Organism Physiology of a Fish (Essay Sample)

Organism Physiology of A Fish
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Organism Physiology of a Fish
Even at your home, you can find one of the most fascinating organisms on earth.There are chances that you have seen and observed fish in an aquarium, lake, or ocean. The anatomy and physiology of fish are so unique that it enablems them to thrive in underwater environments.
Fish are aquatic organisms. They have various features that enable them to be able to survive in their environment. They are cold-blooded, with fins and a backbone. They also have scales and use gills for breathing. Abaout 480 million years ago, around 20,000 species of fish started evolving. The illustration above is of a large mouth bass. It has a torpedo-like shape, which common with many other fishes
Fish have closed circulatory systems similar to human beings, although blood flows differently throughout their body systems if not even simpler. The blood in a fish flows from the heart, through the gills, to the body and back. Gills take in oxygen very uniquely even though they are analogous to the lungs of humans. Fish use fins, which are appendages that help them to maintain their position, move stop or steer. They are either single fins located at the centerline of the fish, and they include;
1 a) dorsal (back)fins,
* anal fins,
* caudal (tail) fins,
Other fins are paired fins, which comprise of;
2 a) pelvic (hip) fins
* pectoral (chest) fins.
Other fishes such as the catfish also have a fleshy lobe called an adipose (fat) fin located at the back of the dorsal fin. The importance of the dorsal and anal fins is that they help the fish not to roll over onto either of their sides. The caudal fin is mainly for propulsion to assist the fish in moving forward. The paired fins assist the fish to steer, stop and hover.
In most fishes, scales are either cycloid or ctenoid. Cycloid scales have smooth edges while ctenoid scales have jagged ones. Bass fish and other fishes with spines have ctenoid scales that have connective tissues covered with calcium. Many fish also have a layer of mucus that covers the body. This layer of mucus helps prevent the body from infection. When in contact with a fish that is to be released, anglers should be careful not to rub the slime off. The fishes in fresh water fishes are given support by rigid spines that may be quite sharp, thus having a defensive purpose. Catfish have very hard and sharp fins, of which anglers should be wary.
The dorsal and caudal fins are soft and have rays, as well as portions of other fins. Gills, the breathing apparatus of fish, are very vascularized, and this gives them their bright red cover. There is a slightly flexible, bony plate that protects the sensitive gills. That bone is called an operculum (gill cover). The mouth inhales the water, passes over the gills and exhales it from beneath the operculum. Fish also have the ability to detect color. The eyes are rounder than mammals because the focus is achieved by moving the lens in and out and not reshaping the lens like in mammals. In fish, paired nostrils are used to detect smell in water and are relatively sensitive. Catfish and eels have well developed sense of smell.
The shape of the mouth of fishes gives a good clue o...