Circulatory system is responsible for movement of nutrients, gases and wastes within blood vessels. Open and Closed Circulatory Systems Circulatory system is not found in Porifera, Cnidaria, Platyhelminthes,...
Respiration is the entire process of taking air in, exchanging needed gases for unnecessary gases, using the needed gases, and releasing the waste form of gases. The Human...
The digestive system performs four functions viz. ingestion, digestion, absorption and elimination. Ingestion is intake of food. Digestion is of two types viz. mechanical (food is broken down...
In all the animals, tissues develop from the embryonic germ layers during the blastula (early stage of embryonic development) phase. On the basis of germ layers, all animals...
Both birds and mammals have evolved from a reptile ancestor. In terms of evolution, mammals are most advanced organisms found in almost all habitats in Earth’s biosphere including...
Sometime during the early Jurassic, two groups of reptiles gained the ability to fly and one of these groups later gave rise to the Aves (birds). They developed...
Reptiles are the first entirely terrestrial vertebrate class, totally independent from the aquatic habitat for survival. They have excellent evolutionary innovation to get them rid of water life....
Amphibians were the first vertebrates to venture out onto land. Early amphibians retained many fish-like characteristics but during the Carboniferous period amphibians diversified. Even today, Amphibians live a...
All the true fishes have been classified into two main classes as follows: Chondrichthyes: These are the fishes with soft cartilaginous skeletons. Examples are sharks, rays, dog-fish, skates,...
