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Japanese Sleeper Ray
The Japanese sleeper ray (''Narke japonica'') is a species of electric ray in the family Narkidae. It is common in the inshore and offshore waters of the northwestern Pacific Ocean from southern Japan to southern China. Growing up to long, the Japanese sleeper ray has a nearly circular pectoral fin disc colored reddish to chocolate brown above, sometimes with darker or lighter spots, and lighter brown below. The spiracles behind its small eyes have raised, smooth rims. Its short and muscular tail bears a single dorsal fin positioned aft of the rounded pelvic fins, and terminates in a large caudal fin. Inhabiting shallow, sandy areas near rocky reefs, the Japanese sleeper ray is a bottom-dwelling predator of invertebrates. Like other members of its family, it can produce a strong electric shock from its electric organs for defensive purposes. Females give live birth to litters of up to five pups. The gestating young are sustained at first by yolk, and later by histotroph ("uteri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coenraad Jacob Temminck
Coenraad Jacob Temminck (; 31 March 1778 – 30 January 1858) was a Dutch people, Dutch Aristocracy (class), aristocrat, Zoology, zoologist and museum director. Biography Coenraad Jacob Temminck was born on 31 March 1778 in Amsterdam in the Dutch Republic. From his father, Jacob Temminck, who was treasurer of the Dutch East India Company with links to numerous travellers and collectors, he inherited a large collection of bird specimens. His father was a good friend of Francois Levaillant who also guided Coenraad. Temminck's ''Manuel d'ornithologie, ou Tableau systématique des oiseaux qui se trouvent en Europe'' (1815) was the standard work on European birds for many years. He was also the author of ''Histoire naturelle générale des Pigeons et des Gallinacées'' (1813–1817), ''Nouveau Recueil de Planches coloriées d'Oiseaux'' (1820–1839), and contributed to the mammalian sections of Philipp Franz von Siebold's ''Fauna japonica'' (1844–1850). Temminck was the first dire ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Invertebrate
Invertebrates are a paraphyletic group of animals that neither possess nor develop a vertebral column (commonly known as a ''backbone'' or ''spine''), derived from the notochord. This is a grouping including all animals apart from the chordate subphylum Vertebrata. Familiar examples of invertebrates include arthropods, mollusks, annelids, echinoderms and cnidarians. The majority of animal species are invertebrates; one estimate puts the figure at 97%. Many invertebrate taxa have a greater number and variety of species than the entire subphylum of Vertebrata. Invertebrates vary widely in size, from 50 μm (0.002 in) rotifers to the 9–10 m (30–33 ft) colossal squid. Some so-called invertebrates, such as the Tunicata and Cephalochordata, are more closely related to vertebrates than to other invertebrates. This makes the invertebrates paraphyletic, so the term has little meaning in taxonomy. Etymology The word "invertebrate" comes from the Latin word ''vertebra'', whi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heinrich Burger (naturalist)
Heinrich Burger (31 May 1881 – 27 April 1942) was a German figure skater. He competed in both singles and pairs events. He was Olympic champion and two-time World champion together with Anna Hübler. Burger and Hübler were the first world champions and the first Olympic champions in pairs figure skating. They never became European champions, because the European championships did not include a pairs competition until 1930. They skated for the club Müchener EV (Munich EV). Heinrich Burger was also a lawyer in Munich. Results (men's singles) (pairs with Anna Hübler Anna "Annie" Hübler (2 January 1885 – 5 July 1976) was a German pair skater, born in Munich. She was an Olympic Games, Olympic champion and two-time World Figure Skating Championships, World champion with skating partner Heinrich Burger. Hü ...) References Sources * journal Eis- und Rollsport, 49th year, No. 9, 5 January 1939 1881 births 1942 deaths Sportspeople from Munich German ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Philipp Franz Von Siebold
Philipp Franz Balthasar von Siebold (17 February 1796 – 18 October 1866) was a German physician, botanist and traveler. He achieved prominence by his studies of Japanese flora (plants), flora and fauna (animals), fauna and the introduction of Western medicine in Japan. He was the father of the first female Japanese doctor educated in Western medicine, Kusumoto Ine. Career Early life Born into a family of doctors and professors of medicine in Würzburg (then in the Bishopric of Würzburg, later part of Bavaria), Siebold initially studied medicine at the University of Würzburg from November 1815, where he became a member of the German Student Corps, Corps Moenania Würzburg. One of his professors was Franz Xaver Heller (1775–1840), author of the ' ("Flora of the Grand Duchy of Würzburg", 1810–1811). Ignaz Döllinger (1770–1841), his professor of anatomy and physiology, however, most influenced him. Döllinger was one of the first professors to understand and tr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fisheries
Fishery can mean either the enterprise of raising or harvesting fish and other aquatic life; or more commonly, the site where such enterprise takes place ( a.k.a. fishing ground). Commercial fisheries include wild fisheries and fish farms, both in freshwater waterbodies (about 10% of all catch) and the oceans (about 90%). About 500 million people worldwide are economically dependent on fisheries. 171 million tonnes of fish were produced in 2016, but overfishing is an increasing problem — causing declines in some populations. Because of their economic and social importance, fisheries are governed by complex fisheries management practices and legal regimes that vary widely across countries. Historically, fisheries were treated with a " first-come, first-served " approach, but recent threats by human overfishing and environmental issues have required increased regulation of fisheries to prevent conflict and increase profitable economic activity on the fishery. Modern jurisdicti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trawl
