Haryana State Board HBSE 10th Class Science Notes Chapter 15 Our Environment Notes.
Haryana Board 10th Class Science Notes Chapter 15 Our Environment
What Happens When we Add Our Waste to the Environment?
Environment:
- The air, water and land in or on which people, animals and plants live is called environment.
- Biotic components such as plants and animals and abiotic components such as air, water, soil,etc. are the two components of environment.
Waste:
Unwanted or unusable items, remains or leftovers or by-products of household garbage together are termed as waste.
Biodegradable and non-biodegradable waste:
The waste materials, which are broken down to simpler substances by biological processes, are called biodegradable wastes, while those which cannot be broken down to simpler substances are called non-biodegradable wastes. For example, vegetables and fruits are biodegradable, while glass, plastics and polythene, etc. are non-biodegradable.
Ecosystem – What are its Components?
Food Chains and Webs
Food chain:
Living organisms of an ecosystem depend on each other for their food requirement and form a chain which is known as food chain.
In a food chain, the producers are at the first trophic level, the primary consumers (herbivores) at second, small carnivores i.e. secondary consumers at the third level and large carnivores or tertiary consumers at the fourth trophic level. The flow of energy in an ecosystem is always unidirectional.
Food web:
- The network of interconnected food chains functioning in an ecosystem is called food web.
- The relationship among individuals in the food chain is not represented by a straight line but as a series of branching lines which together form the food web.
Biological magnification:
When harmful chemicals and pesticides such as DOT, BHC, etc. enter in the food chain, level. The phenomenon is called biological magnification. Humans occupy the top level of any food chain. Hence, there is maximum concentration of harmful chemicals in humans. In other words blo-magnification is highest at the human level.
Ozone:
- Ozone (O3) is a gaseous molecule formed by three atoms of oxygen. It is a deadly poisonous gas. Ozone layer is located at the higher levels of the atmosphere i.e. in stratosphere.
- The ozone layer absorbs harmful ultraviolet rays coming from the sun and protects us. Unfortunately, this layer is depleting and this is posing a serious problem for our planet.