Question

The animals which can live both in water as well as on land are called _________ .

Answer 1

They belong to the group of vertebrate animals characterized by their ability to live in both aquatic and terrestrial habitats. These groups of animals are represented by order Anura (frogs and toads), order Caudata (newts and salamanders) and order Gymnophiona (caecilians). These animals have several unique traits such as moist skin, cutaneous respiration, double channel hearing system, green rods in their retinas, pedicellate teeth etc.

Complete step by step answer:
The animals which can live both in water and land are called amphibians. The word Amphibian is derived from the Greek word Amphibios, which means “to live a double life”. They are cold-blooded, vertebrate animals that have both an aquatic phase and a terrestrial phase of life.
The word Cold-blooded means that amphibians cannot generate their own body heat. Their temperature varies with the temperature of the surrounding environment. Amphibians have moist bodies and don't have any scales. They have smooth skin that is able to absorb water and oxygen, which prevents them from getting dehydrated. They die if their body dries out.
Their special ability is that they can aestivate. It means that the amphibians are able to enter a dormant state if the environment becomes too hot and dry. They return to normal once cooler, moist conditions return. Some amphibians are also poisonous. They release toxic chemicals through their skin to harm their predators.

Note:
There has been a dramatic decline in amphibian populations, including localized extinction. The amphibian decline is perceived to be one of the most critical threats to global biodiversity. The causes for the decline include habitat destruction, over-exploitation, pollution, introduced predator species, global warming, destruction of ozone layer etc. The amphibians are considered to be ecological indicators due to their complex reproductive needs and permeable skin.