15. Our Environment
1. Biodegradable Wastes: Substances that are broken down by biological processes are said to be biodegradable wastes.
Examples: cattle dung, cotton, jute, paper, fruit and vegetable peels, leaves etc.
Properties of biodegradable:
(i) These substances are broken down by biological process.
(ii) These mostly come from organic matters.
(iii) They do not harm environment.
2. Non-biodegradable Wastes: Substances that are not broken down in this manner are said to be non-biodegradable wastes.
Examples: plastics, polythene bags, synthetic fibres, metals, radioactive wastes.
Properties of non-biodegradable:
(i) These substances are not broken down by biological process.
(ii) These belong to non-organic matters.
(iii) These substances persist in environment and harmful for environment.
Eco-system: There are biotics components like plants, animals, microorganisms and human beings and abiotic components like air, land, temperature, rain, wind and minerals in our environment. These biotic and abiotic components form an eco-system.
Type of Eco-system:
(A) Natural eco-sysytem: The eco-system which is formed naturaly is said to be natural eco-system.
Example: Lake, Hills, Forest, River etc.
(B) Artificial eco-system: The eco-system which is made by human being is said to be artificial eco system.
Example: Farms, Garden, Ochard, Pond etc.
Components of Eco-system: There are two types of Components present in an eco-system.
(i) Biotic components: All organisms such as plants, animals, mircoorganisms and human being are known as biotic componnents.
(ii) Abiotic components: All physical factors of an environment like temperature, rainfall, wind, soil and minerals are known as abiotic componemts.
The dependence of biotic components:
In a eco-system all biotic components depend on abiotic components to grow and maintain their survival. As all these living organisms (biotic components of an eco-system) interact with each other and their growth, reproduction and other activities are affected by the abiotic components of ecosystem.
Example - All living organisms need temparature, water, nutrients and soil to live and grow. These all influence them.
Classification of Living organisms
On the basis of nutrition all living organisms are classified into following categories:
(1) Producers: Organisms which can produces their own food like sugar and starch from inorganic substances using photosynthesis in the presence of chlorophyll are called producers.
Examples: All green plants and certain bluegreen algae.
(2) Consumers: Organisms which consume the food produced, either directly from producers or indirectly by feeding on other consumers are the consumers.
Consumers are categorised into following categories.
(i) Herbivores: Organisms which take their food only by plants and plants products are called herbivores. Eg. Goats, cows, rabits etc.
(ii) Carnivores: Organisms which take their food only by animals and animals products are called carnivores. Eg. Lions, Tigers and Jackles etc.
(iii) Omnivores: Organisms which take their food by both plants and animals or their products are called omnivores. Eg. Crows, Humen and dogs etc.
(iv) Parasites: Some organisms take their food from other organisms to live in a host body such organisms are called parastes. Eg. Plasmodium, Lice, abdominal worms like scariasis, tape worm, round worm etc.
(3) Decomposers: Some organisms such as fungi and bacterias break-down the complex organic substances like dead and decay animals and plants into simple inorganic substances to decompose them into soil such microorganisms are called decomposers.