AQA A Level Biology

Revision Notes

3.4.7 Animal Adaptations For Their Environment

Animal Adaptations For Their Environment

Different types of haemoglobin

  • Haemoglobin is a quaternary protein
    • It is made up of four globin polypeptides and four haem groups
  • The structure of haem is identical in all types of haemoglobin
  • The globin chains however can differ substantially between species
    • The globin polypeptides determine the precise properties of haemoglobin
  • There are a wide range of haemoglobin types that exist
    • They vary in their oxygen-binding properties
    • They bind to and release oxygen in different conditions
  • Environmental factors can have a major impact on the evolution of haemoglobin within a species

Effects of altitude

  • The partial pressure of oxygen is lower at higher altitudes
  • Species living at high altitudes have haemoglobin that is adapted to these conditions
  • For example, llamas have haemoglobin that binds much more readily to oxygen
  • This is beneficial as it allows them to obtain a sufficient level of oxygen saturation in their blood when the partial pressure of oxygen in the air is low

Foetal haemoglobin

  • The haemoglobin of a developing foetus has different properties to that of adult haemoglobin
    • It is more efficient at absorbing oxygen at lower concentrations
  • This is vital as it allows for a baby to obtain oxygen from its mother’s blood
    • The oxygen concentration in the mother’s blood is much lower than the oxygen concentration of the air inside the lungs
  • After birth, a baby begins to produce adult haemoglobin
    • It is better suited for the uptake of oxygen from air

Exam Tip

You may be shown the oxygen dissociation curves of different types of haemoglobin and asked to explain how they are adapted to the environment the animal is living in.

Remember that the curve furthest to the left represents the haemoglobin with the highest affinity for oxygen.

Author: Lára

Lára graduated from Oxford University in Biological Sciences and has now been a science tutor working in the UK for several years. Lára has a particular interest in the area of infectious disease and epidemiology, and enjoys creating original educational materials that develop confidence and facilitate learning.
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