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Bathybius Haeckelii
''Bathybius haeckelii'' was a substance that British biologist Thomas Henry Huxley discovered and initially believed to be a form of primordial matter, a source of all organic life. He later admitted his mistake when it proved to be just the product of an inorganic chemical process (precipitation). In 1868, Huxley studied an old sample of mud from the Atlantic seafloor taken in 1857. When he first examined it, he had found only protozoan cells and placed the sample into a jar of alcohol to preserve it. Now he noticed that the sample contained an albuminous slime that appeared to be criss-crossed with veins. Huxley thought he had discovered a new organic substance and named it ''Bathybius haeckelii'', in honor of German biologist Ernst Haeckel. Haeckel had theorized about ''Urschleim'' ("primordial slime"), a protoplasm from which all life had originated. Huxley thought ''Bathybius'' could be that protoplasm, a missing link (in modern terms) between inorganic matter and organic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transitional Fossil
A transitional fossil is any fossilized remains of a life form that exhibits traits common to both an ancestral group and its derived descendant group. This is especially important where the descendant group is sharply differentiated by gross anatomy and mode of living from the ancestral group. These fossils serve as a reminder that taxonomic divisions are human constructs that have been imposed in hindsight on a continuum of variation. Because of the incompleteness of the fossil record, there is usually no way to know exactly how close a transitional fossil is to the point of divergence. Therefore, it cannot be assumed that transitional fossils are direct ancestors of more recent groups, though they are frequently used as models for such ancestors. In 1859, when Charles Darwin's ''On the Origin of Species'' was first published, the fossil record was poorly known. Darwin described the perceived lack of transitional fossils as "the most obvious and gravest objection which can be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nature (journal)
''Nature'' is a British weekly scientific journal founded and based in London, England. As a multidisciplinary publication, ''Nature'' features Peer review, peer-reviewed research from a variety of academic disciplines, mainly in science and technology. It has core editorial offices across the United States, continental Europe, and Asia under the international scientific publishing company Springer Nature. ''Nature'' was one of the world's most cited scientific journals by the Science Edition of the 2022 ''Journal Citation Reports'' (with an ascribed impact factor of 50.5), making it one of the world's most-read and most prestigious academic journals. , it claimed an online readership of about three million unique readers per month. Founded in the autumn of 1869, ''Nature'' was first circulated by Norman Lockyer and Alexander MacMillan (publisher), Alexander MacMillan as a public forum for scientific innovations. The mid-20th century facilitated an editorial expansion for the j ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seawater
Seawater, or sea water, is water from a sea or ocean. On average, seawater in the world's oceans has a salinity of about 3.5% (35 g/L, 35 ppt, 600 mM). This means that every kilogram (roughly one liter by volume) of seawater has approximately of dissolved salts (predominantly sodium () and chloride () ions). The average density at the surface is 1.025 kg/L. Seawater is denser than both fresh water and pure water (density 1.0 kg/L at ) because the dissolved salts increase the mass by a larger proportion than the volume. The freezing point of seawater decreases as salt concentration increases. At typical salinity, it freezes at about . The coldest seawater still in the liquid state ever recorded was found in 2010, in a stream under an Antarctic glacier: the measured temperature was . Seawater pH is typically limited to a range between 7.5 and 8.4. However, there is no universally accepted reference pH-scale for seawater and the difference between measuremen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calcium Sulfate
Calcium sulfate (or calcium sulphate) is an inorganic salt with the chemical formula . It occurs in several hydrated forms; the anhydrous state (known as anhydrite) is a white crystalline solid often found in evaporite deposits. Its dihydrate form is the mineral gypsum, which may be dehydrated to produce bassanite, the hemihydrate state. Gypsum occurs in nature as crystals ( selenite) or fibrous masses ( satin spar), typically colorless to white, though impurities can impart other hues. All forms of calcium sulfate are sparingly soluble in waterFranz Wirsching "Calcium Sulfate" in Ullmann's Encyclopedia of Industrial Chemistry, 2012 Wiley-VCH, Weinheim. and cause permanent hardness when dissolved therein. Hydration states Calcium sulfate occurs at three levels of hydration with different crystallographic structures: anhydrous, dihydrate, and hemihydrate. The anhydrous ( anhydrite) crystallizes as an tightly-bound orthohombic lattice with space group Pnma, in which each ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Precipitate
In an aqueous solution, precipitation is the "sedimentation of a solid material (a precipitate) from a liquid solution". The solid formed is called the precipitate. In case of an inorganic chemical reaction leading to precipitation, the chemical reagent causing the solid to form is called the precipitant. The clear liquid remaining above the precipitated or the centrifuged solid phase is also called the supernate or supernatant. The notion of precipitation can also be extended to other domains of chemistry (organic chemistry and biochemistry) and even be applied to the solid phases (e.g. metallurgy and alloys) when solid impurities segregate from a solid phase. Supersaturation The precipitation of a compound may occur when its concentration exceeds its solubility. This can be due to temperature changes, solvent evaporation, or by mixing solvents. Precipitation occurs more rapidly from a strongly supersaturated solution. The formation of a precipitate can be caused by a ch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
