Vertebrata

• These animals have a true vertebral column and internal skeleton.
• The epidermis is multi-layered.
• Vertebrates are bilaterally symmetrical, triploblastic, coelomic and segmented, with complex differentiation of body tissues and organs.
• The heart is three or four-chambered.
• They have well-developed respiratory and excretory system.
• Endocrine glands are present in all.
• All chordates possess the following features:
1. have a notochord
2. have a dorsal nerve cord
3. are triploblastic
4. have paired gill pouches
5. are coelomate.

Cyclostomes:

• Cyclostomes are jawless vertebrates.
• They are found in aquatic, marine and fresh water.
• They are characterised by having an elongated eel-like body , circular mouth, slimy skin.
• They are scaleless.
• They are ectoparasites or borers of other vertebrates.
• Single and median nostril is present.
• They have two-chambered heart.

For Example: Petromyzon(Lamprey) and Myxine(Hagfish)

Pisces:

• These are fish. They are exclusively aquatic animals.
• Their skin is covered with scales/ plates.
• These are cold-blooded organisms.
• Fertilization may be external or internal.
• The body is usually streamlined . Some have a spindle-shaped or elongated body as well.
• They swim with the help of their tail.
• They obtain oxygen dissolved in water by using gills.

For Example: Synchiropus splendidus(Mandarin fish), Caulophyryne jordani (Angler fish), Scoliodon (Dog fish).

Amphibia:

• Amphibians are found both in water and on land.
• These animals differ from the fish in the lack of scales, in having mucus glands in the skin, and a three-chambered heart.
•  Respiration is through either gills or lungs. 
• They lay eggs.
• Their body is divided into head and trunk. The tail may or may not be present.
• They have two pairs of limbs for locomotion.
• They excrete either ammonia or urea.

For Example: Frogs, toads and salamanders

Reptilia:

• These animals are cold-blooded and have scales.
• Most of them have a three-chambered heart but crocodiles have four heart chambers.
• They lay eggs with tough coverings and do not need to lay their eggs in water.
• Body varies in form and is usually divided into head, neck, trunk and tail.
• Teeth are present in all reptiles except in tortoise and turtles.
• Respiration is through lungs only. No gills are present.
• Fertilization is internal.
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For Example: Snakes, turtles, lizards and crocodiles

Aves:

• Birds are warm-blooded animals.
• A toothless beak is present.
• They have a four-chambered heart with two auricles and two ventricles.
• They lay eggs. 
• There is an outside covering of feathers , and two forelimbs are modified for flight.
• They breathe through lungs. 
• All birds fall in this category. 
• Size ranges from smallest humming bird to largest ostrich.
• Birds have highly developed voice, hearing and vision. They also have specialized sense for nest building and caring for the young.
• Fertilization is internal. They are oviparous and lay large, yolk-laden eggs having hard shell.

For Example: All birds like crow, sparrow, ostrich, pigeon etc.

Mammalia:

• They are warm-blooded , breath through their lungs and have a four-chambered heart.
• Their skin is soft, slimy, smooth and scaleless.
• Respiration is through gills contained in pouches.
• Presence of hair on their body, sweat and oil glands are exclusive characters of mammals.
• Presence of pinna i.e external ear is also seen only in mammals.
• They also have mammary glands to feed their young ones.
• They usually give birth to live young ones.

For Example: Cat, Rat, Whale, human beings, Rabbit, dog