Problem 5 - Objective Biology for NEET

Question

Nervous system of hydra is composed of (a) Ganglia chain (b) Vertical ganglion chain interconnected by commissure (c) Network of nerves (d) Brain

Step-by-Step Solution

Answer

The correct answer is (c) Network of nerves.

Step 1: Understanding the Hydra's Nervous System

The nervous system of a hydra isn't as complex as that of more developed animals. It does not have a brain or a central nervous system. Instead, it has a simple nerve net, which is a type of nervous system found in more simple organisms.

Step 2: Matching the Given Options With the Correct Answer

Knowing about the hydra's simple nerve net, it's easier to select the correct choice from the given options. The nerve net of a hydra is not organized into ganglia or a brain, so option (a), (b) and (d) are incorrect. The correct match would be a 'network of nerves' which corresponds to option (c).

Key Concepts

Nerve Net

A nerve net is one of the simplest forms of a nervous system. It is commonly found in organisms that do not have a centralized nervous system, like brains or ganglia. Instead, the nerve net is a diffuse network of interconnected nerve cells, or neurons.

• This network is spread throughout the body of the organism, allowing it to respond to stimuli from any direction.
• Since there are no central hubs, the nerve net can coordinate basic movements and actions.
• It helps organisms detect sensations such as touch, aiding them in responding to their environments.

In hydras, the nerve net does not control complex processes. It manages simpler tasks like contracting the body, which is fundamental for feeding and movement.

Simple Organisms

Simple organisms, like hydras, provide fascinating insights into early nervous systems. These organisms often possess basic structures, reflecting their less complex life processes.

• They do not require intricate systems because their survival tasks are straightforward and repetitive.
• The simpler nervous systems form the basis of understanding how more complex nervous systems evolved over time.

Despite their simplicity, these organisms are well adapted to their environments. Their nerve nets allow them to interact with the world, even if in basic ways. Understanding simple organisms helps explain the evolutionary path leading to complex brains and intricate networks seen in more advanced life forms.

Hydra

The hydra is a small, freshwater organism that is often used in biological studies. These creatures belong to the phylum Cnidaria and showcase very rudimentary nervous systems.

• Hydras are known for their regenerative abilities, which allow them to recover from injuries effectively.
• They lack a brain and a centralized nervous system, relying instead on their nerve net for various bodily functions.

The simplicity of a hydra’s body plan makes it an ideal candidate for studying basic biological and neural processes. They are quite small, typically measuring just a few millimeters. Their ability to regenerate and their simple nerve net make hydras excellent subjects for research into cellular biology and neural development.