Phylum Chordata

Akanksha Soni, Academic Content Writer at Edumarz

Phylum Chordata:-

S.No. Chordata	Non-Chordata
1 Chordata have notochord.	Absent.
2 Central nervous system is dorsal, hollow, and single.	The ventral, solid, and double central nervous system.
3 Pharyngeal gill slits are present.	Pharyngeal gill slits are absent.
4 Chordata heart is ventral.	Non-Chordata heart is dorsal. ( If present )
5 Post anal tail is present.	Absent.

Subphylum of Chordata

Division

Class- Cyclostamata

Superclass

Class Class

3. Mammalia

4. Aves

Fig:- Diagrammatic representation of Division of Chordata

The notochord extends from the head to the tail region and remains constant throughout their lives.
They are marine animals.
Example:- Branchiostoma (Amphioxus or Lancelet).

During the embryonic stage, the notochord is present. A bony or cartilaginous vertebral column replaces the notochord. Vertebrates have two, three, or four chambers in their ventral muscular heart.
Vertebrates have kidneys for excretion and osmoregulation, as well as paired appendages like fins or limbs.

Class- Cyclostomata:-

It is ectoparasites on fishes.
Cyclostamata have an elongated body with 6-15 pairs of gill slits for breathing.
Cyclostomes have a circular sucking mouth with no jaws.
Cyclostomata lacks scales and paired fins on its body.
The cranium and vertebral columns are cartilaginous.
Cyclostomata have a closed circulation system.
Cyclostomes are marine creatures that migrate to freshwater to spawn. They die within a few days of spawning. After metamorphosis, their larvae return to the ocean.

Superclass Pisces:-

Chondrichthyes are marine animals with a streamlined bodies and have a cartilaginous endoskeleton.
The mouth is ventrally located.
Notochord persists throughout life.
Gill slits are separated and without operculum.
Chondrichthyes are predaceous.
The heart is two-chambered.
Chondrichthyes’ skin is tough and covered in minute placoid scales. Jaws have teeth that have been modified into placoid scales.
Some of them have electric organs for example Torpedo.
Some of them have poison stings for example Trygon.
They are poikilothermous.
Sexes are separate. In males pelvic fins bear claspers.
Internal fertilization takes place.
Viviparous in nature.
Example of Chondrichthyes is Scoliodon (Dogfish), Pristis (Sawfish), Carcharodon (Great white shark), Trygon (Stingray).

It includes both fresh and marine water fish.
Bony Endoskeleton.
The operculum covers four pairs of gill slits.
Osteichthyes skin is covered with cycloid or ctenoid scales.
The presence of an air bladder, which regulates buoyancy.
The heart is two-chambered which one auricle and one ventricle.
They are cold-blooded animals are known as poikilothermous.
Sexes are separate or dioecious.
Fertilization is external takes place.
Oviparous animals.
Development is direct takes place.
Example of Osteichthyes:- Marine – Exocoetus (Flying fish), Hippocampus (Sea horse)

Example of Freshwater of osteichthyes is Rohu, Catla, Fighting fish etc.

Superclass Tetrapoda:-

They can be found in both aquatic and terrestrial environments.
They have two pairs of limbs.
The body is segmented into the trunk and head.
Skin moist and without scales.
The tympanum represents the ear.
Cloaca is a common chambered of the alimentary canal, urinary tract, and reproductive tract, which open into the oustside.
Amphibian heart is three-chambered .
Respiration through the gills, lungs, and skin.
These are poikilothermous animals.
Dioecious.
Fertilization is external takes place.
They
Amphibians are oviparous and development is direct or indirect.
Toad, Rana (Frog), Hyla (Tree frog), Salamandra (Salamander), Ichthyophis (Limbless amphibia) is example of Amphibia.

Fig:- Class Amphibia (Frog)

Creeping or crawling mode of locomotion.
Reptiles are mostly terrestrial animals with dry and cornified skin, epidermal scales, or scutes covering their bodies.
Trypanum represents the ear.
Limbs when present two pairs.
The heart is usually three-chambered but crocodiles have four-chambered.
They are poikilotherms.

As skin cast, snakes and lizards shed their scales.
Sexes are separate.
Fertilisation is internal.
They are oviparous.
Development is direct.
It is an examples of reptiles, Chelone (Turtle), Testudo (Tortoise), Chameleon (Tree lizard), Calotes (Garden lizard), Crocodilus (Crocodile), Alligator (Alligator). Reptilia also includes poisonous snakes such as Naja (Cobra), Bangarus (Krait), and Vipera (Viper).

Fig:- Calss Reptilia (Cobra)

The presence of feathers distinguishes Aves (birds), and most of them can fly, but the exception of flightless birds, are Ostrich.
They have a beak.
Forelimbs are modified into wings.
The hind limbs are scaled and modified for walking, swimming, or grasping tree branches.
Oil glands present at the base of the tail.
The endoskeleton is fully ossified (bony), and the long bones are hollow and filled with air cavities (pneumatic).
The crop and gizzard are additional chambers in the digestive tract of birds.
The heart is completely four-chambered.
They are homoiothermic animals.
Respiration takes place in the lungs.
Sexes are separate.
Fertilisation is internal.
They are oviparous and development is direct.
Corvus (Crow), Columba (Pigeon), Psittacula (Parrot), Struthio (Ostrich), Pavo (Peacock), Aptenodytes (Penguin), Neophron (Vulture), etc is exaples of aves.

Fig:- Class Aves (Pigeon)

The presence of milk-producing glands (mammary glands) that nourish the young is the most distinctive mammalian feature.
They have two pairs of limbs, allowing them to walk, run, climb, burrow, swim, and fly.
The skin has hairs.
External ear or pinnae are present.
In the jaw, there are various types of teeth.
The heart is four-chambered.
They are warm-blooded animals.
Respiration takes place in the lungs.
Sexes are separate.
Internal fertilization takes place.
Viviparous or oviparous.
Development is direct.
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) is examples of mammlia.