(DIV) Archaea and Eubacteria Lesson

Archaea and Eubacteria Lesson

Recall that the three domains of life are Eukarya, Archaea, and Bacteria. In the late 1970, the kingdom Monera was divided into two groups of prokaryotes- Archaea and Bacteria. This change led to the six kingdoms: Animalia, Plantae, Protista, Fungi, Archaea, and Bacteria. Biologists also recognized Eubacteria instead of Bacteria as one of the six kingdoms. Although both are single-celled organisms; Archaea and Eubacteria have distinctive characteristics that have classified them into two different groups. Archaea have many shapes. Eubacteria have three shapes: rod, spiral, and spherical. The cell walls of Archaea and Eubacteria are composed of different chemical compounds. While both have a cell wall; the cell wall of Archaea does not contain peptidoglycan. The lipids that make up their cell membrane are also different. Eubacteria and Archaea can live just about anywhere. They can be found in the polar ice caps, living things, and rocks.  

There are three major groups of Archaea. They are methanogens, thermophiles, and halophiles. As their name may imply, methanogens produce methane gas when they carry out their biological activities.

Methanogens can be found in swamps. Thermophiles can live in extremely hot environments such as deep sea hydrothermal vents and geysers. Halophiles live in very salty environments such as the Dead Sea and the Great Salt Lake in Utah. They can survive in waters with a saline content 10-15 times greater than the ocean. Halophiles are also aerobic, a living thing that needs oxygen to stay alive.

Eubacteria can live with or without oxygen. Blue green algae are an example of a photosynthetic eubacteria that lives in the ocean.   Eubacteria can also live in or on your body. Therefore eubacteria can sometimes make you sick. Salmonella is a type of eubacteria found in raw meat and eggs. Salmonella poisoning can make you very ill if your food is not cooked properly. Lactobacillus bulgaricus is a useful eubacteria. It is used in the production of yogurt.

 

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