Tetrapods

The early Devonian period was thought to be the world of various Hirenamazu, mainly lung fish, coelacanth fish, teleost fish etc. As time goes on, vertebrates have made evolutionary progress and they can move on land. Coelacanth developed another bone shoulder strap. And the lungfish formed a pair of fins, and sauripterus formed the main structure on the arms (tibia, humerus and ulna). As these developments progress and environmental pressures affect the aquatic environment, vertebrate animals begin to advance into the land.

During the Devonian period, two major animal populations dominated. Tetrapod (4 legged terrestrial vertebrate) and arthropods (including spider and wingless insect). The first tetrapod is an amphibious animal such as a fish (Ichthyostega) and is closely related to a group of fish called clams like Eusthenopteron. Coelacanth that was thought to be extinct is the living representative of this group. Eusthenopteron has some life on the land adapted to it: it has limbs that allow it to move to the bottom of the pool, to the lungs - it swallows the surface of the air and ends at the neck The terrestrial predator can not rely on water to put food in his mouth, but you must move your head to capture the prey. The skeleton of Eusthenopteron fins is almost identical to the limbs of the earliest amphibian animals, which is an example of homology.

Prior to discovering other early quadruped and closely related fish in the late 20th century Ichthyostega used it as a transitional fossil between fish and quadruped alone. And we combined the skull of the fish tail, cricket and amphibian, limbs. It has seven figures of the lungs and limbs to help navigate in the shallow water of the swamp. By the late Devonian, land plants stabilized freshwater habitats, allowing the development of first wetland ecosystems, and increasingly complicated food webs provided new opportunities. Freshwater habitats are not the only place you can find water filled with organic matter and dense vegetation near the edge of the water. There are moist habitats such as shallow wetlands, coastal lagoons, large saltwater river deltas, and there are many signs that this is an evolutionary environment of tetrapod.

Tiktaalik roseae is a fish fossil that produces the characteristics of a quadruped or quadruped. Its history can be traced back to millions of years ago of the first quadruped animal, which indicates that it is one of the satirical fish which rose from the water and started walking on land. Other fossils that occurred before and after Tiktaalik during transition showed different features in quadruped evolution of fish including Eusthenopteron, Panderichthys, Ventastega, Acanthostega, Ichthyostega and Pederpes.