Phylum Chordata
$\displaystyle \small \bullet$ Animals belonging to this phylum are characterized by the presence of Notocord.
$\displaystyle \small \bullet$ They have dorsal hollow nerve cord and paired pharyngeal gill slits.
$\displaystyle \small \bullet$ They are bilaterally symmetrical, triploblastic, coelomate and have organ system of organization.
$\displaystyle \small \bullet$ They posses post anal tail and closed circulatory system.
$\displaystyle \small \bullet$ The Phylum Chordata is divided into three subphyla
i) Urochordata: This subphyla is also known as Tunicata. Notochord is present only in larval tail. The body is covered by tunic made up of tunicin. The organisms are hermaphrodite. Ex. Ascidia, Salpa, Doliolum.
ii) Cephalochordata: The notochord extends from head to tail region and persists throughout the life of an organism. They have sac like pharynx with gill slits. Sexes are separate. Ex. Branchiostoma.
Urochordata and cephalochordate often referred as protochordates and are exclusively marine.
iii) Vertibrata: Notochord is present in the embryonic stage, it gets replaced by Vertebral Column in adults. They have ventral muscular heart with two, three or four chambers. They have paired appendages which may be fins or legs. They have kidney for excretion and osmoregulation. Sub-phylum Vertebrata is further divided into two division Agnatha( lacks jaw) and Gnathostomata ( bears jaw).
Class Cyclostomata (Circular mouthed fishes)
$\displaystyle \small \bullet$ They live as ectoparasites on some fishes.
$\displaystyle \small \bullet$ Body is elongated with 6-15 pairs of gill slits, helps in respiration
$\displaystyle \small \bullet$ Cyclostomes have sucking and circular mouth without jaws.
$\displaystyle \small \bullet$ Scales and paired fins are absent.
$\displaystyle \small \bullet$ They have cartilaginous cranium and vertebral column.
$\displaystyle \small \bullet$ All are marine but migrate to fresh water for spawning and die after spawning.
$\displaystyle \small \bullet$ Larva returns to ocean after metamorphosis.
$\displaystyle \small \bullet$ Ex: Petromyzon (Lampray), Myxine (Hagfish).
Class Chondrichthyes (The Cartilaginous Fish)
$\displaystyle \small \bullet$ They are marine animals with stream lined body.
$\displaystyle \small \bullet$ They have cartilaginous endoskeleton.
$\displaystyle \small \bullet$ Mouth is located ventrally.
$\displaystyle \small \bullet$ Gill slits are separate and without operculum or gill cover.
$\displaystyle \small \bullet$ Skin is tough and has placoid scales; Jaws are very powerful.
$\displaystyle \small \bullet$ Teeth are modified placoid scales and are backwardly directed.
$\displaystyle \small \bullet$ Notocord is persistent throughout life.
$\displaystyle \small \bullet$ These animals are predaceous.
$\displaystyle \small \bullet$ Swim bladders are absent hence they have to swim constantly to avoid sinking.
$\displaystyle \small \bullet$ They are poikilotherms (cold blooded) with two chambered heart.
$\displaystyle \small \bullet$ Sexes are separate; males have claspers on pelvic fins.
$\displaystyle \small \bullet$ Fertilization is internal and many of them are viviparous.
$\displaystyle \small \bullet$ Ex: Tarpedo (Electric ray), Trygon (String ray), Scoliodon(Dog fish), Pristis (Saw fish).
Class Osteichthyes (The bony fish)
$\displaystyle \small \bullet$ They are aquatic includes both marine and fresh water forms.
$\displaystyle \small \bullet$ Body streamlined and have bony endoskeleton.
$\displaystyle \small \bullet$ Mouth is terminal.
$\displaystyle \small \bullet$ Four pairs of gill slits covered by operculum.
$\displaystyle \small \bullet$ Skin is covered by cycloid/ctenoid scales.
$\displaystyle \small \bullet$ Air bladder is present and regulates buoyancy.
$\displaystyle \small \bullet$ Heart is two chambered (one auricle and one ventricle) and are cold blooded animals.
$\displaystyle \small \bullet$ Adult kidneys mesonephric. Excretion is ureotelic.
