| S.No. | Chordates | Non-chordates |
|---|---|---|
| 1. | Notochord present. | Notochord absent. |
| 2. | Central nervous system is dorsal, hollow and single. | Central nervous system is ventral, solid and double. |
| 3. | Pharynx perforated by gill slits. | Gill slits are absent. |
| 4. | Heart is ventral. | Heart is dorsal (if present). |
| 5. | A post-anal part (tail) is present. | Post-anal tail is absent. |
| 6. | Endostyle or thyroid gland present. | Endostyle or thyroid gland absent. |
| 7. | Segmented muscles. | Unsegmented muscles. |
Chordata Characteristics
| Characteristic | Description |
|---|---|
| Phylum | Chordata |
| Basic Features | Notochord, dorsal hollow nerve cord, paired pharyngeal gill slits, bilateral symmetry, triploblastic, coelomate, organ-system level of organisation, post anal tail, closed circulatory system |
| Subphyla | Urochordata (Tunicata), Cephalochordata, Vertebrata |
| Urochordata | Notochord present only in larval tail |
| Cephalochordata | Notochord extends from head to tail region and persists throughout life |
| Vertebrata | Notochord present during embryonic period, replaced by cartilaginous or bony vertebral column in adults |
| Additional Features (Vertebrates) | Ventral muscular heart with two, three, or four chambers, kidneys for excretion and osmoregulation, paired appendages (fins or limbs) |
| Examples | Urochordata – Ascidia, Salpa, Doliolum; Cephalochordata – Branchiostoma (Amphioxus or Lancelet) |
+-------------------+ | Deuterostomes | +-------------------+ | | | | | +--------------+------------------------+ | | | | | Chordata | | | | | | (Possess Notochord) | | | | | +--------------+-----------+----------+ | | | | | | | | | Craniata (Possess Skull) Cephalochordata (e.g., Lancelets) | | | (e.g., Amphioxus) | | | | +--------------+-------------------+-----------------+ | | | | | | | Myxini (Hagfishes) Vertebrata Urochordata (e.g., Tunicates) | | (e.g., Hagfishes) (Possess True Vertebrae) (e.g., Sea squirts) | | | | | | | +-------------------+-----------------+ | | | | +----------------------+---------------+ | | | +-------------------------+-----------+ | | | | | | | | | Agnatha (Jawless Vertebrates) Gnathostomata (Jawed Vertebrates) | | (Includes Hagfishes, Lampreys) | | | +------------------------------------------+-----------+--------------+ | | | | | | | | | | | | | Petromyzontida (e.g., Lampreys) Chondrichthyes Osteichthyes Other Chordates | (e.g., Sharks, Rays) (e.g., Bony Fishes, Lungfishes, Coelacanths) | | | | | Tetrapoda (Four-Legged Vertebrates) | (Includes Amphibians, Reptiles, Birds, Mammals) | | | | +------------------------------------------------------------------------+ | | | Other Deuterostomes | | (e.g., Echinodermata, Hemichordata, Chaetognatha) | | | +------------------------------------------------------------------------+
Cyclostomata Characteristics
| Characteristic | Description |
|---|---|
| Class | Cyclostomata |
| Habitat | Ectoparasites on fishes, marine, migrate to fresh water for spawning |
| Body Structure | Elongated body, 6-15 pairs of gill slits for Respiration, sucking and circular mouth without jaws, devoid of scales and paired fins |
| Skeleton | Cartilaginous cranium and vertebral column |
| Circulation | Closed type |
| Life Cycle | Larvae metamorphose and return to the ocean after spawning |
| Examples | Petromyzon (Lamprey)belongs to Craniate as well asto Vertebrata , on the other hand Myxine (Hagfish) belongs to Craniate but do not belongs to Vertebrata |
Chondrichthyes vs Osteichthyes
| Characteristic | Chondrichthyes | Osteichthyes |
|---|---|---|
| Habitat | Marine | Marine and freshwater |
| Endoskeleton | Cartilaginous | Bony |
| Body Structure | Streamlined | Streamlined |
| Mouth Position | Ventral | Terminal |
| Notochord | Persistent throughout life | Replaced by vertebral column |
| Gill Slits | Separate, without operculum | Covered by operculum |
| Scales | Minute placoid scales | Cycloid/ctenoid scales |
| Teeth | Modified placoid scales, backwardly directed | – |
| Jaws | Powerful | – |
| Feeding Behavior | Predaceous | – |
| Air Bladder | Absent, Due to the absence of air bladder, they have to swim constantly to avoid sinking. | Present for buoyancy regulation |
| Heart | Two-chambered (one auricle and one ventricle) | Two-chambered (one auricle and one ventricle) |
| Special Organs | Some have electric organs (e.g., Torpedo), some possess poison sting (e.g., Trygon) | – |
| Temperature Regulation | Cold-blooded (poikilothermous), i.e., they lack the capacity to regulate their body temperature. | Cold-blooded |
| Sexes | Separate | Separate |
| Claspers | Claspers are specialized organs found in male cartilaginous fish, such as sharks, skates, and rays. They are located on the pelvic fins and are used during mating to grasp onto the female’s body. These structures are modified pelvic fins that have grooves or hooks, allowing the male to hold onto the female securely during copulation. Claspers are essential for successful reproduction in these species, as they ensure proper positioning and transfer of sperm from the male to the female during mating. | – |
