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
Cavalier-Smith's system of classification distinguishes chromists from plants. Cavalier-Smith's eighth kingdom, Archezoa is now defunct. He now assigns former members of the kingdom Archezoa to the phylum Amoebozoa. Cavalier-Smith referred to what remained of the protist kingdom, after he removed the kingdoms Archezoa and Chromista, as the "kingdom Protozoa". In 1993, this kingdom contained 18 phyla as summarized in the following table: The phylum Opalozoa was established by Cavalier-Smith in 1991. By 1998, Cavalier-Smith had reduced the total number of kingdoms from eight to six: Animalia, Protozoa, Fungi, Plantae (including red and green algae), Chromista and Bacteria. Five of Cavalier-Smith's kingdoms are classified as