Spiders+and+Relatives

Basics of Chelicerates

 Ò Chelicerates are arthropods which are invertebrate animals that has a segmented body, jointed appendages, and an exoskeleton.  Ò Arthropods are classified based on the number and structure of their body segments and appendages, particularly their mouthparts since that is the main difference between them.  Ò They have mouthparts called chelicerae and they have two body sections, the cephalothorax and the abdomen, and most have four of walking legs.  Ò The cephalothorax is usually the body section in which the brain, eyes, and the stomach are. Also the bases for the walking legs are there.  Ò The abdomen is the body section in which the heart, intestine, reproductive organs, and the anus are.  Ò This features make Chelicerates similar to crustaceans  Ò They have appendages near the mouth which became known as mouthparts.  Ò Chelicerae contain fangs and are used to stab and paralyze. These are usually filled with poison from their poison sack.  Ò Pedipalps are longer than the chelicerae and they use them to trap or grab prey.  Ò They breathe by using book gills or book lungs ﻿Horseshoe crabs  Ò Horseshoe crabs have been around for more than 500 million years. They have not evolved much mostly due to their hard shells which make it hard for predators to turn them over and eat them.  Ò They have also survived because it can go a year without eating and can endure extreme temperatures.  Ò They may be called crabs but they have an anatomy closer to spiders. <span style="color: #000000; margin: 0in 0in 10pt 0.5in; tabstops: list .5in; tabstops: list .5in; text-indent: -0.25in;"> Ò The horseshoe crabs have a pair of eyes on its hard shell. They use it mostly for finding mates. <span style="color: #000000; margin: 0in 0in 10pt 0.5in; tabstops: list .5in; tabstops: list .5in; text-indent: -0.25in;"> Ò It breathes through book gills because it mostly lives under water. <span style="color: #000000; margin: 0in 0in 10pt 0.5in; tabstops: list .5in; tabstops: list .5in; text-indent: -0.25in;"> Ò Horseshoe crabs are not harmful at all, even though they might look intimidating. <span style="color: #000000; margin: 0in 0in 10pt 0.5in; tabstops: list .5in; tabstops: list .5in; text-indent: -0.25in;"> Ò The reason why people see them on beaches is because they are either mating or laying eggs. <span style="color: #000000; font-family: Calibri; font-size: 36pt; font-variant: normal; language: en-US; text-transform: uppercase; vertical-align: baseline;">

<span style="color: #4e3b30; font-family: 'Franklin Gothic Medium'; font-size: 36pt; font-variant: normal; language: en-US; text-transform: uppercase; vertical-align: baseline;">Spiders <span style="color: #000000; margin: 0in 0in 10pt 0.5in; tabstops: list .5in; tabstops: list .5in; text-indent: -0.25in;"> Ò Spiders all have eight legs. <span style="color: #000000; margin: 0in 0in 10pt 0.5in; tabstops: list .5in; tabstops: list .5in; text-indent: -0.25in;"> Ò Some spiders spin webs from their silk glands and their spinnerets. The silk they produce is much stronger than steel. Though some spiders may not spin webs, all of them produce silk. <span style="color: #000000; margin: 0in 0in 10pt 0.5in; tabstops: list .5in; tabstops: list .5in; text-indent: -0.25in;"> Ò Spiders are classified in the group of animals called arachnids, along with tick, mites and scorpions. <span style="color: #000000; margin: 0in 0in 10pt 0.5in; tabstops: list .5in; tabstops: list .5in; text-indent: -0.25in;"> Ò Spiders live in almost any habitat. <span style="color: #000000; margin: 0in 0in 10pt 0.5in; tabstops: list .5in; tabstops: list .5in; text-indent: -0.25in;"> Ò Spiders do not chew their food. Once they capture their prey they inject their venom into the animal. Once the animal is completely paralyzed, the spiders liquefy the animal and then the food goes through a pumping stomach which pushes the food to the intestines. <span style="color: #000000; margin: 0in 0in 10pt 0.5in; tabstops: list .5in; tabstops: list .5in; text-indent: -0.25in;"> Ò Spiders can get their food in many ways. <span style="color: #000000; margin: 0in 0in 10pt 0.5in; tabstops: list .5in; tabstops: list .5in; text-indent: -0.25in;"> Ò Ways Spiders Get Their Food: <span style="color: #000000; margin: 0in 0in 10pt 0.5in; tabstops: list .5in; tabstops: list .5in; text-indent: -0.25in;"> Ò 1. They spin webs to catch flying prey. <span style="color: #000000; margin: 0in 0in 10pt 0.5in; tabstops: list .5in; tabstops: list .5in; text-indent: -0.25in;"> Ò 2. They stalk and pounce on their prey. <span style="color: #000000; margin: 0in 0in 10pt 0.5in; tabstops: list .5in; tabstops: list .5in; text-indent: -0.25in;"> Ò Or.. <span style="color: #000000; margin: 0in 0in 10pt 0.5in; tabstops: list .5in; tabstops: list .5in; text-indent: -0.25in;"> Ò 3. They wait in a camouflaged burrow and capture prey that come to close. <span style="color: #000000; font-family: Calibri; font-size: 36pt; font-variant: normal; language: en-US; text-transform: uppercase; vertical-align: baseline;">

