Dictionary > Archaea

Archaea

Archaea are the unicellular prokaryotes that comprise the domain of the same name, Archaea. These microorganisms are typically found inhabiting and thriving in extreme environmental conditions. They include the halophiles (archaea inhabiting extremely salty environments), methanogens (archaea producing methane), and thermophiles (archaea that thrive in scorching environments).

Archaea definition

Halobacterium sp. strain NRC-1, an archaeon species. In this photo, the cells of Halobacterium sp. strain NRC-1 are in a cluster.

Archaea refers to the microorganisms that physically resemble the bacteria but are genetically distinct from the latter.

Etymology

The term archaea (ar-KAY-ə) (singular: archeon) came from Greek arkhaion, arkhaios, meaning “ancient”. Synonyms: archaebacteria. Compare: eubacteria.

Characteristics

Archaea or archaebacteria evolved separately from eubacteria and eukaryotes. They are similar with eubacteria in being prokaryotes and lacking distinct cell nucleus. They differ in terms of ribosomal structure, the possession of introns (in some species) and in membrane structure or composition. They are similar to eukaryotes in ways that archaea possess genes and several metabolic pathways that are more closely related to those of eukaryotes: notably the enzymes involved in transcription and translation.(1)
They are regarded to be living fossils and survivors of an ancient group of organisms that bridged the gap in evolution between eubacteria and eukaryotes.

See also

References

  1. Pace, N. R. (May 2006). “Time for a change”. Nature. 441 (7091): 289. doi:10.1038/441289a

© Biology Online. Content provided and moderated by Biology Online Editors



You will also like...

Lights' Effect on Growth
Lights’ Effect on Growth

This tutorial elaborates on the effect of light on plant growth. It describes how different plants require different amo..

Energy pyramid
Freshwater Community Energy Relationships – Producers & Consumers

This tutorial looks at the relationship between organisms. It also explores how energy is passed on in the food chain an..

Growth Patterns
Growth Patterns

This tutorial describes the sigmoid curve, annual plant growth, tree growth, human growth, and insect growth as the grow..

Genetics and Evolution
Genetics and Evolution

Tutorials in Genetics and Evolution immerse on the molecular aspects and the works of nature that led to what every livi..

Ecosystem Succession
Ecosystem Succession

If the balance of nature is left untouched, landscapes can change dramatically over time. A previous ecosystem is supers..

Homeostasis by water regulation
Homeostasis of Organism Water Regulation

Osmoregulation is the regulation of water concentrations in the bloodstream, effectively controlling the amount of water..