All of life on Earth is divided into three major domains: the Bacteria, Archaea and Eukarya. This is the universal phylogenetic tree based on a gene that we all have, the ribosomal RNA. We (humans) are located in the crown group of animals, but the majority of diversity on this planet is in the microbial (bacterial and archaeal) world.
Three Domains of Life
Image adapted from Woese et al. 1990. Download larger version (jpg, 1 MB).

All of life on Earth is divided into three major domains: the Bacteria, Archaea and Eukarya. This is the universal phylogenetic tree based on a gene that we all have, the ribosomal RNA. We (humans) are located in the crown group of animals, but the majority of diversity on this planet is in the microbial (bacterial and archaeal) world.

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