User:Abyssal/Portal:Permian
The Permian Portal
IntroductionSelected article on the Permian world and its legaciesSince then, sharks have diversified into over 470 species. They range in size from the small dwarf lanternshark (Etmopterus perryi), a deep sea species of only 17 centimetres (6.7 in) in length, to the whale shark (Rhincodon typus), the largest fish in the world, which reaches approximately 12 metres (39 ft). Sharks are found in all seas and are common to depths of 2,000 metres (6,600 ft). They generally do not live in freshwater although there are a few known exceptions, such as the bull shark and the river shark, which can survive in both seawater and freshwater. They breathe through five to seven gill slits. Sharks have a covering of dermal denticles that protects their skin from damage and parasites in addition to improving their fluid dynamics. They have several sets of replaceable teeth. (see more...) Did you know?
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Selected article on the Permian in human science, culture and economicsPaleontology lies on the border between biology and geology. It now uses techniques drawn from a wide range of sciences, including biochemistry, mathematics and engineering. Use of all these techniques has enabled paleontologists to discover much of the evolutionary history of life, almost all the way back to when Earth became capable of supporting life, about 3,800 million years ago. As knowledge has increased, paleontology has developed specialized sub-divisions, some of which focus on different types of fossil organisms while others study ecology and environmental history, such as ancient climates. Body fossils and trace fossils are the principal types of evidence about ancient life, and geochemical evidence has helped to decipher the evolution of life before there were organisms large enough to leave fossils. (see more...) GeochronologyEpochs - Cisuralian - Guadalupian - Lopingian Geography - Pangaea - Panthalassa Stratigraphic units - Red Beds of Texas and Oklahoma Researchers - Edward Drinker Cope SubcategoriesQuality ContentFeatured Permian articles - Amphibian Things you can doRelated contentAssociated WikimediaThe following Wikimedia Foundation sister projects provide more on this subject:
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