Domain Archaea

Domain Archaea consists of single-celled prokaryotic organisms — cells lacking a true, membrane-bound nucleus — specially adapted to survive in some of the most physically and chemically extreme environments on Earth, which is why they are collectively called extremophiles. Typical archaeal habitats include volcanic vents, hot springs and polar ice caps, conditions lethal to most other organisms.

Many Archaea can synthesise their own food without sunlight or oxygen, instead using inorganic chemicals such as hydrogen sulphide drawn from volcanic vents. Based on their specific habitat and metabolism, Archaea are grouped into methanogens (which produce methane as a metabolic by-product), halophiles (which thrive in extremely salty environments), and thermoacidophiles (which flourish in conditions that are simultaneously very acidic and very hot). A well-known example bridging Archaea biology with everyday laboratory science is Thermus aquaticus, a heat-tolerant organism from which the first thermostable …