Question

1. Draw a picture predicting how the oxygen-hemoglobin curves measured in Tibetan peoples, whose ancestors have lived at high elevations for thousands of years, should compare to curves from people whose ancestors have lived at sea level for thousands of years.

2. Explain why ventilation in birds is considered much more efficient than the respiratory system of humans and other mammals.

3. Toadfish are fishes that live in stagnant-water habitats with low PO2. Compared with the hemoglobin of many other fish species, toadfish hemoglobin has an extremely high affinity for O2. Is this trait adaptive? Explain your answer.

Answer 1

2) The respiratory system in birds is different from that of other animals and humans.Birds have relatively small lungs and about nine air sacs which play a crucial role in respiration.The air sacs permits an unidirectional flow of air through the bird lungs, which means that the air that is moving through the bird's lungs is largely fresh air and it has got the higher oxygen content.

In contrast to it the air flow in mammals is bidirectional ( Back and forth into and out of the lungs). As a result the air coming to the mammal's lungs is mixed with the old air and this mixed air usually has got less oxygen content.So the ventilation in birds is treated as more efficient than mammal's.