Locomotion and Movement

Introduction:

· Movement is one of the significant features of living beings. Animals and plants exhibit a wide range of movements.

· Streaming of protoplasm in the unicellular organisms like Amoeba is a simple form of movement.

· Movement of cilia, flagella and tentacles are shown by many organisms.

· Human beings can move limbs, jaws, eyelids, tongue, etc.

· Locomotion: Some of the movements result in a change of place or location. Such voluntary movements are called locomotion. Walking, running, climbing, flying, swimming are all some forms of locomotory movements. Locomotory structures need not be different from those affecting other types of movements. For example,

ü In Paramoecium, cilia helps in the movement of food through cytopharynx and in locomotion as well.

ü Hydra can use its tentacles for capturing its prey and also use them for locomotion.

ü We use limbs for changes in body postures and locomotion as well.

Hydra vulgaris

Paramecium

· The above observations suggest that movements and locomotion cannot be studied separately. The two may be linked by stating that all locomotions are movements but all movements are not locomotions.

· Methods of locomotion performed by animals vary with their habitats and the demand of the situation. However, locomotion is generally for search of food, shelter, mate, suitable breeding grounds, favourable climatic conditions or to escape from enemies/predators.

Types of Movement:

Cells of the human body exhibit three main types of movements, namely,

· Amoeboid

· Ciliary

· Muscular

Amoeboid Movement:

Some specialised cells in our body like macrophages and leucocytes in blood exhibit amoeboid movement. It is effected by pseudopodia formed by the streaming of protoplasm (as in Amoeba). Cytoskeletal elements like microfilaments are also involved in amoeboid movement.

Ciliary Movement:

Ciliary Movement occurs in most of our internal tubular organs which are lined by ciliated epithelium. The coordinated movements of cilia in the trachea help us in removing dust particles and some of the foreign substances inhaled along with the atmospheric air. Passage of ova through the female reproductive tract is also facilitated by the ciliary movement.

Muscular Movement:

Movement of our limbs, jaws, tongue, etc., requires muscular movement. The contractile property of muscles is effectively used for locomotion and other movements by human beings and majority of multicellular organisms. Locomotion requires a perfect coordinated activity of muscular, skeletal and neural systems.