LOCOMOTION IN AN EARTHWORM-SPM 2005 ( 5 marks)
-An invertebrate which has a hydrostatic skeleton.
-Body wall has longitudinal and circular muscles
-These muscles act antagonistically to cause movement
-Contractions of circular muscles cause the segments to extend while longitudinal muscles relax //Conversely the contractions of the longitudinal muscles cause segments to shorten.
-Locomotion takes place when the chaetae secure shortened segments in the posterior to the ground while //The anterior segments extend owing to contractions of the circular muscles.
-Fluid in the body cavity helps the earthworm to move.
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