| Biodegradable Substance | Substances that can be broken down into carbon dioxide, water, methane or other simple organic matter naturally by decomposers (microorganisms). |
| Non-Biodegradable Substance | Substances which cannot be decomposed into the soil by natural agents are known as non-biodegradable substances. These substances consist of plastic materials, bottles, hazardous chemicals, etc. |
| Ecosystem | An ecosystem is a natural system that is interactive and self-sustaining system consisting of all plants, animals, and micro-organisms (biotic factors) in an area functioning together with all the non-living physical (abiotic) factors of the environment. |
| Biotic components | It refers to all the living things in an ecosystem. All the animals, the plants, and the microorganisms are considered to be the biotic component of the ecosystem. |
| Abiotic Components | It refers to all the non-living components of the ecosystem. Soil, light, water, temperature, minerals, etc. are the abiotic components of the ecosystem. |
| Natural ecosystem | Ecosystems that occur naturally like the desert, grassland, forest, pond, marine ecosystems. |
| Artificial ecosystem | Man-made ecosystems like the aquarium, park, botanical garden, etc. |
| Autotrophs | Autotrophs are the organism that possesses the capability of producing food on its own using the inorganic raw materials, chlorophyll molecule and solar energy. They are also referred to as producers. The food produced by them are generally sugar and starch. |
| Heterotrophs | The organisms that cannot produce food on its own and depend on the producers for food are referred to as heterotrophs. |
| Producers | Producers are organisms that make their own food. |
| Consumers | Organism that needs to eat (consume) to obtain their energy. |
| Herbivore | All the organisms that depend directly on the producers for food or energy. (e.g., Cow, Goat, deer, grasshopper, etc.) |
| Carnivore | All the organisms that feed on other animals for their food requirements. (e.g., Lions, Tigers,etc.) |
| Omnivore | Organisms that depend on both plants and animals for their food energy are referred to as Omnivores. (e.g., Human, Crow, etc.) |
| Decomposers | These are the organisms that break down complex organic matter into inorganic substances like carbon dioxide, water, and nutrients by the process of decomposition. |
| Food Chain | Food chain refers to a series of event where food and energy are transferred from one organism to the next organism in an ecosystem. |
| Food Web | It refers to a system of interdependent food chains and represents a more realistic view of the consumption relation in an ecosystem. |
| Energy Flow | It refers to the flow of energy in a food chain |
| 10% Law | The 10% law states that, only 10% of energy is transferred from one trophic level to the next trophic level in a food chain, while the rest 90% of it is lost as heat into the environment and some of it is used in digestion or respiration and for doing other work like growth, repair etc. |
| Biological Magnification/ Biomagnification | It is the gradual increase in the concentration of a toxic substance like DDT, in the tissues of an organism at the successive higher trophic levels in a food chain. |
| Ozone Layer | It is a protective layer on the stratosphere consisting of a high concentration of Ozone gas, that prevents the harmful high-frequency ultraviolet rays from damaging life on earth. |
| CFC | It is an organic compound consisting of carbon, chlorine and fluorine used in the manufacture of aerosol sprays, as solvents, as refrigerants, etc. In the stratosphere, it can react with the ozone molecule and break it down for and form ozone hole. Owing to this, the UNEP has decided to phase out CFC. |
| UNEP | United Nation Environment Programme. It is an agency of United Nations and coordinates its environmental activities, assisting developing countries in implementing environmentally sound policies and practices. |
| Biogeochemical cycles | The Cycling of elements like hydrogen, oxygen, nitrogen, carbon, phosphorous and sulfur, through the living organisms and the environment. The term biogeochemical refers to the biological (involving organisms like bacteria, plants, and animals), geological (involves processes like weathering of rocks) and chemical (processes like the formation of new molecules) aspect of each of the cycle. |
