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Did amphibians and mammals descend from reptiles?
Reptiles evolved from a group of reptiliomorph amphibians in the Carboniferous period. Mammals evolved from a groupof synapsidreptiles in the Jurassic period.
When did reptiles start to evolve?
About three hundred million years ago. "The origin of the reptiles lies about 320-310 million years ago, in the steaming swamps of the late Carboniferous, when the first reptiles evolved from advanced reptiliomorph labyrinthodonts. The oldest trace of reptiles is a series of footprints from the fossil strata of Nova Scotia, dated to 315 million years ago. The tracks are attributed to Hylonomus, the oldest known reptile in the biological sense of the word. It was a small, lizard-like animal, about 20 to 30 cm (8-12 in) long, with numerous sharp teeth indicating an insectivorous diet." (According to Wikipedia)
How did the first reptiles evolve on earth?
The first reptiles evolved from amphibians about 310-320 million years ago. It is known that amphibians live life in both water and land, but have to return to the water to lay their soft eggs. As amphibians differentiated one group known as reptiliomorph labyrinthodonts became more accustomed to the dry land. They spent more time on land than in water. Eventually they adapted by growing hard, dry skin rather than the soft, wet skin of amphibians. They also adapted by laying hard shelled eggs on land rather than laying soft eggs in the water. The first reptiles were largely overshadowed by the larger amphibians, which were more diverse and dominant prior to the Permian mass extinction. Hylonomus is the oldest-known reptile, and was about 8 to 12 inches (20 to 30 cm) long. Westlothiana has been suggested as the oldest reptile, but is for the moment considered to be more related to amphibians than amniotes.
What did mammals evolve from?
Reptiles evolved some 320 million years ago from amniote ancestors, specifically from advanced reptiliomorph labyrinthodons. They were among the first vertebrates to successfully sever their ancestral tie to water, as they developed impermeable skin and a mode of reproduction that did not depend upon a body of water (internal fertilization coupled with the amnion, a semi-permeable membrane that protects the embryo in the egg and allows for an exchange of gases such as oxygen and carbon dioxide, allow the developing animal to breathe).
When was the first reptile created?
Hello.First of all, these new-fangled reptiles could mate on dry land! Male reptiles came equipped with an ingenious appendage enabling them to insert sperm inside the female's body. Moreover, inside the female, an eggshell was formed around the developing embryo, and this enabled the egg to be laid on dry land -- something impossible for primitive amphibian eggs. Dry-land nests can be better defended than an amphibian's typically gelatinous egg-mass simply extruded into water.With regard to the second problem, that of retaining water in their bodies, the Gray Rat Snake at the right clearly shows the reptilian "invention" that helped solve that problem: These new reptiles were covered with fairly waterproof scales, so that water stayed inside their bodies much better than it did in the amphibians'. In the picture, each of those little blocky things covering the entire head is a scale. The third problem, that of keeping the body warm when air temperature grew cold, was not overcome by the reptiles. Or, maybe it was in some of them... All of today's reptiles are thought to be "cold blooded," but some paleontologists believe that at least a few species of dinosaurs, which were reptiles, were able to keep their body temperatures up when cold weather arrived -- that they were "warm blooded." The debate of whether some dinosaurs were warm blooded is still going on. These epoch-making advancements of reptiles over amphibians were so beneficial to reptiles that for many millions of years reptiles "ruled the earth." Probably you've heard of the Age of Dinosaurs. If an evolutionary biologist from another planet had visited Earth during the Jurassic period 150,000,000 years ago, he, she, or it surely would have assumed that eventually descendants of the reptiles would be the first Earthlings to set foot on the Moon, and to invent computers. However, something happened about 65 million years ago that killed off all the great dinosaurs, and many other life forms as well. Was it a comet hitting the earth? Or did the first mammals, which were small rat-like things, eat all the dinosaurs' eggs? Or something else? This is one of the most intriguing of all questions concerning the evolution of life on earth.Thank you.
