[Campbell Biology P.945] For a large animal, what significant challenge would a perfectly sp... | Practice Question

For a large animal, what significant challenge would a perfectly spherical body shape pose regarding its exchange with the environment, assuming its internal volume scales with radius cubed R^3 and its surface area scales with radius squared R^2 ?

  • A: Difficulty in movement due to lack of specialized limbs.
  • B: Inefficient exchange of materials (e.g., oxygen, nutrients, waste) with the environment due to a low surface area to volume ratio.
  • C: Increased vulnerability to predators because of its shape.
  • D: Challenges in maintaining a constant internal temperature.

Explanation

As an animal's size increases, its volume grows much faster than its surface area. A spherical shape, while maximizing volume for a given surface area, leads to a very low surface area to volume ratio for large sizes. This makes efficient exchange of essential materials like oxygen, nutrients and removal of waste products across the surface very difficult, as there isn't enough surface area relative to the metabolically active volume that requires these exchanges. This is a fundamental challenge for large organisms.