What is the difference between an amphibian and a reptilian?
967122
Well,\nReptiles have scales. Amphibians have smooth skin (although some are warty). \nReptiles are total land animals. Amphibians need the water. And yet this is not always true. There are many marine reptiles, but they must go ashore to lay their eggs, well the sea snake might be a possible exception there. There are also amphibians that are able to spend their whole lives out of the water. They are rare, but there. \nThe real big difference (other than scales) is that reptiles use hardshelled, amniotic eggs for their babies. All amphibians have soft jellylike eggs. \n\nThere are several anatomical (pertaining to body structure) and reproductive differences between reptiles and amphibians. Reptiles include alligators, crocodiles, turtles, and snakes. Amphibians include salamanders, toads, and frogs.\n\nOne difference between the two is the structure of their outer skin. Reptiles are covered with scales, shields, or plates, and their toes have claws. Amphibians, on the other hand, have moist, glandular skins, and their toes lack claws.\n\nThe eggs of reptiles have a thick, hard shell that protects the developing embryo from moisture loss, even on dry land. In contrast, the eggs of amphibians lack a hard outer covering and, thus, must be laid in water or in damp places.\n\nFinally, young reptiles are miniature replicas of their parents in general appearance, although not always in coloration and pattern....\n\nReptiles and amphibians, along with birds, fish, and mammals, belong to a group of animals known as vertebrates. Vertebrates have a bony backbone–a strong, flexible column to which other body structures are attached. Reptiles and amphibians vary enormously in size, from tiny frogs and lizards only half an inch (1cm) long to some crocodiles and snakes that can reach lengths of nearly 30 feet
25919
Mammals such as your cat and us evolved from early amniotes called Therapsids, as the Professor stated. Therapsids were sometimes called "Mammal-like reptiles" but in fact, all the "modern reptiles" (lizards, snakes, crocs, turtles) evolved from another "branch" of early amniotes. The things that all amniotes have in common either 1) were inherited from a common ancestor or 2) evolved independently and achieved similar aspect. Most of the times you can tell when this is the case because such features look superficially similar, but not so much under closer examination. For example, vertical pupils are characteristic of many nocturnal animals that are very dissimilar, such as cats, alligators, or some frogs; these were acquired independently and these animals regulate their eyes somewhat differently. However, all vertebrates have one pair of eyes; this is an inherited shared trait.
623501
Yes, the earliest life appears to be aquatic life.  But then amphibian species emerged on land (although with part of their lifespan still in water), and later reptiles were all-land-dwelling animals.  Among these are snakes.  Snakes are reptiles, so therefore, yes they did evolve on land. (Incidentally, they evolved from legged-animals ... some snakes still have vestigial leg bones).\n\nSo I'm not sure what your question is.
349915
The modern amphibians (a natural group called Lissamphibia) comprise urodeles (salamanders), anures (frogs and toads) and caecilians or apodes. These are intriguing amphibians because they're highly adapted to life underground or in water, and few people know them or have ever seen them in the wild, although they're fairly common in all the world. \nThe name "caecilia" means "blind", and indeed their eyes are covered by the skin and sometimes by bone too, although they can perceive light and dark. \nI like them, if only because I share my first name with them. \nHere's a picture of one showing their exclusive sensory tentacle:\nhttp://www4.nau.edu/bilby/photo_illustration_page/images_photo_page/Caecilian.jpg
513168
Birds, Definitely. birds, being warm blooded, are much closer to mammals than amphibians. Amphibians only show the faintest glimmer of an R-Complex, known in your brain as a cerebellum - the reptilian part of the brain. Birds, by contrast, have a highly developed R-complex and even show the beginnings of a cerebrum (the big lumpy part of your brain that handles all that rational though stuff). Can you imagine a frog or a salamander uttering, "Polly wants a cracker?" >:)
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Snakes lost their legs on land, not in the sea as previous scientists thought, according to new research by professor of biology S. Blair Hedges and postdoctoral fellow Nicolas Vidal.\n\n"Everyone agrees that snakes evolved from lizards and are close relatives to lizards," Hedges said. "What is controversial is the specific group, whether on the land or in the sea."\n\nScientists estimate that snakes evolved 150 million years ago, Vidal said. For many years, they believed in the terrestrial or land theory, which says that snakes evolved from lizards that burrowed underground.\n\nThen, seven years ago, the discovery of a fossilized marine snake with tiny hind legs fueled the marine hypothesis that snakes lost their legs in the sea. The marine snakes called mosasaurs are now extinct, but their closest cousins, the monitor lizards such as the Komodo Dragon, are still alive today.\n\nHedges and Vidal chose two genes and compared them in lizards and snakes to see how closely they are related. From statistical analysis of these gene sequences, they created a family tree.\n\n"These two genes have accumulated different mutations in the different species," Vidal said. "These differences between the species are used to build the evolutionary trees. Snakes are not closely related to the monitor lizards, which means that they cannot have marine origins."\n\nHedges and Vidal's research is significant because of the comprehensive scope of the snakes and lizards studied. They collected DNA from 64 species representing all 19 families of living lizards and 17 of the 25 families of living snakes, Vidal said.\n\n"We mostly acquired DNA from the soft tissues, blood, shed skin, scales and tips of the tails of the animals," he said. "A very small amount is needed, so we can get the sample without killing the animal."\n\nHedges and Vidal acquired samples from other colleagues, their own collections, fieldwork in South America and pet stores that trade exotic animals, Hedges said.\n\nSome of the samples were difficult to acquire because some snakes and lizards are limited to certain parts of the world, such as remote islands, but it was crucial to their study.\n\n"We felt it was important to analyze genes from all the lizard groups, because almost every lizard family has been suggested as being the one most closely related to snakes," Hedges said. "If we had failed to include genes from even one of the lizard families, we could have missed getting the right answer."\n\nA possible theory to explain why snakes dropped their legs on land is that limbs are not conducive to their burrowing habits, Vidal said.\n\n"The idea is that if you have limbs sticking out, it's difficult to get into small openings," Hedges said. "It's more advantageous, because it enables snakes to get more food and offers safety from predators."\n\nHedges and Vidal did not find the closest lizard relative to snakes, but they did succeed in eliminating the monitor and marine lizards as possibilities.\n\n"This study doesn't answer all the questions," Hedges said. "In most fields, questions aren't answered all at once. They're answered in increments, and in this study, we've ruled out the marine theory, but that still leaves a lot of possibilities."\n\nHedges and Vidal said they hope to find the closest relative to snakes in the next year.\n\n"The work by Dr. Hedges and Dr. Vidal is a tremendous contribution to the body of knowledge," said Bryan Fry, deputy director of the Australian Venom Research Unit at the University of Melbourne in Australia. "Their data provides strong evidence for the terrestrial loss of limbs."
