Class 6 chapter 8 ppt 3
- 2. CARTILAGE • Part of the skeleton that is not hard as bones and can be bent, is cartilage. • They are found in the upper part of the ear, the tip of the nose and at the tips of long bones.
- 3. MUSCLE • Muscles are parts of the body that help in bringing about movement. • Muscles may be attached to bones, (humans) or may work alone (earthworm). • Muscle works in pair . When one of them contracts , the bone is pulled in that direction . The other muscle relaxes .
- 4. GAIT OF ANIMALS • The different patterns of movement of animals due to the differences in their skeletal structure are called gaits of animals. • EARTHWORM : The earthworm does not have any internal skeleton. • The body is made up of many rings joined end to end and muscles attached to these rings help to extend and shorten the body. • The skin of earthworm also has a large number of tiny bristles that help it get a good grip on the ground. • Repeated extension and contraction of the body muscles, enable the earthworm to move through the soil.
- 5. GAIT OF ANIMALS • SNAIL : Snails move with the help of their muscular, flat foot. • They glide along a solid surface which is lubricated with mucus. • This motion is powered by succeeding waves of muscular contractions of the foot.
- 6. GAIT OF ANIMALS • COCKROACH : The body of a cockroach is covered with a hard outer skeleton that is made of different units joined together. • It has three pairs of legs for walking and two pairs of wings attached to the breast for flying. • It has distinct muscles that are used for movement. • The muscles attached to the legs help in walking. • The breast muscles attached to the wings help in flying, although they are not good flyers.
- 7. GAIT OF ANIMALS • FISH : Fishes have a streamlined body that helps them swim with least resistance. • They use tail fin for small jerks through water and other fins assist swimming. • The tail fin is also used for changing directions. • Head and tail of fish is smaller than middle portion , body tapers at both ends . This body shape is called Streamlined
- 8. GAIT OF ANIMALS • BIRDS : Birds have a special skeletal and muscular structures that help them to fly. • The forelimbs are modified to become wings and the bones inside are hollow to suit flying. • The bones of the hind limbs are used for perching and walking. • The shoulder bones and breastbones are strong and support muscles of flight, which move the wings up and down.
- 9. GAIT OF ANIMALS • HOW DO SNAKES MOVE ? • Snakes have long backbone . Snakes do not have legs for movement but use their long backbone along with muscles for movement. • Their body curves into many loops, which gives it a forward push by pressing against the ground.