Our Environment

One Marks Questions

Answer: An ecosystem is a geographical area where all organisms such as plants, animals, human, microorganisms as well as physical surroundings interact with each other.

Answer: All living Organisms like a plant, animal, micro Organisms are biotic components Non-living things like soil, air, water are abiotic components.

Answer: Natural and artificial ecosystem

Answer: producers are green plants that prepare their own food.

Answer: Each step of the food chain is called a trophic level.

Answer: Several food chains are interconnected to form a food web.

Answer: The concentration of chemical substance increase as it moves from one tropic level to other.

Answer: ozone

Answer: chlorofluorocarbons.

Answer: Loss of energy takes place in the form of metabolic heat when one organism consumes another.


Two Marks Questions

Answer: If we kill all the organisms in one trophic level, the transfer of energy and matter to the next tropic level stops it from disturbing the food chain and ecosystem collapse.

Answer: during the transfer of organic food energy from one traffic level to the next traffic level only about 10% of the transfer energy is stored as flesh.

Answer: Grass → Grasshopper → Frog → snake.

Answer: if all decomposers are eliminated From the earth then decomposition of dead organisms do not occur earth will be full of dead bodies.

Answer: according to the 10% law, the energy flow from one tropic level to another traffic level is 10% therefore energy available to a lion is 200 J.

Answer: a food chain’s length is restricted to three or four steps due to energy loss shorter the food chain the more energy that is available to the final consumer.

Answer: the concentration of chemical substance increases as it moves from one Tropic level to another trophic level in a food chain example DDT.

Answer: temperature, rain, soil, wind.

Answer: in a food web, each Organism is eaten by two or more other kinds of organisms so a food web is a complex network of many interconnected food chains.

1. skin cancer
2. Damage to the eye
3. Effect on immunity
4. Can change the structure of DNA

Three Marks Questions

Answer: Trophic levels are different steps in a food chain. The traffic level is the level of species in an ecosystem based on the source of nutrition such as producers, primary consumers, secondary consumers etc the producers from the first traffic level as they manufacture food The primary consumers from the second tropic level, the secondary consumers from the third traffic level and tertiary consumers from the 4th Tropic level.