Science 10 Research Project

Fascinating Creatures Spider and Its Silk

Kyle Chou April 21, 2007 Science 10 Project Kwantlen Park Secondary

Table of Contents

Introduction……3 Spider’s Silk……5 Spider’s Web……7 Artificial Spider Silk……10 Bibliography……11

Introduction Spiders are fascinating creatures in the world. They could be found under the ground to the highest mountain Everest, Sahara desert to your house (especially bathroom because they do need water to survive), almost everywhere in the world. Before we talk about spider’s web and silk, you might want to know some common knowledge about this creature. One important thing is: spiders are not insects; they are below the class of Arachnids, with scorpion, mite, and daddy long legs. Most people hate spiders because of their appearance: dark colour, giant (or tiny), hairy, deadly poison…but the fact is, only few of the spiders could cause people damage to death, the rest of them could help us catch mosquitoes, flies, and other harmful insects live our environment. A spider’s anatomy includes 2 body segments: cephalothorax and opisthosoma. Cephalothorax is the segment which includes head and thorax. Another one is opisthosoma, or abdomen, includes its organs and spinnerets. Spinnerets are the movable telescoping finger-shaped organs where produces silks. Spiders have 8 legs with 6 joints

each (total 48 knees). Most spiders can walk on the walls because they have special pads on their feet. Like starfish, if a spider loses a leg (and they often do for escaping), it can grow another leg; this process is regeneration. Like insects, spiders don’t have bones inside but outside; covered its body. As a spider grows, it will shed its whole skin because it’s too tight; they coming out from the back and then climbing out of it. Their foods mainly are insects; few of them eat fish, small lizards, and birds. “A question, how do spiders catch their food?” Some of them catch their meal by fast moving speed, like Wolf Spiders; some of them pouncing from a hole and grab it inside, like Trapdoor Spiders. But mostly, lots of them capture their preys by making a spider web (cobweb), all they have to do after finished the web is just sit there and waiting. That was some basic information about spiders.

Spider’s Silk Spider silk is a strong material. The strength of a spider silk can compare to a high-grade steel and it’s thinner than it (0.003 millimetres in diameter). And the strand of spider silk about less than 460 grams is long enough to circle the earth! It is also ductile, able to stretch up to 40% of its length without breaking. Spider silk is the strongest fibre then any others. The structure of a spider silk is made up of substances called crystalline regions connected by changeable lines called amorphous linkages. A crystalline is made up of beta-sheets; they assembled together. Different types of spiders make different types of silk because they have different protein sequences. But how do spiders produce their silk? They have organs called spinneret at the end of their body, which is where they produce

silk. A spider has 2-8 spinnerets (usually in pairs) depending on what type of spider is. Their thread is released through small bags in their body connected with their spinnerets called silk glands. Many spiders have different for different usages. Usually, spiders use their silks to: •

Make a web to trap preys

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Climbing up, suspend in the air

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Flying by the wind

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Form smooth walls for their home

Nowadays, human also uses spider silk for their own; not only in business, but also in medical (it could repair human ligaments (helps join bones together).)

Spider’s Web The use of a spider web it is not only to catch flying bugs, but also protect spiders from their enemies such as birds and some big insects like wasps. Not all the spiders build webs to catch their preys but most of them do. The most common type of spider webs are orb web and tangle web. Web allows a spider to catch prey without moving around wasting it energy. However, after a time the web will lose its stickiness and become useless and they have to give up this web; find another place to build it; but some of them eat their old webs and turn the old silk into new silk inside their bodies. The reason of why a spider doesn’t get trapped in its web it’s because an oily substance is covered spider’s body, it keeps its leg from sticking to the web. Interesting information: drugs and caffeine could affect the way spiders build their webs. Scientists from the United States National Aeronautics and NASA did an experiment: what will happen if you let spiders take psychotropic drugs,

the drugs affect your mind work. They didn’t tell us how they let those spiders took drugs, but it did have an effect on the structure of spider webs: it became less structured and less beautiful.

Pictures from: http://www.trinity.edu/jdunn/spiderdrugs.htm Watch a short movie: Spider on Drugs http://www.youtube.com/watch?v=sHzdsFiBbFc There is a spider named Nephila which lives in very hot countries. Their web made from its silk is so strong that the people collect their webs and use the as fishing nets. And if you got cut, you can round clean spider webs on it to stop bleeding.

Artificial Spider Silk Before the biotechnology invented, some fisherman in the indo-pacific ocean already know how to used spider webs to catch small fishes. However, it was too difficult to build a great amount of spider silk to use and it was extremely expensive. In 2000, a Canada biotechnology company, Nexia, tried to producing artificial spider silk protein in transgenic (animals or plants contain genetic material) goat. Those goats carried the gene for spider silk protein, and the milk produced by the goats included spider silk protein. However, they found out that it was too hard to spin the proteins into a fibre similar to natural spider silk because they couldn’t make an environment like the spinnerets does. The spinnerets in spider’s body create a good environment of protein concentration, pH, and pressure to change the protein into the structure of a normal spider silk. At the end, Nexia was forced to abandon research on artificial spider silk. Another researcher is Randolph V. Lewis, a molecular biologist at the University of Wyoming in Laramie. His team cloned spider silk genes and implanted them in the bacteria (to implant something means put it into a person's body by medical operation.). "I think soon we'll be able to make a close analog of spider silk," says Lewis.” Will it be identical to silk? Probably not. But it may still be an excellent fibre." The conclusion is: people could make some similar fibre like spider silk, but we couldn’t make the same fibre as the spider silk; that’s the secret of the nature.

Bibliography Books •

Alexandra Parsons & Jerry Young Amazing Spiders 9 Henrietta Street, London, England: Dorling Kindersley Limited, 1990

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Andreu Llamas Spiders The Great Spinner Wisconsin, USA: Gareth Stevens Publishing, 1997

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Christopher o’ Toole Insects and Spiders New York, USA: Facts On File, 1986

WebPages •

Richard Lipkin.” Science News Magazine Editor's Picks - Artificial spider silk”. March 9, 1996. Science News Online. [cited 21 April 2007]. http://www.sciencenews.org/pages/sn_edpik/ps_5.htm.

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“Spider - Wikipedia, the free encyclopedia. ”. Wikipedia. [cited 21 April 2007]. http://en.wikipedia.org/wiki/Spider.

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“Spider silk - Wikipedia, the free encyclopedia”. Wikipedia. [cited 21 April 2007]. http://en.wikipedia.org/wiki/Spider_silk

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“Spider web - Wikipedia, the free encyclopedia”. Wikipedia. [cited 21 April 2007]. http://en.wikipedia.org/wiki/Spider_web

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“Spiders On Drugs”. Trinity Universty. [cited 21 April 2007]. http://www.trinity.edu/jdunn/spiderdrugs.htm