---------Organism evolve in the Paleozoic era Research Paper

---------Organism evolve in the Paleozoic era - Research Paper Example With the end of Paleozoic era came about the mass extinction of marine species, The Permian/Triassic extinction (Paleozoic era paleobiology). One of the organisms that evolved in Paleozoic era and managed to survive the vast and diverse geological and geographical changes spanning more than 300 years is Spider. Their global presence even today cannot be denied. In the current paper is discussed the unique characteristics of this organism that contributed to its evolutionary success and present a brief description of its journey over the years. Spiders belong to the order Araneae. They are among the most abundant species superseded only by the class Insecta, and comprises of approximately 42000 existing species belonging to 109 families (Platnick). The oldest fossils of true spiders have been reported to be from the carboniferous era (312 million years old), but their evolution can be traced to the Devonian. They are in fact among the first organisms to have inhabited land (Penney & Selden, 8). The unique morphological and behavioral characteristics of spiders continue to amaze researchers and are responsible for the survival and almost ubiquitous presence of spiders. Some of these characteristics are: Silk is the biggest tool and weapon of spider. It is used for shelter, movement, communication, and dispersal of spiderlings. Web making spiders are capable of staying motionless and concealed for long span of time and are mobilized by such stimulus as prey, mate or predator. Further they have adaptations such as median tarsal claws to enable them to walk on silk (Herberstein & Wignall, 8). During movement it leaves a dragline silk formed by the anterior spinnerets which acts as a safety line of communication for mate. Depending on the environment they inhabit, they have developed organs for locomotion such as claw tufts for land and hydrophobic exoskeletons for water. The sense