The present book is an attempt to make the people acquainted thoroughly with the
knowledge of ecosystem, and the factors concerned with the deterioration of the
environment and its valued resources with the view to plan and manage the
development programmes in such a way that exploitation of natural resources may
not upset the balance of nature. For the major part of the terrestrial habitat,
the natural vegetation was forest. All the organisms sharing the habitat had a
balanced but quite competitive adjustment along themselves. Indian region is a
treasure of wild genetic resource. Wild species and relatives of crop plants
contain valuable genes that are of