CARDOPULMINARY(5 classes of vertebrates)
The cardiopulmonary system in fish is used to deliver oxygen and nutrients to body cells. The use of this system is also for the transportation of waste to the gills and kidneys. The cardiopulmonary system for the fish is a single loop system, in which the sinus venosus collects deoxygenated blood from the body and the conus arteriosus transports blood to the gills while making sure it does not return to the main ventricle. The efficiency rate of the heart is 100% but it drops vastly at the gills where the delivery rate is only 6% which is why fish must swim to keep the circulation going. Through countercurrent flow, oxygen flows over the gills in the opposite direction of the blood and oxygenates it.
The cardiopulmonary system of an amphibian deals with the conus arteriosus becoming bifurcated, creating a double loop system in which a large rotation of both deoxygenated and oxygenated blood travel through the heart. As the rotation begins, half of the blood leaves the ventricle and goes to the lungs and half of the blood goes to the heart.(Pulmonary = deoxygenated to lungs, Systemic = oxygenated to the body) All of the blood will eventually return, however this process is not very efficient because blood mixes in the one ventricle. Amphibians can also breathe with their lungs through pulmonary respiration, or they can use their skin through cutaneous respiration
From an amphibian to a reptile the cardiopulmonary system evolves greatly. As the animal evolves there is a slight bifurcation of the ventricle called a septum which helps stop deoxygenated and oxygenated blood from mixing in the ventricle to increase efficiency rate (there are only 2 complete ventricles in crocodiles) Reptiles can also redirect their blood and bypass the lungs to conserve energy and warm themselves faster. Reptiles also have a lot of alveoli in their lungs for more surface area.
A large evolution takes place from reptiles to birds. The...