The sexual dimorphism is found in
Important Questions on Structural Organisation in Animals
a) Chondrichthyes have gill slits covered by operculum and Osteichthyes have gill slits without operculum
b) Chondrichthyes have a swim bladder and Osteichthyes do not have a swim bladder
c) Chondrichthyes contain placoid scales and Osteichthyes contain cycloid scales
d) Chondrichthyes contain terminal mouth and Osteichthyes contain ventral mouth
Identify the wrongly matched Scientific and common name:
| Scientific name | Common name |
| a) Bungarus | Krait |
| b) Exocoetus | Flying fish |
| c) Trygon | Electric ray |
| d) Carcharodon | Dogfish shark |
| e) Myxine | Hagfish |
Statement Chordates have a tail extending posterior to the anus. It contains skeletal elements and muscles but lacks coelom and visceral organs.
Reason In aquatic organisms, it acts as a balancing organ.
Statement I: Sternum appeared for the first time in amphibians.
Statement II: Snakes have pairs of cranial nerves.
The correct option among the following is
Name the classes of Tetrapoda that exhibit the following characters:
| Column (A) | Column (B) |
| Acrodont | Thecodont |
| pairs cranial nerves | pairs cranial nerves |
| Cold-blooded | Warm-blooded |
| Amphicoelous vertebrae | Amphiplatyan vertebrae |
Match the following
| List - I | List - II | ||
| (a) | Chelonia | (i) | Alligator |
| (b) | Rhynchocephalia | (ii) | Chameleon |
| (c) | Crocodilia | (iii) | Sphenodon |
| (d) | Squamata | (iv) | Testudo |
The correct answer is
Which of the key adaptations helped evolutionary success of Reptiles on land?
A Warm-bloodedness
B. Pulmonary respiration and dry scaly skin
C. Internal fertilisation
D. Amniotic & Cleidoic eggs
Match the following
| List - I | List - II | ||
| (a) | Each half of the lower jaw is formed by 6 bones | (i) | Aves |
| (b) | Lacrimal and Harderian glands appeared for the first time | (ii) | Reptiles |
| (c) | Presence of only right systemic arch | (iii) | Amphibians |
| (d) | Each half of the lower jaw is made of single bone | (iv) | Mammals |
Statement (S) : The amphibian blood is composed of erythrocytes, leucocytes and thrombocytes. The thrombocytes help in haemostasis.
Reason (R): The haemostasis regulates the body temperature in poikilotherms.
Which of the following is true?
Study the following table
| Group | Feature | Example | |
| Cyclostomata | Renal portal system is absent | Branchiostoma | |
| Reptilia | Megalecithal and cleidoic eggs | Tropidonotus | |
| Aves | Corpora quadrigemina | Psittacula | |
| Amphibia | Columella auris in middle ear | Rhacophorus |
Identify the correct combinations
Assertion (A): During pulmonary respiration in frog, buccopharyngeal cavity acts like a force pump.
Reason (R): When the floor of buccopharyigeal cavity is lowered, air forces the glottis to open and reach the lungs.
The correct option among the following is:
