Phylum - Vertebrates and its classes

Vertebrates comprise all species of animals within the subphylum Vertebrata. Vertebrates represent the overwhelming majority of the phylum Chordata


All vertebrates are chordates but not all chordates are vertebrates


Vertebrates have


1. Ventral muscular heart with 1,2,3 or 4 chambers

2. Kidneys for excretion and osmoregulation

3. Paired appendages which may be fins or limbs





1. Class: Cyclostomata

·         All are ectoparasites on some fishes

·         Elongated body with 6-15 pairs of gill slits for respiration

·         Sucking and circular mouth without jaws

·         Body is devoid of scales and paired fins

·         Cartilaginous cranium and vertebral column

·         They are marine but migrate to fresh water for spawning and die after spawning

·         The larvae after metamorphosis, return to ocean

·         Eg: Petromyzon (Lamprey), Myxine (Hagfish).


Super class: Pisces


1. Class: Chondrichthyes

·         Cold blooded animal i.e., Poikilothermic

·         Streamlined body with cartilaginous exoskeleton

·         Ventrally located mouth

·         Notochord persistent throughout life

·         Gill slits are separate without operculum (Gill cover)

·         Tough skin with minute placoid scales; Teeth are modified placoid scales and are backwardly directed

·         2 chambered heart

·         Special characteristics include presence of electric organs (Torpedo); Posion sting (Trygon).

·         Eg: Scoliodon (Dog fish), Pristis (Saw fish), Carcharodon (Great white shark), Trygon (Sting ray).


2. Class: Osteichthyes

·         Cold blooded animals

·         Marine fishes with bony exoskeleton

·         Four pairs of gills covered by operculum

·         Skin is covered with cycloid/ctenoid scales

·         Air bladder provides buoyancy

·         2 chambered hear with 1 auricle and 1 ventricle

·         Eg: Marine – Exocoetus (Flying fish), Hippocampus (Sea horse);

·         Freshwater – Labeo (Rohu), Catla (Katla), Clarias (Magur);

·         Aquarium – Betta(Fighting fish), Pterophyllum (Angel fish).


Super class: Tetrapoda


1. Class: Amphibia

·         Aquatic and terrestrial

·         Body is divisible into head and truck

·         Skin is moist without scales

·         Tympanum represents the ear

·         Respiration by skin, lungs and gills

·         2 auricles and 1 ventricle in 3 chambered heart

·         Alimentary canal. Excretory and reproductive tracts open nto cloaca


2. Class: Reptilia

·         Mostly terrestrial

·         Limbs when present are 2 Pairs

·         Dry and cornified skin with Epidermal scales or scutes

·         Tympanum represents ear

·         3chambered heart but 4 in crocodile


3. Class: Aves

·         Most of them fly

·         Fore limbs are modified to wings and hind limbs are modified for walking swimming or clasping

·         Skin is dry without glands except oil gland at the base of tail.

·         Endoskeleton is bony with air cavities called Pneumatic bones

·         Respiration is by lungs, Air sacs are connected to lungs to supplement respiration

·         Completely 4 chambered heart

·         Digestive tract with crop and gizzard


4. Class: Mammalia

·         Terrestrial; some of them are adapted to fly or live In water

·         Two pairs of limbs adapted for walking, running, climbing, burrowing, swimming or flying

·         Skin is unique possessing hair

·         External ears or pinna are present

·         Respiration is by lungs

·         4 chambered heart

Post By : Manish Malhotra 12 Jan, 2019 3678 views Biology