Microorganisms that thrive at conditions deemed too hostile for most other life on earth are called extremophiles. These can include extreme temperatures, highly acidic or alkaline environments, and extremely salty environments. Some organisms have also been found almost as deep as 1.4 kilometres below the surface of the earth.
Extremophiles are classified based on the type of environments they exist. For example, acidophiles are organisms that thrive in very acidic environments – the pH levels would be at least 3.0 or below. On the other end of the spectrum are alkaliphiles that survive in pH levels of 9.0 and above. A halophile is an organism that grows well in an environment with high concentrations of dissolved salts.
Among the many classification of bacteria, the most unusual of these is the radioresistant microbes. Able to easily withstand doses of over 5,000 Grays, the Thermococcus gammatolerans is a single-celled microorganism and the world’s most radiation-resistant organism. For reference, a dose of 5 Grays is lethal to a human, 60 Grays is enough to kill all cells in a colony of E.coli.
These microorganisms may also have been the very first forms of life when the earth was relatively young. Four billion years ago, the earth was a different place that had hellish temperatures and hostile landscapes. It would make sense why extremophiles would have been the first organisms to ever evolve on earth. Moreover, these organisms may easily survive an apocalyptic event or mass extinctions. They are also expected to survive long after humans become extinct.
Today, life on earth is found in many places – from the highest mountains to the deepest caves. However, some microorganisms are found in even more extreme places. Explore more about extremophiles or other related topics by registering at BYJU’S. Discover other fascinating topics from agriculture and dairy farming to chloroplast and plant cells by subscribing to BYJU’S YouTube channel.