How do Setae work in locomotion


Locomotion, Locomotion, the ability of animal organisms to actively change location. It is common to almost all non-fixed animal creatures (as well as some lower plants, fungi, unicellular organisms and some germ cells). At F., chemical energy is converted into mechanical energy. According to the variety of living beings and their habitats, the variations of the F. are very diverse.

Animals without extremities often move through Snaking away. The reciprocal contraction of the longitudinal muscles creates a flexion of the body to one side or upwards or downwards, which runs in waves from front to back. The flexion generates a sideways and a backwards directed force, whereby the sideways directed forces cancel each other out and the rearward directed force is summed up. Typical examples are snakes, creeps, eels and the movement of the side fins of rays and also some mammals living in water such as otters, seals and dolphins. In the peristaltic movement of the earthworm, the force is generated by the ring and longitudinal muscles surrounding the body like a jacket. The contraction of the circular muscles creates pressure on the body cavity fluid, which cannot be compressed; the result is a longitudinal stretching of the animal corresponding to the non-contracted longitudinal muscles, which are stretched at the same time. Conversely, the contraction of the longitudinal muscles causes the circular muscles to stretch by shortening and widening the animal. Waves of contraction of the circular and longitudinal muscles now alternately run from back to front, with propulsion being generated by the contraction of the circular muscles. The movement of the screws is also based on a hydraulic mechanism. Outwardly visible features are from the back to the front Foot waveswhich are brought about by successive phases of contraction and relaxation of the dorsoventral foot muscles. Their contraction causes lifting off the ground and stretching of the sole. In the following relaxation phase, the muscles are stretched again by the fluid pressure in the neighboring tissue, the elastic sole sinks and, moved a little forward, forms a new anchoring point with the ground.

Animals with a hard part skeleton have levers (the extremities) as organs of locomotion. These are lifted by lifting muscles and led forward; flexor muscles attacking in opposite directions are stretched. By placing the extremity on the ground, a solid anchorage point is created. The activity of the flexors pulls the animal's trunk forward. The position of the limbs and the gait are of great importance. Limbs attached to the side of the body (e.g. in amphibians) require part of the muscle power to force the body off the ground. The raised leg must be put forward in an arc around the resting leg. Fast running is excluded. In mammals, on the other hand, the legs start under the torso. The body is carried almost without expenditure of energy. At the same time, a pendulum-like swinging out of the extremities is possible, which also allows a fast run. With the change of gait, the rhythmic and energetic side of the F. in particular changes. There are numerous specializations of the F. with the help of levers (Jump, Leap, Climb, dig).

The locomotion in the substrate, the dig E.g. of mussels in the sea floor, similar to earthworms, are based on contraction waves of the muscles, which generate a pressure in the body cavity that presses uncontracted sections firmly against the substrate. At the same time, they will be extended. In the case of mussels, the shell, which automatically opens when the ligament is pulled, acts as an attachment point, while the foot is driven into the sediment by liquid pressure. Drilling in solid substrate can either be done by dissolving it (e.g. in the case of limestone rock) or, as e.g. in the case of Teredo (shipworm), by rasping the wood. (Bipede, gaits, walking, flight of insects, swimming, flight of birds)