[Campbell Biology P.62] The text highlights that 'even organisms so different share a commo... | Practice Question

The text highlights that 'even organisms so different share a common architecture for their cilia.' What is the most significant implication of this shared, complex structure across diverse eukaryotic life forms, in the context of biological evolution?

  • A: It demonstrates convergent evolution, where unrelated organisms independently evolve similar structures due to similar environmental pressures.
  • B: It provides strong evidence for divergent evolution from a common ancestral eukaryotic cell that possessed this ciliary architecture.
  • C: It suggests that complex structures like cilia can spontaneously arise multiple times throughout evolutionary history without a shared origin.
  • D: It implies that all eukaryotes with cilia are closely related, regardless of other biological differences.

Explanation

The shared complex architecture of cilia across diverse eukaryotes from single-celled Paramecium to humans is a classic example of homology, which provides strong evidence that these organisms diverged from a common ancestor that already possessed this fundamental structure. This is known as divergent evolution.