Locomotion vs Movement
The most visible activities that encounter the stored energy in organisms are the movements and locomotion. These activities keep the organisms or parts of them in motion. Although both locomotion and movement sound similar in the meaning, there are some interesting differences between the terms when those are incorporated with the organisms, especially with animals. Having stated about the animals, it should not be concluded that plants would not show movements; there are very interesting movements in plants too. When the facts about both locomotion and movement are followed, the difference between the two could be easily understood.
Locomotion
Locomotion is the movement of an organism from one place to another. The locomotion of human or other animals is not difficult to understand, and it is accomplished through walking, running, leaping, jumping, gliding, flying, or swimming using their legs, wings, flippers, or fins. However, humans have developed many other ways of locomotion through technological advances in transportation such as aircrafts, boats, or ground vehicles. The natural means of locomotion in other animals such as microorganisms or coelenterates are highly interesting.
Hydra, the coelenterate, shows different types of locomotion; somersaults, walking with upside down body, climbing with tentacles, walking with bent and straightened body, gliding, and floating upside down beneath the water surface. Flagella in Chlamydomonas and cilia in Paramecium could be considered as some classic examples for basic structures of locomotion. However, the adjustment of the body to create temporary locomotion structures is another primitive adaptation for the function, which is depicted in pseudopodia of Amoeba. However, there are organisms (plankton and other microorganisms) without specialized structures developed to accomplish locomotion, yet they move from place to place. The use of water or wind currents happens to be the aid of their locomotion, and they do not spend energy for that.
Movement
All the organisms encounter movement at different levels including cellular, tissue, organ, or entire organism. Movements are the most visible means of the expenditure of energy that have been stored in organisms. When the animals walk, the muscles designed for walking are contracted and relaxed accordingly. Similarly, all the movements are incorporated with a muscle or a set of muscles so that the required movement is accomplished through muscle contraction and relaxation. Movements in organisms could be classified into two major groups known as voluntary and involuntary.
Voluntary movements can be willingly controlled for an organism. Walking, running, speaking, writing, and an umpteen number of movements can be understood as voluntary movements. On the other hand, the involuntary movements cannot be willingly controlled. Beating of the heart is a classic example for the involuntary movements. The movements incorporated with the digestion of food in the digestive system are mostly involuntary while the chewing and swallowing of food at the oral cavity are voluntary. It would be interesting to know that breathing can be controlled willingly as well as it takes place involuntarily. In addition, it would be important to state that there are an infinite number of cellular movements incorporated in all the biological processes.
What is the difference between Locomotion and Movement?
• Locomotion takes place at organism level while movement can take place at any biological level from cellular to organisms.
• Locomotion is usually voluntary while movement could be either voluntary or involuntary.
• Movement essentially requires energy, but locomotion does not essentially require energy when the free-floating organisms are considered.
• Usually plants do not move from place to place, but there are various types of movements take place inside plants.