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Amphibians (class Amphibia) are a taxon of animals that include all tetrapods, four-legged vertebrates, that do not have amniotic eggs.(from Greek αμφις "both" and βιος "life") are ectotherms, and generally spend part of their time on land, but most do not have the adaptations to an entirely terrestrial existence found in most other modern tetrapods (amniotes). There are around 6,000 described, living species of amphibians. The study of amphibians and reptiles is known as herpetology.
History of amphibians
Amphibians developed with the characteristics of pharyngeal slits/gills, a dorsal nerve cord, a notochord, and a post-anal tail at different stages of their life. Though early tetrapods (which appeared 390 million years ago in the Devonian period) are often referred to as "amphibians", the first true amphibians (of the order Temnospondyli) appeared during the early Carboniferous period. During the late Carboniferous, Permian and Triassic periods, amphibians were extremely diverse, including many large and small forms, some newt and salamander-like, others resembling snakes or eels, and some large-snouted forms that were very like small (about 1.5 meter long) crocodiles (e.g. Archegosaurus). The drying out of the coal swamps during the latest Carboniferous and again at the end of the Early Permian diminished many of the environments of these Paleozoic amphibians, with the result that many types died out, and they were supplanted by reptiles. However both large and small amphibians still continued to flourish in rivers and lakes of the Late Permian, alongside the diverse therapsids or mammal-like reptiles that were the dominant land animals of that time. During the following, Triassic period, there were many genera with large, sometimes very flattened heads and very weak limbs; some of these, like Paracyclotosaurus, Cyclotosaurus and Mastodonsaurus were several meters in length. Apart from a few stragglers, all these large amphibians died out at the Triassic-Jurassic extinction event, and the majority of Jurassic amphibians belonged to modern groups, and would look familiar today.
Throughout their history, amphibians have ranged in size from large forms, such as the above mentioned Triassic genera, the 5 foot (150cm) long Eryops of the Permian period, and the Giant Japanese and Chinese Salamanders of today, down to the tiny Brachycephalus didactylus (Brazilian Gold Frog) and Eleutherodactylus iberia (leptodactylid frog) from Cuba, with a total length of 9.6-9.8 millimeters (0.4 inches). Amphibians have mastered almost every climate on earth from the hottest deserts to the frozen arctic.
More on [ Amphibian ]
reptiles, amphibians, and birds all my life, as well as a tendancy to not wash my hands after handling them.
JustinVal (Justin Val Rocha) Wed, 09 Dec 2009 21:19:47 -0000
reptiles, amphibians, and birds all my life, as well as a tendancy to not wash my hands after handling them.
RT @zooconservation: RT @StewardshipNet: Consider the safety of local herps (amphibians and reptiles) before your next prescribed burn. ...
FireInfoGirl (FireInfoGirl) Wed, 09 Dec 2009 19:38:04 -0000
RT @zooconservation: RT @StewardshipNet: Consider the safety of local herps (amphibians and reptiles) before your next prescribed burn. ...
RT @rosamyst: What NOT to give for Christmas: FDA reminds public that frogs and other reptiles, amphibians carry Salmonella http://bit.l ...
nashvillehhgmag (House&Home&GardenMag) Wed, 09 Dec 2009 15:24:16 -0000
RT @rosamyst: What NOT to give for Christmas: FDA reminds public that frogs and other reptiles, amphibians carry Salmonella http://bit.l ...
What NOT to give for Christmas: FDA reminds public that frogs and other reptiles, amphibians carry Salmonella http://bit.ly/6ock48
rosamyst (Sara Long) Wed, 09 Dec 2009 14:32:27 -0000
What NOT to give for Christmas: FDA reminds public that frogs and other reptiles, amphibians carry Salmonella http://bit.ly/6ock48
Salmonella risk associated with pet reptiles and amphibians http://agblog.ok.gov/2009/12/08/frogs-turtles-and-snakes-can-carry-salmonella/
okdepartmentag (Margaret Arthur) Wed, 09 Dec 2009 14:14:33 -0000
Salmonella risk associated with pet reptiles and amphibians http://agblog.ok.gov/2009/12/08/frogs-turtles-and-snakes-can-carry-salmonella/
NYC event: Hall of Reptiles and Amphibians - Amphibians were the first vertebrates to live on land. From them evolv... http://ow.ly/167K9X
nyccom (NYC.com) Wed, 09 Dec 2009 12:22:31 -0000
NYC event: Hall of Reptiles and Amphibians - Amphibians were the first vertebrates to live on land. From them evolv... http://ow.ly/167K9X
Center for Reptile and Amphibian Research - Specializes in collecting and breeding diverse species. Offers assembled species list, research results and images.
Meta Description: [ The Center for Reptile and Amphibian Research specializes in rare and threatened reptile species rangeing from Boelens Pythons to Tentacled Snakes. ]
Reptile and Amphibians of Northern Florida - Watch a virtual slide show pointing out the frogs, lizards, amphibians, and snakes of northeastern Florida.
Ribbit - Daily journal and background on the life cycle of frogs.
Virtual Exhibit on Canada's Biodiversity: Focus on Amphibian - Highlights the amphibians of Canada, examines their life history and habitats, and discusses conservation.
Meta Description: [ Virtual Exhibit on Canada's Biodiversity: focus on Amphibians. In this site, amphibians of Canada are examined in the light of conservation, life history, and habitats. An attempt was made to provide useful information in an interactive way that best reflects the complexity of amphibians, their l... ]
World of Wildlife - Animal Instincts - Includes pictures and articles about toads, tortoises, and alligators.
Meta Description: [ Freelance children's writer and photographer ]
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