevier
Elsevier () is a Dutch academic publishing company specializing in scientific, technical, and medical content. Its products include journals such as ''The Lancet'', ''Cell'', the ScienceDirect collection of electronic journals, '' Trends'', the '' Current Opinion'' series, the online citation database Scopus, the SciVal tool for measuring research performance, the ClinicalKey search engine for clinicians, and the ClinicalPath evidence-based cancer care service. Elsevier's products and services also include digital tools for data management, instruction, research analytics and assessment. Elsevier is part of the RELX Group (known until 2015 as Reed Elsevier), a publicly traded company. According to RELX reports, in 2021 Elsevier published more than 600,000 articles annually in over 2,700 journals; as of 2018 its archives contained over 17 million documents and 40,000 e-books, with over one billion annual downloads. Researchers have criticized Elsevier for its high profit marg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
