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Sunday, June 11, 2017

Unanswered questions wrapped in a spider web

Imagine if you had to build this every time
you got hungry and needed to catch a Big Mac
Walking through the woods with my demon detector, this little fella pictured on the right halted my journey.

Ok, you might be thinking, "What the heck is a demon detector and how do you walk it?"

For now, suffice it to say that my demon detector plays a central role in my next article, The demon lurking in your e-cig.  You really wouldn't want me to spoil the upcoming article by explaining what the demon lurking in your e-cig is and what a demon detector does, now would you?  My couple of faithful readers, however, can probably guess what the heck I'm talking about. 

Now, back to the unanswered questions wrapped in a spider web.

The sunlight shone on this web at the perfect angle to highlight all its intricacies.  You might think dew accentuated the sun's effect, but the picture was taken a couple of hours past noon.  The dew, if there were any that morning, had long since dissipated.  What you're looking at is a web and the glue the spider produces to make the web sticky.  The angle of the sun reflected off the web and drops of glue perfectly.

The sight stopped me in my tracks on my journey with my demon detector.  Usually, I trek through the woods crashing through spider webs woven across the path simply because I don't see them until I've walked into them.  At certain times of the year, I have gotten into a habit of carrying a stick that I wave up and down in front of me to clear the path of these unseen traps that are harmless to you and me, but deadly to other insects.

The intricacy of the web caught my attention first.  What engineering degree from what school did the little fella learn how to build this design? 

Ok, I haven't had that many beers, yet.  Obviously, the little fella didn't go to school to learn how to build an insect trap so he could eat dinner.  He just "knows" how to do it.  So first real question - does the web building abilities of spiders imply knowledge has a genetic basis?  If how to build a web is genetic based, what are the genes encoding this knowledge and how did creatures evolve to start encoding knowledge in the first place?

Yeah, I know what you're thinking.  "Who cares?  Spiders just know how to do it because it's instinctual."

Of course it's instinctual.  That's the definition of "genetic knowledge", I reckon.  Every spider of this species spins the same geometric pattern.  Other species of spiders spin other designs.  The orb spider spins webs three feet across with strands that are more tightly wound.  The writing spider puts a jagged scribble in its web.  Funnel spiders build "white tornado" webs.  Each species is genetically wired to build a web almost identical to every other spider in its species, but the genetic wiring is most definitely different among the species.

Not impressed?  Think of the engineering that must be genetically encoded to get the almost identical webs of each species.  The little fella in this picture had to pick a location where he had at least five points to anchor the web.  Those five points had to be spaced within certain parameters to allow for the shape of the final web that we see.  A mathematician could probably calculate that range of the five points in relation to each other and even calculate the number of probable good locations per cubic foot of forest volume for the little fella to build a web.  A biologist could tell us if the spider only uses five points every time he builds a web or uses more (or less) depending on location without losing the design integrity. 

Fortunately, the spider doesn't need to concern itself with bigger questions this web raises like how does that little body produce so much silk and glue?  Why do insects get stuck in the web, but the spider does not?

Ooops, that last question is answered.  The narrator is a bit of a goofy nerd type, probably high on spider venom or something, but he answers why spiders don't get stuck in their own webs in a quick, fun, and entertaining way.

His answer, however, complicates the idea that knowledge is genetic.  Not only does the spider have to know the proper location, points of anchor, and the geometric design of its final product, but it also has to know which strands to make non-sticky, which ones to make sticky, and where to place the glue.  Look at the picture again.  The sun reveals the web isn't smeared in glue all over.  There are carefully placed droplets on the strands and, yes, strands almost bare of glue, particularly at the center where the spider spends most of its time while it waits for dinner to come to it.

If that's too many questions to ponder at this moment, perhaps it's time to take a wine break or something.  Sip a nice glass of Cabernet and think about all the complexity of genes in that tiny spider that allows it to get dinner.  Then ask yourself, "Why does a spider have all that construction and engineering knowledge in its genes, but we have to spend tens of thousands of dollars each year for four years to learn the same mathematical and engineering principles the spider is born with?"



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Posted by Five Drunk Rednecks

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