Cylindrospermopsis raciborskii mild skin reactions upon exposure. The last two toxins, anatoxin-a and saxitoxin, are thought to be shellfish neurotoxins. Research has shown that "C. raciborskii" can naturally produce butylated hydroxytoluene, an antioxidant, food additive, and industrial chemical. Domain – Bacteria The Tree of Life contains three Domains: Bacteria, Archaea, and Eukarya. Kingdom – Bacteria Bacteria consists of prokaryotic microorganisms. They were among the first life forms to appear on Earth and appear in a wide variety of habitats. Phylum – Cyanobacteria This phylum is characterized by their ability to obtain energy through photosynthesis. They are often called the blue-green algae stemming
Bacteria sizes, called morphologies. Bacterial cells are about one-tenth the size of eukaryotic cells and are typically 0.5–5.0 micrometres in length. However, a few species are visible to the unaided eye—for example, "Thiomargarita namibiensis" is up to half a millimetre long and "Epulopiscium fishelsoni" reaches 0.7 mm. Among the smallest bacteria are members of the genus "Mycoplasma", which measure only 0.3 micrometres, as small as the largest viruses. Some bacteria may be even smaller, but these ultramicrobacteria are not well-studied. Most bacterial species are either spherical, called "cocci" ("sing". coccus, from Greek "kókkos", grain, seed), or rod-shaped, called "bacilli" ("sing". bacillus,