Lesson 1 of 12 · 6 min

Movement and locomotion

NCERT §17 (opening)

On the start line Meher blinks, swallows and shakes out her arms. None of that moves her a step down the track. Then the gun goes and she runs. What makes the running different?

The story this chapter follows: Meher's 800 m, from the inside

On Sports Day Meher ran the 800 m. By the last bend her thighs burned, and the next morning her legs were stiff. At the medical room the nurse pressed around her knee, bent it to and fro, and pointed to a skeleton chart on the wall. At home her grandmother, who takes calcium tablets for thin bones, asked how it went. This chapter follows the muscles that pulled, the bones that carried her and the joints that let her bend.

The lesson in notes

In short

Movement is a key feature of living things. Amoeba moves by streaming of its protoplasm; many organisms move cilia, flagella or tentacles; humans move limbs, jaws, eyelids and tongue.

When a voluntary movement takes the organism to a new place it is locomotion. Walking, running, climbing, flying and swimming all count.

The same structure can serve both purposes: Paramoecium's cilia move food through the cytopharynx and also move the animal, and Hydra's tentacles catch prey and help it move.

So every locomotion is a movement, but not every movement is a locomotion.

Animals move from place to place to find food, shelter, mates, breeding grounds or a better climate, and to escape enemies or predators.