Biology · Locomotion and Movement · NEET
Locomotion is a type of movement. Movement is the bigger, general term for any change in position of a body part. Locomotion is the smaller, special group inside movement where the WHOLE body shifts from one place to another. NCERT states it clearly: all locomotions are movements, but all movements are not locomotions. If a NEET question reverses this and says 'all movements are locomotions', it is wrong.
Because many movements happen without the animal changing its location. Your heart beats, your eyelids blink, your tongue moves, and cilia in your trachea sweep dust, but your body stays in the same place. These are movements but not locomotion. Only when the whole body moves to a new place (walking, running, flying, swimming) does it become locomotion.
Both. The streaming of protoplasm inside Amoeba is a simple movement. But when Amoeba forms pseudopodia and crawls to a new place to catch food, that same mechanism causes locomotion. NCERT uses this to show that the same structure can produce both movement and locomotion, so the two cannot be studied separately.
Cilia in Paramoecium do BOTH. They move food through the cytopharynx (that is movement, no change of place) and they also propel the whole organism forward (that is locomotion). This is a favourite NEET example: locomotory structures need not be different from those used for other movements. Hydra tentacles are another example, used for both capturing prey and locomotion.
NCERT lists the reasons animals perform locomotion: to search for food, shelter, and a mate; to find suitable breeding grounds; to reach favourable climatic conditions; and to escape from enemies or predators. The method of locomotion varies with the animal's habitat and the demand of the situation.
Try the real previous-year questions from this chapter — each with the answer and a full solution.
Movement is any change in the position of a body part; locomotion is movement that changes the location of the whole body. Locomotion always involves movement, but movement need not involve locomotion.
Heartbeat, blinking of eyelids, movement of the tongue or jaws, and the sweeping of cilia in the trachea are all movements without any change of body location, so they are not locomotion.
NCERT describes locomotion as voluntary movements that result in a change of place, such as walking, running, climbing, flying and swimming. Involuntary movements like the heartbeat are movements but not locomotion.
Yes. In Paramoecium cilia move food and also cause locomotion; in Hydra tentacles capture prey and also help in locomotion; in humans limbs change posture and also help in walking. Structures need not be different for the two.
NEET frequently tests the exact NCERT statement 'all locomotions are movements but all movements are not locomotions' and the shared-structure examples (Paramoecium, Hydra, Amoeba). Knowing the direction of this relationship prevents easy silly mistakes.
