The Archaea domain of classification is used to represent organisms that live in extreme environments. Many biologists hypothesize that organisms in the domain archaea were some of the first types of organisms on earth. Thermophilic organisms that live in thermal vents found in the ocean floor are an example of organisms that are classified as archaea.
Unicellular
Archaea organisms are unicellular, meaning that they are made of just a single cell.
Prokaryote
The single cell that archaea organisms are made of is a prokaryotic cell that lacks organelles or a membrane bound nucleus.
Autotroph or Heterotroph
Some archaea organisms produce their own food as autotrophs, while others get their food by consuming other organisms.