$\displaystyle \small \bullet$ Sexes are separate.
$\displaystyle \small \bullet$ Usually oviparous, fertilization is external and development is direct.
$\displaystyle \small \bullet$ Ex: Marine- Hippocampus (Sea horse), Exocoetus (Flying fish), Freshwater- Labeo (Rohu), Catla, Clarias (Magur).
Class Amphibia
$\displaystyle \small \bullet$ They can live in aquatic as well as terrestrial habitats.
$\displaystyle \small \bullet$ Body is divisible into head and trunk.
$\displaystyle \small \bullet$ Paired limbs are present. Tail may be present in some.
$\displaystyle \small \bullet$ Skin is moist and devoid of scales.
$\displaystyle \small \bullet$ Endoskeleton mostly bony. Notochord does not persist. Skull with 2 occipital condyles.
$\displaystyle \small \bullet$ Tympanum represents the ear
$\displaystyle \small \bullet$ Respiration by lungs, skin and mouth lining.
$\displaystyle \small \bullet$ Heart is 3–chambered (2 auricles and 1 ventricle). Cold blooded animals.
$\displaystyle \small \bullet$ Cloaca is the common chamber where alimentary canal, urinary and reproductive tracts open.
$\displaystyle \small \bullet$ Kidneys mesonephric. Excretion is ureotelic.
$\displaystyle \small \bullet$ Sexes are separate
$\displaystyle \small \bullet$ Fertilization is external.
$\displaystyle \small \bullet$ They are oviparous and development is indirect.
$\displaystyle \small \bullet$ Ex: Bufo (Toad), Rana (Frog), Ichthyophis (limbless amphibia), Salamandra.
Class Reptilia
$\displaystyle \small \bullet$ They are mostly terrestrial animals.
$\displaystyle \small \bullet$ Creeping or crawl mode of locomotion.
$\displaystyle \small \bullet$ The body is covered by dry and cornified skin, epidermal scales or scutes.
$\displaystyle \small \bullet$ Body bilaterally symmetrical and divisible into 4 regions-head, neck, trunk and tail.
$\displaystyle \small \bullet$ Limbs when present, in 2 pairs, pentadactyle.
$\displaystyle \small \bullet$ External ear opening is absent, tymphanum represents ear.
$\displaystyle \small \bullet$ Respiration by lungs throughout life.
$\displaystyle \small \bullet$ Alimentary canal terminates into a cloacal aperture.
$\displaystyle \small \bullet$ Heart is usually 3–chambered, 4–chambered in crocodiles. Poikilotherms.
$\displaystyle \small \bullet$ Kidney metanephric. Excretion is uricotelic.
$\displaystyle \small \bullet$ Snakes and lizards shed their scales as skin cast.
$\displaystyle \small \bullet$ Sexes are separate; fertilisation is internal.
$\displaystyle \small \bullet$ Oviparous, Development is direct.
$\displaystyle \small \bullet$ Ex: Chelone (Turtle), Testudo (Tortoise), Crocodilus(Crocodile), Naja(Cobra), Chameleon (Tree Lizard).
Class Aves
$\displaystyle \small \bullet$ Characterized by presence of feathers.
$\displaystyle \small \bullet$ Most of them can fly except few flightless birds.
$\displaystyle \small \bullet$ They have beak (modified jaws) without teeth.
$\displaystyle \small \bullet$ Forelimbs are modified into wings. Hind limbs are modified for walking, swimming and clasping the tree branches.
$\displaystyle \small \bullet$ Skin is dry and devoid of glands except the oil or preen gland at the root of tail.
$\displaystyle \small \bullet$ Endoskeleton is bony with air cavities (pneumatic) and hollow bones helps in flight.
$\displaystyle \small \bullet$ Vertebral column short. Centra of vertebrae heterocoelous (saddle-shaped).
$\displaystyle \small \bullet$ Additional chamber is present in digestive tract called Crop or Gizzard.
$\displaystyle \small \bullet$ Heart is four chambered. Warm blooded (Homoiothermous)animals.
