Plant Science Resource

  Main phytogeographical regions of India            A phytogeographical region is defined as an area of uniform climatic conditions and having a distinctly recognisable type of vegetation.The classification of a land mass on the basis of natural flora i.e., phytogeographical classification does not correspond with the political boundary.   In India ecological factors are variable and so the flora are also quite variable from place to place. Opinion varies from author to author regarding the similarity and dissimilarity. According to  D.Chattarjee (1962) , India can be divided into nine phytogeographical regions.   1. Western Himalayas This region comprises north and south Kashmir, part of Punjab and Kumaon region of Uttaranchal. Average annual rainfall in the region is 100-200 cm.

  Relevance of laws of thermodynamics in ecology.                         Thermodynamics is a branch of science deals with the transformation of energy and the relation between the farms of energy. According to the concept of themodynamic almost all processes including life processes of organism require energy. In energetic, energy has been defined as the capacity to do work. In biological system, the source of energy is the chemical energy which is produced by plants through photo synthesis. All the organisms use these chemical energy either directly or indirectly. This energy not only used to maintain life process but also their survivility in the ecosystem.                         On the basis of quantitative estimation, two laws of thermodynamics have been proposed. Both the laws are applicable in ecosystem. First law of thermodynamics in ecosystem : It states that the amount of energy in the universe is constant. It may change from one farm to another but it can neither be c