Friday, April 29, 2011

Wonderful Webs

Charlotte made hers terrific, radiant and humble. With grace, she expended enormous amounts of energy to spin stunning webs. E.B. White introduced the wonders of spider webs to a general audience in his 1952 children’s novel, Charlotte’s Web. Charlotte was know for spinning elaborate patterns, presenting her piglet friend Wilbur’s admirable qualities in silky web words to convince farmers to spare this sensational pig from being slaughtered.

Charlotte was some spider. But the tool she used to spread her message—silk—is one of spiders’ most basic and fundamental adaptations. Spinning a web allows them to trap prey, cocoon their young and float far away on its strands.

On May 3 from 7:00 to 8:30pm, the Cambridge Public Library is hosting a session called “Spider Silk: Evolution and 400 Million Years of Spinning, Waiting, Snagging, and Mating.” There, science writer Leslie Brunetta and evolutionary biologist Catherine L. Craig will delve deeper into the mysteries of this fantastic material.

In the meantime, did you know:

that spider silk is only 20 per cent as dense as steel, but both materials have about the same tensile strength?

that if you wrapped one strand of spider silk entirely around the widest part of the Earth’s surface, the whole string would weigh about the same as a feather pillow?

that spider silk maintains its strength at minus 40 degrees, the colder end of the average temperature range at the North Pole?

that these awesome properties come about from spider silk’s structure, which is part crystal (for strength) and part elastic (for stretchiness)?

that spider silk is chock full of Vitamin K, which helps blood to clot, and that covering a wound with spider silk is rumored to help it heal faster?

that the pH of spider silk is around 4, meaning it’s acidic, to protect against bacteria and fungi?

that it’s hard for scientists to harvest spider silk to study it because spiders eat each other if kept in close quarters?

that researchers can now make artificial spider silk by taking the silk-coding gene out of spiders and implanting it in other animals, like goats?

that scientists only know the exact sequence of genes for silk production in 14 species of spider? With around 40,000 species identified so far, what scientists know now is really only the tip of a much larger iceberg.

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