Respiratory System

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 respiratory system consists of the following parts, divided into the upper and ..

Digestive System

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 into smaller pieces, this begins as soon as we put food in ..

Teeth: Types, Dental Formula and Tooth Anatomy

Each tooth is embedded in a socket of jaw bone. Most of the animals including humans have two sets of teeth during their life. First set is of temporary milk or deciduous teeth, which is replaced by a set of ..

Types of Animal Tissues

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 except Porifera and Protozoa; there are either two or three germ layers. ..

Salient Features and Types of Mammals: Monotremes, Marsupials, Eutherians

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 polar ice caps, deserts, mountains, forests, grasslands and dark caves. Common features ..

Class Aves: Origin, Adaptations and Key Features

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 a range of adaptations that enabled flight such as feathers, anterior limbs ..

Reptiles

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. Their skin is keratinized and impermeable to water whereas amphibian skin is ..

Amphibians: Examples, Features and Adaptations to Terrestrial Environment

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 dual life. They are totally aquatic during their larval stage and partially ..