Fish use their gills to extract oxygen from the water. So they need them as much as you need your lungs. The main difference between lungs and gills (other than water vs. air) is that lungs are tidal - air flows in one way, and back out the other way.
Why Do Fish Have Gills? Fish have gills because these organs are used to extract oxygen from the surrounding water in which a fish lives. Gills are different from lungs because gills generally work unidirectionally: water moves in one direction across the gills in order for the organs to extract oxygen.
Some fish, like sharks and lampreys, possess multiple gill openings. However, bony fish have a single gill opening on each side. This opening is hidden beneath a protective bony cover called the operculum. Juvenile bichirs have external gills, a very primitive feature that they share with larval amphibians.
Gills are a vital part of the respiratory system in fish and other aquatic organisms. Humans (and other mammals) have tiny air sacs in the lungs, alveoli, that are responsible for the exchange of ...
Fish have gills because they need them to survive underwater. Gills absorb oxygen from the water just like we absorb oxygen from the air. At some point way back in time, the ancestors of fish needed to be able to breathe underwater, and those that evolved gills were able to.
A fish breathes by taking water into its mouth and forcing it out through the gill passages. As water passes over the thin walls of the gills, dissolved oxygen moves into the blood and travels to the fish's cells. If fish can breathe underwater, then why do some fish, like dolphins and whales, swim to the surface of the ocean?
In addition to living in water and having fins, most fish are ectotherms, obtain oxygen through gills, and have scales What are the major groups of fishes and how do they differ? The major groups of fishes are jawless fish bony fish and cartilaginous fish. jawless fish have no scales and no jaws. cartilaginous have jaws and scales and there ...
Fish force water through their gills, past many tiny blood vessels. The gills take oxygen from the water and let water whisk away carbon dioxide. Gill filaments are the red, fleshy part of the gills; they are the smallest division of the gill and they take oxygen into the blood.
The gill arches of bony fish typically have no septum, so the gills alone project from the arch, supported by individual gill rays. Some species retain gill rakers. Though all but the most primitive bony fish lack spiracles, the pseudobranch associated with them often remains, being located at the base of the operculum.
Fish Gills. Fish breathe through gills instead of lungs. Just like all other animals, fish need oxygen to survive. Because they live in water, they have evolved gills which enable them to remove dissolved oxygen from water. Most fish have four gills on both sides of their head.