Archaebacteria

Description

Archaebacteria live in extreme environments, such as near volcanic activity or other dangerous places like that. They do not even need oxygen or sunlight, and they have no cell nucleus nor any other membrane-bound organelles within their cells. There are three divisions of archaebacteria:  Methanogens: Methane producing organisms  Thermophiles: These can live in extremely hot, acidic environments like sulfur springs.  Halophiles: Can only live in bodies of concentrated salt water, like the Dead Sea.

Divergent Event

Live in extreme environments

Bacteria, archaea, and eukaryotes represent separate lines of descent that diverged early on from an ancestral colony of organisms. However, a few biologists argue that the Archaea and Eukaryota arose from a group of bacteria. In any case, it is thought that viruses and archaea began relationships approximately two billion years ago, and that co-evolution may have been occurring between members of these groups. It is possible that the last common ancestor of the bacteria and archaea was a thermophile, which raises the possibility that lower temperatures are "extreme environments" in archaeal terms, and organisms that live in cooler environments appeared only later. Since the Archaea and Bacteria are no more related to each other than they are to eukaryotes, the term prokaryote's only surviving meaning is "not a eukaryote", limiting its value.

Body Plan is unicellular.

Metabolism

• Autotroph - an organism that is able to form their organic nutrients from inorganic substances.
• Chemoautotroph - an organism that obtains its energy by the oxidation of electron donors in their environment.

Archaea exhibit a great variety of chemical reactions in their metabolism and use many sources of energy. These reactions are classified into nutritional groups, depending on energy and carbon sources.

Nutritional Types In Archaeal Metabolism

Nutritional type	Source of energy	Source of carbon	Examples
Phototrophs	Sunlight	Organic compounds	Halobacteria
Lithotrophs	Inorganic compounds	Organic compounds or carbon fixation	Ferroglobus, Methanobacteria or Pyrolobus
Organotrophs	Organic compounds	Organic compounds or carbon fixation	Pyrococcus, Sulfolobus or Methanosarcinales

Digestion: no specific system.

Nervous: no specific system.

The Dead Sea

Circulatory: no specific system.

Respiratory: no specific system.

Reproduction
Archaea reproduce asexually by binary or multiple fission, fragmentation, or budding; meiosis does not occur, so if a species of archaea exists in more than one form, all have the same genetic material. 
Cell division is controlled in a cell cycle; after the cell's chromosome is replicated and the two daughter chromosomes separate, the cell divides. Details have only been investigated in the genus Sulfolobus, but here that cycle has characteristics that are similar to both bacterial and eukaryotic systems. The chromosomes replicate from multiple starting-points (origins of replication) using DNA polymerases that resemble the equivalent eukaryotic enzymes. However, the proteins that direct cell division, such as the protein FtsZ, which forms a contracting ring around the cell, and the components of the septum that is constructed across the center of the cell, are similar to their bacterial equivalents.

Examples

Methanogens

Halophiles

Thermophiles