Archaea weren’t even discovered until 1977, and were thought to be rare and unimportant, but we are beginning to realize that they not only are abundant, but they have roles that have not fully been appreciated. ~ American oceanographer Andrew Thurber
Archaea are among the earliest life. Archaea are found most everywhere: in the seas and soil, the marshlands and the swamp known as the human colon. The methane of marsh gas, and of ruminant and human flatulence, are atmospheric contributions from resident methanogens, archaea all.
The archaea in oceanic plankton make them one of the most abundant organisms, comprising 20% of the Earth’s biomass. As planetary movers and shakers, at least by numbers, archaea have long played important roles in the carbon and nitrogen cycles of the biosphere.
Both bacteria and archaea reproduce asexually, by binary fission, fragmentation, or budding; but, unlike bacteria and some eukaryotes, no known archaea produce spores. Spores are offspring that can ride out hard times.
Many archaea are extremophiles, with exotic chemical processes within their single cell that fend off disruption by the habitat. When the going gets too tough, archaea form tough protective shells, stop their life processes, and wait it out for better days. An archaean itself becomes like a spore. Of all life, archaea are the ultimate survivors.