| Reproductive Features | Internal fertilization, many viviparous | External fertilization, mostly oviparous |
| Examples | Scoliodon (Dog fish), Pristis (Saw fish), Carcharodon (Great white shark), Trygon (Sting ray) | Marine – Exocoetus (Flying fish), Hippocampus (Sea horse); Freshwater – Labeo (Rohu), Catla (Katla), Clarias (Magur); Aquarium – Betta (Fighting fish), Pterophyllum (Angel fish) |
Amphibia vs Reptilia vs Aves vs Mammalia
| Characteristic | Amphibia | Reptilia | Aves | Mammalia |
|---|---|---|---|---|
| Habitat | Aquatic and terrestrial | Terrestrial | Terrestrial, aerial, aquatic | Various habitats including polar ice caps, deserts, forests, etc. |
| Limbs | Most have two pairs | Two pairs (when present) | Two pairs, forelimbs modified into wings | Two pairs, adapted for various activities |
| Body Structure | Head and trunk, tail may be present | Covered by dry and cornified skin | Feathers present, forelimbs modified into wings | Presence of hair, external ears |
| Skin | Moist, without scales | Dry, covered by epidermal scales or scutes | Dry, without glands except oil gland | Unique in possessing hair |
| Respiration | Gills, lungs, and skin | Lungs | Lungs, supplemented by air sacs | Lungs |
| Heart | Three-chambered | Usually three-chambered, four-chambered in crocodiles | Four-chambered | Four-chambered |
| Temperature Regulation | Cold-blooded | Cold-blooded | Warm-blooded | Warm-blooded |
| Sexes | Separate | Separate | Separate | Separate |
| Fertilisation | External | Internal | Internal | Internal |
| Development | Indirect | Direct | Direct | Direct |
| Examples | Bufo (Toad), Rana (Frog), Hyla (Tree frog), Salamandra (Salamander), Ichthyophis (Limbless amphibian) | Chelone (Turtle), Testudo (Tortoise), Chameleon (Tree lizard), Calotes (Garden lizard), Crocodilus (Crocodile), Alligator (Alligator), Hemidactylus (Wall lizard), Poisonous snakes – Naja (Cobra), Bangarus (Krait), Vipera (Viper) | Corvus (Crow), Columba (Pigeon), Psittacula (Parrot), Struthio (Ostrich), Pavo (Peacock), Aptenodytes (Penguin), Neophron (Vulture) | Oviparous-Ornithorhynchus (Platypus); Viviparous – Macropus (Kangaroo), Pteropus (Flying fox), Camelus (Camel), Macaca (Monkey), Rattus (Rat), Canis (Dog), Felis (Cat), Elephas (Elephant), Equus (Horse), Delphinus (Common dolphin), Balaenoptera (Blue whale), Panthera tigris (Tiger), Panthera leo (Lion) |
Comparison Table: Chondrichthyes vs Osteichthyes vs Amphibia vs Reptilia vs Aves vs Mammalia
| Characteristic | Chondrichthyes | Osteichthyes | Amphibia | Reptilia | Aves | Mammalia |
|---|---|---|---|---|---|---|
| Body Structure | Streamlined body, cartilaginous endoskeleton | Streamlined body, bony endoskeleton | Head and trunk, tail may be present, moist skin | Covered by dry and cornified skin, epidermal scales or scutes | Feathers present, forelimbs modified into wings | Presence of hair, external ears |
| Gill Structure | Separate gill slits, no operculum | Four pairs of gills covered by operculum | Gills, lungs, and skin | Lungs | Lungs, supplemented by air sacs | – |
| Heart Chambers | Two-chambered heart (one auricle, one ventricle) | Two-chambered heart (one auricle, one ventricle) | Three-chambered heart (two auricles, one ventricle) | Usually three-chambered heart, four-chambered in some | Four-chambered heart | Four-chambered heart |
| Temperature Regulation | Cold-blooded | Cold-blooded | Cold-blooded | Cold-blooded | Warm-blooded | Warm-blooded |
| Limb Structure | No paired fins, circular mouth without jaws | Paired fins, terminal mouth | Most have two pairs of limbs | Two pairs of limbs (when present) | Two pairs of limbs, forelimbs modified into wings | Two pairs of limbs, adapted for various activities |
| Fertilisation | Internal | External | External | Internal | Internal | Internal |
| Development | Direct | Direct | Indirect | Direct | Direct | Direct |
| Cloaca | – | – | Alimentary canal, urinary and reproductive tracts open into a common chamber that opens to the exterior | – | – | – |
| Additional Characteristics | – | Air bladder for buoyancy regulation | Eyes have eyelids, tympanum represents the ear | No external ear openings, tympanum represents ear, scales shed | Presence of feathers, beak, hollow bones, crop and gizzard | Found in various habitats, presence of mammary glands, external ears, different types of teeth |
| Examples | Petromyzon (Lamprey), Myxine (Hagfish) | Scoliodon (Dog fish), Pristis (Saw fish), Carcharodon (Great white shark), Trygon (Sting ray) | Bufo (Toad), Rana (Frog), Hyla (Tree frog), Salamandra (Salamander), Ichthyophis (Limbless amphibian) | Chelone (Turtle), Testudo (Tortoise), Chameleon (Tree lizard), Calotes (Garden lizard), Crocodilus (Crocodile), Alligator (Alligator), Hemidactylus (Wall lizard), Naja (Cobra), Bangarus (Krait), Vipera (Viper) | Corvus (Crow), Columba (Pigeon), Psittacula (Parrot), Struthio (Ostrich), Pavo (Peacock), Aptenodytes (Penguin), Neophron (Vulture) | Ornithorhynchus (Platypus), Macropus (Kangaroo), Pteropus (Flying fox), Camelus (Camel), Macaca (Monkey), Rattus (Rat), Canis (Dog), Felis (Cat), Elephas (Elephant), Equus (Horse), Delphinus (Common dolphin), Balaenoptera (Blue whale), Panthera tigris (Tiger), Panthera leo (Lion) |