It is necessary in mammals and birds to separate oxygenated and de-oxygenated blood because this makes their circulatory system is more efficient and helps in maintaining constant body temperature.

Mammals and birds are warm blooded animals which require a lot of energy to maintain their body temperature.

So it is efficient to separate Oxygenated and De-oxygenated blood so that more oxygen is available to meet the energy requirement.

I hope it's helpful for us......

Importance of Separating Oxygenated and Deoxygenated Blood in Mammals and Birds
In mammals and birds, it is crucial to separate oxygenated and deoxygenated blood to ensure efficient transport of oxygen throughout the body. This separation is achieved through the presence of a double circulatory system, consisting of pulmonary circulation for oxygenation and systemic circulation for distribution.

Optimal Oxygenation
- Separating oxygenated and deoxygenated blood allows for optimal oxygenation of tissues and organs.
- Oxygen-rich blood is pumped from the lungs (or respiratory organs) to the rest of the body, providing essential oxygen for cellular respiration and energy production.

Prevention of Mixing
- The separation of oxygenated and deoxygenated blood helps prevent the mixing of the two types of blood.
- Mixing would result in decreased oxygen delivery to tissues and organs, leading to inadequate oxygen supply and potential cell damage.

Efficient Transport
- By keeping oxygenated and deoxygenated blood separate, the circulatory system can efficiently transport oxygen to where it is needed most.
- Oxygenated blood travels through arteries to reach tissues, while deoxygenated blood returns to the heart and lungs for reoxygenation.

Maximizing Oxygen Exchange
- The separation of blood allows for maximized oxygen exchange in specialized respiratory organs (such as lungs in mammals and air sacs in birds).
- This ensures that oxygen is efficiently loaded onto hemoglobin in the lungs and delivered to tissues during systemic circulation.
In conclusion, the separation of oxygenated and deoxygenated blood in mammals and birds is essential for maintaining optimal oxygen delivery, preventing mixing, ensuring efficient transport, and maximizing oxygen exchange. This organized system is vital for sustaining life and supporting the metabolic needs of complex organisms.