Archaea evolved from LUCA about 3.5 billion years ago. They were long thought to be bacteria, but advanced genetic analysis placed them in their own domain. Like bacteria, some Archaea have flagella for mobility. Transition forms have been found in deep sediments off Arctic coast, and later elsewhere, showing that the Eukaryote cells of advanced life forms evolved from Archaea. The tangle in the center is the cell's DNA. The little blue dots are Ribosomes, without which it couldn't be a living cell. For the important function of Ribosomes see our page for Eukaryots. Illustration of Archaea Cell Structure by K. Gottlieb, V. Wacher, J. Sliman and M. Pimentel distributed under license Creative Commons Attribution-ShareAlike v4.0 International .
More on the origin of Plants and Animals.