The Living Organisms and Their Surroundings

Living organisms are found almost everywhere, from hot deserts and snowy mountains to oceans, ponds and grasslands. The place where an organism lives and gets food, water, shelter and other needs is its habitat. Habitats on land are terrestrial, such as forests, grasslands, deserts and mountains, and those in water are aquatic, such as ponds, lakes, rivers and oceans. Each habitat has biotic components, the living plants and animals, and abiotic components, the non-living rocks, soil, air, water, light and temperature. In this chapter you will learn that the special features that help an organism survive in its habitat are called adaptations. The camel has long legs, humps and passes little urine; the fish has a streamlined body, gills and fins; mountain trees are cone-shaped with sloping branches; the cactus has spines instead of leaves and a fleshy stem. Small changes within one lifetime are acclimatisation. Finally, you will study the characteristics of living things: they need food, grow, respire, respond to stimuli, excrete, reproduce and move.

Detailed Worksheet: The Living Organisms and Their Surroundings Section A - Definitions (10 marks) 1. What is a habitat? Name the two main types of habitats with one example each. (2 marks) 2. Distinguish between biotic and abiotic components with two examples each. (2 marks) 3. What is adaptation? How is it different from acclimatisation? (2 marks) 4. What is a stimulus? Give two examples of responses to stimuli. (2 marks) 5. What is excretion? How do plants get rid of wastes? (2 marks) Section B - Calculations and Applications (15 marks) 6. Name the habitat and one adaptation of each: (i) camel (ii) fish (iii) yak (iv) cactus (v) lotus (vi) polar bear. (3 marks) 7. Classify into biotic and abiotic components of a pond: water, fish, frog, sunlight, algae, soil at the bottom, air, lotus, temperature. (3 marks) 8. A student kept seeds in three conditions: (i) dry cotton (ii) wet cotton in sunlight (iii) seeds under water. After 4 days, only set (ii) germinated. State which abiotic factors were missing in sets (i) and (iii), and what this shows. (3 marks) 9. In desert areas, day temperatures may reach 50 degrees C and night temperatures may fall to 5 degrees C. (i) Find the difference. (ii) How do desert animals like rats and snakes cope with daytime heat? (iii) Why does a camel pass small amounts of urine? (3 marks) 10. A frog lives both in water and on land. (i) What are such animals called? (ii) Give two adaptations of the frog for water. (iii) Give one adaptation for land. (3 marks) Section C - Diagrams (10 marks) 11. Draw a labelled diagram of a fish showing its streamlined body, gills, fins and scales. Explain how each feature helps it live in water. (4 marks) 12. Draw a labelled diagram of a cactus plant showing spines, fleshy stem and roots. State how each part helps it survive in the desert. (3 marks) 13. Draw a labelled diagram of a mountain tree showing its cone shape and sloping branches. Explain how this shape helps in snowy regions. (3 marks) Section D - Analysis and Higher-order Thinking (15 marks) 14. A deer and a lion live in the same forest. (i) Give two adaptations of the deer that help it escape from predators. (ii) Give two adaptations of the lion that help it hunt. (iii) Why do both have eyes in different positions? (iv) What would happen to the deer population if all lions disappeared? (5 marks) 15. A person from the plains goes to a high mountain and feels breathless for a few days, but slowly gets used to it. (i) Why does she feel breathless? (ii) What is this getting used to called? (iii) How is it different from the adaptation of a yak? (iv) Name one adaptation of mountain animals for cold. (5 marks) 16. Paheli says, "A car moves, uses fuel and gives out smoke, so it is a living thing." (i) List the characteristics of living things. (ii) Which of these does a car not show? (iii) Is the car living? Explain. (iv) Why is a seed considered living even though it does not move? (5 marks) Instructions: Time allowed 2 hours. Attempt all sections. Draw all diagrams neatly in pencil and label every part.