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We now know that there are so many environmental conditions—regardless of how extreme they may appear to be—that are capable of supporting life, so we can widen the boundaries of our search for life on other planets like Mars, perhaps. Haloarchaea , for example, are known for surviving in super-salty conditions with very little water and are capable of surviving in a state of near-starvation for a very long time—as in, potentially millions of years at a time.
Even exposure to high levels of UV radiation doesn't bother them. This raises the possibility that other living things might be able to exist in similarly salty, rocky, dry places on other planets, meteorites or moons. So, what's out there? Are there archaea-like living things on other planets? We still have so much to discover about the world of archaea here on Earth, but as they continue to challenge and broaden our very definitions of where life can thrive, it's an exciting time for new biological discoveries.
Extreme living—literally. What are archaea? It's extremely acidic and full of heavy metals, but this doesn't bother the many species of microbes including archaea that live in Spain's Rio Tinto river. Yet we have no reliable evidence pointing to any archaean as the causative agent of any human disease.
Still, scientists have attempted to find links between human disease and archaea. For example, in , Lepp et al. The authors suggested that the activity of these methanogens causes the disease. It seems more likely that periodontal disease causes an enlargement of anaerobic regions in the mouth that are subsequently populated by M.
There remains no good answer as to why archaea do not seem to be pathogenic, but scientists continue to speculate and hope to find the answer. It oxidizes sulfur and produces sulfuric acid. Skip to main content. Prokaryotic Diversity. Search for:. Archaea Learning Objectives Describe the unique features of each category of Archaea Explain why archaea might not be associated with human microbiomes or pathology Give common examples of archaea commonly associated with unique environmental habitats.
Think about It What types of environments do Crenarchaeota prefer? Think about It Where do Halobacteria live? Finding a Link Between Archaea and Disease Archaea are not known to cause any disease in humans, animals, plants, bacteria, or in other archaea. Key Concepts and Summary Archaea are unicellular, prokaryotic microorganisms that differ from bacteria in their genetics, biochemistry, and ecology.
Some archaea are extremophiles, living in environments with extremely high or low temperatures, or extreme salinity. Only archaea are known to produce methane.
Methane-producing archaea are called methanogens. Halophilic archaea prefer a concentration of salt close to saturation and perform photosynthesis using bacteriorhodopsin. Some archaea, based on fossil evidence, are among the oldest organisms on earth. Archaea do not live in great numbers in human microbiomes and are not known to cause disease. Archaea and Bacteria are most similar in terms of their unicellular structure. Show Answer Answer b. They live in the most extreme environments. Show Answer Sulfolobus is a genus of Archaea.
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Updated March 13, What Are Archaea? Key Takeaways Originally thought to be bacteria, Archaea are a separate group of microscopic organisms discovered in the s. Archaeans are single-celled prokaryotes. Archaeans are extreme organisms. They can survive and even thrive under some of the most difficult conditions on planet Earth like very hot, extremely acidic, or very alkaline environments.
Similar to bacteria, Archaeans have a number of different shapes. Cocci round , bacilli rod-shaped , and irregular are some examples. Archaeans possess the typical prokaryotic cell anatomy that includes plasmid DNA, a cell wall, a cell membrane, a cytoplasmic area, and ribosomes.
Some archaeans can also have flagella. Cite this Article Format. Bailey, Regina. Archaea Domain. Watch Now: 6 Kingdoms of Life. Differences Between Bacteria and Viruses. What Are Prokaryotic Cells?
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