This photograph shows what Eubacteria look like under a
microscope. The Domain Eubacteria Eubacteria, also know as “true
bacteria”, are microscopic organisms that have prokaryotic
cells. Because of their prokaryotic cells, they have a rigid
cell wall but no mitochondria or other large organelles, and
they have a single chromosome that is not within a nucleus. Most
reproduce asexually. Cyanobacteria, also called blue-green
algae, are Eubacteria that have been living on our planet for
over 3 billion years. This bacterium grows in mats and mounds in
the shallow parts of the ocean. Today it is only common in
certain regions, but a few billion years ago, there was so much
of it that, through photosynthesis, it was able to add enough
oxygen to Earth’s primitive atmosphere for animals that require
oxygen could survive. Some Eubacteria can cause problems for
human health. For instance, Streptococci bacteria cause strep
throat. If Staphylococci bacteria gets into a cut in your skin
is can cause an infection that is ca