Eubacteria vs Archaebacteria
All living things are categorized into two main groups such as prokaryotes and eukaryotes. Bacteria, which belong to the Monera kingdom, are a well-known prokaryotic organism. In 1970, a new organism was identified, and it was different from bacteria as implied in DNA analysis. So, later this classification was changed as Eubacteria, Archaebacteria and Eukaryota. However, “Archaebacteria” is not an accurate term for this new organism since they are not bacteria, so they are called Archaea. This group is considered as the primitive living organisms of the planet. Although Archaea and eubacteria are considered as two groups, they are prokaryotic organisms.
Archaea is unicellular, and it is found in extreme environments such as in deep sea, hot springs, alkaline or acid water. The early planet had different environment composition from the environment of today. This oldest living organism had tolerance for that harsh environment.
The three phyla of Archaea are methanogens, halophiles, and thermoacidophiles. Methanogens can produce methane and are obligate anaerobes. They can be seen in human and some other animal’s intestinal tracts. Halophiles, as their name implies, can be found in salt environments such as Dead Sea, the Great Salt Lake. Habitats of the thermoacidophiles are high tempered acidic environments such as volcanic and hydrothermal vents.
Eubacteria are all bacteria except Archaea, and they are more complex than Archaea. Eubacteria can live in both harsh conditions and normal conditions. Generally the term “bacteria” is used for the eubacteria and can be seen everywhere. Eubacteria can be categorized into several groups according to several common characteristics. The way of obtaining food, shape and structure, the way of respiration, and the way of mobility are some of them.
Eubacteria can be classified into three phyla; namely, cyanobacteria, spirochetes and proteoticbacteria. Cyanobacteria have chlorophyll pigments like in plants and do not have flagella. Spirochetes are long and slender bacteria, which have rotating movements. For such kind of movement, they have flagella. They are symbionts in ruminants as well as cause diseases. This phylum consists free-living organisms and parasitic forms as well as aerobes and anaerobes. Proteoticbacteria belong to gram positive bacteria, which are aerobes or anaerobes, but most of them are anaerobic.
What is the difference between Archaea and Eubacteria (or Bacteria)?
• Archaea is a separate kingdom from the eubacteria, although both of them are prokaryotes.
• Archaea has different evolution from the eubacteria as DNA analysis implies.
• Archaea membrane lipids are ether linked, while eubacteria membrane lipids are ester linked.
• Archaea is single celled or simple structure compared to eubacteria.
• Archaea live in harsh conditions such as in deep sea, hot springs, alkaline or acid water, whereas eubacteria can be found in either environment.
• Archaea has three phyla called methanogens, halophiles, and thermoacidophiles, while eubacteria has cyanobacteria, spirochetes and proteoticbacteria.
• Eubacteria has photosynthetic members, whereas Archaea has not.
• It is hard to study about Archaea since they live in harsh conditions and culturing of Archaea is much difficult than eubacteria.
• Transcription factors are needed for the protein synthesis in eubacteria, but not in Archaea.