Question

Which period is known for the origin of amphibians?

Answer 1

Amphibians are vertebrates that belong to a variety of habitats and living within terrestrial, arboreal, and fossorial ecosystems. They breathe on land with their lungs and guilds inside the water.

Complete answer:
The Devonian period is known for the origin of amphibians. They developed around 370 million years ago which was similar to the modern coelacanth and lungfish from lobe-finned fish. The fishes had evolved multi-jointed leg-like fins that enable them to crawl on the sea bottom and had developed primitive lungs in some species of fishes that help them in breathing air when the stagnant pools of the Devonian swamps but low in oxygen. Amphibians are adapted that allows them to stay out of the water for a longer period and have improved lungs and skeletons which became heavier and stronger for better support to the weight of their bodies on land. The fishes use their strong fins to hoist themselves out of the water and evolve into limbs that would become the ancestors to all of the tetrapods that include modern amphibians such as reptiles, mammals, and birds. Besides crawling on land they spent most of their time in the water.

Additional Information: Amphibians are usually found near the feeding, breeding sites where they exhibit such behavior in some species. Some species of frogs constitute the female which are larger than the males and the males are actively involved in territorial defence. It involves adopting an aggressive posture and necessary attacking towards the intruder which involves snapping, chasing, and biting occasionally that cause the loss of a tail. They require fresh water for the reproduction and lay their eggs on land where they develop a means of keeping them moist. Some amphibians breed continuously or at any time of the year in the tropical and temperate regions where the breathing is mostly seasonal and usually in the spring which is triggered by the increasing day length and the rising in the temperatures or rainfall.

Note: The moist skin of the amphibians helps them to breathe and are considered as vertebrates because of the presence of backbone. They swallow their food whole and cannot live in saltwater. They are cold-blooded and develop several mechanisms to keep their eggs in moist conditions. Frogs can drown in water if their lungs are filled with water.