Problem 183 - Objective Biology for NEET

Question

Air bladder which regulates buoyancy is present in (a) Cyclostomata (b) Cartilaginous fish (c) Bony fishes (d) Amphibians

Step-by-Step Solution

Answer

The correct answer is (c) Bony fishes. Bony fishes are the only group among the given options that possess a swim bladder or air bladder, which helps them to control their buoyancy.

Step 1: Review Available Information

The question asks which of the following categories of animals has an air bladder. The choices are Cyclostomata, Cartilaginous fish, Bony fishes, and Amphibians. To answer this question, one must possess knowledge about animal taxonomy and the characteristics of these animal groups.

Step 2: Identification of the correct group

Consider the animal groups which typically contain a swim bladder or air bladder. Among the given options, Bony fishes possess an air bladder that allows them to control their buoyancy. So, Bony fishes is the correct answer.

Step 3: Making the final conclusion

After evaluating the given options and matching them with the available information on the presence of air bladder, it can be concluded that the Bony fishes is the animal group that has an air bladder.

Key Concepts

Buoyancy Regulation

Buoyancy regulation is an essential feature in aquatic life, especially for bony fishes. This is because it helps them maintain a stable position in the water without constantly expending energy to swim. Imagine trying to stay afloat without becoming too buoyant or sinking; that's how fishes regulate their position in the water column. This regulation involves controlling their density relative to the water around them. Key points to understand about buoyancy regulation:

• Bony fishes have an adaptation that helps them control buoyancy, known as the swim bladder. It's like a built-in, biologically-controlled buoyancy device.
• The swim bladder aids the fish in rising or sinking in the water by adjusting the volume of gas within the bladder.
• Without such regulation, fishes would either sink to the bottom or float to the surface, requiring much energy to swim constantly.

By regulating their buoyancy, bony fishes can conserve energy, move efficiently, and thrive in diverse aquatic environments.

Swim Bladder

The swim bladder is a fascinating organ found mainly in bony fishes, playing a crucial role in their ability to control buoyancy. Located in the dorsal region of the fish, the swim bladder can inflate or deflate to help maintain neutral buoyancy. Think of it as the fish's personal flotation device. Here's how the swim bladder works:

• It is a gas-filled sac, whose gas volume can be varied to control the fish's buoyancy.
• The bladder fills with gas from the bloodstream. By increasing the amount of gas, the fish becomes more buoyant and can ascend.
• Conversely, by losing some gas, the fish becomes less buoyant and can descend.

This simple yet vital organ allows bony fishes to hover at different depths, adapt to various aquatic conditions, and remain energetically efficient.

Animal Taxonomy

Animal taxonomy is a scientific system used for classifying and naming organisms. It helps organize and categorize living things, like a library system for animals, allowing scientists to study and understand the incredible diversity of life. Some aspects of animal taxonomy related to our discussion:

• "Bony fishes" are classified under the class Osteichthyes. They are distinguished from other fish by having a skeleton primarily made of bone, unlike cartilaginous fishes whose skeleton is made of cartilage.
• Animal taxonomy also distinguishes between other groups mentioned in the exercise, like Cyclostomata (jawless fishes) and cartilaginous fishes.
• Categorizing animals helps in understanding evolutionary relationships, such as why certain fish have swim bladders and others don't.

With taxonomy, we can grasp why bony fishes possess certain traits, like the swim bladder, which sets them apart in the ecological landscape.