Essay On Arthropods

Arthropods have been on Earth for an incredible length of time, diverging from their annelid ancestor five hundred or six hundred million years ago (John R. Meyer). In their transition from an aquatic environment to a terrestrial environment they encountered many problems just as plants did. These problems were the effect of gravity, water conservation, accessibility to oxygen, reproduction and dispersal as well as establishing niches on land. Gravity posed as a problem to animals on land as the buoyant effect of water reduced the effect of gravity in the marine ecosystem but on land, they experienced the full effect. Water conservation served as another problem as these organisms were no longer surrounded by a vast body of water they had to develop means in which water could be stored, since it

The traits that all arthropods share are bilateral symmetry, body segmentation (head, thorax, abdomen), an exoskeleton made up of articulated plates, articulated appendages, growth via molting, a pair of compound eyes and an open circulatory system featuring a dorsal heart with lateral valves (Grimaldi and Engel 2005).

The Arthropods (especially the insects) were able to adapt to survive in their new environment, so well they became the most successful and abundant group compared to the others under animalia. Insects, as a member of the phylum arthropoda, possessed an exoskeleton, which supported them. Additionally, terrestrial arthropods generally adopt a more stable hanging stance, standing on the underside of their limbs whose ends are at a low angle to the ground (Stormer 1970). Both characteristics allowed them to move quite easily on land. Another problem they faced with terrestrial life was water loss. Insects had to minimise water loss as well as ensure that they had means of obtaining it. A major part of this fight to avoid desiccation is the arthropods' exoskeleton, the outermost layer of which (the epicuticle) is waxy