The respiratory system is a complex organ structure that is vital to any form of life. The main purpose of this system in any organism is to supply the blood with enough oxygen for the entire body in order to complete cell respiration. The respiratory system is able to complete this task through inspiration; oxygen is taken in and then processed in the lungs. This process occurs simultaneously with exhalation, as the body takes in oxygen in releases carbon dioxide. The respiratory system is comprised of different organs in every organism, but they all have lungs and a means by which the gas exchange occurs. (Haldane, J. S., 1917.) Many years worth of evolution occurred from the respiratory system of the perch to that of the frog. The perch breathes through gills while, the frog breathes through the lung and mainly, its’ skin.
The yellow perch (Perca Flavescens) is a fresh water perciform fish native to North America. The Perch is the descendant of the first fish, whose fossil dates back to about 480 million years ago. (Lord, R. 2012). The yellow perch is most typically referred to as just the “perch.” The perch is easily recognizable because of its coloration; it is a dark green on the very top that fades into yellow on the sides and bright orange fins. (Morgan, A. H.,1930.) Fish are considered vertebrate animals. Their skeleton is made of either bone or cartilage. It is one of the most common fish found in either fresh-water ponds or lakes, where their respiratory system is able to function adequately through the use of gills. (Lord, R. 2012).
The northern leopard frog (Lithobates pipiens) is the species of frog most common to North America. It is the state amphibian of both Minnesota and Vermont. It is fairly large and is a green-brown color with dark spots on its back. Frogs have a very interesting life cycle, in which they go through three phases; tadpoles, froglets and lastly fully developed frogs. During this process frogs go from being invertebrates, living solely in the water to