Test: Animal kingdom - Chordates (April 15) - NEET MCQ

Leech possesses a ventral central nervous System, Scorpion has a dorsal heart. Pharyngeal gill S|its and post- anal tail are characteristic features of chordates  Chameleon is a chordate, so it possesses pharyngeal gill-slits in embryonic stage. Octopus is a non-chordate.

Mollusca is normally oviparous and its development may be direct or indirect. If development is indirect then a occurs  through trochophore or veliger larva. Echinoder show bilateral symmetry in larvae but pentamerous rafers symmetry in adult. Fertilization is external. In arthropods body is divided into head thorax and abdomen. Respiratory organs consists of book gills, book lungs and tracheae Notochord is present in chordates at some stage of  their lives. Urinary and anal openings, may or may not be separate.

Presence of a muscular diaphragm is an exclusive character of class Mammalia. Diaphragm is a complex muscular partition that separates the thoracic cavity from fix abdominal cavity. It increases the efficiency of breathing.

In Cephalochordata, notochored extends from heaft tail and is persistent throughout their life. In Urochordate notochord is present only in larval stage restricted to.

Lchthyophis (Blind worm) is a limbless amphibian.

Chordates are those animals that have rod-like notochord. Notochord is also present in vertebrates but in most adult vertebrates, the notochord is replaced by vertebral column, which is the peculiar feature of vertebrates. Thus, we can say that all vertebrates are chordates but as chordates are not vertebrates.

Uricotelic animals are those animals that excrete their waste matter in the form of uric acid. Reptiles, birds, lard snals and insects are uricotelic animals.

Animals show four different grades of organization, (i) Protoplasmic grade found in protozoans. (ii) cellular grade is the characteristic of sponges and mesozoans because in a sponge, cells exhibit division of labour for performing specialized functions. (iii) Tissue grade is of two types : Cell-tissue grade is seen in coelenterates as there are cells not only specialized for different functions but also certain similar cells gather together to form tissue as well. Tissue - organ grade appears in flatworms (Platyhelminthes) with arrangement of tissues to form organs, (iv) In organ system level of organisation, organs are joined in a system to perform basic functions. It is found in higher invertebrates and all vertebrates.

Frog (Amphibian) is a cold blooded animal i.e. its body temperature varies with the temperatue of the environment. Pigeon (Aves) is a warm blooded animal i.e. its body temperature remains constant irrespective of the temperature of the environment. Wall lizard (Reptile) possesses dry and cornified skin. Earthworm (Annelid) is a dioecious animal i.e. both male and female sex organs are present in the Single individual.

An animal having characters like triploblastic, bilateral symmetry, coelomate, chitinous exoskeleton, head, thorax, abdomen as body parts, and jointed appendages is placed under 'Arthropoda'.