User:Abyssal/Portal:Permian

The Permian Portal Introduction Selected article on the Permian world and its legacies Fossils of Ditomopyge decurrata. Arthropods are members of the phylum Arthropoda, and include the insects, arachnids, and crustaceans. They are characterized by their jointed limbs and cuticles. The rigid cuticle inhibits growth, so arthropods replace it periodically by moulting. The arthropod body plan consists of repeated segments, each with a pair of appendages. Their versatility has enabled them to become the most species-rich members of all ecological guilds in most environments. They have over a million described species, making up more than 80% of all described living animal species. They range in size from microscopic plankton up to forms a few meters long. Like their exteriors, the internal organs of arthropods are generally built of repeated segments. Their vision relies on various combinations of compound eyes and pigment-pit ocelli. Arthropods also have a wide range of chemical and mechanical sensors, mostly based on modifications of the many setae (bristles) that project through their cuticles. Nearly all arthropods lay eggs. Arthropod hatchlings vary from miniature adults to grubs and caterpillars that lack jointed limbs and eventually undergo a total metamorphosis to produce the adult form. The evolutionary ancestry of arthropods dates back to the Cambrian period. The group is generally regarded as monophyletic, and many analyses support the placement of arthropods with cycloneuralians (or their constituent clades) in a superphylum Ecdysozoa. Overall however, the basal relationships of Metazoa are not yet well resolved. Likewise, the relationships between various arthropod groups are still actively debated. (see more...) Did you know? Methanosarcina barkeri fusaro. ... that the single-celled Methanosarcina (Methanosarcina barkeri fusaro pictured) may have played a significant role in both the evolution of early life and the worst extinction event in history? ... that Gerobatrachus is considered to be a missing link that supports the hypothesis offered by cladistics, that frogs and salamanders had a common ancestor? ... that Arthropleuridea is an extinct class of myriapods which includes, at over 2 meters long, the largest terrestrial arthropods that ever lived? Need help? Do you have a question about Abyssal/Portal:Permian that you can't find the answer to? Consider asking it at the Wikipedia reference desk. Selected image Fossil of Glossopteris. Photo credit: Ghedoghedo Selected article on the Permian in human science, culture and economics Edward Drinker Cope (left) and Othniel Charles Marsh (right). The Bone Wars is the name given to a period of intense fossil speculation and discovery during the Gilded Age of American history, marked by a heated rivalry between Edward Drinker Cope and Othniel Charles Marsh. The two paleontologists used underhanded methods to out-compete the other in the field, resorting to bribery, theft, and destruction of bones. The scientists also attacked each other in scientific publications, attempting to ruin the other's credibility and cut off his funding. Originally colleagues who were civil to each other, Cope and Marsh became bitter enemies after several personal slights between them. Their pursuit of bones led them west to rich bone beds in Colorado, Nebraska, and Wyoming. From 1877 to 1892, both paleontologists used their wealth and influence to finance their own expeditions and to procure services and fossils from dinosaur hunters. By the end of the Bone Wars, both men exhausted their funds in fueling their intense rivalry. Cope and Marsh were financially and socially ruined by their efforts to disgrace each other, but their contributions to science and the field of paleontology were massive; the scientists left behind tons of unopened boxes of fossils on their deaths. The feud between the two men led to over 142 new species of dinosaurs being discovered and described. Several historical books and fictional adaptations have also been published about this period of intense paleontological activity. (see more...) Geochronology Epochs - Cisuralian - Guadalupian - Lopingian Ages - Asselian - Sakmarian - Artinskian - Kungurian - Roadian - Wordian - Capitanian -Wuchiapingian - Changhsingian Events - Hunter-Bowen orogeny - Permian–Triassic extinction event Geography - Pangaea - Panthalassa Animals - Ammonoids - Blattopterans - Dicynodonts - Dinocephalians - Fusulinids - Gorgonopsians - Lepospondyls - Pareiasaurs - Pelycosaurs - Temnospondyls - Trilobites Plants - Conifers - Cycads - Ginkgos - Seed ferns Stratigraphic units - Red Beds of Texas and Oklahoma Researchers - Edward Drinker Cope Culture - Animal Armageddon - The Day The Earth Nearly Died - List of creatures in the Walking with... series - Walking with Monsters Subcategories Permian Permian Africa Permian Antarctica Permian Asia Permian Europe Permian North America Permian Oceania Permian South America Permian geochronology Permian events Permian geology Permian life Permian paleogeography Permian stubs Quality Content Featured Permian articles - Amphibian Good Permian articles - Dimetrodon - Temnospondyli Things you can do Here are some tasks awaiting attention: Stubs : Permian stubs Current Permian FACs - none currently Related content Time Earth sciences Paleontology Extinct and Endangered Species Paleozoic Cambrian Ordovician Silurian Devonian Carboniferous Permian Mesozoic Associated Wikimedia The following Wikimedia Foundation sister projects provide more on this subject: Commons Free media repository Wikibooks Free textbooks and manuals Wikidata Free knowledge base Wikinews Free-content news Wikiquote Collection of quotations Wikisource Free-content library Wikiversity Free learning tools Wiktionary Dictionary and thesaurus ¤ Category:Geologic time portals