Animal kingdom Chordates

Animal Kingdom Chordates is for class XI CBSE course.

1. Animal Kingdom Chordates CLASS XI DR. U.P.PANI PGT (BIOLOGY) JNV DURG

2. 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. Excretory organ proboscis gland. Sexes separate, fertilisation external & indirect development. e.g. Balanoglossus and Saccoglossus . PHYLUM HEMICHORDATA Balanoglossus

3. Presence of a notochord A dorsal hollow nerve chord Paired pharyngeal gill slits Coelomate with organ system level of organisation Post anal tail PHYLUM CHORDATA IMPOTANT FEATURES OF A CHORDATA :

4. PROTOCHORDATES: Subphylum Urochordata and Cephalochordata are called Protochordates .

5. 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

6. 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

7. 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 ocean e.g . Petromyzon (Lamprey ), Myxine (Hagfish) CYCLOSTOMATA

8. 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

9. 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

10. 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

11. 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

12. 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

13. 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)