258574
a jellyfish is an invertebrete.\na cuttlefish is not a fish!! it is a cnidarian, henceforth an invertebrate\n\nan eel is a vertebrate
273979
A group of frog tadpoles (or a group of frogs) is called an Army.\n\nA group of toad tadpoles (or a group of toads) is called a Knot.
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What is the difference between a crocodile and an alligator? \nRonnie-Jo\nBayonne, New Jersey  \n \nDear Ronnie-Jo: \nA classic question! Fortunately, a quick investigation of our very own Crocodiles and Alligators category reveals several differences between alligators and crocodiles: \nYou can't see an alligator's teeth when it's mouth is closed; its lower teeth fit snugly into pits in the upper jaw. In contrast, a crocodile's lower teeth are always visible. \n\nAlligators have a broad snout, while crocodiles have a thinner snout. \n\nAlligators tend to be grayish black in color, whereas crocodiles have a light tan appearance. \n\nAlligators can only be found in the southeastern United States and in some parts of China. Crocodiles can be found all over the world. \n\nIn the wild, alligators tend to run away. While not exactly wallflowers, they certainly prefer their own company. Some species of crocodiles, on the other hand, have legendary tempers. The Salt Water Crocodile and the Nile Crocodile have been known to eat people. \nObviously, these two creatures have more in common than not. Alligators, caimans, crocodiles, and gharials are all referred to as crocodilians, and the last 25 years have been very kind to them. Thanks to conservation efforts and threatened animal legislation, 16 of the 23 species have been returned to sustainable population levels.
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Alligators have a depressed (flattened) body and a compressed tail. Also, most young specimes are more brightly colored than "dull black" as you describe it. If you see it again, check the snout (long and with terminal nostrils in alligators), and the eyes (vertical pupils in alligators... but also in many lizards such as geckos). I'm puzzled by your reference to a chameleon, though, because those are not precisely typically lizard-like. I'm guessing it was probably a lizard; the dull coloration could be due to its being a large, rather old specimen.\n\n---------------\nUpdate: Thanks Suttkus! I wasn't thinking of anoles, and I know that no chameleons occur there :-P
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Most lizards are green, probably for camouflage.\n\nSince dinosaurs are lizard-like, they are expected to be green.\n\nHowever, dinosaurs are expected to be a variety of colors, green does not have much of an advantage. Lizards, though primarily green, can have a variety of colors or be able to change colors.\n\nAlso, it's easier to imagine a green dinosaur then a bright pink dinosaur. :D
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A tadpole is just a juvenille version of a frog, which is a vertebrate.  This would be like saying that you weren't a vertebrate until you were an adult, which you know is false.\n\nPegnuin feathers are very small and have been selected by evolution to keep the birds as warm as possible.  See a picture of them in the sources link.
146631
Many survive the same way reptiles and amphibians do. They hibernate by digging into the mud and burying themselves within. Others are capable of surviving in low-temperature water. The rest migrate like birds.
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The crocodile has longer snout.\n\nCompared to the Crocodile, Alligators have short, rounded snouts while Crocodiles have longer and tapered snouts. \n\nAn alligator has a broad and blunt snout. Their lower teeth fit inside the edge of the upper jaw and cannot be seen when their mouth is closed. Crocodiles on the other hand, have a narrow head and longer snout. Their upper and lower teeth can be seen. \n\nAlligators are characterized by a broader snout and eyes more dorsally located than their crocodile cousins however crocodiles have longer snout than alligators. Alligators (and caimans) have a wide "U"-shaped, rounded snout (like a shovel), whereas crocodiles tend to have longer and more pointed "V"-shaped noses. \n\nThe broad snout of alligators is designed for strength, capable of withstanding the stress caused to bone when massive force is applied to crack open turtles and hard-shelled invertebrates which form part of their diet. Conversely, the pointed snout of a crocodile isn't quite as strong as the alligatorine shape, but the crocodile is still capable of exerting massive biting power. Crocodile jaws can be thought of as being more generalised - ideal for a wide variety of prey.\n\nGharials have a thin and extremely long snout. Caimans also have a short and blunt snout.♥
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Most amphibians eat insects, however their are alos species that prey primarily on fish, crustations and even mammals. \n\nCrocodiles are NOT amphibians. Thay are amphibious which is quite a different thing.
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Because they develop similarly. Read this: http://www.ucmp.berkeley.edu/chordata/chordata.html
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Reptiles\nAmphibians\n"mammal-like reptiles" (reptiles who'se outer jaw bones had migrated to become ear bones)\nMammals (in the final dinosaur age, the Jurassic)\nInsects\nArachnids