i) Biodegradable wastes :- are wastes which aredecomposed into harmless substances bymicroorganisms. Eg :-vegetables, fruits, pulses, cereals, cotton, jute, wool,wood, leather, paper, animal dung, animal bones etc.ii) Non biodegradable wastes :- are wastes which arenotdecomposed by microorganisms. Eg :- polythene bags, plastics, syntheticfibres, glass,metals, synthetic rubber, insecticides, pesticides etc.
Ecosystem :- An ecosystem consists of all the living organisms in an area along with the non living components and their interaction. There are different types of ecosystems. They are :- i) Natural ecosystems :- like forests, deserts, grass lands, mountains, ponds, lakes, rivers, oceans etc.ii) Artificial ecosystems :- like gardens, parks, crop fields, aquarium, zooetc.Components of an ecosystem :- An ecosystem consists of two main components. They are biotic andabiotic components. i) Biotic components :- are the living components like plants, animalsand microorganisms. They consist of producers, consumers and decomposers. Producers :- are green plants which produce food by photosynthesis. Consumers :- are herbivores which get their food directly from plants, carnivores which get their food indirectly from plants and omnivoreswhich get their food directly or indirectly from plants. Decomposers :- are microorganisms which decompose dead plants and animals. They decompose complex organic substances into simpleinorganic substances in the soil which are again used by plants.ii) Abiotic components :- are the non living components likeair, water, soil, minerals, sunlight , temperature, wind etc.
FOOD CHAIN:-A food chain is the flow of food energy from one organism to thenext and to the next and so on. They usually start with a producer(plants) and end with a carnivore. In a food chain an organism getsfood from one group of organisms.
FOOD WEB:-Food web is a group of several interconnected food chains.In a food web an organism gets food from more than onegroup of organisms.
Human activities affect the environment :-Depletion of ozone layer in the atmosphereManaging garbage we produceSeawage treatment
Land fills RecyclingProduction of biogas and manure Preparation of compost
Natural resources:-Natural resources are the resources available in a nature likeair, water, sunlight, soil, minerals, forests, wild life etc. Natural resources are of two main types. They are renewable and nonrenewable natural resources. i) Renewable natural resources :- Are the resources which can be replenished in a short period of timelike air, water, sunlight, forests etc.ii) Non renewable natural resources :- Are the resources which cannot be replenished in a short period oftime like minerals (coal, petroleum, natural gas, metals etc.) becausethey take millions of years to be formed. Human activities produce a lot of waste materials which are thrownaway into the environment. These wastes cause pollution of naturalresources like air, water and soil.
WE ARE GOING TO KNOW ABOUT:NEED FOR MANAGEMENTING NATURALRESOURCESIMPORTANCE OF FORESTSCONSERVATION OF FORESTSUSES OF WATERADVATAGES &DISADVANTAGES OF DAMSIMPORTANCE OF WILDLIFECONSERVATION OF WILDLIFECOAL AND PETROLEUMACID RAIN FORMATION