Spider - is an insect or not?

not only inquisitive students, but also many adults are interested in the question: Spider - is an insect or not?Indeed, at first glance it may seem that the answer is obvious, and spiders are one of the species of insects, but it is not.They belong to a separate class of arachnids, because they have a lot of differences with insects.

Spiders appeared on our planet for a long time, about 400 million years ago.It is believed that they came from kraboobraznogo ancestor.Insects were almost 100 million years later and created a separate class.Today, the land is home to about 40,000 species of arachnids.If you consider in detail the anatomy of these creatures, then questions like "Spider - is an insect or not?"should not occur.We all know that insects have six legs, and here are eight of them in arachnids, also have eight eyes, only some species of six or two.These creatures do not have teeth, but there are hook-shaped jaw with special channels designed for penetration of the poison in the victim's body.

doubt about spider - insect or not disappear immediately, if we consider how it is powered.If mantis eat the captured flies, so the spider can not do, because they have extra-intestinal digestion.They are injected into the victim digestive enzymes that make the soup insect and spiders can only suck out the contents of the envelope.

Many beings are able to spin a web, but they do not get it so strong and supple as a trap for the victims, which prepares the spider.Breeding also makes these creatures weave cocoons for special conservation egg laying and small spiders.If we compare with the web of steel, the first to be five times stronger than the second, and the thread thickness of a pencil will not break the plane crashed into the net.

unclear why many ponder the question of whether the spider - is an insect or not, between these two classes there is a significant number of differences.The body of these creatures are not divisible by three, but only two sections: cephalothorax and abdomen.Webs are made of liquid secreted from warts, located at the end of the belly.From this material spiders build houses for themselves, doing magic carpet on which travel long distances, spin cocoons for eggs networks prey on insects.

These creatures move fairly quickly on their networks, while the mosquitoes, flies and other accidents just stick to it.The fact that spiders spin sticky and non-sticky threads first need to catch the victim, but on the second they move.Even if they accidentally fall on the sticky part, do not get confused, because their body is fat coating.

Modern science has already given a precise answer to the question: "Spider - is an insect or not?", Highlighting these creatures in a separate class.In central Russia is not dangerous to human life arachnids, though you must behave with care.The spider will never attack first, it only protected or biting when frightened.The bite can only be accompanied by a burning sensation, severe pain and fever.But there are also representatives of this dangerous species: the greatest fame acquired Tarantula and Black Widow.Their bite causes a general poisoning of the body, which sometimes leads to death.