Breathing is essential in all living beings because it is the process in which the blood is oxygenated, providing the body with activity, energy, movement, growth and life, also eliminating other gases such as carbon dioxide. All living organisms require some form of energy to obtain and digest food, which is why it is important that the organism can obtain oxygen which can then be transformed into ATP, which is usable energy. There are various ways in which an organism can obtain oxygen and this process is known as gas exchange. Gills, spread, and lungs are all examples of what an animal can use to take in air. In the class of mammals, the respiratory system includes the procedure that allows mammals to breathe, obtain energy, then be able to take in food, which provides more energy. Without the respiratory system, mammals (and other classes of animals) would not be able to obtain a sufficient amount of energy, resulting in being unable to obtain food, resulting in the death of the animal. respiratory system, making the structure (anatomy) more complex, resulting in function (philosophy) related to achieving the purpose of the system. The upper respiratory system in mammals is responsible for filtering and warming air before it enters the lower system. The upper respiratory system includes the nose, nasal/paranasal cavity, and pharynx (throat). The nose is the area where oxygen typically enters the body, through the external nares, or nares. The cavities act as walls divided by a nasal septum, which allows air to travel into the pharynx. There are three parts in the pharynx, nasopharynx, oropharynx and oropharynx. The nasoph......middle of paper......ory system performs similar actions in both mammals and molluscs, thus resulting in the same end product. Breathing is crucial for the survival of all animals, relating the Phylum Chordata, Class Mammalia, to the Phylum Mollusca, on a parallel level. Although each animal in these taxonomic groups has different ways of obtaining the oxygen it uses to produce energy for food, both result in the same end product, which provides life for the animal. Whether diffusion, gills or lungs, the purpose of the respiratory system in mammals and molluscs is to deliver oxygen from the surrounding environment to the lungs which will then pump the air through the rest of the body, resulting in a usable form of energy that allows them to take in food, thus allowing that animal's survival, while also disposing of other gases such as carbon dioxide in the process.