The organism survives only if the surrounding environment favours. But it takes thousands of years of evolution to find its right place. Its existence is only to restore the balance in the nature as much as fast it can. Because the organism moves one place to another and help elements to meet one another which can't do themselves, in a result the reaction happen. The extinction happens when the balance between naturally existing elements and living organism was disturbed. The Earth has seen such five mass extinctions and now on the verge of s... read the rest.