Question

Double circulation is found in (a) Birds (b) Crocodile (c) Mammals (d) All of these

Short answer

The correct answer is (d) All of these.

Step-by-step solution

Understand Animal Physiology

Firstly, it's important to understand that double circulation generally occurs in organisms with high metabolic rates, which include birds, mammals, as well as reptiles such as crocodiles. Over the course of the evolution, these organisms have developed a more efficient way for circulating blood to supply their tissues with sufficient oxygen.

Evaluate Each Option

Next up, consider each given option. It is known that birds and mammals have double circulation. The heart structure of both these organisms support a full separation of oxygenated and deoxygenated blood, which is a cornerstone of double circulation. Moving to the next option, crocodiles, which are reptiles, also share this characteristic, possessing a four-chambered heart allowing double circulation.

Choose the Correct Answer

Looking at all the options and based on the information processed, it's clear that double circulation is found in birds, mammals, and crocodiles. Therefore, 'All of these' is the correct answer.

Key concepts

Animal Physiology

Animal physiology is the study of how animal bodies function. This includes understanding how organs and systems work together to keep animals alive and healthy. Among these systems, the circulatory system is crucial as it transports nutrients and oxygen to cells and removes waste products.
Double circulation is a fascinating feature of the circulatory system. It means that blood passes through the heart twice during each complete circuit of the body. This feature is primarily seen in animals with a four-chambered heart, like mammals, birds, and even crocodiles.
Understanding this aspect of animal physiology helps to appreciate how these animals have evolved to efficiently supply oxygen to tissues, which supports their active lifestyles.

High Metabolic Rates

Animals with double circulation typically have high metabolic rates. A high metabolic rate means that the body needs a large amount of energy to perform essential functions, including moving, growing, and maintaining body heat. This is especially important for warm-blooded animals like birds and mammals.
Because of their active lifestyles, these animals need more oxygen to support their metabolism.

• Birds, especially those that migrate long distances, require a lot of energy. Their high metabolic rate ensures they maintain energy levels despite rapid and prolonged activity.
• Mammals, including humans, utilize a high metabolic rate to maintain body temperature and energy production necessary for survival.

Double circulation gives these animals an edge by delivering oxygen more efficiently to the body, which in turn supports their high energy demands.

Four-Chambered Heart

The design of a four-chambered heart is one of evolution's efficient solutions for double circulation. It is ingeniously divided into two atria and two ventricles. This structure ensures the complete separation of oxygen-rich and oxygen-poor blood.
In animals with this heart type, such as mammals, birds, and crocodiles, the separation is crucial for maximizing the efficiency of their circulatory systems.
- The atria receive blood; the right atrium from the body (deoxygenated), and the left atrium from the lungs (oxygenated). - Blood then moves into the ventricles; the right ventricle sends deoxygenated blood to the lungs, while the left ventricle pumps oxygenated blood to the rest of the body.
This complex yet highly efficient system supports the significant oxygen demands of animals with high metabolic rates.

Oxygenated and Deoxygenated Blood Separation

One of the key components of double circulation is the complete separation of oxygenated and deoxygenated blood. In simpler animals, these two types of blood sometimes mix, which reduces the efficiency of oxygen transport.
Animals with double circulation benefit from a fully separated bloodstream, thanks to their four-chambered heart structure.

• In the lungs or gills, blood receives oxygen, becoming oxygenated.
• This oxygen-rich blood is then delivered to body tissues efficiently without mixing with deoxygenated blood, which returns from the body to the heart.

Such separation ensures that every part of the body gets the required oxygen to function optimally, which is especially crucial for animals with high energy needs.