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Micraster Desori
''Micraster'' is an extinct genus of echinoids from the Late Cretaceous to the early Eocene. Its remains have been found in Africa, Antarctica, Europe, and North America. Micraster was an infaunal echinoid living in a burrow below the sediment surface. The test is clearly bilateral and there is a deep anterior groove to take in water containing organic particles to the mouth. The tube feet keep a supply of nutrient-laden water moving into the burrow. The anus has a waste tube behind it. Continuous evolution In the classic text ''The Science of Life'' (1931), H. G. Wells, Julian Huxley and G. P. Wells use Micraster as an example of a fossil whose continuous evolution can be traced over some 10 million years through 450–500 feet of chalk beds of the Late Cretaceous. They point out: :"During this long period the fossil Micrasters are so abundant that hundreds of thousands can be collected and a gradual evolution can be traced as we pass upward. The changes are apparently trivi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Late Cretaceous
The Late Cretaceous (100.5–66 Ma) is the younger of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''creta'', the Latin word for the white limestone known as chalk. The chalk of northern France and the white cliffs of south-eastern England date from the Cretaceous Period. Climate During the Late Cretaceous, the climate was warmer than present, although throughout the period a cooling trend is evident. The tropics became restricted to equatorial regions and northern latitudes experienced markedly more seasonal climatic conditions. Geography Due to plate tectonics, the Americas were gradually moving westward, causing the Atlantic Ocean to expand. The Western Interior Seaway divided North America into eastern and western halves; Appalachia and Laramidia. India maintained a northward course towards Asia. In the Southern Hemisphere, Australia and Ant ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Test (biology)
In biology, a test is the hard shell of some spherical marine animals and protists, notably sea urchins and microorganisms such as testate foraminiferans, radiolarians, and testate amoebae. The term is also applied to the covering of scale insects. The related Latin term testa is used for the hard seed coat of plant seeds. Etymology The anatomical term "test" derives from the Latin ''testa'' (which means a rounded bowl, amphora or bottle). Structure The test is a skeletal structure, made of hard material such as calcium carbonate, silica, chitin or composite materials. As such, it allows the protection of the internal organs and the attachment of soft flesh. In sea urchins The test of sea urchins is made of calcium carbonate, strengthened by a framework of calcite monocrystals, in a characteristic "stereomic" structure. These two ingredients provide sea urchins with a great solidity and a moderate weight, as well as the capacity to regenerate the mesh from the cuticle ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Micraster Gappi
''Micraster'' is an extinct genus of echinoids from the Late Cretaceous to the early Eocene. Its remains have been found in Africa, Antarctica, Europe, and North America. Micraster was an infaunal echinoid living in a burrow below the sediment surface. The test is clearly bilateral and there is a deep anterior groove to take in water containing organic particles to the mouth. The tube feet keep a supply of nutrient-laden water moving into the burrow. The anus has a waste tube behind it. Continuous evolution In the classic text ''The Science of Life'' (1931), H. G. Wells, Julian Huxley and G. P. Wells use Micraster as an example of a fossil whose continuous evolution can be traced over some 10 million years through 450–500 feet of chalk beds of the Late Cretaceous. They point out: :"During this long period the fossil Micrasters are so abundant that hundreds of thousands can be collected and a gradual evolution can be traced as we pass upward. The changes are apparently trivi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Micraster Elevatus
''Micraster'' is an extinct genus of echinoids from the Late Cretaceous to the early Eocene. Its remains have been found in Africa, Antarctica, Europe, and North America. Micraster was an infaunal echinoid living in a burrow below the sediment surface. The test is clearly bilateral and there is a deep anterior groove to take in water containing organic particles to the mouth. The tube feet keep a supply of nutrient-laden water moving into the burrow. The anus has a waste tube behind it. Continuous evolution In the classic text ''The Science of Life'' (1931), H. G. Wells, Julian Huxley and G. P. Wells use Micraster as an example of a fossil whose continuous evolution can be traced over some 10 million years through 450–500 feet of chalk beds of the Late Cretaceous. They point out: :"During this long period the fossil Micrasters are so abundant that hundreds of thousands can be collected and a gradual evolution can be traced as we pass upward. The changes are apparently trivi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Micraster Desori
''Micraster'' is an extinct genus of echinoids from the Late Cretaceous to the early Eocene. Its remains have been found in Africa, Antarctica, Europe, and North America. Micraster was an infaunal echinoid living in a burrow below the sediment surface. The test is clearly bilateral and there is a deep anterior groove to take in water containing organic particles to the mouth. The tube feet keep a supply of nutrient-laden water moving into the burrow. The anus has a waste tube behind it. Continuous evolution In the classic text ''The Science of Life'' (1931), H. G. Wells, Julian Huxley and G. P. Wells use Micraster as an example of a fossil whose continuous evolution can be traced over some 10 million years through 450–500 feet of chalk beds of the Late Cretaceous. They point out: :"During this long period the fossil Micrasters are so abundant that hundreds of thousands can be collected and a gradual evolution can be traced as we pass upward. The changes are apparently trivi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Micraster Depressus
''Micraster'' is an extinct genus of echinoids from the Late Cretaceous to the early Eocene. Its remains have been found in Africa, Antarctica, Europe, and North America. Micraster was an infaunal echinoid living in a burrow below the sediment surface. The test is clearly bilateral and there is a deep anterior groove to take in water containing organic particles to the mouth. The tube feet keep a supply of nutrient-laden water moving into the burrow. The anus has a waste tube behind it. Continuous evolution In the classic text ''The Science of Life'' (1931), H. G. Wells, Julian Huxley and G. P. Wells use Micraster as an example of a fossil whose continuous evolution can be traced over some 10 million years through 450–500 feet of chalk beds of the Late Cretaceous. They point out: :"During this long period the fossil Micrasters are so abundant that hundreds of thousands can be collected and a gradual evolution can be traced as we pass upward. The changes are apparently trivi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Micraster Decipiens
