The prokaryotic flagellum is a complex structure consisting of several dozen different proteins. Which of the following statements best describes the origin of flagella in prokaryotes?
A) Natural selection cannot account for the evolution of the prokaryotic flagellum.
B) Ancestral versions of this protein assemblage were either less functional or had different functions than modern prokaryotic flagella.
C) Flagella could not have arisen by evolution because the structure is too complex to have evolved gradually.
D) The need for more complex structure must have driven evolution.

Question

Quizplus · Accepted Answer

The evolution of the prokaryotic flagellum is best explained by the concept that ancestral versions of the proteins involved were either less functional or served different functions, which gradually evolved into the highly specialized and complex structure seen today. This is consistent with the principle of gradual evolution and natural selection, where simple structures evolve over time into more complex ones as mutations and natural selection act on variations within populations.

The Prokaryotic Flagellum Is a Complex Structure Consisting of Several