Any organism or group of organisms Essay Example | Topics and Well Written Essays - 1000 words

Any organism or group of organisms - Essay Example Most have two auxiliary pairs of appendages. The first is the chelicerae, or mouthparts on which you find their fangs. These are used for feeding and defense functions, grabbing or poisoning prey. The second pair is called the pedipalps. They have mainly three functions: for feeding, movement and reproducing. Another feature of arachnids that makes distinguishing insects from them easy are the fact that arachnids do not possess any antennae or wings. All arachnids also contain exoskeletons just as all arthropods. Arachnids are typically meat-eating organisms. They feed on pre-digested remains of insects and other little organisms such as flies, bees, ants, crickets, wasps, grasshoppers, beetles, bugs and even others of their kind. Only two kinds, the  harvestmen also known and commonly called as the daddy longlegs,  and several mites like the house dust mite for instance, consume solid food particles. Because of this, they are out in the open to other internal parasites, though i t is not obscure for spiders to digest their own silk. Quite a lot of groups have the ability to exude  toxin and lethal venom  from specific  ducts or glands  to poison prey or threats. ... At the back of the mouth, there is a powerful hardened pharynx. This operates as a pump, drawing the food in to the body, from the esophagus which sometimes functions as a secondary further pump. The stomach in an arachnid is shaped like a tube, with a couple of outpouchings stretching all the way through the entire body. Both the stomach and these outpouchings called diverticula manufacture digestive proteins. They also soak up nutrients from the prey. This connects to a tiny hardened intestine and anus which is found in the rear part of the abdomen of the arachnid’s body. Eyes of arachnids are complex and very complicated, having two kinds namely the median ocelli and the lateral ocelli. Compound eyes have probably evolved into the lateral ocelli. They may possibly have a  tapetum. This helps in enhancing the absorption and the gathering of light. At the same time, the median ocelli may have been arisen from a crosswise crease of the  ectoderm. These eyes, in its ancient form, were probably both present in ancestors of arachnids. In contrast, modern arachnids that we see today are either lacking in one type or the other. The  cornea  acts as a light-focusing lens. underneath is a see-through body that resembles that of glass, then the  retina and sometimes, the tapetum. Nearly all arachnids have two other sensory organs. One of the most common and the most fundamental for most arachnids are the sensory hairs that are cover up the entire body. This also provides the arachnid’s sense of touch. Most other arachnids possess other sensory organs, even more complex and intricate such as trichobothria, or elongated hair-like structures that is used in detecting