$\displaystyle \small \bullet$ Respiration is by lungs. Air sacs connected to lungs supplement respiration.
$\displaystyle \small \bullet$ Kidneys metanephric and 3–lobed.
$\displaystyle \small \bullet$ Sexes are separate, fertilization internal.
$\displaystyle \small \bullet$ Oviparous, direct development.
$\displaystyle \small \bullet$ Ex: Corvus(Crow), Columba(Pigeon), Psittacula(Parrot), Aptenodytes (Penguin), Struthio (Ostrich), Pavo (Peacock), Neophron (Vulture).
Class Mammalia
$\displaystyle \small \bullet$ Most of them are terrestrial. Adopted for variety of habitats like polar ice caps, deserts, forests, dark caves etc.
$\displaystyle \small \bullet$ Presence of mammary gland to nourish young ones is the unique characteristic.
$\displaystyle \small \bullet$ Pair of limbs are present adopted for walking, running, climbing, swimming etc.
$\displaystyle \small \bullet$ Presence of hairs on skin is another unique character.
$\displaystyle \small \bullet$ External ear or pinnae present.
$\displaystyle \small \bullet$ Skin richly glandular containing sweat, sebaceous (oil) and sometimes scent glands.
$\displaystyle \small \bullet$ Teeth are of several types (heterodont), borne is sockets (thecodont) and represented by two sets (diphyodont).
$\displaystyle \small \bullet$ Respiration by lungs (pulmonary).
$\displaystyle \small \bullet$ Heart 4-chambered with double circulation. Homoiothermous.
$\displaystyle \small \bullet$ Kidneys metanephric.
$\displaystyle \small \bullet$ Sexes are separate, fertilization internal
$\displaystyle \small \bullet$ Viviparous( few exceptions). Direct development.
$\displaystyle \small \bullet$ Ex: Equus(Horse), Canis(Dog), Elephas(Elephant), Ornithorhynchus (Platypus), Balaenoptera(Blue whale), Marcopus (Kangaroo), Pteropus (Flying fox).
$\displaystyle \small \bullet$ Animals belonging to this phylum are characterized by the presence of Notocord.
$\displaystyle \small \bullet$ They have dorsal hollow nerve cord and paired pharyngeal gill slits.
$\displaystyle \small \bullet$ They are bilaterally symmetrical, triploblastic, coelomate and have organ system of organization.
$\displaystyle \small \bullet$ They posses post anal tail and closed circulatory system.
| Chordates | Non-chordates |
|---|---|
| Notochord present. | Notochord absent. |
| Central nervous system is dorsal, hollow and single. | Central nervous system is ventral, solid and double. |
| Pharynx perforated by gill slits. | Gill slits are absent. |
| Heart is ventral. | Heart is dorsal (if present). |
| A post-anal part (tail) is present. | Post-anal tail is absent |
$\displaystyle \small \bullet$ The Phylum Chordata is divided into three subphyla
i) Urochordata: This subphyla is also known as Tunicata. Notochord is present only in larval tail. The body is covered by tunic made up of tunicin. The organisms are hermaphrodite. Ex. Ascidia, Salpa, Doliolum.
ii) Cephalochordata: The notochord extends from head to tail region and persists throughout the life of an organism. They have sac like pharynx with gill slits. Sexes are separate. Ex. Branchiostoma.
Urochordata and cephalochordate often referred as protochordates and are exclusively marine.
iii) Vertibrata: Notochord is present in the embryonic stage, it gets replaced by Vertebral Column in adults. They have ventral muscular heart with two, three or four chambers. They have paired appendages which may be fins or legs. They have kidney for excretion and osmoregulation. Sub-phylum Vertebrata is further divided into two division Agnatha( lacks jaw) and Gnathostomata ( bears jaw).
Class Cyclostomata (Circular mouthed fishes)
$\displaystyle \small \bullet$ They live as ectoparasites on some fishes.
$\displaystyle \small \bullet$ Body is elongated with 6-15 pairs of gill slits, helps in respiration
$\displaystyle \small \bullet$ Cyclostomes have sucking and circular mouth without jaws.
$\displaystyle \small \bullet$ Scales and paired fins are absent.
