Spiders Essay, Research Paper
This report deals with testing the toxicity of certain chemicals on spiders,
and determining the toxicity by how it affects it?s ability to weave it?s web. This report contains research on the four chemicals (benzedrine, chloral hydrate, caffeine, and alcohol) as wellas the spiders and their webs.
Spiders are of course found in the class Arachnidia, which also contain mites, scorpions, and other arthropods. The order which spiders are classified under is called Araneae, a word of Latin origin. Most spiders are land dwelling, but some can be aquatic. Those that are aquatic spend most of their lives in or around water. Spiders can live in a vast amount of different places around the world. Jumping spiders have been collected on Mt. Everest at a height of 22,000 feet, the highest elevation at which any animal has been collected (Orkin, Insect Zoo 1).
Adult species vary greatly in size, which is a contributing factor in the prey they choose, and also the way they catch this prey. Spiders range from less than three hundredths of an inch to more than 10 inches. All spiders are carnivorous in their eating habits, insects being first on their menu. Spiders usually catch live animals because the movement of the prey attracts its attention. Some spiders have poor vision, and rather depend on the movement of it?s web to locate an insect. (Orkin, Insect Zoo 2). The prey is usually wrapped in silk before the spider injects the venom to kill it. Yet the larger the spiders, the larger its prey. Some spiders have been known to kill vertebrate animals, such as fishing spiders, who thrive on small fish, or bird spiders, feeding on small birds from South America, as well as a variety of lizards. Some species have even been known to attack snakes. When food is scarce, mainly during winter months,
spiders have no trouble have no trouble with food, most can go months without eating.
A spider?s structure is irregular when compared to other animals, yet similar to those of other arachnids. An arachnid is of course classified on the number of it?s legs, which happens to be eight. Spiders have two main body regions: the cephalothorax and the abdomen . The cephalothorax consists of the head and the thorax, which are fused together. Insects have three main body regions, a head, thorax, and abdomen. Other arachnids have those two regions connected through a broad waist. All spiders also have simple eyes, lacking compound eyes only found in insects. Spiders can have many pairs of eyes however, this number often reaches four. Spiders do not have an antenna either. (Orkin, Insect Zoo 6)
Many spiders secrete a fluid in their posterior abdomens which is later extruded as a silk. This fibrous protein is used to weave webs, snares, shelters, and/or egg sacs. A spider uses fingerlike spinnerets to disperse this silk. Most spin more than one kind of silk to customize its web, or to just fit its purpose. For example, the spider makes some parts of its web not sticky so that it can run across it and not get caught. Another source says that spiders first lay down a type of silk known as ?dry thread?, with which they weave a ?dry spiral. Once this is completed, the spider lays down a sticky spiral of thread and goes on to eat the dry one. The sticky spiral must be replaced every couple days because it loses its ?stickiness.?
Some scientists suggest that the pattern of an orb web (most common type of web used by spiders) is designed to attracted insects. These webs are thought to produce patterns that resemble those reflected by numerous flowers in UV light. Since insects only see in UV light, they might as well fly into a trap (Lyons, Spider Silk 1).
Spider silk has been recognized for centuries as a high quality fiber. A few pairs of stockings and gloves have been made from the silk as early as the 16th century. Various attempts have been made to produce it commercially, yet have failed. New efforts are currently under
construction as more people are finding new ways to use a strong, elastic fiber. A few of these ideas are bulletproof vests, or replacement tissues for tendons and ligaments. Advanced techniques, such as molecular biology are being used to determine the exact composition of spider silk, and the changes it undergoes as the liquid proteins inside the spider become the actual silk itself (Lyons, Spider Silk 1).
Moving on, chloral hydrate (one of the substances being used in the experiment)is the oldest of hypnotic, sleep inducing depressants. This organic chemical was first synthesized in 1832 (DEA, Chloral Hydrate 1). Chloral hydrate takes about 30 minutes to take effect, and should induce sleep within an hour. Chloral hydrate will not affect respiration and blood pressure when taken at the recommended doses, yet larger dosage can lead to severe respiratory depression and extremely low blood pressure. It may also irritate mucous membranes as well as the skin (Versaware Inc., Chloral Hydrate 1). Chloral hydrate is still being relied on by many to this day, yet its use declined with the introduction of barbiturates.
The next drug, benzedrine, is also known as speed. The drug can takes various forms, including tablets, pills and capsules. In this case for the experiment, the drug will take the form of powder. Benzedrine can be taken orally, injected, or inhaled, and its effects can be severe, if not fatal. Benzedrine is a stimulant, therefore causing increased heart and respiratory rates, elevated blood pressure, dilated pupils, decreased appetite, sweating, headaches, blurred vision, dizziness, sleeplessness, anxiety, restlessness, and moodiness. High doses or injections have the potential to cause a rapid or irregular heartbeat, tremors, loss of coordination, physical collapse, sudden increase in blood pressure, very high fever, and possibly heart failure.
Alcohol, on the other hand, is a depressant. This drug slows the nervous system, and requires no ingestion. Once in the body, it enters the bloodstream, and passes through the stomach lining. Alcohol passes through the three main areas of the brain via the bloodstream.
The frontal lobe, which controls judgment and reasoning, the midbrain, which regulates muscle control and coordinates movement, and the hindbrain, which controls bodily functions such as respiratory rate and heart rate, can all be affected. Death can result from a BAC (blood alcohol content) of 0.5 or higher. (Schroeder, Alcohol Awareness 23)
Caffeine is another stimulant that is widely used throughout the world. Found in coffee beans, caffeine can be just as dangerous as other drugs. Signs of intoxication include restlessness, nervousness, excitement, insomnia, flushed face, diuresis, gastrointestinal disturbance, muscle twitching, periods on inexhaustibility, cardiac arrhythmia, and/or agitation. People have lost their lives to caffeine, most having ingested more than 20 grams. Serious intoxication can lead to delirium, seizures, and hyperglycemia.
Though these statistics are for humans only, they strongly correlate to other animals as well, because their toxicity does not change based on who the recipient is. Unless spiders have an unprecedented immune system to certain chemicals, the results should be on the same scale as the human?s effects.
Caffeine FAQs [Online] Available http://aomt.netmegs.com/coffee/caffaq.html, Nov. 7th, 1999
Community Policing. Stimulants [Online] Available http://www.ci.chi.il.us/CommunityPolicing/Districts/Dist08/Drug Awareness/Stimulants.html, Nov. 7, 1999
DEA. Drugs of Abuse [Online] Available http://mir.drugtext.org/druglibrary/schaffer/dea/pubs/abuse/chap3/depress/chloral.htm, Nov. 7, 1999
Lansing State Journal. How Does a Spider Web Work?. [Online] Available htttp://www.pa.msu.edu/~sciencet/ask_st/071697.html, Nov. 8, 1999
Lyons, Ron. Alcohol Awareness. New York: Anderson Publishing, 1995
O. Orkin. Insect Zoo [Online] Available http://www.naturalpartners.org/InsectZoo/Students/aranea.html, November 7th, 1999
Versaware Inc. Chloral Hydrate [Online] Available http://www.funkandwagnalls.com/encyclopedia/low/articles/c/c005000376f.html, Nov. 6, 1999
Комментариев на модерации: 1.