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Phytolith
Phytoliths (from Greek language, Greek, "plant stone") are rigid, microscopic mineral deposits found in some plant tissues, often persisting after the decay of the plant. Although some use "phytolith" to refer to all mineral secretions by plants, it more commonly refers to Silicon dioxide, siliceous plant remains. Phytoliths come in varying shapes and sizes. The plants which exhibit them take up dissolved silica from the groundwater, whereupon it is deposited within different intracellular and extracellular structures of the plant.Piperno, Dolores R. (2006). Phytoliths: A Comprehensive Guide for Archaeologists and Paleoecologists. AltaMira Press . The silica is absorbed in the form of orthosilicic acid, monosilicic acid (Si(OH)4), and is carried by the plant's Circulatory system, vascular system to the cell walls, cell lumen, and intercellular spaces. Depending on the plant Taxon, taxa and soil condition, absorbed silica can range from 0.1% to 10% of the plant's total dry weight ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phytoliths Types II
Phytoliths (from Greek, "plant stone") are rigid, microscopic mineral deposits found in some plant tissues, often persisting after the decay of the plant. Although some use "phytolith" to refer to all mineral secretions by plants, it more commonly refers to siliceous plant remains. Phytoliths come in varying shapes and sizes. The plants which exhibit them take up dissolved silica from the groundwater, whereupon it is deposited within different intracellular and extracellular structures of the plant.Piperno, Dolores R. (2006). Phytoliths: A Comprehensive Guide for Archaeologists and Paleoecologists. AltaMira Press . The silica is absorbed in the form of monosilicic acid (Si(OH)4), and is carried by the plant's vascular system to the cell walls, cell lumen, and intercellular spaces. Depending on the plant taxa and soil condition, absorbed silica can range from 0.1% to 10% of the plant's total dry weight. When deposited, the silica replicates the structure of the cells, providing ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dolores Piperno
Dolores Rita Piperno (born 1949) is an American archaeologist specializing in archaeobotany. She is a senior scientist emeritus of the Smithsonian Tropical Research Institute in Balboa, Panama and the Smithsonian National Museum of Natural History, Washington. Early life and education Piperno grew up in Philadelphia before her family moved to Pennsauken, N.J. Piperno earned a B.S. in Medical Technology (Rutgers University, 1971). After graduating, she began her career as a medical technician at the Hematology Research Center of Presbyterian Hospital in Philadelphia. She says she used this training and experience in this field when she moved into archaeology. She then pursued an M.A. in Anthropology (Temple University, 1979), and a Ph.D. in Anthropology (Temple University, 1983). Research and career Dr. Piperno has worked extensively in the Amazon and Central America. She has also worked in Israel. Her research interests include the study of phytoliths, starch grains, and pollen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alcyonacea
Alcyonacea is the old scientific order name for the informal group known as "soft corals". It is now an unaccepted name for class Octocorallia. It became deprecated . The following text should be considered a historical, outdated way of treating the taxonomy of Anthozoa and Octocorallia. Some, or many parts of it, are no longer valid. Any remaining information found to be still valid, should be carefully merged into Octocorallia. Alcyonacea are an order of sessile colonial cnidarians that are found throughout the oceans of the world, especially in the deep sea, polar waters, tropics and subtropics. Whilst not in a strict taxonomic sense, Alcyonacea are commonly known as soft corals. The term "soft coral" generally applies to organisms in the two orders Pennatulacea and Alcyonacea with their polyps embedded within a fleshy mass of coenenchymal tissue. Consequently, the term "gorgonian coral" is commonly handed to multiple species in the order Alcyonacea that produce a min ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cape Verde Islands
Cape Verde or Cabo Verde, officially the Republic of Cabo Verde, is an island country and archipelagic state of West Africa in the central Atlantic Ocean, consisting of ten volcanic islands with a combined land area of about . These islands lie between west of Cap-Vert, the westernmost point of continental Africa. The Cape Verde islands form part of the Macaronesia ecoregion, along with the Azores, the Canary Islands, Madeira and the Savage Isles. The Cape Verde archipelago was uninhabited until the 15th century, when Portuguese explorers colonized the islands, establishing one of the first European settlements in the tropics. Due to its strategic position, Cape Verde became a significant location in the transatlantic slave trade during the 16th and 17th centuries. The islands experienced economic growth during this period, driven by their role by the rapid emergence of merchants, privateers, and pirates. It declined economically in the 19th century, and many of its inh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Charles Darwin
Charles Robert Darwin ( ; 12 February 1809 – 19 April 1882) was an English Natural history#Before 1900, naturalist, geologist, and biologist, widely known for his contributions to evolutionary biology. His proposition that all species of life have descended from a Common descent, common ancestor is now generally accepted and considered a fundamental scientific concept. In a joint presentation with Alfred Russel Wallace, he introduced his scientific theory that this Phylogenetics, branching pattern of evolution resulted from a process he called natural selection, in which the struggle for existence has a similar effect to the artificial selection involved in selective breeding.. Darwin has been described as one of the most influential figures in human history and was honoured by Burials and memorials in Westminster Abbey, burial in Westminster Abbey. Darwin's early interest in nature led him to neglect his medical education at the University of Edinburgh Medical Schoo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Christian Gottfried Ehrenberg
