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Locomotion is the ability to move or the movement itself. Learn more about this formal word, its synonyms and how to use it in sentences from the Cambridge Dictionary.
- Overview
- Principles
- Microorganisms
locomotion, in ethology, any of a variety of movements among animals that results in progression from one place to another.
To locomote, all animals require both propulsive and control mechanisms. The diverse propulsive mechanisms of animals involve a contractile structure—muscle in most cases—to generate a propulsive force. The quantity, quality, and position of contractions are initiated and coordinated by the nervous system: through this coordination, rhythmic movements of the appendages or body produce locomotion.
Animals successfully occupy a majority of the vast number of different physical environments (ecological niches) on Earth; in a discussion of locomotion, however, these environments can be divided into four types: aerial (including arboreal), aquatic, fossorial (underground), and terrestrial. The physical restraints to movement—gravity and drag—are the same in each environment: they differ only in degree. Gravity is here considered as the weight and inertia (resistance to motion) of a body, drag as any force reducing movement. Although these are not the definitions of a physicist, they are adequate for a general understanding of the forces that impede animal locomotion.
To counteract the force of gravity, which is particularly important in aerial, fossorial, and terrestrial locomotion, all animals that live in these three environments have evolved skeletal systems to support their body and to prevent the body from collapsing upon itself. The skeletal system may be internal or external, and it may act either as a rigid framework or as a flexible hydraulic (fluid) support.
To initiate movement, a sufficient amount of muscular work must be performed by aerial, fossorial, and terrestrial animals to overcome inertia. Aquatic animals must also overcome inertia; the buoyancy of water, however, reduces the influence of gravity on movement. Actually, because many aquatic animals are weightless—i.e., they possess neutral buoyancy by displacing a volume of water that is equal in weight to their dry weight—little muscular work is needed to overcome inertia. But not all aquatic animals are weightless. Those with negative buoyancy sink as a result of their weight; hence, the greater their weight, the more muscular energy they must expend to remain at a given level. Conversely, an animal with positive buoyancy floats to and rests on the surface and must expend muscular energy to remain submerged.
In water, the primary force that retards or resists forward movement is drag, the amount of which depends upon the animal’s shape and how that shape cleaves the water. Drag results mainly from the friction of the water as it flows over the surface of the animal and the adherence of the water to the animal’s surface (i.e., the viscosity of the water). Because of the water’s viscosity, its flow tends to be lamellar; i.e., different layers of the water flow at different speeds, with the slowest layer of flow being the one adjacent to the body surface. As the flow speed increases, the lamellar pattern is lost, and turbulence develops, thereby increasing the drag.
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Most motile protozoans, which are strictly aquatic animals, move by locomotion involving one of three types of appendages: flagella, cilia, or pseudopodia. Cilia and flagella are indistinguishable in that both are flexible filamentous structures containing two central fibrils (very small fibres) surrounded by a ring of nine double fibrils. The peri...
The movement of an organism from one place to another, often by the action of appendages such as flagella, limbs, or wings. In some animals, such as fish, locomotion results from a wavelike series of muscle contractions.
The meaning of LOCOMOTION is an act or the power of moving from place to place. How to use locomotion in a sentence.
Locomotion is the ability to move or the way things move and travel. Learn how to use this word in different contexts, see examples from literature and science, and find translations in various languages.
Unit 5: Locomotion and movement. 400 possible mastery points. Mastered. Proficient. Familiar. Attempted. Not started. Quiz.
Feb 24, 2022 · noun. The ability of cells or organisms to move and propel itself from place to place. Supplement. Locomotion in biology pertains to the various movements of organisms (single-celled or multicellular organisms) to propel themselves from one place to another.
