Animal Kingdom Chordates

CLASS XI

DR. U.P.PANI

PGT (BIOLOGY)JNV DURG

Characteristics: Worm-like marine animals. Body cylindrical and composed of an

anterior proboscis, a collar and a long trunk.

Bilaterally symmetrical, triploblastic and coelomate.

Organ-system level of organisation. Respiration through gills & open type

circulation.o Excretory organ proboscis gland. o Sexes separate, fertilisation external &

indirect development. e.g. Balanoglossus and Saccoglossus.

PHYLUM HEMICHORDATA

Balanoglossus

1. Presence of a notochord2. A dorsal hollow nerve chord3. Paired pharyngeal gill slits4. Coelomate with organ system level of

organisation5. Post anal tail

PHYLUM CHORDATA

IMPOTANT FEATURES OF A CHORDATA :

PROTOCHORDATES: Subphylum Urochordata and Cephalochordata are called Protochordates.

Phylum Chordata 1. Subphyla Urochordata

or Tunicata2. Subphyla

Cephalochordata

3. Subphyla Vertebrata

Notochord is present only in larval tail.

Eg. Ascidia.

Notochord extends from head to tail region and persistent throughout their life.

Eg. Branchiostoma (Amphioxus)

UROCHODATA CEPHALOCHORDATA

PROTOCHORDATES

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 not vertebrates.

SUBPHYLUM VERTEBRATA

CLASSES OF VERTEBRATA

1. Cylostomata

2. Chondrichthyes

3. Osteichthyes

4. Amphibia

5. Reptilia

6. Aves

7. Mammalia

Characteristics: 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 respiration. Cranium and vertebral column cartilaginous. Circulation closed type. Marine but migrate to fresh water for

spawning & larva after metamorphosis return to oceane.g. Petromyzon (Lamprey), Myxine (Hagfish)

CYCLOSTOMATA

Characteristics: 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 chambers.Sexes separate, internal fertilisation, many of them are viviparous.Torpedo possess electric organs & Trygon have poison sting

CHONDRICHTHYES

Both marine & fresh water fishes with bony endoskeleton.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.

OSTEICHTHYES

AMPHIBIA

Characteristics:Habitats - Aquatic as well as terrestrial.Frogs have smooth, moist skin; Toads have rough, dry skin.Body divisible into head and trunk.Two pairs of limbs. Tympanum represents ear & eyes have eyelids. Alimentary canal, urinary and reproductive tracts open into cloaca.Respiration is by gills, lungs and through skin. Heart is three chambered (two auricles & one ventricle). Cold-blooded animals, sexes separate, fertilisation external. Oviparous and development is direct or indirect.

Toad

Characteristics: 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 crocodiles. Poikilotherms & sexes are separate. Snakes and lizards shed their scales as skin cast. Fertilisation internal, oviparous and development is direct.Example : Chameleon (Tree lizard), Calotes (Garden lizard), Crocodilus (Crocodile), Hemidactylus (Wall lizard)

REPTILIA

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 branches.

Possess beak. 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.

BIRDS

Indian Sparrow

Presence mammary glands. Skin possess hair & homoiothermous. Two pairs of limbs adapted for walking,

running, climbing, burrowing, swimming or flying.

Different types of teeth are present in the jaw.

External ears or pinnae present. Heart four chambered, respiration by

lungs. Sexes are separate; viviparous;

fertilisation internal & development is direct.

Monotremes lay eggs & Marsupials are pouched mammals.

e.g. Platypus, Dolphin

MAMMALS

Delphinus (Dolphin)