Trawling is a method of fishing that involves pulling a fishing net through the water behind one or more boats. The net used for trawling is called a trawl. This principle requires netting bags which are towed through water to catch different species of fishes or sometimes targeted species. Trawls are often called towed gear or dragged gear. The boats that are used for trawling are called trawlers or draggers. Trawlers vary in size from small open boats with as little as 30 hp (22 kW) engines to large factory trawlers with over 10,000 hp (7.5 MW). Trawling can be carried out by one trawler or by two trawlers fishing cooperatively ( pair trawling). Trawling can be contrasted with trolling. While trawling involves a net and is typically done for commercial usage, trolling instead involves a reed, rod and a bait or a lure and is typically done for recreational purposes. Trawling is also commonly used as a scientific sampling, or survey, method. Bottom vs. midwater trawlin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vulnerable Species
A vulnerable species is a species which has been Conservation status, categorized by the International Union for Conservation of Nature as being threatened species, threatened with extinction unless the circumstances that are threatened species, threatening its survival and reproduction improve. Vulnerability is mainly caused by habitat loss or destruction of the species' home. Vulnerable habitat or species are monitored and can become increasingly threatened. Some species listed as "vulnerable" may be common in captivity (animal), captivity, an example being the military macaw. There are currently 5196 animals and 6789 plants classified as Vulnerable, compared with 1998 levels of 2815 and 3222, respectively. Practices such as cryoconservation of animal genetic resources have been enforced in efforts to conserve vulnerable breeds of livestock specifically. Criteria The International Union for Conservation of Nature uses several criteria to enter species in this category. A tax ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
International Union For Conservation Of Nature
The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of natural resources. It is involved in data gathering and analysis, research, field projects, advocacy, and education. IUCN's mission is to "influence, encourage and assist societies throughout the world to conserve nature and to ensure that any use of natural resources is equitable and ecologically sustainable". Over the past decades, IUCN has widened its focus beyond conservation ecology and now incorporates issues related to sustainable development in its projects. IUCN does not itself aim to mobilize the public in support of nature conservation. It tries to influence the actions of governments, business and other stakeholders by providing information and advice and through building partnerships. The organization is best known to the wider pu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Histotroph
Uterine glands or endometrial glands are tubular glands, lined by ciliated columnar epithelium, found in the functional layer of the endometrium that lines the uterus. Their appearance varies during the menstrual cycle. During the proliferative phase, uterine glands appear long due to estrogen secretion by the ovaries. During the secretory phase, the uterine glands become very coiled with wide lumens and produce a glycogen-rich secretion known as ''histotroph'' or ''uterine milk''. This change corresponds with an increase in blood flow to spiral arteries due to increased progesterone secretion from the corpus luteum. During the pre-menstrual phase, progesterone secretion decreases as the corpus luteum degenerates, which results in decreased blood flow to the spiral arteries. The functional layer of the uterus containing the glands becomes necrotic, and eventually sloughs off during the menstrual phase of the cycle. They are of small size in the unimpregnated uterus, but shortly aft ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yolk
Among animals which produce eggs, the yolk (; also known as the vitellus) is the nutrient-bearing portion of the egg whose primary function is to supply food for the development of the embryo. Some types of egg contain no yolk, for example because they are laid in situations where the food supply is sufficient (such as in the body of the host of a parasitoid) or because the embryo develops in the parent's body, which supplies the food, usually through a placenta. Reproductive systems in which the mother's body supplies the embryo directly are said to be matrotrophic; those in which the embryo is supplied by yolk are said to be lecithotrophic. In many species, such as all birds, and most reptiles and insects, the yolk takes the form of a special storage organ constructed in the reproductive tract of the mother. In many other animals, especially very small species such as some fish and invertebrates, the yolk material is not in a special organ, but inside the egg cell. As sto ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gestation
Gestation is the period of development during the carrying of an embryo, and later fetus, inside viviparous animals (the embryo develops within the parent). It is typical for mammals, but also occurs for some non-mammals. Mammals during pregnancy can have one or more gestations at the same time, for example in a multiple birth. The time interval of a gestation is called the '' gestation period''. In obstetrics, ''gestational age'' refers to the time since the onset of the last menses, which on average is fertilization age plus two weeks. Mammals In mammals, pregnancy begins when a zygote (fertilized ovum) implants in the female's uterus and ends once the fetus leaves the uterus during labor or an abortion (whether induced or spontaneous). Humans In humans, pregnancy can be defined clinically or biochemically. Clinically, pregnancy starts from first day of the mother's last period. Biochemically, pregnancy starts when a woman's human chorionic gonadotropin (hCG) levels ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
