Question

Explain the adaptation in the fish body which makes floating on water as well as going in deep water.

Answer 1

Hint: Fish have gills that allow them to breathe or respiratory systems and take oxygen in water. Water enters the mouth, passes over the gills and exits the body through a special opening.

Complete Answer:
- Fishes have a special kind of adaptation by which they can float on water whether it is Shallow or deep water, River or sea, that does not matter. The special type of adaptation is aquatic adaptation.
- Aquatic adaptation is the adjustment in behaviour, physiology or structure of an organism which enables them to live in an aquatic environment.
- The adaptive characters in fish have four types, which contain gills to breathe in water without any problem, they have a streamlined body which helps them to swim freely in water, they are Cold-blooded which helps them to survive in the cold water, they have general fins which help them to swim also.

1) Gills- Fish, like us and all other animals, need a constant supply of oxygen to survive. Our atmosphere is 20% oxygen, so we can take it easily from air through our lungs. Gills enable fish to absorb oxygen from the water, as they do not chemically break down water, ${H_2}O$ to derive Oxygen. They absorb ${O_2}$ that is dissolved in the water. There are only about 4 to 8 parts per million of oxygen in water, compared to 20% in the atmosphere of lung-breathing.
2) Colouration- Fish are often coloured to match their background, and some can change colour to blend in with their surroundings. Large spots on the rear parts of some fish fool predators.
3) Sense Organ- Light does not penetrate to the deepest depths of the ocean, other senses have become much more refined in fish, some fist has also adapted to detecting vibrations in the water. A Shark can detect one part per million of blood in water.
4) Locomotion- The streamlined bodies of fish are perfectly adapted to moving through the water.

Note: Dolphin and Sharks are more efficient than other fishes, that can directly collect Oxygen from water.