Saturday, November 19, 2022

From two domains to three domains to two domains: Prokarya, Eucarya, and Archaea from 1977 to today

When I took high-school biology in the late 1970s, we learned about two basic domains of life: the Prokarya and the Eucarya (roughly, bacteria and multicellular organisms). But at the same time, in the Woesian revolution (after Carl Woese) a third domain of life was beginning to be identified: the Archaea (originally discovered as extremophiles in extreme conditions, such as hot springs, but now known to be everywhere). I learned about the three-domain system about twenty years ago, but today I learned that the recent discovery of the Asgard group of Archaea has led to hypotheses that there are only two domains after all, with Eucarya being included in the Archaea. (Andrew Shields, #111words, 19 November 2022)


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