Question

Which group-Pisces or Amphibia is advanced? Give reason.

Answer 1

Hint: Group Pisces consists of fishes whereas the group Amphibia are another group of vertebrate organisms that can survive in both land and water. Evolutionary evidence suggests that amphibians have evolved from Pisces.

Complete answer: Both Amphibia and Pisces belong to the kingdom Animalia. They mainly differ in the anatomical structures they possess. Amphibia is supposed to be more advanced than Pisces; who are said to be their ancestors. Some of the major reasons for their advancements are;
1. The presence of a three-chambered heart; amphibians possess a three-chambered heart, consisting of two atria and a single ventricle, while, Pisces possess a heart having only two chambers, i.e. a single atrium and a ventricle.
2. Amphibians have a more developed organ for respiration, that is, they respire through lungs, while Pisces respire through gills, which is a primitive organ where the respiration is due to simple diffusion of gases with the outside environment.
3. Amphibians breathe through the skin, apart from lungs, which give them the ability to exchange gases through the ski; the presence of a moist skin allows a sufficient rate of gas exchange.

Note: The other major characteristics of Amphibians are: They are cold-blooded animals or poikilotherms or ectotherms and they do not possess any internal mechanism to control the body temperature. They bask under sunlight to increase body temperature. During reproduction, eggs fertilize outside the body. Amphibians are mainly carnivores.