Locomotion in Animals
Locomotion is the ability of moving from one place to another. Any variety of movements of animals that results in their progression from one place to another is known as animal locomotion. Usually, animals move by the means of walking, swimming, jumping, creeping, flying, contraction, or gliding. Let us have a look on the locomotion of few animals.
Locomotion in Jellyfish:
The jellyfish moves by the rhythmic contraction of its umbrella-shaped body. This rhythmic contraction is brought about by the contraction of muscles process. When body of jellyfish contracts, a jet of water is forced out of it which results in motion of jellyfish in the opposite direction. This type of motion is called “jet prospulsion”. Normally, jellyfish floats freely in water without any control over its locomotion.
Locomotion in Earthworm:
The body wall of earthworm consists of two types of muscles, which are longitudinal muscles and circular muscles. These are the “antagonistic muscles”. The contraction of circular muscles results in lengthening of body and contraction of longitudinal muscle results in shortening of body. The body is also covered with minute “setae” which are also used for locomotion. When the animal has to move, the posterior end of the body gets attached with the soil with the help of setae and the circular muscles of interior parts contracts, this result in lengthening of body. Then anterior end of the body anchors the soil and draws the posterior portion forward by the contraction of longitudinal muscles. Thus, locomotion of the earthworm is a co-ordinated activity of longitudinal muscles, circular muscles, and setae.
Locomotion in Starfish:
Locomotion in starfish and other echinoderms takes place by tube feet and system of fluid-filled tubes, together forming water vascular system. Tube feet is a muscular organ consisting of an upper sac like portion which is called AMPULLA. Ampulla is a tubular podium and a sucker like base. This type of locomotion in starfish is called hydraulic method for locomotion. When the starfish has to move, the muscle of Ampulla contracts and the water is forced out to the podium which extends the sucker-like base attached to the substratum. Thus, the water is withdrawn and the tube feet contracts, pulling the starfish forward.
Locomotion in Snakes:
Snake and other legless animals move by the means of anchoring with portions of body and pushing and pulling other parts of the body to that direction. This type of movement is called Concertina movement. When snake moves, its every single part has to experience the altering cycles of static state and moving state.