My high school biology class looked in detail at a stinging nettle, which uses a toxic irritant as a defense against being eaten. The surface is covered with small spines, and anything brushing against these spines can be injected with the irritant. It's a wonderful defense strategy for a plant, which cannot move to evade attack, and the details fascinated me enough that I remember them over a half-century later.
Sunday, June 24, 2018
Design In Nature
written 16 June 2018
published 23 June 2018
Each spine is made of a brittle crystalline material, hollow up the center, but closed with an off-center knob at the tip. When an animal presses against the tip of the spine, the knob shears off, leaving a surgically sharp point, which can penetrate the animal's skin. The pressure that shears the tip also compresses the spine into the body of the plant, pressurizing a flexible sack of toxic juice at the base of the spine. When the tip shears, and injects the animal, the pressurized toxin races up the hollow spine into the body of the animal. This irritating chemical is what gives the nettle a sting.
The simplicity of the design, and the elegance of the features, all working with minimum effort, using the force of the predator to power the defensive reaction, left me in awe. I had been building things for years at that age, and could appreciate good design and craftsmanship. That a plant could execute such a design gave me pause to consider the wonder of natural design. The relatively recent field of bio-mimicry examines biological systems for inspiration in technological advances.
The idea of design intention in nature is contrary to materialist science, which postulates a world of dead matter, evolving through meaningless accidental mutations. At the other extreme, Intelligent Design, an anti-evolution variation of Creationism, is based on a literal interpretation of the Bible and assumes God created everything in the relatively recent past. Both seem inadequate.
An example of ongoing evolution is insects developing resistance to the insecticides used to control them. In addition to becoming resistant, one species of grasshopper placed a metabolized variation of the insecticide into the foam it builds around its egg case, creating a toxic barrier against predation by other insects. Materialist science would say that many grasshoppers died before a random mutation induced resistance, but this doesn't explain how a simple insect seemed to be aware of the function of the toxic material, and applied it for its own benefit.
In a previous article, I talked about the concept of randomness, which implies a lack of pattern, or meaning, in a process. The only accurate statement an observer can make is that there "appears" to be no pattern, rather than the system "has" no pattern. Darwinian evolutionary theory declares that evolution is random, without purpose, so the proposal that there is meaning in evolution is a challenge, but there are rigorous, peer reviewed experiments that support this challenge.
In the late 80s, a team of researchers, led by the British biologist John Cairn, experimented on bacteria that lived only on lactose. They disabled the gene that fabricated the enzyme which metabolized lactose, fundamental to cell function. They put these disabled bacteria in a lactose environment, to see what would happen. Classic mechanistic biology suggests that evolution can come only from mutation during cell division, but cell division takes energy. The disabled bacteria couldn't access any of the energy in their surroundings, so they should have died, but the experimenters found thriving colonies of cells. Further investigation showed there had been a specific repair to the disabled gene for lactose metabolism.
Cairns submitted these results to the British science journal Nature, which was reluctant to publish such a revolutionary result, but Cairns was a respected biologist in England, and the article was published. The US journal Science wrote scathing reviews, calling it a step backward for science. Subsequent replication of the experiment by other researchers confirmed the results, and biological theory had to evolve. Even at the single cell level, meaningful evolution takes place. There is immanent, purposeful intelligence in nature.