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.
2. 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.
3. Identify two anatomical features shared by gills, lungs, and tracheoles. Then, identify one feature that is unique to each.