Answer to Question #281359 in Zoology for Applied Biology

Question

explain about origin of tetra pods and their fish ancestors

Answer 1

Tetrapods evolved from a group of animals known as the Tetrapodomorpha which, in turn, evolved from ancient sarcopterygian fish around 390 million years ago in the middle Devonian period; their forms were transitional between lobe-finned fishes and the four-limbed tetrapods.

The bottom fins of lobe-finned fishes are arranged in pairs and supported by internal bones—Lobe-finned fishes of the Devonian period were already able to breathe air, when necessary, via "spiracles" in their skulls.

the necessary conditions for these fins to evolve into primitive legs. Most tetrapod species today are amniotes, most of which are terrestrial tetrapods whose branch evolved from earlier tetrapods about 340 million years ago. The key innovation in amniotes over amphibians is the amnion, which enables the eggs to retain their aqueous contents on land, rather than needing to stay in water.