Christian Gottfried Ehrenberg (19 April 1795 – 27 June 1876) was a German Natural history, naturalist, zoologist, Botany, botanist, comparative anatomist, geologist, and microscopy, microscopist. He is considered to be one of the most famous and productive scientists of his time. Early collections The son of a judge, Christian Gottfried Ehrenberg was born in Delitzsch, near Leipzig. He first studied theology at the University of Leipzig, then medicine and natural sciences in Humboldt University of Berlin, Berlin and became a friend of the famous List of explorers, explorer Alexander von Humboldt. In 1818, he completed his doctoral dissertation on fungi, ''Sylvae mycologicae Berolinenses.'' In 1820–1825, on a scientific expedition to the Middle East with his friend Wilhelm Hemprich, he collected thousands of specimens of plants and animals. He investigated parts of Egypt, the Libyan Desert, the Nile, Nile valley and the northern coasts of the Red Sea, where he made a special ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Baobab
''Adansonia'' is a genus of medium-to-large deciduous trees known as baobabs ( or ). The eight species of ''Adansonia'' are native to Africa, Australia, and Madagascar but have also been introduced to other regions of the world, including Barbados, where several of the baobabs there are suspected to have originated from Africa. Other baobabs have been introduced to Asia. A genomic and ecological analysis further suggests that the genus itself originated from Madagascar. The generic name ''Adansonia'' honours Michel Adanson, the French naturalist and explorer who provided the first detailed botanical description and illustrations of ''Adansonia digitata''. The baobab, however, is also known as the "upside down tree," a name attributable to the trees' overall appearance and historical myths. Baobabs are among the most long-lived of vascular plants and have large flowers that are reproductive for a maximum of 15 hours. The flowers open around dusk with sufficiently rapid movemen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stomata
In botany, a stoma (: stomata, from Greek ''στόμα'', "mouth"), also called a stomate (: stomates), is a pore found in the epidermis of leaves, stems, and other organs, that controls the rate of gas exchange between the internal air spaces of the leaf and the atmosphere. The pore is bordered by a pair of specialized parenchyma cells known as guard cells that regulate the size of the stomatal opening. The term is usually used collectively to refer to the entire stomatal complex, consisting of the paired guard cells and the pore itself, which is referred to as the stomatal aperture. Air, containing oxygen, which is used in respiration, and carbon dioxide, which is used in photosynthesis, passes through stomata by gaseous diffusion. Water vapour diffuses through the stomata into the atmosphere as part of a process called transpiration. Stomata are present in the sporophyte generation of the vast majority of land plants, with the exception of liverworts, as well as so ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photosynthesis
Photosynthesis ( ) is a system of biological processes by which photosynthetic organisms, such as most plants, algae, and cyanobacteria, convert light energy, typically from sunlight, into the chemical energy necessary to fuel their metabolism. ''Photosynthesis'' usually refers to oxygenic photosynthesis, a process that produces oxygen. Photosynthetic organisms store the chemical energy so produced within intracellular organic compounds (compounds containing carbon) like sugars, glycogen, cellulose and starches. To use this stored chemical energy, an organism's cells metabolize the organic compounds through cellular respiration. Photosynthesis plays a critical role in producing and maintaining the oxygen content of the Earth's atmosphere, and it supplies most of the biological energy necessary for complex life on Earth. Some bacteria also perform anoxygenic photosynthesis, which uses bacteriochlorophyll to split hydrogen sulfide as a reductant instead of water, p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cacti
A cactus (: cacti, cactuses, or less commonly, cactus) is a member of the plant family Cactaceae (), a family of the order Caryophyllales comprising about 127 genera with some 1,750 known species. The word ''cactus'' derives, through Latin, from the Ancient Greek word (''káktos''), a name originally used by Theophrastus for a spiny plant whose identity is now not certain. Cacti occur in a wide range of shapes and sizes. They are native to the Americas, ranging from Patagonia in the south to parts of western Canada in the north, with the exception of '' Rhipsalis baccifera'', which is also found in Africa and Sri Lanka. Cacti are adapted to live in very dry environments, including the Atacama Desert, one of the driest places on Earth. Because of this, cacti show many adaptations to conserve water. For example, almost all cacti are succulents, meaning they have thickened, fleshy parts adapted to store water. Unlike many other succulents, the stem is the only part of most cacti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alarm Photosynthesis
Alarm photosynthesis is a variation of photosynthesis where calcium oxalate crystals function as dynamic carbon pools, supplying carbon dioxide ( CO2) to photosynthetic cells when stomata are partially or totally closed. This biochemical appendance of the photosynthetic machinery is a means to alleviate the perpetual plant dilemma of using atmospheric CO2 for photosynthesis and losing water vapor, or saving water and reducing photosynthesis. The function of alarm photosynthesis seems to be rather auxiliary to the overall photosynthetic performance. It supports a low photosynthetic rate, aiming at the maintenance and photoprotection of the photosynthetic apparatus rather than a substantial carbon gain. History The alarm photosynthesis process was first evidenced in pigweed '' Amaranthus hybridus'' plant in 2016 when ''A. hybridus'' leaves were exposed to drought conditions or exogenous application of abscisic acid. The same study showed similar results in '' Dianthus chinensis'', ' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carbon Dioxide
Carbon dioxide is a chemical compound with the chemical formula . It is made up of molecules that each have one carbon atom covalent bond, covalently double bonded to two oxygen atoms. It is found in a gas state at room temperature and at normally-encountered concentrations it is odorless. As the source of carbon in the carbon cycle, atmospheric is the primary carbon source for life on Earth. In the air, carbon dioxide is transparent to visible light but absorbs infrared, infrared radiation, acting as a greenhouse gas. Carbon dioxide is soluble in water and is found in groundwater, lakes, ice caps, and seawater. It is a trace gas Carbon dioxide in Earth's atmosphere, in Earth's atmosphere at 421 parts per million (ppm), or about 0.042% (as of May 2022) having risen from pre-industrial levels of 280 ppm or about 0.028%. Burning fossil fuels is the main cause of these increased concentrations, which are the primary cause of climate change.IPCC (2022Summary for pol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
