When one species occupy an area leading to declining or disappearance of other species; this changes in the composition of species in any given area is called ecological succession. When succession occurs in an area where no living organism ever existed; it is called Primary Succession and when it takes place in the area that has lost all living organisms that had existed there; it is called Secondary Succession. Newly created ponds, bare rock are examples of primary succession. Abandoned farmlands and burned forests are examples of secondary succession.