Bacteria in Nature

Abstract

Bacteria share this earth with all other living organisms. They appeared first about 3.5 billion years ago and monopolized this planet for the next two billion years before other types of single-celled organisms evolved. Multicellular organisms arrived a mere 700 million years ago. Owing to their metabolic versatility, bacteria established themselves not only in the earth’s three elements, soil, water, and air but have also occupied almost all possible ecological niches. They are thus ubiquitous in true sense. In order to accomplish successful establishment in a particular environment, all living organisms have to adapt and adjust to the prevailing physico-chemical conditions as well as with the other members of the living populations, and bacteria are no exception. The ecological adaptations may be broadly reflected in two directions: (i) occupying a niche where biological competitions can be avoided. This would be exemplified by extreme environmental conditions such as hot geothermal vents or freezing icy conditions, and (ii) associating with other organisms occupying the same niche.