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,...
With currently 64000, species, majority of the members of Phylum Chordata belong to sub-phylum Vertebrata. All vertebrates possess notochord during the embryonic period only and later it is...
Members of Echinodermata (Spiny bodied) have an endoskeleton of calcareous ossicles. Starfish, sea cucumbers (holothurians), sea urchins and brittle stars are examples of echinoderms. All echinoderms are marine...
Phylum Mollusca is the second largest animal phylum after Arthropoda. They are terrestrial or aquatic (both marine and freshwater). Members of this phylum include snails, octopuses, squids, oysters...
