Characteristics of Class Reptilia   i) Members of these groups are called reptiles.   ii) Most of animals of this group are terrestrial. A few live in water.   iii) They are also called crawlers.   iv) Their skin is thick, dry and rough.   v) Lungs are present for respiration.   vi) Teeth are…

Characteristics of Class Amphibia   i) Members of this class are called amphibians.   ii) Their bodies are covered with thin and lose skin. This skin is moist and slimy.   iii) Small teeth are present in upper jaw, which are used for grasping.   iv) Lungs are present, which help it to respire.  …

Breathing Mechanism   The process of breathing consists of 2 phases:   Inspiration:   In this process diaphragm contracts. The inter coastal muscles contacts raising the rib cage, which in turn expands the lungs. As a result air pressure within the lungs decreases and air from outside is pulled into the lungs.     Expiration:…

Characteristics of Pisces   Characteristics:   i) Members of this class also called fishes.   ii) Their body has three parts, i.e. head, trunk, tail.   iii) Body of fish is flexible.   iv) They can swim in water with the help of fins.   v) Their bodies are covered with scales, which remains most…

Why Gaseous Exchange is Important in Living Organisms   The exchange of gases is necessary because:   i) When organism get oxygen from environment to oxidize their compounds. In this process Co2 is produced which is harmful for body. Therefore this must be expelled out from the body. ii) Aerobic organisms take up oxygen form…

Characteristics of Vertebrates   i) Among chordates vertebrates is the largest group.   ii) There are more than 47000 of vertebrates are present on land.   iii) Vertebrates are divided into 5 different classes.   iv) These classes are Pisces, Amphibia, Reptilia, Aves, mammalia.   v) A common characteristic of vertebrates is presence of vertebral…

Chordates and their Characteristics   The basic characteristics of chordates are:   Notochord:   It is rod like structure made up on semi-rigid body of cells. It is enclosed in the sheath of connective tissues. It is located dorsal to the alimentary canal and ventral to nervous system running for anterior to posterior end. Its…

Process of Respiration in Plants   The process of respiration in plants continues day and night.   Entry of Oxygen:   Oxygen from air spaces on leaves diffused into tissues and cells. Then this oxygen dissolves in film of water present over cells. In cells this oxygen oxidizes the carbohydrates to produce energy.   Excretion…

Short Note on Starfish   Habitat:   Actually it is not a fish. Its body is not a star shape.     Structure:   Starfish have five arms but some have more. Central part is disc like. Mouth is present on ventral side of disc.     Locomotion:   Every arm has many tube feet.…

Note on Exchange of Gases in Terrestrial Animals   Through Trachea:   Insects and other land arthropods use tracheal tubes for exchange of gases. This is very simple and effective method. These animals have network of tracheal tubes. These tubes on reaching near the cells divide into very minute tubes called tracheoles. A fluid is…