|Section 1: Design in Nature|
Predation and Defense
|Slugs with stolen stingers. Predation is combined with
defense in a most amazing way by the spurred nudibranch, Eolidoidea, a type of sea slug
which feeds primarily on sea anemones. But anemones are armed with tiny stinging cells
which explode at the slightest touch and plunge a poisoned dart into any intruder. The sea
slug, however, can tear an anemone apart violently, chew it up, swallow and digest it
without either exploding or digesting the stinging cells. And the most fantastic part of
this story is yet to come.
Leading from the sea slug's stomach to small pouches in the fluffy spurs on its sides are very narrow channels lined with moving cilia. The cilia sweep the stinging cells out of the stomach and up the channels to the pouches, where they are arranged and stored for the sea slug's defense. If an unwary fish should nip at a sea slug, it would be stung in the mouth by stinging cells which the hapless sea anemone had prepared for its own hunting and defense.15
Cyanide is good for the millipede. The millipede, Apheloria corrugata, is a very clever chemist. On both sides of each segment of its body where a pair of legs attach, sub-surface glands produce a liquid containing the chemical compound, mandelonitrile. When the millipede is attacked by ants or other enemies, it mixes the mandelonitrile with a catalyst, causing it to decompose to form benzaldehyde, a mild irritant, and hydrogen cyanide gas. Hydrogen cyanide is the deadly poison gas used in the gas chamber to execute criminals. For chemistry enthusiasts the equation for the reaction is as follows:
C6H5-C-CN -- C6H5CHO + HCN
mandelonitrile -- benzaldehyde + hydrogen cyanide
There the millipede sits, happily basking in a cloud of lethal fumes, while his attackers flee in all directions. When the coast is clear he crawls away, for some unknown reason totally unaffected by his own deadly poison.16
The cowboy fungus. An earthy example of intelligent and purposeful design in living creatures is that of the predatory molds. There are many species of soil mold which capture and feed upon the tiny, exceedingly numerous nematode worms which inhabit the soil. Some of these molds grow sticky knobs with which they entrap the worms. But the star predatory mold species is Arthrobotrys dactryloides, which lassos its prey like a cowboy lassos steers. It is only when nematodes are present in the soil that this mold grows tiny loops, each one formed of three cells. When a worm chances to stick its neck into one of the loops, within one-tenth of a second the loop cells swell and the loop clamps shut on the worm, strangling it. The worm is then digested at leisure. The cowboy fungus has struck again!17
The motorized microbe. The most thoroughly studied bacterium is Escherichia coli, E. coli for short. Shaped like a fat sausage about 1/10,000 inch long, this bacterial cell has some half-dozen flagella which protrude from its sides and trail behind. Motion of these flagella propels the bacterium through the fluid medium in which it lives--in our intestinal tract. But don't worry; it is a friendly resident--usually. Until the late 'sixties it was assumed that the flagella wiggled, but the discovery that they rotate initiated a wave of intense scientific study that continues to this day.18 It was found that the flagella, not completely flexible, actually have the form of a corkscrew or helical propeller. Each one is attached to a flexible tubular structure, a kind of universal joint which transmits rotary motion around a corner. This connects to a shaft which passes through a disk fixed in the cell wall which serves as a sleeve bearing and is probably also the stator of the motor. On the inner end of the shaft is the rotor of a constant torque, variable speed, reversible rotary motor! This motor is energized by a flow of positively charged protons, so it is in a sense an electric motor. Adding to this complexity is a sophisticated control system.
Surely evolutionary scientists can explain how this fantastic biological mechanism evolved. But the fact is that they can't. In the final paragraph of a 50-page review article, Dr. Robert Macnab says, "As a final comment, one can only marvel at the intricacy, in a simple bacterium, of the total motor and sensory system which has been the subject of this review and remark that our concept of evolution by selective advantage must surely be an oversimplification. What advantage could derive, for example, from a `preflagellum'(meaning a subset of its components), and yet what is the probability of `simultaneous' development of the organelle at a level where it becomes advantageous?"19 In 1980 Prof. Howard Berg of the California Institute of Technology, when challenged, could offer no evolutionary explanation except to assert, "It can be done." Nor could biology Prof. William Thwaites of San Diego State University explain the origin of the microbe's motors in a phone conversation aired on talk radio in April of 1983.
In the light of this and the other examples of design in biology which have described in this chapter, we assert that one is not the least bit "unscientific" if he believes that bacterial flagella and all of the other basic design features of living organisms are, indeed, what they appear to be, the products of intelligent, purposeful design.