Concept of movement and locomotion

Movement in organisms

Movement is the act of changing position or posture, either by the whole organism or part of the organism. There are different types of movement in organisms, including movement of curvature (growth movement) and locomotion.

Types of movement

Movement of locomotion

1. This type of movement involves the whole organism moving from one place to another.
2. It is exhibited in animals and some protoctists (single-celled organisms), with various forms of movement such as:
   1. Amoeboid movement
   2. Ciliary movement
   3. Flagellar movement
   4. Muscular movement

Amoeboid movement

1. Organisms: Seen in protozoans like Amoeba and white blood cells (WBC).
2. Mechanism: This movement is caused by the streaming of cytoplasm towards a peripheral region of the cell, forming projections called pseudopodia. The cytoplasm flows into these projections, pulling the rest of the cell in the same direction, resulting in movement.

Ciliary movement

1. Organisms: Exhibited by some protozoans like Paramecium and larvae of some aquatic animals.
2. Mechanism: The body of these organisms is covered by cilia (tiny hair-like structures). The cilia beat in a coordinated way, moving backward and forward. This motion propels water backward, which, in turn, pushes the organism forward.

Flagellar movement

1. Organisms: Seen in organisms like Euglena, Chlamydomonas, Trypanosoma, and some bacteria.
2. Mechanism: Flagella (whip-like structures) are similar to cilia but longer. In organisms like Euglena, the whipping action of the flagellum creates a swirling of water around the organism. This causes the organism to rotate and move forward.

Muscular movement

1. Organisms: Found in animals where muscles contract and relax to bring about movement.
2. Mechanism: Muscles alone can't create fast movement without support, so animals have a skeleton (a firm, hard structure) to which muscles attach, allowing the organism to move quickly and efficiently.

Importance of movement in animals and plants

1. Search for food and shelter: Movement allows organisms to find food and suitable places for shelter.
2. Avoiding negative stimuli: Movement helps organisms escape from harmful stimuli like predators, chemicals, or fire, providing protection.
3. Mating: Movement enables organisms to come together for mating, ensuring reproduction.
4. Response to positive stimuli: Movement allows organisms to move towards beneficial stimuli like light, gravity, and water, promoting growth and survival.