Describe the adaptations of blood in terrestrial animals living in the following environmental conditions

• Extreme oxygen tensions (08 marks)

Extremes of oxygen tension can the very high or very low values of oxygen partial pressure. In all these conditions, the blood of terrestrial animals must be adapted to deliver adequate oxygen efficiently to the tissues.

At high oxygen partial pressure,

• The hemoglobin concentration in blood is lower but adequate, since enough oxygen is always available to the mammal.
• The number of red blood cells is also lower.

At low oxygen tensions;

• The volume of blood is higher in order to increase the amount of oxygen carried to the tissues in a unit time.
• The hemoglobin concentration of blood increases. This increases the oxygen carrying of the blood.
• The number of red blood cells increases in order to increase the oxygen carrying capacity of blood.
• The hemoglobin/respiratory pigment has a high affinity for oxygen so as to pick up a lot of oxygen.
• High altitudes (04 marks)

At high altitude the oxygen tension is very low. Thus, the adaptations of blood are the same as those for the mammal at a low oxygen tension.

• The hemoglobin concentration of blood increases. This increases the oxygen carrying capacity of the blood.
• The number of red blood cells increases in order to increase the oxygen carrying capacity of the blood.
• The hemoglobin/respiratory pigment has a high affinity for oxygen so as to pick up a lot of oxygen.