Physiological Adaptations of the Plesiosaur for ?Holding its Breath? :: essays research papers

Physiological Adaptations of the Plesiosaur for Holding its Breath unitary hundred and fifty million years ago, large aquatic species of reptilian such as the Plesiosaur dominated the ocean, and were pre-eminent predators of the sea. The branch of now nonexistent Plesiosaurs, or near lizards, evolved into variant closely related species specialised to transport different niches in the food chain. Such species of Plesiosaur include the phenotypically standardised Plesiosauroid and Pliosauroid. The physiological adaptations of the long necked variant, the Plesiosauroid, as it relates to deep sea diving, go forth be addressed in depth.Oxygen breathing lungs are a universal trait of class reptilia. As such, it would have been necessary for the Plesiosauroid - a marine reptile, to return to the ocean surface to inhale air. Oxygen intake in reptiles is proportional to strenuosity of locomotion (Frappell, Schultz & Christian, 2002). Therefore the Plesiosauroid mustiness have held physiological traits that enabled the species to avoid oxygen deficit while catch deep-sea dwelling prey. This essay will outline the hypothesised respiratory, circulatory, pulmonary and afferent attributes of the Plesiosauroid as they relate to diving. These hypotheses will be supported by canvass the physiological adaptations of the Plesiosaurs biological analogues, and the prospect of similar adaptations in the former will be speculated upon.Reptiles have a low metabolic rate they consume energy, and therefore oxygen, silently. According to Robinson (1975), Plesiosauroids were enduring swimmers with lower tail fin aspect ratios and drag-causing long necks. Massare (1988) made the same conclusion, since the hydrodynamic properties of the Plesiosauroids indicate the species go no faster than 2.3 metres every second. Therefore, the species was confronted by a conundrum it seek to dive hundreds of metres to hunt its prey yet was constrained, by virtue of its torso shape, to travel at slow speed. Invariably, the animal would have been required to come before oxygen for periods of more than a minute, while keeping the presence of drumhead to hunt.Fortunately, when making its descent of hundreds of metres, the Plesiosauroid would have been able to exploit traits possessed by many of the reptile class. Many reptiles hold the ability to temporarily slow their heart rate to reduce their oxygen consumption, via bradycardia. This effect may be caused by low temperatures, such as is found deeper in the ocean, or may be voluntarily triggered by the animal. There would be no need for the Plesiosauroid to retain all of its oxygen-consuming faculties during the long descent.