$\displaystyle \small \bullet$ They have cartilaginous cranium and vertebral column.
$\displaystyle \small \bullet$ All are marine but migrate to fresh water for spawning and die after spawning.
$\displaystyle \small \bullet$ Larva returns to ocean after metamorphosis.
$\displaystyle \small \bullet$ Ex: Petromyzon (Lampray), Myxine (Hagfish).
$\displaystyle \small \bullet$ They are marine animals with stream lined body.
$\displaystyle \small \bullet$ They have cartilaginous endoskeleton.
$\displaystyle \small \bullet$ Mouth is located ventrally.
$\displaystyle \small \bullet$ Gill slits are separate and without operculum or gill cover.
$\displaystyle \small \bullet$ Skin is tough and has placoid scales; Jaws are very powerful.
$\displaystyle \small \bullet$ Teeth are modified placoid scales and are backwardly directed.
$\displaystyle \small \bullet$ Notocord is persistent throughout life.
$\displaystyle \small \bullet$ These animals are predaceous.
$\displaystyle \small \bullet$ Swim bladders are absent hence they have to swim constantly to avoid sinking.
$\displaystyle \small \bullet$ They are poikilotherms (cold blooded) with two chambered heart.
$\displaystyle \small \bullet$ Sexes are separate; males have claspers on pelvic fins.
$\displaystyle \small \bullet$ Fertilization is internal and many of them are viviparous.
$\displaystyle \small \bullet$ Ex: Tarpedo (Electric ray), Trygon (String ray), Scoliodon(Dog fish), Pristis (Saw fish).
$\displaystyle \small \bullet$ They are aquatic includes both marine and fresh water forms.
$\displaystyle \small \bullet$ Body streamlined and have bony endoskeleton.
$\displaystyle \small \bullet$ Mouth is terminal.
$\displaystyle \small \bullet$ Four pairs of gill slits covered by operculum.
$\displaystyle \small \bullet$ Skin is covered by cycloid/ctenoid scales.
$\displaystyle \small \bullet$ Air bladder is present and regulates buoyancy.
$\displaystyle \small \bullet$ Heart is two chambered (one auricle and one ventricle) and are cold blooded animals.
$\displaystyle \small \bullet$ Adult kidneys mesonephric. Excretion is ureotelic.
$\displaystyle \small \bullet$ Sexes are separate.
$\displaystyle \small \bullet$ Usually oviparous, fertilization is external and development is direct.
$\displaystyle \small \bullet$ Ex: Marine- Hippocampus (Sea horse), Exocoetus (Flying fish), Freshwater- Labeo (Rohu), Catla, Clarias (Magur).
$\displaystyle \small \bullet$ They can live in aquatic as well as terrestrial habitats.
$\displaystyle \small \bullet$ Body is divisible into head and trunk.
$\displaystyle \small \bullet$ Paired limbs are present. Tail may be present in some.
$\displaystyle \small \bullet$ Skin is moist and devoid of scales.
$\displaystyle \small \bullet$ Endoskeleton mostly bony. Notochord does not persist. Skull with 2 occipital condyles.
$\displaystyle \small \bullet$ Tympanum represents the ear
$\displaystyle \small \bullet$ Respiration by lungs, skin and mouth lining.
$\displaystyle \small \bullet$ Heart is 3–chambered (2 auricles and 1 ventricle). Cold blooded animals.
$\displaystyle \small \bullet$ Cloaca is the common chamber where alimentary canal, urinary and reproductive tracts open.
$\displaystyle \small \bullet$ Kidneys mesonephric. Excretion is ureotelic.
$\displaystyle \small \bullet$ Sexes are separate
$\displaystyle \small \bullet$ Fertilization is external.
$\displaystyle \small \bullet$ They are oviparous and development is indirect.
$\displaystyle \small \bullet$ Ex: Bufo (Toad), Rana (Frog), Ichthyophis (limbless amphibia), Salamandra.
$\displaystyle \small \bullet$ They are mostly terrestrial animals.
$\displaystyle \small \bullet$ Creeping or crawl mode of locomotion.
$\displaystyle \small \bullet$ The body is covered by dry and cornified skin, epidermal scales or scutes.
