1. Archaea
Korarchaeota
- Of the 4, Korarchaeota is the lesser known kingdom. They have only been found in high
temperature hydrothermal environments. They have evolved differently through different
phylogenetic levels according to temperature, salinity of their environment, and/or geography.
Korarchaeota are commonly found in low quantities. Korarchaeotais from the hot spring
obsidian pool (Yellowstone national park) and is one of the most primitive of all life forms.
Because the kingdom is so unexplored, only their nucleic acids have been detected, and no
organisms have been isolated or cultured.
Euryarchaeotes
-This group is separated from others because of their rRNA sequences. This kingdom is
separated in mainly two classes that include: methanogens which produce methane and are found
in the intestines, as well as halobacteria that survive in extreme concentrations of salt. Other
microorganisms from this kingdom include extremely thermophilic aerobes and anaerobes.
Crenarchaeotes
-They are classified as either a phylum of the Archaea kingdomor a kingdom of its own. They
also were thought to be extremophiles but they have also been identified abundantly in marine
environments. Many have the ability to grow at up to 113 °C.These organisms stain Gram
negative and are diverse having rod, cocci, filamentous and oddly shaped cells.
Nanoarchaeota
-It has just been recently discovered in the sea. Very small in size and has a minimalist genome.
To help the scientist discover this species, an electron micrograph was used. It was found in a

2. submarine hot vent deep in the ocean. The cells are spherical and 400 nm in diameter. They grow
attached to the surface of an archaeal host.
Bacteria
Proteobacteria
-This includes a variety of pathogens. They are Gram-negative and this means that they do not
retain the violet dye in the Gram staining protocol. The other organisms that are not pathogens
are free-living bacteria that are responsible for nitrogen fixation. This group is defined in terms
of their ribosomal RNA sequences. Also, this is the second largest group of bacteria.
Chlamydias
- This is a bacterium that is known as obligate intracellular parasites. Also, this bacterium
is the most common bacterial sexually transmitted infections in humans, and causes
blindness. And commonly the infection doesn’t have symptoms.
Spirochetes
- They belong to a phylum of Gram-negativebacteria, which have long, helically coiled
(spiral-shaped) cells. Their lengths range between 5 and 250 µm. They are distinguished
from the other bacterial phyla by the location of their flagella. Most of the spirochaetes
are free-living and anaerobic, although there are numerous exceptions.
Cyanobacteria
-Also known as blue-green algae, blue-green bacteria, and Cyanophyta. They obtain their energy
through photosynthesis. The name "cyanobacteria" comes from the color of the bacteria. The
ability of cyanobacteria to do oxygenic photosynthesis is thought to have converted the reducing
atmosphere into an oxidizing one, which changed the composition of life forms on Earth by

3. making biodiversity and leading to the near-extinction of oxygen-intolerant organisms.
Cyanobacteria can be found in almost every terrestrial and aquatic habitat.
Gram-positive bacteria
-They are distinguished by when staining; they appear dark blue or violet by Gram staining. This
is in contrast to Gram-negative bacteria, in which they cannot retain the crystal violet stain.
Gram-positive organisms are able to retain the crystal violet stain because of the high amount of
peptidoglycan in the cell wall. Most pathogens in humans are Gram-positive. They have a
cytoplasmic lipid membrane and a thick peptidoglycan layer as well as a flagellum in certain
species.