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Flagellum's Funny Flailing

One of the "icons" of the Neo-Paleyist "intelligent" design concepts is the bacterial flagellum. Whether or not this concept has been debunked as an "irreducibly complex" mechanism is open to some discussion, but here we look at whether this "icon" of many an ID essay has the markings of "intelligent" design or those of "silly" design.

Flagellum Fun Facts

First lets look at a diagram of this mechanism, drawn to make it look as mechanical as possible:

What happens is that ions cause the base to rotate, the "hook" is fixed (to aim the whip-like end of the flagellum) and the end whips about while it spins, at speeds that can reach many 100 Hertz (revolutions per second), and driving the bacterial cell at several body lengths a second ⁽¹⁾.

An nice animation of this mechanism can be seen at the Access Research Network Molecular Machines Museum website on The Bacterial Flagellum.

Obviously a highly efficient motor design, making maximum usage of the energy expended ... or is it?

Here we have a similar arrangement, the spinning drive mechanism extends down a tube, is turned and then exits the "hook" to turn the drive part of the motor, a small propeller.

We know one of these mechanisms was intentionally designed as a method of locomotion and for maximum efficiency in it's use of energy. Furthermore we know that the elements of this design have been developed over the course of many years of experimentation to select the best gear ratios, material strengths, power ratings and propeller design. Propellers in particular have undergone extreme design for improved efficiency, borrowing from the more prolific design of airplane wings and propellers in the process (such borrowing being an element frequently seen in good design when some other design element already is known to work and work well).

So the question is whether the flagellum design measures up to the known reference intelligent design, or is it just flailing about?

Any Bubba Can Do This Experiment

There is a simple experiment that anyone with ready access to a couple of similar boats with similar engines can do evaluate the question:

• Use one boat as-is: this is the control, the known intelligent design
• On the other remove the propeller and replace it with a 50 foot length of 1" diameter hose, hose clamped tightly to the driveshaft\spindle of the outboard
• Load up the boats with kids (so they can ask "are we there yet?")
• Race. See who gets "out of the hole" first, who tops out first and what their tops speeds are.
• Put in reverse and repeat.
• Match speed and compare engine RPM (revolutions per minute) and fuel consumption.
• If you feel that you need more evidence, try different size hoses and different lengths.
• See if the kids are laughing at the hose or the propeller.

Oh, and if the flagellum design wins? Publish, become a national hero to endangered manatees, broken propellers sufferers, etcetera and put many propeller design companies out of work.

Note: a 25 foot boat traveling at 50 mph is traveling ~3 times its length in a second.

Silliness

Now consider that it would be extremely easy to make the flagellum become a propeller by the intelligent input of design information from other available systems. The flagellum could be easily split into two (or more) filaments that are then flattened and angled apart in a "Y" type pattern, and with one leg bent up and one down and both shortened (less material overall = more efficient design) you have a rudimentary propeller. Add some twist and some shape (such as you find on a penguin wing - used to "fly" underwater) and you have a more efficient design.

We can get an idea of what this simple modification would look like by again referring to known intelligent design, this time to an early propeller design before scientific methods were applied ⁽²⁾:

Except of course that a central spindle is not necessary and could be eliminated. But even these early propellers are silly by today's standards of design ⁽³⁾.

The hose on the other hand can be nothing but a silly way to waste gas and amuse kids.

This mechanism displays an excessively high Silliness Index (SI).

Enjoy.

References

1. The bacterial flagella motor. PubMed on-line article from Adv Microb Physiol. 1999;41:291-337.
2. Timetable: Development of the Propeller. On line article.
3. History & Design of Propeller. On line article.

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