Archaebacteria include many unique characteristics and traits: they comprise one kingdom of living organisms, are among the oldest life forms on earth and prefer to live in the most extreme environments on the earth to name a few. Archeaebacteria are often grouped with eubacteria, although the two are quite distinct. Archaebatecteria predate eubacteria by millions of years and are more closely related to eukarya than actual bacteria.
Archaebacteria have some of the most unusual cell structures of all living microbial organisms. Their cell walls lack peptidoglycan, which makes them unable to perform the important task of breaking down sugars and other substances to give living creatures the fuel and energy they need to survive. Archaebacteria thrive in the coldest and hottest regions on earth: they congregate en masse in the semifrozen Arctic waters around the North and South poles and can be found in droves within cliffs and domes of scorching hot deserts. Archaebacteria might look menacing when placed under slides and examined with microscopes, but unlike eukaryotes and other bacteria, the kingdom of archaebacteria does not include a single malicious organism. These humble single-celled organisms are among the oldest inhabitants of earth: they appeared while dinosaurs still roamed the earth and survived natural events and dramatic climate changes that exterminated their more glamorous peers.