Question

Assertion: amphibians are warm blooded animals.
Reason : Amphibians never undergo summer sleep.
A. Both assertion and reason are correct and reason is the correct explanation for assertion.
B. Both assertion and reason are correct but reason is not the correct explanation for assertion.
C. Assertion is correct but reason is incorrect.
D. Both assertion and reason are incorrect

Answer 1

Hint:-Class Amphibia belongs to the superclass Tetrapoda under phylum Chordata. The class Amphibia includes frog salamanders, toads and caecilians. Amphibians are on the borderline between Terrestrial and aquatic modes of life. The name amphibia indicates that they live partly on water and partly on land. Amphibians were the first vertebrates to colonize the land. They are capable of Aquatic as well as aerial respiration.

Complete step-by-step solution:-
● Amphibians are poikilothermic vertebrates or cold-blooded vertebrates. Cold-blooded or poikilothermic means that these animals cannot control their body temperature and the body temperature varies with the environment and atmospheric temperature.
● Warm-blooded animals or homeotherms like birds and mammals can control and maintain their body temperature. As amphibians are cold-blooded vertebrates and cannot control their body temperature they undergo a period of dormancy when extreme climatic conditions arise.
● The summer dormancy or summer sleep is called aestivation. It is a dormant period to escape from the extreme heat and drought conditions. Many amphibians undergo aestivation or summer sleep.
● During aestivation, metabolic activities decrease very much. This decrease in metabolic activities decreases the need for food and water also decreases and thereby the organisms can survive the extreme climatic condition of heat and drought.
● Most animals bury themselves in the ground which protects them from the heat and wait for the colder temperatures to arise to come from the ground. Frogs usually tend to go to the deepest part of the Ponds or water bodies to protect themselves from the direct sun and extreme heat.
● Among amphibians, frogs, toads and salamanders usually undergo summer sleep. Some examples of such organisms are cane toad, greater siren, California red-legged frog, etc.
● Amphibians can also make a cocoon of dried mucus for summer sleep. Some desert frogs also shed their epidermal layers. Cocoons usually cover the entire body except the nostrils to prevent the epidermal loss of water. An example of an amphibian that makes a cocoon for aestivation is Cyclorana cultripes.
As Both assertion and reason are incorrect, option (D) is the correct answer.

Note:- Similar to the summer sleep or aestivation the dormancy period during the winter season is called winter sleep or hibernation. Amphibians not only aestivate but also undergo hibernation. Amphibians hibernate because they have no way to keep themselves warm during the winter season especially because they have got slime and wet skin. When the weather gets cold they move down to the bottom of lakes and ponds and some even borrow into the mud as like in summer sleep.