There is 78% nitrogen in atmosphere. But this cannot be taken in by the organisms. It needs to be fixed as nitrates and then utilised. This cycle is divided into four phases - nitrogen fixation, ammonification, nitrification, and denitrification (Fig. 12). Phase # 1. Nitrogen Fixation: Fixation of nitrogen takes place by atmospheric and biological agents. Other than this it [...]
Decomposers are the final step in the food chain and they reduce the organic matter into inorganic forms so that it is once again available to the producers. The upper layer of soil is the main site for the action of decomposers. In this way, decomposers provide energy and nutrients to the producers. The upper layer of soil consists of [...]
Different populations interact with each other for the sake of food, shelter and for defense purposes. Interspecific interaction arise from the interaction between populations of two different species. These interactions may be positive, negative or neutral in nature to one of the species or both. The different interactions are summarised in Table 1. Type # 1. Positive Interaction: Mutualism and [...]