$\displaystyle \small \bullet$ Body bilaterally symmetrical and divisible into 4 regions-head, neck, trunk and tail.
$\displaystyle \small \bullet$ Limbs when present, in 2 pairs, pentadactyle.
$\displaystyle \small \bullet$ External ear opening is absent, tymphanum represents ear.
$\displaystyle \small \bullet$ Respiration by lungs throughout life.
$\displaystyle \small \bullet$ Alimentary canal terminates into a cloacal aperture.
$\displaystyle \small \bullet$ Heart is usually 3–chambered, 4–chambered in crocodiles. Poikilotherms.
$\displaystyle \small \bullet$ Kidney metanephric. Excretion is uricotelic.
$\displaystyle \small \bullet$ Snakes and lizards shed their scales as skin cast.
$\displaystyle \small \bullet$ Sexes are separate; fertilisation is internal.
$\displaystyle \small \bullet$ Oviparous, Development is direct.
$\displaystyle \small \bullet$ Ex: Chelone (Turtle), Testudo (Tortoise), Crocodilus(Crocodile), Naja(Cobra), Chameleon (Tree Lizard).
$\displaystyle \small \bullet$ Characterized by presence of feathers.
$\displaystyle \small \bullet$ Most of them can fly except few flightless birds.
$\displaystyle \small \bullet$ They have beak (modified jaws) without teeth.
$\displaystyle \small \bullet$ Forelimbs are modified into wings. Hind limbs are modified for walking, swimming and clasping the tree branches.
$\displaystyle \small \bullet$ Skin is dry and devoid of glands except the oil or preen gland at the root of tail.
$\displaystyle \small \bullet$ Endoskeleton is bony with air cavities (pneumatic) and hollow bones helps in flight.
$\displaystyle \small \bullet$ Vertebral column short. Centra of vertebrae heterocoelous (saddle-shaped).
$\displaystyle \small \bullet$ Additional chamber is present in digestive tract called Crop or Gizzard.
$\displaystyle \small \bullet$ Heart is four chambered. Warm blooded (Homoiothermous)animals.
$\displaystyle \small \bullet$ Respiration is by lungs. Air sacs connected to lungs supplement respiration.
$\displaystyle \small \bullet$ Kidneys metanephric and 3–lobed.
$\displaystyle \small \bullet$ Sexes are separate, fertilization internal.
$\displaystyle \small \bullet$ Oviparous, direct development.
$\displaystyle \small \bullet$ Ex: Corvus(Crow), Columba(Pigeon), Psittacula(Parrot), Aptenodytes (Penguin), Struthio (Ostrich), Pavo (Peacock), Neophron (Vulture).
$\displaystyle \small \bullet$ Most of them are terrestrial. Adopted for variety of habitats like polar ice caps, deserts, forests, dark caves etc.
$\displaystyle \small \bullet$ Presence of mammary gland to nourish young ones is the unique characteristic.
$\displaystyle \small \bullet$ Pair of limbs are present adopted for walking, running, climbing, swimming etc.
$\displaystyle \small \bullet$ Presence of hairs on skin is another unique character.
$\displaystyle \small \bullet$ External ear or pinnae present.
$\displaystyle \small \bullet$ Skin richly glandular containing sweat, sebaceous (oil) and sometimes scent glands.
$\displaystyle \small \bullet$ Teeth are of several types (heterodont), borne is sockets (thecodont) and represented by two sets (diphyodont).
$\displaystyle \small \bullet$ Respiration by lungs (pulmonary).
$\displaystyle \small \bullet$ Heart 4-chambered with double circulation. Homoiothermous.
$\displaystyle \small \bullet$ Kidneys metanephric.
$\displaystyle \small \bullet$ Sexes are separate, fertilization internal
$\displaystyle \small \bullet$ Viviparous( few exceptions). Direct development.
$\displaystyle \small \bullet$ Ex: Equus(Horse), Canis(Dog), Elephas(Elephant), Ornithorhynchus (Platypus), Balaenoptera(Blue whale), Marcopus (Kangaroo), Pteropus (Flying fox).
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