For example, organisms living inside hot rocks deep under Earth's surface are thermophilic and barophilic such as Thermococcus barophilus.A polyextremophile living at the summit of a mountain in the Atacama Desert might be a radioresistant xerophile, a psychrophile, and an oligotroph.Psychrophilic proteins have a small amount of proline amino acids because they cause a rigid structure.These adaptations allow psychrophilic proteins to be more flexible so they do not freeze under cold conditions.
They have a high amount of glycine amino acids, which small size allows for more flexibility within the protein once it is folded.
Some scientists even concluded that life may have begun on Earth in hydrothermal vents far under the ocean's surface. The domain Archaea contains renowned examples, but extremophiles are present in numerous and diverse genetic lineages of bacteria and archaeans.
Furthermore, it is erroneous to use the term extremophile to encompass all archaeans, as some are mesophilic.
Their chances of dying increase the longer they are exposed to the extreme environment.
There are many classes of extremophiles that range all around the globe, each corresponding to the way its environmental niche differs from mesophilic conditions. Many extremophiles fall under multiple categories and are classified as polyextremophiles.