Worm-like marine animals.
Body cylindrical and composed of an
anterior proboscis, a collar and a long
Bilaterally symmetrical, triploblastic and
Organ-system level of organisation.
Respiration through gills & open type
o Excretory organ proboscis gland.
o Sexes separate, fertilisation external &
e.g. Balanoglossus and Saccoglossus.
1. Presence of a notochord
2. A dorsal hollow nerve chord
3. Paired pharyngeal gill slits
4. Coelomate with organ system level of organisation
5. Post anal tail
IMPOTANT FEATURES OF A CHORDATA :
Subphylum Urochordata and Cephalochordata
are called Protochordates.
1. Subphyla Urochordata or
2. Subphyla Cephalochordata
3. Subphyla Vertebrata
Notochord is present
only in larval tail.
from head to tail region
throughout their life.
Notochord persist during embryonic period.
Notochord is replaced by a cartilaginous or bony
vertebral column in the adult.
Ventral muscular heart present.
Kidney for excretion & osmoregulation.
Paired appendages may be fins or limbs.
All vertebrates are chordates but all chordates are
Agnatha (Circular mouth without jaws).
Ectoparasites on some fishes.
Body is without scales and paired fins.
Elongated body bearing 6-15 pairs of gill slits for
Cranium and vertebral column cartilaginous.
Circulation closed type.
Marine but migrate to fresh water for spawning &
larva after metamorphosis return to ocean
e.g. Petromyzon (Lamprey), Myxine (Hagfish)
Streamline body, cartilaginous endoskeleton.
Notochord persist throughout life.
Ventral mouth, powerful jaw, teeth are modified
into placoid scales, predaceous.
Gill slits are separate & without operculum.
Cold-blooded (poikilothermous), Heart two
Sexes separate, internal fertilisation, many of
them are viviparous.
Torpedo possess electric organs & Trygon
have poison sting
Both marine & fresh water fishes with bony
Body streamlined & mouth terminal.
Four pairs of gills covered by operculum.
Body covered with cycloid/ctenoid scales.
Air blader regulates buoyancy.
Heart is two chamber, cold-blooded.
Fins are its locomotory organs.
Sexes separate, fertilisation external.
Mostly oviparous, development is direct.
Habitats - Aquatic as well as terrestrial.
Frogs have smooth, moist skin; Toads have rough, dry
Body divisible into head and trunk.
Two pairs of limbs.
Tympanum represents ear & eyes have eyelids.
Alimentary canal, urinary and reproductive tracts open
Respiration is by gills, lungs and through skin.
Heart is three chambered (two auricles & one ventricle).
Cold-blooded animals, sexes separate, fertilisation
Oviparous and development is direct or indirect.
Body is covered by cornified dry skin, epidermal scales.
Habitat - mostly terrestrial.
Creeping or crawling mode of locomotion.
Two pairs of limbs and tympanum represents ear.
Three-chambered heart, but four-chambered in
Poikilotherms & sexes are separate.
Snakes and lizards shed their scales as skin cast.
Fertilisation internal, oviparous and development is
Example : Chameleon (Tree lizard), Calotes (Garden
lizard), Crocodilus (Crocodile), Hemidactylus (Wall lizard) Wall lizard
Warm-blooded (homoiothermous) animals.
Forelimbs modified into wings & also possess
feathers used in flight, to regulate temperature
and camouflage purposes.
Hind limbs have scales and modified for
walking, swimming or clasping the tree
Bones are pneumatic (hollow with air cavities).
The digestive tract contains crop and gizzard.
Heart is four chambered.
Respiration through lungs & air sacs.
Sexes are separate; oviparous, fertilisation
internal and development is direct.
Presence mammary glands.
Skin possess hair & homoiothermous.
Two pairs of limbs adapted for walking,
running, climbing, burrowing, swimming
Different types of teeth are present in the
External ears or pinnae present.
Heart four chambered, respiration by
Sexes are separate; viviparous;
fertilisation internal & development is
Monotremes lay eggs & Marsupials are
e.g. Platypus, Dolphin