<span style="color: #4e3b30; font-family: 'Franklin Gothic Medium'; font-size: 36pt; font-variant: normal; language: en-US; text-transform: uppercase; vertical-align: baseline;">Mites and ticks <span style="color: #000000; margin: 0in 0in 10pt 0.5in; tabstops: list .5in; tabstops: list .5in; text-indent: -0.25in;"> Ò Mites and ticks are usually parasitic. <span style="color: #000000; margin: 0in 0in 10pt 0.5in; tabstops: list .5in; tabstops: list .5in; text-indent: -0.25in;"> Ò Mites usually eat plant related food, while ticks usually eat animal related food. <span style="color: #000000; margin: 0in 0in 10pt 0.5in; tabstops: list .5in; tabstops: list .5in; text-indent: -0.25in;"> Ò Ticks are very harmful to humans because they cause sicknesses and diseases. Mites cause sickness in plants mostly. <span style="color: #000000; font-family: Calibri; font-size: 36pt; font-variant: normal; language: en-US; margin: 0in 0in 10pt 0.5in; tabstops: list .5in; tabstops: list .5in; text-indent: -0.25in; text-transform: uppercase; vertical-align: baseline;"> <span style="color: #4e3b30; font-family: 'Franklin Gothic Medium'; font-size: 36pt; font-variant: normal; language: en-US; margin: 0in 0in 10pt 0.5in; tabstops: list .5in; text-indent: -0.25in; text-transform: uppercase; vertical-align: baseline;">Scorpions <span style="color: #000000; margin: 0in 0in 10pt 0.5in; tabstops: list .5in; tabstops: list .5in; text-indent: -0.25in;"> Ò Scorpions are mostly related to spiders. <span style="color: #000000; margin: 0in 0in 10pt 0.5in; tabstops: list .5in; tabstops: list .5in; text-indent: -0.25in;"> Ò Scorpions have Pedipalps that are enlarged into claws. <span style="color: #000000; margin: 0in 0in 10pt 0.5in; tabstops: list .5in; tabstops: list .5in; text-indent: -0.25in;"> Ò They chew their prey, however, unlike spiders. <span style="color: #000000; font-family: Calibri; font-size: 36pt; font-variant: normal; language: en-US; margin: 0in 0in 10pt 0.5in; tabstops: list .5in; tabstops: list .5in; text-indent: -0.25in; text-transform: uppercase; vertical-align: baseline;">﻿<span style="font-family: 'Calibri','sans-serif'; font-size: 11pt; line-height: 115%;">Usually the clear scorpions are more deadly than the colored scorpions. <span style="color: #000000; font-family: Calibri; font-size: 36pt; font-variant: normal; language: en-US; margin: 0in 0in 10pt 0.5in; tabstops: list .5in; tabstops: list .5in; text-indent: -0.25in; text-transform: uppercase; vertical-align: baseline;"> <span style="color: #000000; font-family: Calibri; font-size: 36pt; font-variant: normal; language: en-US; margin: 0in 0in 10pt 0.5in; tabstops: list .5in; tabstops: list .5in; text-indent: -0.25in; text-transform: uppercase; vertical-align: baseline;"> Reproduction All Chelicerates reproduce sexually, with differences in sex organs in males and females. Fertilization happens internally. Some Chelicerates must have physical contact in order to transmit sperm to the ovary in another Chelicerate. However in the Arachnids they do not have physical contact with their sex organs. Then the sperm fertilizes the egg(s) and then embryos begin to form. Then after a certain period of time the eggs hatch and then stay with the mother. In some Chelicerates, mostly with the Spiders and Scorpions, sexual cannibalism is practiced. Below shows a picture of two horseshoe crabs mating, an example of a step in Chelicerates' reproductive cycle.

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