The modern, six-kingdom system has evolved from those earlier systems. Keep in mind that as we learn more about life on Earth, this system will most likely be revised. The chart below illustrates the six-system classification model. They differ from other forms of life by having distinctive cell membranes and different genetic and chemical properties. Autotrophic species of archaebacteria produce food by chemosynthesis.
Some members produce flammable gases, such as methane, as waste products.
Archaebacteria are known to live in harsh environments such as sulfurous hot springs, very salty lakes, and oxygen deprived environments such as the intestines of animals. You are in constant contact with these types of bacteria for they are responsible for such things as tooth decay, changing milk into yogurt, and some types of food poisoning. Most species of eubacteria use oxygen but there are a few species that are anaerobic. Even though eubacteria and archaebacteria are small organisms, they are very important for they make up the largest number of living things on Earth. They both reproduce primarily by binary fission.