Can Evolution Explain the Appearance of Design in Biology?
by J Warner Wallace
The “appearance of design” in biological organisms is rather uncontroversial, even amongst atheists who reject the existence of a Designer. Richard Dawkins would be the first to agree: “Biology is the study of complicated things that give the appearance of having been designed for a purpose.” Many other scientists affirm this observation and extend it to include the larger ecosystems in which many symbiotic organisms are dependent on one another for their survival. Smith College professor of biological sciences, Robert Dorit says, “The apparent fit between organisms seems to suggest some higher intelligence at work, some supervisory gardener bringing harmony and color to the garden.” For scientists looking for an explanation within the “garden” to avoid the inference of an external “supervisory gardener,” this appearance of design is difficult to explain.
One cellular micro-machine remains the iconic “poster child” for an external intelligent cause related to the design we observe in molecular organisms. Some bacteria swim by rotating a long filament in a whip-like fashion. This spinning motor assembly is called a flagellum. Bacterial flagella are incredibly difficult to explain for scientists who recognize them as a marvel of machine-like precision. Harvard biophysicist Howard Berg has publicly described the bacterial flagellum as “the most efficient machine in the universe.”
In an effort to nullify the powerful design inference from the irreducible complexity of the flagellum, some have offered a “short cut” of sorts. Philosopher Robert T. Pennock believes the complex flagellum can be formed through an evolutionary process whereby a less complex micro-machine is borrowed from within the cell and used to build something new. Some scientists have suggested Type III secretion systems (T3SS) as a perfect example of one of these borrowed micro-machines. T3SS are needle-like sensory probes used by bacteria. They detect the presence of organisms the bacteria can infect and secrete proteins to aid the infection process. T3SS share many common proteins and are constructed similarly to bacterial flagella.
Scientists sometimes offer these T3SS in an effort to explain how evolutionary processes could jump the divide from a single protein to the complexity of flagellum. By borrowing the T3SS, flagella have a significant head start in their construction. This approach is problematic, however…
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