presentation of a perch
Perch dissection - PAP Biology 4th period Guzmann
objectives
The objectives of today is for the reader to learn about the external and internal anatomy of a perch, focusing on the circulatory system. The reader will also learn about the perch's habitat, predators and prey, life cycle, as well as evolutionary relationships with other organisms and their role in out ecosystem.
background information and anatomy
The perch, a fish also known as the Perca flavescens, belongs to the family Percidae. Perches are aquatic creatures. The main purpose of the fins is to stabilize the fish while it is swimming. The function of the gills is to enable it to exchange gases (takes in oxygen, releases carbon dioxide). The perch has an elastic esophagus which allows it to consume large things. The lateral line system is sensitive to vibrations in the water. The swim bladder provides buoyancy for motion.
circulatory system
The circulatory system of a perch is a low pressure, single loop system, which means that the blood flows in one direction. The heart acts as a pump. Deoxygenated blood is received by the atrium (part of the heart) and pumped through the heart by the ventricle to the gills, where it becomes oxygenated and gets rid of carbon dioxide, and is distributed to the rest of the body. This is known as a closed system.
habitat
Perch are found mainly in lakes or sometimes in inpoundments of larger rivers, usually in clear water with lots of vegetation; silt can lead to death. Perches inhabit water of moderate temperature. They spend their summer in shallow water.
predators / prey
Predators of perch include larger fish (Largemouth Bass, Smallmouth Bass, Channel Catfish, Bluegill), turtles, and bullfrogs. Perch usually eat mostly algae and plankton at a young age, and as they get older aquatic insects, small fish, snails, fish eggs, worms, and sometimes even other perch.
life cycle
Perch spawn in the spring during March or April. They prefer water with vegetation at the bottom. The female lays eggs in a jelly-like string, which protects the eggs. The eggs take 20 to 25 days to hatch. When they are born the baby perch is not adapted to swimming yet and they hide in the vegetation. Parents do not guard them. By the end of their first summer, they will be about 3 inches long.
ecological importance
Perches are important in our ecosystem because they are a food source. They are also important to humans on an economic level. For example, they support commercial fishing in Lake Michigan, Lake Erie, and Lake Huron, and serve as a recreation and attract tourism there as well.