Реферат: Spiders Essay Research Paper This report deals

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


Caffeine FAQs [Online] Available aomt.netmegs.com/coffee/caffaq.html,

Nov. 7th, 1999 Community Policing. Stimulants [Online] Available www.ci.chi.il.us/CommunityPolicing/Districts/Dist08/Drug

Awareness/Stimulants.html, Nov. 7, 1999 DEA. Drugs of Abuse [Online] Available


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 www.naturalpartners.org/InsectZoo/Students/aranea.html,

November 7th, 1999 Versaware Inc. Chloral Hydrate [Online] Available www.funkandwagnalls.com/encyclopedia/low/articles/c/c005000376f.html,

Nov. 6, 1999

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