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SA – 1 (2016-17) Class – 6 Science Lesson - 7 Getting to know plants Define the following: 3.stem-The part of the plant above the ground that is generally green .It forms the main axis of the plant body which bears leaves , flowers and fruits. 6.venation-The pattern of veins on the leaf blade is called venation. A leaf can have a number of veins running parallel to each other or a network of veins called reticulate venation. 7. climbers-Plants in which weak stem take support of the neighbouring structures and climb up. Ex-pea and money plant. 8. Creepers-Plants having weak stems that spread on the ground and cannot stand upright. Ex-mint Rest definitions from keywords Answer the following: VII. 1. Functions of Root (i) Roots fix the plant (or anchor the plant) to the soil and provide support. (ii) Roots absorb water and mineral salts from the soil which are then conducted upwards to the stem and leaves. (iii) Roots help in holding the soil together, thus, preventing erosion or blowing away of the soil particles. 2. Root system and shoot system.Refer page 72 3. Tap root and Fibrous root. Refer page 72 4. Tap roots : Mustard, pea, tulsi, rose (any two) Fibrous roots : Wheat, maize, banana, sugarcane (any two) 5. Root, stem and leaves. 6. Functions of Stem : (i) A stem bears the leaves, flowers and fruits. It serves as a link between the roots, the leaves and flowers. (ii) The stem and its branches hold the leaves in such a manner that the leaves get maximum possible sunlight. (iii) When young it is green and manufactures food through the process of photosynthesis. (iv) It carries water and mineral salts from the roots to the leaves and flowers. (v) It carries food manufactured in the leaves to roots and other parts of the plant body. 7. Node : Place on the stem from where the leaves and branches arise. Internode : Part of the stem between two nodes. 8. Differences between Root and Stem : Root (a) Nodes and internodes absent. (b) Never green. (c) Leaves and buds absent. (d) Generally develops below ground. Stem (a) Nodes and internodes present. (b) Often green. (c) Bears leaves and buds. (d) Generally develops above ground. 9. Photosynthesis is essential as this is the process by which food is prepared by the leaves for the plant body.refer page no 77 for detail 10. The central part of the flower is the female part, consisting of a flask-shaped organ, called the Diagram pistil. Each carpel consists of a basal swollen part called the ovary. The ovary continues into a long style and ends in a knob like part, called the stigma. The ovary contains small, bead-like structures called ovules. Female sex cell is present inside the ovule. Ovules and ovary finally develop into seeds and fruits respectively. 11. Functions of a Flower (i) A flower is the seat or organ of sexual reproduction and results in the formation of fruits and seeds. Seeds on germination give rise to new plants. A flower, thus, results in multiplication of plants. (ii) It is the source of food for many insects. For example, bees collect nectar from flowers and make honey. (iii) Flowering plants are grown in gardens and in homes because of the bright colours and fragrance of the flowers. They, thus, beautify the surroundings and provide aesthetic value. 12. Sepals, petals, stamens and pistil. write all the points given on page no 80 in figure 7.16 VIII. 1. Lower line – root Upper line – stem 2. Stem 3. Leaf 4. Flower 5. Stem Lesson 8 Body Movements V.Name the structure: 1. Cockroach : Muscles near the legs help in walking; breast muscles attached to the wings help in flying. 2. Snail : Snail deposits a little fluid at its front end and walks over it; the shell is dragged along with the foot on the fluid. 3. Earthworm : Circular and longitudinal muscle fibres present on the body wall. 4. Fish : Streamlined body; strong muscles in the fins and tail. 5. Birds : Streamlined body; strong breast muscles attached to the forelimb bones push or pull the wings. 6. Snakes : Muscles attached to the backbone, ribs and skin. VI. Define the following: 1. Skeleton : Framework of the body formed by bones and cartilages which support and protect the organs and keep the body upright. 2. Locomotion : Act 0f moving from place to place in search of food, shelter or better environmental condition. 3. Movement : Change in position of only a part of the body. 4. Joint : Place where two or more bones meet is called joint. They allow movement to take place. 5. Tendons : Fibres which attach muscles to bones. 6. Cartilage : Soft, elastic structure of the skeletal System which can bent easily. 