Our environment Worksheet-9

Our environment Worksheet-9


  1. What are functions of an ecosystem?


  1. Name the main components of an ecosystem.


  1. What do you call a functional unit, comprising of living and non-living components?


  1. Give two examples of man-made ecosystems.


  1. Why do all food chains start with plants?


  1. Give an example of a food chain that is the shortest.


  1. Give an example of an organism that acts and prey as well as predator in a food chain.


  1. Give two examples of organisms that generally occupy the top carnivore level.


  1. What are phytoplanktons?


  1. What are zooplanktons?


  1. Can an organism occupy position in more than one food chain? If so, give an example.


  1. Give proper term for each of the following :

(a) Smaller constituent operations unit of biosphere.

(b) Accumulation of non-biodegradable toxic substance in the increasing order in food chain.


  1. How is ozone layer formed?


  1. Which radiation is absorbed by ozone?


  1. Write the harmful effects of the ultraviolet rays.


  1. In which zone of atmosphere, ozone layer is present?


  1. What would happen if ozone layer in the atmosphere disappears?


  1. How does the ozone layer protect us from the harmful effects of the environment?


  1. What destructive effects do the chlorofluorocarbons bring about in the atmosphere?


  1. Name any two environmental problems caused by the various activities of human beings.



  1. (i) It draws nutrient from soil, air and water,

(ii) It fixes solar energy.


  1. Lithosphere, hydrosphere, atmosphere, biotic and abiotic components.


  1. Ecosystem.


  1. Aquarium, Wildlife sanctuary.


  1. Only plants can transform light energy into chemical energy by photosynthesis and produce food.


  1. Plants → Man.


  1. Frog is the prey and predator of insect in a food chain.


  1. Vulture and Kite.


  1. The aquatic plants which are photosynthetic microscopic, free floating and form producers in the aquatic ecosystem are called phytoplanktons.


  1. The aquatic animals which are microscopic, free floating and depend upon phytoplanktons for their food are zooplanktons.


  1. Yes.

For example, snake can occupy third and fourth trophic levels in different food chains:

(i)  Plants → Insects → Frogs → Snakes

(ii) Plants → Mice → Snakes.


  1. (a) Ecosystem (b) Biological magnification.


  1. Ozone is formed by the action of sunlight on oxygen of the air in the upper atmosphere, starting

at a height of about 16 km

The concentration of ozone is maximum at a height of about 23 km. This blanket of ozone around the earth is called ozone layer.


  1. Ultraviolet radiation.


  1. Harmful effects of UV rays are cataract, inflammatory diseases, cancer, etc.


  1. Stratosphere.


  1. Ultraviolet radiation would reach the earth and cause skin cancer and other problems.


  1. Ozone layer absorbs the harmful ultraviolet (UV) radiation of sunlight and thus protects us.


  1. Chlorofluorocarbons cause depletion of ozone layer.


  1. Our activities pollute the environment in various ways and some of the environmental problems are depletion of ozone layer and disposal of waste.