Notes On Our Environment - CBSE Class 10 Science
Balance in nature is maintained by the interaction between biotic components with that of abiotic components. The ecosystem is a community of organisms and their physical environment interacting with each other as an ecological unit, involving the flow of energy.        •  An ecosystem consists of biotic components including living organisms and abiotic components, the physical factors like temperature, rainfall, wind, soil and minerals.        •  An ecosystem can be natural or artificial. Organisms in the ecosystem can be categorised into producers, consumers and decomposers. Producers are the organisms that produce their own food without the help of any other organism.        •  They are also known as autotrophs.        •  They make their food from inorganic substances through a process called photosynthesis.        •  Autotrophs are green plants, phytoplankton and blue green algae. Consumers are the organisms which cannot produce food but depend on producers for the same.        •  These are also called as called heterotrophs.        •  Heterotrophs are the animals can be classified into herbivores, omnivores, carnivores and parasites based on their food pattern. Decomposers are the organisms which feed on dead and decaying matter.        •  Decomposers break down the complex organic compounds present in dead animals and plants, which are then used by other members of the ecosystem.        •  Decomposers like bacteria and fungi are known as saprobes. Food chains describe the feeding relationship between the organisms of an ecosystem.        •  The flow of energy from one species to another at various biotic levels forms a food chain.        •  The successive levels in the food chains of a community are called as trophic levels.        •  Various trophic levels in a food chain include producers, primary consumers, secondary consumers and tertiary consumers.        •  A web of cross-linked food chains is called a food web. Biological magnification is a phenomenon by which toxic substances accumulate from one trophic level to another. As human beings occupy the top level in any food chain, the maximum concentration of these toxic chemicals gets accumulated in your body which becomes toxic to us. Ozone is molecule formed by the combination of three oxygen atoms. There is a layer of ozone in the stratosphere. It acts as a natural sun-block and shields us from the UV radiations of the sun which are dangerous to living organisms.Ozone depletion is the sharp reduction of ozone in the stratosphere due to chlorofluorocarbons (CFC’s) used as refrigerants and in fire extinguishers. Increased use of non-biodegradable items have left the environment polluted with them.

#### Summary

Balance in nature is maintained by the interaction between biotic components with that of abiotic components. The ecosystem is a community of organisms and their physical environment interacting with each other as an ecological unit, involving the flow of energy.        •  An ecosystem consists of biotic components including living organisms and abiotic components, the physical factors like temperature, rainfall, wind, soil and minerals.        •  An ecosystem can be natural or artificial. Organisms in the ecosystem can be categorised into producers, consumers and decomposers. Producers are the organisms that produce their own food without the help of any other organism.        •  They are also known as autotrophs.        •  They make their food from inorganic substances through a process called photosynthesis.        •  Autotrophs are green plants, phytoplankton and blue green algae. Consumers are the organisms which cannot produce food but depend on producers for the same.        •  These are also called as called heterotrophs.        •  Heterotrophs are the animals can be classified into herbivores, omnivores, carnivores and parasites based on their food pattern. Decomposers are the organisms which feed on dead and decaying matter.        •  Decomposers break down the complex organic compounds present in dead animals and plants, which are then used by other members of the ecosystem.        •  Decomposers like bacteria and fungi are known as saprobes. Food chains describe the feeding relationship between the organisms of an ecosystem.        •  The flow of energy from one species to another at various biotic levels forms a food chain.        •  The successive levels in the food chains of a community are called as trophic levels.        •  Various trophic levels in a food chain include producers, primary consumers, secondary consumers and tertiary consumers.        •  A web of cross-linked food chains is called a food web. Biological magnification is a phenomenon by which toxic substances accumulate from one trophic level to another. As human beings occupy the top level in any food chain, the maximum concentration of these toxic chemicals gets accumulated in your body which becomes toxic to us. Ozone is molecule formed by the combination of three oxygen atoms. There is a layer of ozone in the stratosphere. It acts as a natural sun-block and shields us from the UV radiations of the sun which are dangerous to living organisms.Ozone depletion is the sharp reduction of ozone in the stratosphere due to chlorofluorocarbons (CFC’s) used as refrigerants and in fire extinguishers. Increased use of non-biodegradable items have left the environment polluted with them.

#### Activities

Activity 1 Wiley.com has composed an user interface to demonstrate the components of 'Ecosystem'. It interpreted different concepts like Communities, Interelationships, Energy flow, Components of ecosystem etc. Competition, Predator-prey relationship and Symbiosis are deciphered. Summary given at the end is an added feature. Review quiz is an added feature for this template. Go to Activity   Activity 2 Brainpop.com has devised a new game making the user construct food chain and food web with animals of his own choice. the game allows the user to select 2 animals of his own choice and start the food chain. It makes the interrelationships between the food chains and scores the selected animals. User feels the game interesting and is given 10 minutes for constructing his food web.   Go to Activity Activity 3 Ecokids.ca has provided the students with a simple template where it allows the user to know and construct an aquatic food chain and forest food chain.It also provides information about the energy flow in the food chain. Go to Activity Activity 4 Ozzyozone.org has designed a template in a comic way to explain the concept of 'Ozone layer and its Depletion'. It provides a clear explanation about ozone, location of ozone, what are the chemicals with which ozone reacts, and the process of hole formation in ozone are. This template is user-friendly and provides the information immediately when the button is clicked by the user. Go to Activity Activity 5 Manchester.ac.uk has created an interactive video to explain the concept of 'Global Warming'. It gives the student a chance to work on exercises as per the instructions given. Each and every stepis explained with reasons in a simple language. By getting equipped with information, user can understand the concept of global warming.   Go to Activity