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Chapter 2: Locomotion and Transport (F5)
Locomotion involves the movement of the whole organism from one place to another.Movement refers to a change in position of any part of the an organism's body. Insects and crustaceans such as crabs have exoskeleton . Exoskeleton consists of a hard material formed outside the body. Vertebrates have endoskeletons. An endoskeleton is a hard bony structure made of calcium and phosphate. The human skeleton has two main parts : the axial sekelton and the appendicular skeleton. The axial skeleton consists of the skull, the vertebral column, sternum and ribs. The appendicular skeleton consists of the pectoral girdle, forelimb, pelvic girdle and hindlimb. A joint is the place where bones meet. Bones are held together by ligaments at the joint. Muscles are attached to bones through tendons . A limb moves when a pair of muscles carry out opposite actions. When the biceps contracts and triceps relaxes, the forearm is raised. It is lowered when the triceps contracts and the biceps relaxes. Earthworms, grasshoppers and fish move with the help of antagonistic muscles which are attached to the surface of the skeleton. Balanced diet , good posture , proper attire for daily activities and proper exercise techniques keep our skeleton and muscles healthy.Problems associated with movement and support include muscle cramps, osteoporosis , muscular dystrophy and arthritis . Support in plants is achieved by having air sacs, aerenchyma tissue and buoyancy in water for aquatic plants. In terrestrial plants, support can be through turgidity in herbaceous plants or through schlerenchyma tissue and lignified xylem vessels and tracheids in woody plants.
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