The crustacean Grapsus grapsus is often found all along the coasts of America, Chile and Africa’s intertidal rocks. Its adults has a bright red carapace and can reach up to 5-7cm in width, they use their spoon shaped tipped pinchers to feed on algae. Its surviving adaptability to its predators the rapacious birds is when it runs with unusual speed and agility going to the upright side of the rocks and it possess the creepy ability to cover into crevices.
The organic jointed skeleton of Grapsus grapsus takes a great part to its evolution which protects and supports along with the muscle system which contribute to well-organized locomotion (Kricher, 2006). Evolutionary Adaptations Crabs under the infraorder Brachyura which has 93 families its evolution can be characterized by the increasing heftiness of the body and the reduction in the size of the abdomen. Depending on the kind of crabs they will undergo carcinisation mainly in highly developed crabs while the telson is no longer functional and the uropod are missing it most likely evolved into small parts.
The ancient crab named Carboniferous Imocaris which is known for its carapace the first unambiguous crab fossil during the Jurassic era. The radiation of crabs that happens during the Cretaceous period can be associated to the concurrent radiation of bony fishes which is its main predator. The evolution of the exoskeleton of Grapsus grapsus was used to the formation of levers and such tubular levers functions for apodemes and projections that allow muscle to attach the joints amid the lever system produces jointed appendages.
Furthermore, every segment was attached to each other thru a ring of arthrodial membrane and some inner strips of resilin. This is a kind of elastomeric protein which can be initiated from arthropods that allows segment to act as lever that can move independently to its neighboring component. Because of the exoskeleton present in Grapsus grapsus contribute an important role in the evolution and success of the species but harshly constrains development and growth of the said species.
The evolution of arthropods particularly Grapsus grapsus which has larger bodies compared to other arthropods and can be limited by the physics of its exoskeleton. Throughout the Pre-Cambrian era it was believed that arthropods have evolved form segmented worms. Similarly, the species Grapsus grapsus did not evolved just like chitinous mouthparts like other worm that are segmented because it also has chitinous structures throughout its body generally arthropods has a distinct segments which was covered with one or more plate one pair of legs or limbs per segment.
In the middle of Cambrian period it was believed that over two million species of arthropods arrived on earth the species in this era has evolved more than its ancestors in several ways which acquire their distinctive characteristics. (Hall, et al 2007). The illustration of arthropods exoskeleton today shows what was their life before, they are considered to be the mainly the triumphant animal phylum in the planet concerning the size of the population and species diversity (Sadava, et al 2008).
The exoskeleton of Grapsus grapsus shows that competition among species was quite ferocious during the Cambrian era from predators. Among other species this crab that belongs to the arthropods were also the first taxon to demonstrate a more highly developed receptors in the form of their eyes along with its chemoreceptor’s that the species used equally in its external and internal environment. These types of survivability have been advantageous which resulted to genetic diversity. Recommendations
It would be helpful for the future studies on Grapsus grapsus to study the previous fossils of this species at the same time comparing it to the present species it should be a collection of fossils to be studied by group of experts in geology, morphology, paleontology, functional anatomy, behavior and biochemistry all species should be described their interaction and habitats should be compared. Reference The Arthropod Story. April 28, 2009 Retrieved from http://evolution. berkeley. edu Hall B. K. , Hallgrimsson B. , Strickberger M.
W. (2007). Strickberger’s Evolution: The Integration of Genes, Organisms and Populations. Published by Jones & Bartlett Publishers. Kricher, J. C. (2006). Galapagos: A Natural History. Published by Princeton University Press. Sadava, D. E. , Heller H. C. , Purves W. , Orians G. H. , Hillis D. M. (2008). Life: the Science of Biology. 8th Edition. Published by Sinauer Associates. How The Arthropod Skeleton Has Been Exploited In The Colonization of The Land. April 28, 2009 Retrieved from http://www. insects. org. uk/ectoskel. htm