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Asaphida Genera
Asaphida is a large, morphologically diverse order (biology), order of trilobites found in marine Stratum, strata dated from the Middle Cambrian until their extinction during the Silurian. Asaphida contains six Superfamily (zoology), superfamilies (Anomocaroidea, Asaphoidea, Cyclopygoidea, Dikelocephaloidea, Remopleuridoidea and Trinucleioidea), but no suborders. Asaphids comprise some 20% of described fossil trilobites. In 2020, the superfamily Trinucleoidea was proposed to be raised to an order (Trinucleida) and removed from Asaphida. Morphology The Asaphids generally have cephalon (arthropod anatomy), cephalon (head) and pygidium (tail) parts similar in size, and most species have a prominent median ventral suture. Heads are often flat, and carapace furrows in the head area are often faint or not visible. Thoracic segments typically number 5 - 12, though some species have as few as two and some as many as 30. They also generally have a wide doublure, or rim, that surrounds t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Richard Fortey
Richard Alan Fortey FRS FRSL (born 15 February 1946 in London) is a British palaeontologist, natural historian, writer and television presenter, who served as president of the Geological Society of London for its bicentennial year of 2007. Early life and education Fortey was educated at Ealing Grammar School for Boys and King's College, Cambridge, where he read Natural Sciences specialising in geology. He received a PhD and DSc from the University of Cambridge. Career Fortey has had a long career as a palaeontologist at the Natural History Museum in London; his research interests include above all, trilobites: at the age of 14, he discovered his first trilobite, sparking a passionate interest that later became a career. He has named numerous trilobite species and still continues his research despite having retired from the Museum. He studies trilobites and graptolites, especially those from the Ordovician and their systematics, evolution and modes of life; he is also involved ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sediment
Sediment is a naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of wind, water, or ice or by the force of gravity acting on the particles. For example, sand and silt can be carried in suspension in river water and on reaching the sea bed deposited by sedimentation; if buried, they may eventually become sandstone and siltstone (sedimentary rocks) through lithification. Sediments are most often transported by water ( fluvial processes), but also wind ( aeolian processes) and glaciers. Beach sands and river channel deposits are examples of fluvial transport and deposition, though sediment also often settles out of slow-moving or standing water in lakes and oceans. Desert sand dunes and loess are examples of aeolian transport and deposition. Glacial moraine deposits and till are ice-transported sediments. Classification Sediment can be classified based on its grain size, grain sh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Europe
Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a subcontinent of Eurasia and it is located entirely in the Northern Hemisphere and mostly in the Eastern Hemisphere. Comprising the westernmost peninsulas of Eurasia, it shares the continental landmass of Afro-Eurasia with both Africa and Asia. It is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, the Mediterranean Sea to the south and Asia to the east. Europe is commonly considered to be separated from Asia by the watershed of the Ural Mountains, the Ural River, the Caspian Sea, the Greater Caucasus, the Black Sea and the waterways of the Turkish Straits. "Europe" (pp. 68–69); "Asia" (pp. 90–91): "A commonly accepted division between Asia and Europe ... is formed by the Ural Mountains, Ural River, Caspian Sea, Caucasus Mountains, and the Blac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Russia
Russia (, , ), or the Russian Federation, is a transcontinental country spanning Eastern Europe and Northern Asia. It is the largest country in the world, with its internationally recognised territory covering , and encompassing one-eighth of Earth's inhabitable landmass. Russia extends across eleven time zones and shares land boundaries with fourteen countries, more than any other country but China. It is the world's ninth-most populous country and Europe's most populous country, with a population of 146 million people. The country's capital and largest city is Moscow, the largest city entirely within Europe. Saint Petersburg is Russia's cultural centre and second-largest city. Other major urban areas include Novosibirsk, Yekaterinburg, Nizhny Novgorod, and Kazan. The East Slavs emerged as a recognisable group in Europe between the 3rd and 8th centuries CE. Kievan Rus' arose as a state in the 9th century, and in 988, it adopted Orthodox Christianity from the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Saint Petersburg
Saint Petersburg ( rus, links=no, Санкт-Петербург, a=Ru-Sankt Peterburg Leningrad Petrograd Piter.ogg, r=Sankt-Peterburg, p=ˈsankt pʲɪtʲɪrˈburk), formerly known as Petrograd (1914–1924) and later Leningrad (1924–1991), is the List of cities and towns in Russia by population, second-largest city in Russia. It is situated on the Neva River, at the head of the Gulf of Finland on the Baltic Sea, with a population of roughly 5.4 million residents. Saint Petersburg is the List of European cities by population within city limits, fourth-most populous city in Europe after Istanbul, Moscow and London, the List of cities and towns around the Baltic Sea, most populous city on the Baltic Sea, and the world's List of northernmost items#Cities and settlements, northernmost city of more than 1 million residents. As Russia's Imperial capital, and a Ports of the Baltic Sea, historically strategic port, it is governed as a Federal cities of Russia, federal city. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Volkhov River
The Volkhov (russian: Во́лхов) is a river in Novgorodsky and Chudovsky Districts of Novgorod Oblast and Kirishsky and Volkhovsky Districts of Leningrad Oblast in northwestern Russia. It connects Lake Ilmen and Lake Ladoga and forms part of the basin of the Neva. The length of the river is , and the area of its drainage basin is . The city of Veliky Novgorod, the towns of Kirishi, Volkhov and Novaya Ladoga, and the historically important village of Staraya Ladoga are located along the Volkhov. Etymology A number of etymologies, none universally accepted, have been proposed for the name of the river. In his ''Etymological dictionary of the Russian language'', Max Vasmer doubted some philologists' opinion that the river's name is related to the Finnish ''velho'' ("magician") or Russian ''volkhv'' ("pagan priest"). Geography The Volkhov flows out of Lake Ilmen north into Lake Ladoga, the largest lake in Europe. It is the second largest tributary of Lake Ladoga. It is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asaphus Kowalewskii
''Asaphus kowalewskii'' () is one of the 35 species of trilobites of the genus ''Asaphus'' (this particular species is sometimes placed in its own genus, ''Neoasaphus''). Fossils of this species are popular among collectors because of their prominent stalked eyes In anatomy, an eyestalk (sometimes spelled eye stalk and also known as an ommatophore) is a protrusion that extends an eye away from the body, giving the eye a better field of view. It is a common feature in nature and frequently appears in fict ... (termed "peduncles"), many an inch or more in length. In the Ordovician period, an inland sea formed in what is now Eastern Europe. The sea contained a remarkably diverse trilobite fauna. Over a dozen species of ''Asaphus'' developed in this sea, with many species, including unrelated species, developing long eyestalks in various lengths. That so many species of trilobite developed eyestalks suggests that they were trying to overcome increased turbidity, or there was ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Evolution
Evolution is change in the heritable characteristics of biological populations over successive generations. These characteristics are the expressions of genes, which are passed on from parent to offspring during reproduction. Variation tends to exist within any given population as a result of genetic mutation and recombination. Evolution occurs when evolutionary processes such as natural selection (including sexual selection) and genetic drift act on this variation, resulting in certain characteristics becoming more common or more rare within a population. The evolutionary pressures that determine whether a characteristic is common or rare within a population constantly change, resulting in a change in heritable characteristics arising over successive generations. It is this process of evolution that has given rise to biodiversity at every level of biological organisation, including the levels of species, individual organisms, and molecules. The theory of evol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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