One of the most important & evoluted Kingdom is Animalia. Most complex & beautiful organisms fall into this category. It involves two divisions’ viz. chordates & non chordates. Chordates have more specified characters as compared to the non-chordates.  If you learn this classification properly, you have specified certain marks in your pocket already. You can see the categorization of Kingdom Animalia in this flow chart.


Can you see that tetrapoda (Tetra means 4 + Poda means limbs) category? Great! Yes I am going to tell you the features of the animals involved in those categories.-


Amphibians – They are the creatures with dual life.  They are cold blooded animals. They lie between fishes & terrestrial animals. In their larval form, they breathe like fishes. But after maturation (metamorphosis), they develop lungs as well. Let me tell you some of the features of class amphibian à

  • Amphibians have moist, scale less skin which absorbs water & oxygen.
  • They are very prone to dehydration condition therefore they have to live nearby water area.
  • Different glands (poison glands too) used to be present on the skin.
  • Certain amphibians can change their color just to protect themselves from the enemies.
  • Their life cycle begins in water where fertilization occurs. Fertilized egg forms the larva which later on forms the tadpole. Tadpole breaths through gills.

Amphibians are categorized into 3 orders viz. Apoda, Urodela, Anura.


Reptiles – They are cold blooded animals. They are covered by scales. And more of the properties are here


  • Reptiles lay eggs, even when they are aquatic. Some of them are ovoviviparous as well in which fertilized eggs remain in mother’s womb.
  • Internal fertilization occurs in them.
  • Scaly skin is use for movement & not for respiration. Protein Keratin & waxy lipid is present in their skin which reduces water loss.
  • Cold blooded animals.
  • Reptiles use lungs for respiration.
  • Heart is 3 chambered with partially divided
  • Reptiles show brumation which is similar to hibernation. During this time, they are less active & don’t eat much.
  • True sternum is present in reptiles.
  • RBCs are nucleated.
  • 12 pairs of cranial nerves are present in them.

Aves – It include birds. Field of biology in which we study about birds is known as ornithology.  And their characteristics are



  • They are warm blooded & their fore limbs are modified to form feathers.
  • Birds have streamlined body which reduces the friction.
  • Birds do not have any sweat glands.
  • Rudimentary pinna is present.
  • Bones are pneumatic types which have air spaces in it. That’s why they have light body weight.
  • Heart is four chambered in heart.
  • Pelvic girdle is known as
  • In many species. Navigational abilities are present.
  • Nervous system is well developed. 12 pairs of cranial nerves are also present.
  • Separate sexes are present & they show parental care.
  • Aves include 10,000 species of birds with 29 orders.
  • Their eggs are hard shelled.
  • Birds are bipedal (walk on 2 legs only)
  • In feet, hand, head & pelvis. Fused bone is present.

Mammals – It include breast feeding animals. They are warm blooded. Some of the features are


  • Most important feature in mammals is adaptation.
  • Their body is hairy which provide them protection.
  • Mammary glands are also present.
  • Their lower jaw is made up of a single bone.
  • Their teeth are replaced once in a lifetime.
  • They have 3 bones in the middle ear viz. incus, malleus & stapes. They are also known as hammer, anvil & stirrup.
  • Mammals have diaphragm in their thoracic cavity which separates it from abdominal cavity.
  • Heart is four chambered which is repeatedly contracting.

Want more information over Kingdom Animalia & detailed characteristics? Not an issue! Click over this link & grab the information. Animal Kingdom

Have any doubt? Not an issue! 🙂 Put your doubts on this link. Your all queries will be answered.

Well Guys! Thank you for reading my article. I am Anjali Ahuja, Biology educator. We (me with askIITians) have prepared interesting & useful study material for you. It is surely going to make your study informal & interesting. Please visit the link & you will get to know….

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