Archaebacteria
Domain: Archaea
Description: Organisms of the Kingdom Archaebacteria are fascinating creatures. They lack membrane-bound organelles and have a circular chromosome like eubacteria. At the same time, Archaebacteria lack peptidoglycan in their cell walls yet have several kinds of RNA polymerase like eukaryotes. Finally, Archaebacteria have the potential to survive in extreme environments, a trait exclusive to its kingdom only. Whether it be in extreme heat, cold, salinity, radiation or acidity, it is certain that Archaebacteria will flourish. Divergent Event: Having split from Eubacteria nearly 3 billion years ago, Archaebacteria is an ancient kingdom. Living in areas such as sulfur-rich volcano springs and deep-sea hydrothermal vents, Archaebacteria display traits different from Eubacteria in order for survival in extreme conditions. |
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Body Plan: Archaebacteria are unicellular. Due to their small
size, Archaebacteria prize quantity, cooperating in the millions to enhance
their survival rates.
Metabolism: Some Archaebacteria are chemoautotrophs, like obligate anaerobic methanogens which use carbon dioxide and inorganic chemicals while releasing methane as a by-product. Others, like Halobacteria, are photoautotrophs, using sunlight for their metabolism. Finally, some are heterotrophic, like Sulfolobus which uses hydrogen sulfide or elemental sulfur.
Digestion: Heterotrophic Archaebacteria use extracellular digestion. They secrete enzymes to break down compounds into smaller and easily absorb the pieces.
Nervous: Archaebacteria do not have nervous systems.
Circulatory: Archaebacteria, due to their high surface-area to volume ration, can rely on passive and active transport for the intake of substances.
Respiratory: Archaebacteria do not have respiratory systems.
Reproductive: Archaebacteria, like Eubacteria, reproduce by binary fission. They split into identical organisms, but mutations occur often. They can improve genetic diversity through conjugation between two organisms, which is the transfer of genetic material (plasmids) via a pilus tube. Transformation, or the intake of plasmids from the environment, is another source of genetic diversity. Finally, viruses can inject their own genetic material into Archaebacteria, called transduction, and enhance genetic diversity.
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Metabolism: Some Archaebacteria are chemoautotrophs, like obligate anaerobic methanogens which use carbon dioxide and inorganic chemicals while releasing methane as a by-product. Others, like Halobacteria, are photoautotrophs, using sunlight for their metabolism. Finally, some are heterotrophic, like Sulfolobus which uses hydrogen sulfide or elemental sulfur.
Digestion: Heterotrophic Archaebacteria use extracellular digestion. They secrete enzymes to break down compounds into smaller and easily absorb the pieces.
Nervous: Archaebacteria do not have nervous systems.
Circulatory: Archaebacteria, due to their high surface-area to volume ration, can rely on passive and active transport for the intake of substances.
Respiratory: Archaebacteria do not have respiratory systems.
Reproductive: Archaebacteria, like Eubacteria, reproduce by binary fission. They split into identical organisms, but mutations occur often. They can improve genetic diversity through conjugation between two organisms, which is the transfer of genetic material (plasmids) via a pilus tube. Transformation, or the intake of plasmids from the environment, is another source of genetic diversity. Finally, viruses can inject their own genetic material into Archaebacteria, called transduction, and enhance genetic diversity.
Click on the following link to view the works cited: