This Smells Fishy-Perch Dissection

Elizabeth Tyska-Vu-7th Period Pre-AP Biology

O-FISH-al Objectives

Students were to learn the internal and external anatomy of a perch, and the characteristics of the Osteichthyes class.

FISHing for Background Information

Perch belong to the class Osteichthyes, and their scientific name is Perca fluviatilis. Fish are the largest group of vertebrates found in both fresh and saltwater, and over 25,000 species of fish comprise about 50% of the vertebrate population.

It lives in freshwater lakes with submerged vegetation. You can find this fish almost everywhere in the United States and other areas in North America. Perch prefer standing water near shore with some vegetation for protection, food, and cover.

They eat insect and their larvae, some invertebrates, small fish and crustaceans, and snails, depending on where they live. Perch are carnivorous, but some species have been know to eat zoo plankton. Perch are eaten by larger fish, like Largemouth and Smallmouth Basses, Black Crappies, Walleyes, and Bluegills. Some large birds also eat perch, including herons, gulls, eagles, hawks, kingfishers, and mergansers. Humans also eat perch. They are a popular fish to catch for recreational purposes, and there are many recipes for how to properly cook them.

Perch are in the middle of the freshwater lake food chain, as they are carnivores, and eat smaller fish, but are eaten by other predators. They help maintain the populations of pests in areas, and in turn their populations are maintained by other predators.

Perch have adapted well in their habitats, with coloring designed for them to blend in to the plants and teeth that can catch other smaller fish. Their gills are also designed to filter out zoo plankton from the water. They have evolved from the spiny ray fish, alongside the catfish, bass, and carp.

Internal Anatomy

FISHy Circulatory System

The perch's circulatory system consists of one atrium and one ventricle, which pump the blood to the capillaries in the gills first. The gills, whose function it is as part of the respiratory system is to filter oxygen out of the water for the fish to use to breathe, then oxygenate the blood and it moves from there to the tissues of the organism. The tissues, of various types, absorb all the oxygen needed for cellular respiration, and the blood is pumped back the heart in order to be reoxygenated.

A perch's circulatory system is closed, meaning the blood stays in the vessels. This blood travels throughout the body in a single loop of veins, with a few branching arteries.

A Simplified Anatomical Representation