Spiders Web Biomimicry

Biomimicry – sometimes called biomimetics – is “the examination of nature, its models, systems, processes, and elements to emulate or take inspiration from in order to solve human problems.” Creationists love it, of course, seeing it as confirmation that their Designer is superior to mere human intelligence. Of course, as natural selection has been going for far longer and operates via different mechanisms it would be unsurprising for there to be a few things we could learn from its products – the pointing out of an instance of biomimicry thus is merely a preaching to the choir, and requires other elements to form part of a Creationist Claim. An example of biomimicry being twisted into a CC can be found here, along with a response (of course).

Our latest instance comes from Mr Thomas’ Daily Science Update for Monday the 19th: Scientists Decode Key to Spider Web Strength. The study (and only reference) is Nonlinear material behaviour of spider silk yields robust webs from Nature.

A diagram of the web of the spider Nephila clavipes, which is being focussed on in the paper

Imagine a cloth that gets stronger after it is damaged. That is what scientists recently discovered when probing the strength of garden spider webs.

Mr Thomas needs to read more science fiction: that’s not all that hard to imagine, and we’ll soon see why.

A research team tested the resistance of a spider web’s supporting radial threads and compared that with the thinner spiral threads. They found that placing a certain amount of pressure on just one thread caused it to suddenly stiffen and distribute the stress to the rest of the web.

Of course, too much damage eventually weakened the web, but the initial damage had the opposite effect. After investigators applied even more pressure, the additional stress was not transferred to the whole web, but to tiny protein crystals acting as stress points on the targeted strand. Whether the scientists pushed on a spiral or radial thread, only that strand broke, leaving the whole web intact.

In fact, the whole web strengthened with a few broken strands! The study authors wrote, “The ultimate load capacity increased by 3-10% with the introduction of defects.”

Indeed so.

“Given the presumed metabolic effort required by the spider for rebuilding an entire web, localized failure is preferential as it does not compromise the structural integrity of the web and hence allows it to continue to function for prey capture in spite of the damage,” according their report in the journal Nature.

That would be what is generally called a ‘selective benefit’.

If the entire web broke apart because of stress in one area, like when catching an insect, then the spider would have to constantly recycle and recast a new web. Spiders might not survive the energy cost required by all that work.

But because of the superior engineering in both the material and structural layout, spiders can catch multiple meals with the same web, and the web holds its overall strength even in very strong winds. The study authors called this an “optimized” system, meaning that it could not be improved. And if human engineers copy spider web construction tactics, they must conform to “a design stipulation that requires the consideration of both material and structural architecture.”

I’m not sure that Mr Thomas’ quote there makes sense in the context he gives it – here is the full sentence, along with the one previous to it:

This allows a spider to repair rather than rebuild completely, should failure occur. Such an engineering design could ignore the requirements for the magnitude of a potential load and allow local failure to occur, a design stipulation that requires the consideration of both material behaviour and structural architecture.

This is in the context of a paragraph suggesting “that web design principles might be considered in engineering, where current practice uses sacrificial elements solely to dissipate energy”. Natural selection, following a route leading to this outcome, no more has to ‘consider’ these factors than water ‘considers’ the composition of the stream bed through which it flows.

But that wont stop B.T.:

Did nature optimize spider webs, or was this design feature programmed by the Creator? If making mere copies of spider web structure “requires the consideration” of specific elements, then it stands to reason that the origin of spider web construction also required consideration. Nature is, in fact, mindless and cannot consider anything. Since only a real engineer can consider and construct, the Intelligent Designer—our Creator—is certainly responsible for the garden spider web’s “enhanced mechanical performance.”

No, that does not ‘stand to reason’. Consider, please, the travelling salesman problem:

The task is to find the shortest round trip covering all of the cities - here, via the use of an ant foraging simulation

The task is to find the shortest round-trip route that goes to all of the cities. If for some strange reason you decided to do this manually, you would have to ‘consider’ things like the arrangements of the cities and the distances between them (along with why the hell you decided to do it unaided by machine). But if you set up a genetic algorithm to do if for you – which would take a random path and mutate it and select for the shorter route until it found the shortest – it would not have to consider these things. It would just do it. “Nature is … mindless and cannot consider anything.” It doesn’t have to.

Does Mr Thomas know this? Presumably. But he is certainly counting on his readers to not.

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One thought on “Spiders Web Biomimicry

  1. And yet there are examples where human design far surpasses the natural one. For those of you who can cast your mind back that far, Lego used to create “bionicle” figurines. These had superb joints between the arms/legs and body that offered far greater mobility and security than their natural counterparts (the human glenohumeral joint, for example, is notoriously easily dislocated).

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