This article is about the bacterium. For the disease, see Salmonellosis. Salmonella /ËsÃ¦lmÉËnÉlÉ/ is a genus of rod-shaped (bacillus) gram-negative bacteria of the Enterobacteriaceae family. The two species of Salmonella are Salmonella enterica and Salmonella bongori. Salmonella enterica is the type species and is further divided into six subspecies that include over 2,500 serotypes. S. enterica subspecies are found worldwide in all warm-blooded animals, and in the environment.
The Four Geologic Eras. Geology is a complex and difficult subject, especially for the novice. I recommend that beginners first concentrate on the four major divisions of geologic history: the Geologic Eras.he Precambrian Era (4.6 billion years ago to 600 million years ago) encompasses the great majority of Earth's geologic history, stretching from the formation of our planet to the appearance of shelled marine life.
Era (geology) (Redirected from Geologic era) A geologic era is a subdivision of geologic time that divides an eon into smaller units of time. The Phanerozoic Eon is divided into three such time frames: the Paleozoic, Mesozoic, and Cenozoic represent the major stages in the macroscopic fossil record.