Lynn Margulis, an evolutionary biologist, believes that spirochetes, like T. pall. have contributed to the evolution of eukaryotic cells. In agreement with the theory of endosymbiosis she believes that spirochetes became the cillia and flagella of eukaryotes. One step further, it has also been suggested that spirochetes are the precursors of sensory perception, specifically the rods and cones of the eye and kinocilium of the ear.