Phylum Chordata The chordates

Five Chordate Hallmarks Notochord – flexible rodlike structure; extending length of body

Five Chordate Hallmarks Dorsal tubular nerve cord

Five Chordate Hallmarks Pharyngeal pouches and gill slits

Five Chordate Hallmarks Endostyle or thyroid gland – secretes mucous that traps food particles in pharyngeal cavity

Five Chordate Hallmarks Postanal tail – tail extends beyond anus

Sixth Chordate Feature Ventral Heart – heart located ventrally

Higher Classification of Chordata Phylum Chordata Subphylum Urochordata – tunicates, sea squirts Subphylum Cephalachordata – lancelets Subphlum Vertebrata- vertebrates

Urochordate Characteristics Have a notochord and nerve chord during tadpole stage. Adults lack notochord and nerve chord. Most chordate features found in the free living acidian larva Adults sessile filter feeders Also known as Tunicates.

Subphylum Cephalochordata Lancelets

Cephalochordate Characteristics Notochord and nerve cord found along entire length of body, persists throughout life Fish-like in form Includes the lancelets (amphioxus)

Amphioxus

Subphylum Vertebrata The Vertebrates

Vertebrate Characteristics Bony or cartilaginous vertebrae surrounding spinal cord Notochord only in embryonic stages, persisting in some fishes Two superclasses according to presence of jaws

Vertebrate Higher Classification Superclass Agnatha - without jaws - Teeth on tongue - Larvae are different from adult forms. Includes one Class: Cyclostomata Class Cyclostomata Circular mouth( sucking type), no teeth Cartilagenous endoskeleton, ectoparasites Marine, return to fresh water for spawning. After spawning, they die. Larvae return to ocean after metamorphosis. Eg: Lampreys, Hagfish

Division : Gnathostomata Mouth with jaws Includes 2 super- classes: Pisces and Tetrapods Pisces: includes two classes ; viz Chondrychthyes and Osteichthyes

Class Chondrichthyes Shark ( Scoliodon), Pristis ( Saw fish) Cartilagenous, stream-lined,marine Ventral mouth , gills without Operculum 2 chambered heart, electric organs for defense Unisexual, male with claspers Viviparous, internal fertilisation

Class Osteichthyes Eg: Exocoetus( flying fish), Hippocampus ( sea horse)-marine Fresh water- Labeo rohita, Catla catla Mouth : terminal, bony endoskeleton 4 pairs of gill slits with operculum ( can breathe without swimming) Swim bladder present- stays deep without sinking. Oviparous, internal fertilization, direct dev.

Class Amphibia Eg: Bufo ( toad) , Rana ( frog) Tetrapods: with pentadactyl limbs Skin without scales, moist due to mucus glands One opening- cloaca for excretion, urino-genitals 3 chambered heart Ectotherms/poikilotherms Aestivation and hibernation

Class Reptila Dry scales, ecdysis/moulting, autotomy Excretion: kidneys; improper auditory sys Heart: 3 chambered, ectotherms Hibernation, camouflage: defense Brain with 12 pairs of cranial nerves Eg: Turtles, tortoise, alligators, lizards,…

Class Aves Feathers- modified epidermal scales Skin- dry without glands except oil glands Hind-limbs with scales : swim/walk/clasp Bony endoskeleton- air filled Digestive system with crop and gizzard Respiration: lungs Double circulation, 4 chambered heart Warm-blooded,high rate of metabolism

Class Mammalia Mammary glands- modified sweat glands Hair, ear with incus, malleus and stapes 4 chambered heart, endotherms Excretion- kidneys Monotrems/ oviparous: Platypus, Echidna