The predominant bacterial species change dramatically across different anatomical sites of the same individual. For instance, Streptococcus is predominant on the inner cheek but decreases in the throat, palatine tonsils, and saliva, where Fusobacterium is more abundant. Furthermore, Fusobacterium dominates gum plaque, but both Streptococcus and Fusobacterium are absent in the intestine, where Bacteroides becomes the dominant genus.