The document discusses different ways of classifying bacteria based on their shape, staining properties, temperature and oxygen requirements, cell wall structure, and ability to form spores. Bacteria can be classified as cocci, bacilli, spirochetes, or vibro based on their shape. Classification is also done based on whether bacteria are gram positive or gram negative based on staining, or acid fast. Some bacteria are thermophiles, mesophiles, or psychrophiles depending on the temperature at which they grow best. Classification also considers if bacteria are aerobic, anaerobic, or facultative based on their oxygen requirements. The cell wall structure and ability to form spores are other bases for bacterial classification.