''Micraster'' is an extinct genus of echinoids from the Late Cretaceous to the early Eocene. Its remains have been found in Africa, Antarctica, Europe, and North America. Micraster was an infaunal echinoid living in a burrow below the sediment surface. The test is clearly bilateral and there is a deep anterior groove to take in water containing organic particles to the mouth. The tube feet keep a supply of nutrient-laden water moving into the burrow. The anus has a waste tube behind it. Continuous evolution In the classic text ''The Science of Life'' (1931), H. G. Wells, Julian Huxley and G. P. Wells use Micraster as an example of a fossil whose continuous evolution can be traced over some 10 million years through 450–500 feet of chalk beds of the Late Cretaceous. They point out: :"During this long period the fossil Micrasters are so abundant that hundreds of thousands can be collected and a gradual evolution can be traced as we pass upward. The changes are apparently trivi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Micraster Coravium
''Micraster'' is an extinct genus of echinoids from the Late Cretaceous to the early Eocene. Its remains have been found in Africa, Antarctica, Europe, and North America. Micraster was an infaunal echinoid living in a burrow below the sediment surface. The test is clearly bilateral and there is a deep anterior groove to take in water containing organic particles to the mouth. The tube feet keep a supply of nutrient-laden water moving into the burrow. The anus has a waste tube behind it. Continuous evolution In the classic text ''The Science of Life'' (1931), H. G. Wells, Julian Huxley and G. P. Wells use Micraster as an example of a fossil whose continuous evolution can be traced over some 10 million years through 450–500 feet of chalk beds of the Late Cretaceous. They point out: :"During this long period the fossil Micrasters are so abundant that hundreds of thousands can be collected and a gradual evolution can be traced as we pass upward. The changes are apparently trivi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Micraster Burgiensis
''Micraster'' is an extinct genus of echinoids from the Late Cretaceous to the early Eocene. Its remains have been found in Africa, Antarctica, Europe, and North America. Micraster was an infaunal echinoid living in a burrow below the sediment surface. The test is clearly bilateral and there is a deep anterior groove to take in water containing organic particles to the mouth. The tube feet keep a supply of nutrient-laden water moving into the burrow. The anus has a waste tube behind it. Continuous evolution In the classic text ''The Science of Life'' (1931), H. G. Wells, Julian Huxley and G. P. Wells use Micraster as an example of a fossil whose continuous evolution can be traced over some 10 million years through 450–500 feet of chalk beds of the Late Cretaceous. They point out: :"During this long period the fossil Micrasters are so abundant that hundreds of thousands can be collected and a gradual evolution can be traced as we pass upward. The changes are apparently trivi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Micraster Norfolkensis
''Micraster'' is an extinct genus of echinoids from the Late Cretaceous to the early Eocene. Its remains have been found in Africa, Antarctica, Europe, and North America. Micraster was an infaunal echinoid living in a burrow below the sediment surface. The test is clearly bilateral and there is a deep anterior groove to take in water containing organic particles to the mouth. The tube feet keep a supply of nutrient-laden water moving into the burrow. The anus has a waste tube behind it. Continuous evolution In the classic text ''The Science of Life'' (1931), H. G. Wells, Julian Huxley and G. P. Wells use Micraster as an example of a fossil whose continuous evolution can be traced over some 10 million years through 450–500 feet of chalk beds of the Late Cretaceous. They point out: :"During this long period the fossil Micrasters are so abundant that hundreds of thousands can be collected and a gradual evolution can be traced as we pass upward. The changes are apparently trivi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Micraster Bajo
''Micraster'' is an extinct genus of echinoids from the Late Cretaceous to the early Eocene. Its remains have been found in Africa, Antarctica, Europe, and North America. Micraster was an infaunal echinoid living in a burrow below the sediment surface. The test is clearly bilateral and there is a deep anterior groove to take in water containing organic particles to the mouth. The tube feet keep a supply of nutrient-laden water moving into the burrow. The anus has a waste tube behind it. Continuous evolution In the classic text ''The Science of Life'' (1931), H. G. Wells, Julian Huxley and G. P. Wells use Micraster as an example of a fossil whose continuous evolution can be traced over some 10 million years through 450–500 feet of chalk beds of the Late Cretaceous. They point out: :"During this long period the fossil Micrasters are so abundant that hundreds of thousands can be collected and a gradual evolution can be traced as we pass upward. The changes are apparently trivi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Julian Huxley
Sir Julian Sorell Huxley (22 June 1887 – 14 February 1975) was an English evolutionary biologist, eugenicist, and internationalist. He was a proponent of natural selection, and a leading figure in the mid-twentieth century modern synthesis. He was secretary of the Zoological Society of London (1935–1942), the first Director of UNESCO, a founding member of the World Wildlife Fund, the president of the British Eugenics Society (1959-1962), and the first President of the British Humanist Association. Huxley was well known for his presentation of science in books and articles, and on radio and television. He directed an Oscar-winning wildlife film. He was awarded UNESCO's Kalinga Prize for the popularisation of science in 1953, the Darwin Medal of the Royal Society in 1956, and the Darwin–Wallace Medal of the Linnaean Society in 1958. He was also knighted in that same year, 1958, a hundred years after Charles Darwin and Alfred Russel Wallace announced the theory of evoluti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
