These Archaea species live in extreme heat near deep sea vents.
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Image courtesy of NOAA


Archaea was originally thought to be just another form of bacteria, but archaea is a much simpler form of life, simpler than a single-celled organism, which nevertheless contains DNA, the gene-code of life. If it weren't found at the bottom of the sea or buried inside of rocks, Archaea might resemble blue-green algae.

Archaea may be the oldest and oddest form of life. Most live in extreme environments. These are called extremophiles. Other Archaea species are not extremophiles and live in ordinary temperatures and salinities. Some even live in your guts!

Some extremophile species love the heat! They like to live in boiling water, like the geysers of Yellowstone Park, and inside volcanoes. They like the heat so much that it has earned the nickname "thermophile", which means "loving heat", and it would probably freeze to death at ordinary room temperature. Other extremophile Archaea love to live in very salty, called hypersaline, environments. They are able to survive in these extreme places where other organisms cannot. These salt-loving Archaea are called halophyles.

For energy, Archaea does not require sunlight as do plants on Earth, neither does it require oxygen as do animals. Archaea absorbs CO2, N2, or H2S for food, chemically transforms them, and gives off methane gas or sulfur as a waste product. An example for one of the relationships is given below. Notice that free oxygen is not involved. This is among secondary pathways for photosynthesis employed by these early bacteria.

Excess sulfur, as produced in this relationship was found in Earth's early atmosphere and ocean.

Planets which contain an environment wherein archaea might survive include Venus, the past environment of Mars, Jupiter, Saturn, and Jupiter's moon Io.

Last modified April 29, 2004 by Lisa Gardiner.

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