They're an amazingly complex and fascinating group of creatures. Bacteria have been found that can live in temperatures above the boiling point and in cold that would freeze your blood. They "eat" everything from sugar and starch to sunlight, sulfur and iron. There's even a species of bacteria--Deinococcus radiodurans--that can withstand blasts of radiation 1,000 times greater than would kill a human being.

Bacteria fall into a category of life called the Prokaryotes (pro-carry-oats). Prokaryotes' genetic material, or DNA, is not enclosed in a cellular compartment called the nucleus. Bacteria do a lot of things. Bacteria aren't always bad. The definition of bacteria is any of the unicellular prokaryotic microorganisms of the class Schizomycetes. These are some characteristics of bacteria. Bacteria don't have a recognizable nucleus. Some bacteria have chlorophyll and are producers. Bacteria break down waste for energy. Those are some characteristics of bacteria.

These are the shapes...