Question

Give general characters of phylum chordata and classify labeo with reasons?

Answer 1

On studying in detail of classification of organisms, a five kingdom classification was given. In which fifth kingdom is Kingdom Animalia. It includes all the multicellular organisms.
The animal kingdom is again divided into two sub-kingdom CHORDATA and NON CHORDATA. And important characters which differentiate these two kingdoms are Notochord, nerve cord, Pharyngeal gill clefts.

Complete answer:
GENERAL CHARACTERS OF PHYLUM CHORDATA:-
Chordates (chorda - string) are characterized by the presence of a rod-like structure called notochord. They conquered all the habitats like land, water and air.
Chordates are better organized and include the most intelligent animal, man.
CHARACTERS:-
1.Notochord: All chordates possess notochord either in embryonic stage or in adult. Notochord is an elastic, solid, ensheathed rod-like structure which develops between the alimentary canal and nervous system.
It is mesodermal in origin and persists throughout the life in primitive chordates and is replaced by vertebral column (backbone) in higher adult chordates while exists in their embryo.
2. Dorsal tubular nervous system: A dorsal tubular or hollow nerve cord is present in the mid dorsal line above the notochord. Its cavity is called neurocoel.
In most chordates the anterior end of the nerve cord gets enlarged to form the brain. The rest of the nerve cord is called the spinal cord.
3. Pharyngeal gill clefts : These are paired perforations found in the pharyngeal wall of all chordates either in embryonic stage or adult stage.In lower aquatic chordates they are found in adults and help in respiration.
In higher chordates they are found only in the embryonic stage. These are formed by outpocketing of the pharyngeal wall and the outpocketing of body walls which merge together to connect the pharyngeal cavity with exterior.
4. Coelom: Coelom is a true enterocoel lined by parietal and visceral peritoneum In chordates it is found as a pericardial cavity around the heart, pleural cavity for lungs and abdominal cavity.
5. Blood vascular system: It is closed type that is; blood flows in well-defined blood vessels in fixed direction.
6. Blood: Blood is red due to presence of hemoglobin in RBC.
7. Heart: Heart is present on the ventral side
8. Kidney: One pair of Kidneys are found as excretory organs in all chordates.
9. Endoskeleton: A living endoskeleton of bones and cartilage is present.
10. Organisation : Chordates are triploblastic, organ-system level of organisation and tube within tube body plan.
11. Tail: Tail is post anal part.
12. Reproduction: The mode of reproduction is sexual. Animals are unisexual.
CLASSIFICATION OF LABEO -
Kingdom- Animalia
Phylum- Chordata
Subphylum- Vertebrata
Class- Actinopterygii
Order- Cypriniformes
Family- Cyprinidae
Genus- Labeo
Species- Labeo rohita
REASONS:-
Labeo is a fish comes under kingdom Animalia because having bilateral symmetrical body, Phylum chordata having notochord, Sub phylum Actinopterygii having ray- fin, Order Cypriniforme
having a number of small bones that connect the swim bladder to the hearing apparatus in the skull.
Genus Labeo of the carp family and freshwater fishes.

Note: Classification of organisms was made by scientist on studying their habitat , organisation of body features and so is the phylum chordata with distinct characters of having notochord,
Coelom, and also labeo , the fresh water fish shows features of chordates so come under the same and classified accordingly.