John Young Buchanan
John Young Buchanan FRSE FRS FCS (20 February 1844 – 16 October 1925) was a Scottish chemist, oceanographer and Arctic explorer. He was an important part of the Challenger Expedition. Life He was born in Partickhill, Glasgow on 20 February 1844, the son of Jane Young and her husband, John Buchanan of Dowanhill, a relatively affluent landowner. His brother was the statesman Thomas Ryburn Buchanan. He attended High School of Glasgow, Glasgow High School and then studied chemistry at the University of Glasgow. He also spent time in Europe studying at the universities of Marburg, Leipzig, Bonn and Paris. He graduated in 1863. His first role was as an assistant to Prof Alexander Crum Brown at the University of Edinburgh. In 1870 he was elected a Fellow of the Royal Society of Edinburgh, his proposer being Alexander Crum Brown. He was then living at the prestigious address of 10 Moray Place in Edinburgh's West End. The Society awarded him its Keith Prize for 1885 to 1887. In 18 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemist
A chemist (from Greek ''chēm(ía)'' alchemy; replacing ''chymist'' from Medieval Latin ''alchemist'') is a graduated scientist trained in the study of chemistry, or an officially enrolled student in the field. Chemists study the composition of matter and its properties. Chemists carefully describe the properties they study in terms of quantities, with detail on the level of molecules and their component atoms. Chemists carefully measure substance proportions, chemical reaction rates, and other chemical properties. In Commonwealth English, pharmacists are often called chemists. Chemists use their knowledge to learn the composition and properties of unfamiliar substances, as well as to reproduce and synthesize large quantities of useful naturally occurring substances and create new artificial substances and useful processes. Chemists may specialize in any number of Chemistry#Subdisciplines, subdisciplines of chemistry. Materials science, Materials scientists and metallurgists sha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Challenger Expedition
The ''Challenger'' expedition of 1872–1876 was a scientific programme that made many discoveries to lay the foundation of oceanography. The expedition was named after the naval vessel that undertook the trip, . The expedition, initiated by William Benjamin Carpenter, was placed under the scientific supervision of Sir Charles Wyville Thomson—of the University of Edinburgh and Merchiston Castle School—assisted by five other scientists, including Sir John Murray (oceanographer), John Murray, a secretary-artist and a photographer. The Royal Society of London obtained the use of ''Challenger'' from the Royal Navy and in 1872 modified the ship for scientific tasks at Sheerness, equipping it with separate laboratories for natural history and chemistry. The expedition, led by Captain George Nares, sailed from Portsmouth, England, on 21 December 1872. Other naval officers included Commander John Maclear. – pages 19 and 20 list the civilian staff and naval officers and crew, along ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
George Charles Wallich
George Charles Wallich (16 November 1815 – 31 March 1899) was a British medical doctor, marine biologist and professional photographer. He was born in Calcutta where his father, the Danish naturalist Nathaniel Wallich, was Superintendent of the Royal Botanical Gardens. As a Surgeon-Major in the Indian Medical Service, he served 'during the Sutlej and Punjab campaigns, and also during the Santhal rebellion of 1855–56. He retired from the service in 1858.' In 1860 he accompanied Sir Leopold M'Clintock aboard the ''Bulldog'' on a voyage across the North Atlantic to survey the sea-bottom for the laying of the proposed trans-Atlantic cable. He won the Linnean Medal in 1898 'in recognition of the valuable work accomplished by him in connection with the exploration of the fauna of the deep sea' (''St James's Gazette'', 16 April 1898). See also * European and American voyages of scientific exploration The era of European and American voyages of scientific exploration followed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mycelium
Mycelium (: mycelia) is a root-like structure of a fungus consisting of a mass of branching, thread-like hyphae. Its normal form is that of branched, slender, entangled, anastomosing, hyaline threads. Fungal colonies composed of mycelium are found in and on soil and many other substrates. A typical single spore germinates into a monokaryotic mycelium, which cannot reproduce sexually; when two compatible monokaryotic mycelia join and form a dikaryotic mycelium, that mycelium may form fruiting bodies such as mushrooms. A mycelium may be minute, forming a colony that is too small to see, or may grow to span thousands of acres as in '' Armillaria''. Through the mycelium, a fungus absorbs nutrients from its environment. It does this in a two-stage process. First, the hyphae secrete enzymes onto or into the food source, which break down biological polymers into smaller units such as monomers. These monomers are then absorbed into the mycelium by facilitated diffusion and ac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Charles Wyville Thomson
Sir Charles Wyville Thomson (5 March 1830 – 10 March 1882) was a Scottish natural historian and marine zoologist. He served as the chief scientist on the ''Challenger'' expedition; his work there revolutionized oceanography and led to his being knighted. Life Thomson was born at Bonsyde, in Linlithgow, West Lothian, on 5 March 1830, the son of Andrew Thomson, a surgeon in the service of the East India Company, and his wife Sarah Ann Drummond Smith. He was baptised Wyville Thomas Charles Thomson, but changed his name formally upon being knighted in 1876. He was educated under Charles Chalmers at Merchiston Castle School, then from 1845 studied medicine at the University of Edinburgh graduating with an MD. However, his focus turned from medicine to natural science, and he joined the Botanical Society of Edinburgh in 1847, and soon after became secretary to the Royal Physical Society of Edinburgh. In 1850 he was attending the botany class of John Hutton Balfour at the un ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
