What are Archaea?
Archaea are a major group of prokaryotes, single-celled organisms without nuclei. In the three-domain system of classification introduced by Carl Woese in 1990, Archaea are one of the three groups, along with Bacteria and Eukaryota. When they were first discovered, in extreme environments like the hot springs in Yellowstone Park, Archaea were miscategorized as bacteria, and were called Archaebacteria. Sometimes archaea are still referred to as archaebacteria, although this term has fallen out of favor, since archaea are not bacteria. Despite this, many archaea have the suffix –bacteria included in their species name, a carryover from the time when archaea were thought to be bacteria. Archaea may among the first living things on Earth, dating back to the Archean era, 3800 – 2500 million years ago. Their name means “old ones” in Greek. Although archaea are prokaryotes like bacteria, they are more closely related to eukaryotes such as amoeba. Archaea were first only found in small quantit
They are single-celled microorganisms (prokaryotes), similar to but distinct from Bacteria. In fact, they make up a third domain of life alongside Bacteria and Eukarya (Eukarya are organisms with organelles like you and me, animals, plants, amoebae and so on). What kinds of environments do Archaea live in today? All kinds. They are ubquitous (everywhere) in the environment – found in the oceans, the guts of cows, on your teeth, in hot springs. You have been asked this question for a reason. Many Archaea are what are known as extremophiles – they live in environments that we would consider extreme, such as boiling water, icy pools in Antarctica, very salty or alkaline lakes and acidic waste dumps. We think that when the ancient earth was a more hostile place, organisms like Archaea might have been amongst the first forms of cellular life. We also think that were microbial life to be found outside of Earth, for example on Mars, the organisms there might be rather like Archaea. But it’s i
