- 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:
- have a notochord
- have a dorsal nerve cord
- are triploblastic
- have paired gill pouches
- 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.
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
