What are tetrapods?

tetraPodes are animals of vertebrates with four feet, legs or leggings. In Greek means "tetrappod" "four -legged". TetraPods include amphibians, reptiles, dinosaurs, birds, mammals and several ancient medium forms between fish and amphibians. Several tetraples have evolved into legless forms such as snakes. In the scientific classification, Tetrapoda is a supercust inside the vertebral prompts. While sharks, beams, skates and fish are representatives of vertebrates in the seas, tetrapes are representatives of vertebrates on the ground. One of the first evolutionary steps towards the tetraons and far from the fish was panderichthys (dated 380 million years ago), a fish with a large, tetrapod head, a large strong fins on its underside, which probably lived in muddy shallows. Others were tictalik (dated to 375 millions years ago), sometimes called "fishpond" due to a mixture of tetrapod and fish similar to characteristics. tictalik had fins similar to the limbs that could take itto the ground. Both panderichthys and tictalik were part of the line of sarcopterygians who evolved to cope with oxygen water in shallow seas.

Some sarkopterygics eventually evolved on intermediates between fish and tetraples that show recognizable limbs, including acanthostega and ichthyostega . These animals are tetrapods of the tribal group, classified in their own groups in tetrapod, rather than included in contemporary animal classes such as amphibians. These animals lived in shallow, weeds covered with swamps, and initially their legs would originally rise to weeds to walk on the ground. Since evolution does not have anticipation, it could not plan to create an animal capable on the ground and the limbs of animals would have to develop to meet the adaptive challenge of their originally water lifestyle.

during the prickTry 100 million years have been diversified by amphibians and reptiles, and eventually liberated from the need to lay eggs in the water. These tetrapes lived among the extremely strong forests of the carbon era, about 360 to 300 million years ago. In the Permian period, 300 to 250 million years ago, some large and very impressive tetraples, especially therapy, have now been disappeared. Shortly thereafter, the age of dinosaurs followed.