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www.researchgate.net/profile/J_Ta...chapter+2.pdf

Organisms interact and establish themselves in the ecosystem through population. Population is the assemblage of individuals belonging to a particular species. Population biology provides the first basic information about any species and is regulated by both abiotic and biotic factors. Earthworms are fundamental to the dynamics of the ecosystem. The principal functions of earthworms are decomposing organic materials, cycling nutrients, improving plant growth by providing nutrients in easily assimilable form and improving soil structure. They also provide suitable growing media for microorganisms by ejecting casts. The population size of the earthworms is influenced by various edaphic factors like temperature, moisture, pH and mineral nutrients.