-SYSTEM — WHAT ARE ITS COMPONENTS? All organisms such as plants, animals, microorganisms and human beings as well as the physical surroundings interact with each other and maintain a balance in nature. All the interacting organisms in an area together with the non-living constituents of the environment form an ecosystem. Thus, an ecosystem consists of biotic components comprising living organisms and abiotic components comprising physical factors like temperature, rainfall, wind, soil and minerals.
For example, if you visit a garden you will find different plants, such as grasses, trees; flower bearing plants like rose, jasmine, sunflower; and animals like frogs, insects and birds. All these living organisms interact with each other and their growth, reproduction and other activities are affected by the abiotic components of ecosystem. So a garden is an ecosystem. Other types of ecosystems are forests, ponds and lakes.
These are natural ecosystems while gardens and crop-fields are human- made (artificial) ecosystems. You might have seen an aquarium. Let us try to design one. What are the things that we need to keep in mind when we create an aquarium?
The fish would need a free space for swimming (it could be a large jar), water, oxygen and food. We can provide oxygen through an oxygen pump (aerator) and fish food which is available in the market. If we add a few aquatic plants and animals it can become a self- sustaining system. Can you think how this happens?
An aquarium is an example of a human-made ecosystem. Can we leave the aquarium as such after we set it up? Why does it have to be cleaned once in a while? Do we have to clean ponds or lakes in the same manner?
Why or why not? We have seen in earlier classes that organisms can be grouped as producers, consumers and decomposers according to the manner in which they obtain their sustenance from the environment. Let us recall what we have learnt through the self sustaining ecosystem created by us above. Which organisms can make organic compounds like sugar and starch from inorganic substances using the