Spider Silk and Webs

From the March 2012 issue of the Creation Answers newsletter

    People have often wondered at spider silk and spider webs.  The silk is so strong for its weight and spiders just innately know how to make complex webs that serve their purposes very well, though they are unintelligent creatures.  I think it is evidence of an intelligent Creator.  The capabilities of spider silk and the apparently intelligent engineering being discovered in spider silk is amazing scientists today.  Scientists have been studying spider silk at the atomic level.  Also, it is not just biologists doing this research, but others such as mechanical engineers and chemists.

    Spider silk is made up of a combination of different components, some of it soft amorphous materials and some stronger crystaline fibers.  The soft material and strong crystaline material alternate in a particular way that makes the silk strand elastic and yet strong and light.  Spider silk has been described as tougher than steel or kevlar by weight.  How spiders make their silk is largely a mystery, though some chemists in Germany have been making progress in beginning to figure out some of the process.  Apparently the formation of spider silk is a very carefully controlled chemical process where the acidity must be controlled, as well as adding the right about of salt and potassium phosphate in order to control the type of proteins that make up the silk.  

    There are two main types of spider silk, one type is sticky and stretchy and the other is stiff, dry, and strong.  The first type is called viscid silk (sticky) and the other is known as dragline silk (strong).  A spider web will have a combination of both types.  So the dragline silk makes the radially outward fibers that create the overall organized structure of the spider web, and the sticky viscid silk makes it a trap for unfortunate prey.  One of the most amazing things to me was something an engineering team at MIT found.  They found that as you put more stress or force on a spider's silk thread, it has four distinct phases it goes through in its mechanical properties.  This allows it to sort of step up its strength to taylor it to the type of stress on it.  It was described this way in an article on Sciencedaily.com: "When a filament is pulled, the silk's unique molecular structure--a combination of amorphous proteins and ordered, nanoscale crystals--unfurls as stress increases, leading to a stretching effect that has four distinct phases: an initial, linear tugging; a drawn out stretching as the proteins unfold; a stiffening phase that absorbs the greatest amount of force; and then a final, stick-slip phase before the silk breaks (quote from sciencedaily.com website; click here to go to this)."  

    The MIT engineers were also impressed by how a spider web breaks.  When it breaks, it doesn't usually break in a way that makes the whole web fail.  The break is always confined to a limited region of the web, so even if one part fails the rest of the web will still function.  One other really surprising fact comes from researchers at Iowa State University.  A mechanical engineering professor and his team found that spider silk conducts heat more than aluminum, silicon, or even copper!  This is astonishing for an organic material.  Also, when the silk is stretched, its heat conduction increases, which is very unusual.  This could have interesting applications for the benefit of people.

    Does all this sound like something that came about by random mutations?  There is clearly engineering principles at work in spider webs.  Enough to teach MIT engineers. The engineering specifications of spider webs represents information that evolution does not explain.  I think we should thank God for the many clever things he made that give us tangible examples of his wisdom.  Engineers and medical researchers are getting ideas for very useful applications of spider web science.


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