Bacteria

The physical and chemical requirements for growth can vary widely among different species of bacteria, and some are found in environments as extreme as cold polar regions and hot, acid springs.

In general, the physical requirements for bacteria include proper temperature, pH and osmotic pressure. The anatomy of a typical bacterium. Illustration by Hans & Cassidy. Courtesy of Gale Group. Most bacteria thrive only within narrow ranges of these conditions, however extreme those ranges may be.