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Bullseye Electric Ray
The ocellated electric ray or bullseye electric ray (''Diplobatis ommata'') is a species of electric ray in the family Narcinidae, native to the shallow inshore waters of the eastern central Pacific from the Gulf of California to Ecuador. Reaching in length, this species has a rounded pectoral fin disc and pelvic fins with convex margins. Its short and thick tail bears two dorsal fins and terminates in a triangular caudal fin. The ocellated electric ray is named for the distinctive large eyespot on the middle of its disc, consisting of a black or yellow center surrounded by concentric rings. Its dorsal coloration is otherwise highly variable, ranging from plain to ornately patterned on a light to dark brown background. The front part of its disc is darker brown. Solitary and nocturnal in nature, the ocellated electric ray is a bottom-dweller found in sandy and rocky habitats. It moves along the bottom by "hopping" on its pelvic fins, and feeds on small crustaceans and polychaet ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
David Starr Jordan
David Starr Jordan (January 19, 1851 – September 19, 1931) was the founding president of Stanford University, serving from 1891 to 1913. He was an ichthyologist during his research career. Prior to serving as president of Stanford University, he had served as president of Indiana University from 1884 to 1891. Starr was also a strong supporter of eugenics, and his published views expressed a fear of "race-degeneration" and asserted that cattle and human beings are "governed by the same laws of selection". He was an antimilitarist since he believed that war killed off the best members of the gene pool, and he initially opposed American involvement in World War I. Early life and career Jordan was born in Gainesville, New York, and grew up on a farm in upstate New York. His parents made the unorthodox decision to educate him at a local girls' high school. His middle name, Starr, does not appear in early census records, and was apparently self-selected; he had begun using ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polychaete Worm
Polychaeta () is a paraphyletic class of generally marine annelid worms, commonly called bristle worms or polychaetes (). Each body segment has a pair of fleshy protrusions called parapodia that bear many bristles, called chaetae, which are made of chitin. More than 10,000 species are described in this class. Common representatives include the lugworm (''Arenicola marina'') and the sandworm or clam worm ''Alitta''. Polychaetes as a class are robust and widespread, with species that live in the coldest ocean temperatures of the abyssal plain, to forms which tolerate the extremely high temperatures near hydrothermal vents. Polychaetes occur throughout the Earth's oceans at all depths, from forms that live as plankton near the surface, to a 2- to 3-cm specimen (still unclassified) observed by the robot ocean probe ''Nereus'' at the bottom of the Challenger Deep, the deepest known spot in the Earth's oceans. Only 168 species (less than 2% of all polychaetes) are known from fresh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Colombia
Colombia (, ; ), officially the Republic of Colombia, is a country in South America with insular regions in North America—near Nicaragua's Caribbean coast—as well as in the Pacific Ocean. The Colombian mainland is bordered by the Caribbean Sea to the north, Venezuela to the east and northeast, Brazil to the southeast, Ecuador and Peru to the south and southwest, the Pacific Ocean to the west, and Panama to the northwest. Colombia is divided into 32 departments and the Capital District of Bogotá, the country's largest city. It covers an area of 1,141,748 square kilometers (440,831 sq mi), and has a population of 52 million. Colombia's cultural heritage—including language, religion, cuisine, and art—reflects its history as a Spanish colony, fusing cultural elements brought by immigration from Europe and the Middle East, with those brought by enslaved Africans, as well as with those of the various Amerindian civilizations that predate colonization. Spanish is th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
USS Albatross (1882)
The second USS ''Albatross'', often seen as ''USFC Albatross'' in scientific literature citations, was an iron-hulled, twin-screw steamer in the United States Navy and reputedly the first research vessel ever built especially for marine research. ''Albatross'' was laid down at Wilmington, Delaware, by Pusey and Jones in March 1882; launched on 19 August 1882, and commissioned on 11 November 1882, with Lt. Zera L. Tanner in command. Tanner, who had superintended the ship's design and construction, would command ''Albatross'', a Navy-crewed vessel assigned to the United States Fish Commission, a civilian government agency, for nearly 12 years. Early years Following trial operations between Wilmington and Washington, D.C. from 30 December 1882 to 13 February 1883, ''Albatross'' returned to her builder's yard for engine alterations. While steaming back to Washington, the ship experimented with her dredging equipment, and arrived at the nation's capital on 25 March 1883. She left th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Steamship
A steamship, often referred to as a steamer, is a type of steam-powered vessel, typically ocean-faring and seaworthy, that is propelled by one or more steam engines that typically move (turn) propellers or paddlewheels. The first steamships came into practical usage during the early 1800s; however, there were exceptions that came before. Steamships usually use the prefix designations of "PS" for ''paddle steamer'' or "SS" for ''screw steamer'' (using a propeller or screw). As paddle steamers became less common, "SS" is assumed by many to stand for "steamship". Ships powered by internal combustion engines use a prefix such as "MV" for ''motor vessel'', so it is not correct to use "SS" for most modern vessels. As steamships were less dependent on wind patterns, new trade routes opened up. The steamship has been described as a "major driver of the first wave of trade globalization (1870–1913)" and contributor to "an increase in international trade that was unprecedented in hu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States Fish Commission
The United States Fish Commission, formally known as the United States Commission of Fish and Fisheries, was an agency of the United States government created in 1871 to investigate, promote, and preserve the fisheries of the United States. In 1903, it was reorganized as the United States Bureau of Fisheries, sometimes referred to as the United States Fisheries Service, which operated until 1940. In 1940, the Bureau of Fisheries was abolished when its personnel and facilities became part of the newly created Fish and Wildlife Service, under the United States Department of the Interior. Organizational history U.S. Fish Commission (1871–1903) By the 1860s, increasing human pressure on the fish and game resources of the United States had become apparent to the United States Government, and fisheries became the first aspect of the problem to receive U.S. Government attention when Robert Barnwell Roosevelt, a Democratic congressmen from New Yorks 4th Congressional District, ori ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scientific Journal
In academic publishing, a scientific journal is a periodical publication intended to further the progress of science, usually by reporting new research. Content Articles in scientific journals are mostly written by active scientists such as students, researchers, and professors instead of professional journalists. There are thousands of scientific journals in publication, and many more have been published at various points in the past (see list of scientific journals). Most journals are highly specialized, although some of the oldest journals such as ''Nature'' publish articles and scientific papers across a wide range of scientific fields. Scientific journals contain articles that have been peer reviewed, in an attempt to ensure that articles meet the journal's standards of quality and scientific validity. Although scientific journals are superficially similar to professional magazines, they are actually quite different. Issues of a scientific journal are rarely read casuall ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ichthyologist
Ichthyology is the branch of zoology devoted to the study of fish, including bony fish ( Osteichthyes), cartilaginous fish (Chondrichthyes), and jawless fish (Agnatha). According to FishBase, 33,400 species of fish had been described as of October 2016, with approximately 250 new species described each year. Etymology The word is derived from the Greek words ἰχθύς, ''ikhthus'', meaning "fish"; and λογία, ''logia'', meaning "to study". History The study of fish dates from the Upper Paleolithic Revolution (with the advent of "high culture"). The science of ichthyology was developed in several interconnecting epochs, each with various significant advancements. The study of fish receives its origins from humans' desire to feed, clothe, and equip themselves with useful implements. According to Michael Barton, a prominent ichthyologist and professor at Centre College, "the earliest ichthyologists were ''hunters and gatherers'' who had learned how to obtain the most usef ... [...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] |
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] |
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] |
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] |
