Antoni van Leeuwenhoek observed individual living cells for the first time in history in 1674. Two years later, he noted microbes with long, thin appendages protruding from globular cells that seemed to provide locomotion, like “little feet” as they moved in drops of water. He gave credit to God in his writings over these new moving wonders. These appendages are now known as flagella (fig. 1), meaning “little whips” (from Latin).
More than 300 years later, Dr. Michael J. Behe used the flagellum and its nanomotor to introduce the concept of “irreducible complexity”—the idea that a structure is so complex that all its parts must initially be present in a suitably functioning manner. The bacterial flagellum is a perfect example of irreducible complexity because all its parts must be present from the start for it to function at all.
According to Darwinian theory, any component that does not offer an advantage to an organism (i.e., does not function) will be lost or discarded. How such a structure as the bacterial flagellum could have evolved in a gradual, step-by-step process as required by classical Darwinian evolution is an insurmountable problem for evolutionists. How a flagellum operates adds an additional level of complexity to the picture.
In the twenty-first century, we know that bacteria are intricately designed but can cause problems if displaced (e.g., urinary tract infections). In the last couple years, bioengineers have taken advantage of microbe motility and “designed displacement” to deliver drugs to diseased body organs.
Gillen, Alan L., "A New Spin on the Bacterial Flagellum: Its Normal Niche and Displacement" (2022). Faculty Publications and Presentations. 203.