7. Endoskeleton : Internal skeleton system which is made up of bones. VII.Name the joints: 1. Teeth and gums - Immovables joint 2. Finger - Hinge joint 3. Skull - Immovable joint 4. Knee - Hinge joint 5. Shoulder - Ball and socket joint VIII.Differentiate between: 1. Tendons Ligaments Fibres which attach muscles to bones are called Tendons . The bones are held together at a joint by tough structures called ligaments. 2. Hinge joint Ball and socket joint 1. Allows movement in 1. Allows movement in one direction only. all directions 2. Bones are fixed in such 2. Spherical end of one a way that a hinge-like bone fixes into socketstructure is produced. like (cup-shaped) cavity of another bone. IX. Answer the following: 1. Locomotion helps the animals in many ways. (i) Animals need to move from place to place in search of food, since they are heterotrophic. Locomotion helps the animals to move in search of food. (ii) Locomotion enables animals to move from an unfavourable place or environment to a favourable place or environment. (iii) It helps them to escape from their enemies and predators. (iv) It helps animals to find their partners for reproduction, and to move to favourable areas for egg laying or rearing of the young ones. 2. Joints allow the locomotion in humans with the help of bones and muscles. 3. Functions of Skeletal System (i) Protection : It protects delicate internal organs from injury. (ii) Provides form and shape to the body. (iii) Movement : Bones provide a surface to which muscles are attached. Contraction and relaxation of muscles produce movement. 4. The act of moving from place to place is known as locomotion. It involves the movement of the whole body, as in walking, running, swimming or flying. Movement is the change in position of only a part of the body, as movement of stem towards light in plants. 5. Cockroaches are insects which come out at night to feed. They can walk, climb as well as fly in the air. Two pairs of wings are present. Also, three pairs of legs are present which help in walking. Bones are not present and the body is covered with a hard outer skeleton. This outer skeleton is made of different units joined together, and this permits movement. Muscles present near the legs help in walking, while the breast muscles attached to the wings help in flying. 6. You can observe the movements in an earthworm by placing it on a piece of paper. When it moves, the front (anterior) end becomes long and thin while its hind (posterior) end becomes short and thick. This is due to the contraction and expansion (relaxation) of body muscles. Thus, locomotion in earthworm is brought about by contraction and relaxation of body muscles. The body secretes a slimy substance which helps in movement. For locomotion in a snail perform Activity 5. 7. Ball and socket joint : In this joint, the round head (like a ball) of one bone fits into a cup-shaped cavity formed by the other bone. This allows movement in all directions. For example, you can move your shoulder and hip in all directions. 8. Fins and tail are present on the body of a fish. Strong muscles are also present. During swimming, muscles make the front part of the body curve to one side and the tail moves towards the opposite side, forming a curve. Then, quickly, the body and tail curve to the other side. This produces a jerk and pushes the body forward. A series of such quick jerks make the fish swim forward. 9. Birds are adapted to fly in the air and walk on the ground. Like the fish, birds too have a streamlined body. The bones are hollow and light. Bones of the forelimbs are modified into wings. The strong breast muscles which are attached to the forelimb bones help in pushing or pulling the wings. This action of the breast muscles helps in flying. 10. (i) Immovable joints : There is a fixed joint between the upper jaw and the rest of the head. (ii) Slightly movable joints : Such joints are present between adjacent vertebrae in the backbone. (iii) Freely movable joints : Freely movable joints are of three types : (i) Ball and socket joint - Found in hip and shoulder. (ii) Hinge joint - Found in elbow, knee and fingers. (iii) Pivot joint - Found in neck. 11. On both sides of the upper arm bone, there is a pair of voluntary muscles. When one of these muscles contracts, it pulls the bones of the arm. This act bends or straightens the elbow joint. The muscles at the joint work in pairs — one makes the joint bend while the other makes it straight. The biceps muscle contracts when bending of arm takes place. When it contracts, it pulls the two bones of the forearm, bringing them close together. This makes the arm bend at the hinge joint at the elbow. When the arm is straightened, the biceps muscle relaxes. The triceps muscle, however, contracts and helps in straightening. The working together of the biceps and triceps muscles allow the arm to move in both directions. *****************