Archées

Archées, also known as Archaea, are a domain of single-celled microorganisms that are distinct from bacteria and eukaryotes. They are prokaryotic, meaning their cells lack a nucleus and other membrane-bound organelles. Archées were once thought to be a type of bacterium, but genetic and biochemical studies have revealed them to be a separate and ancient branch of life.

Archées are found in a wide variety of environments, including extreme habitats such as hot springs, salt lakes, and deep-sea hydrothermal vents. Some archées are also found in more common environments like soil, oceans, and even in the digestive tracts of animals. Their ability to thrive in extreme conditions is often due to unique metabolic pathways and cell membrane structures.

Metabolically, archées exhibit diverse strategies. Some are autotrophs, producing their own food, while others are heterotrophs, obtaining nutrients from organic matter. Many archées are anaerobes, living in environments without oxygen, and some are methanogens, producing methane as a metabolic byproduct. Others are extremophiles, adapted to high temperatures, high salinity, or extreme pH levels.

The study of archées has provided significant insights into the early evolution of life on Earth. Their unique biochemical features, such as ether-linked lipids in their cell membranes and distinct ribosomal RNA sequences, place them as a separate domain of life alongside Bacteria and Eukarya. Understanding archées helps researchers reconstruct ancient ecosystems and explore the boundaries of life.