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.
Map of the volcanic arcs in the Andes, and subducted structures affecting volcanism. The Andean Volcanic Belt is a major volcanic belt along the Andean cordillera in Colombia, Bolivia, Peru, Ecuador, Chile and Argentina.It formed as a result of subduction of the Nazca Plate and Antarctic Plate underneath the South American Plate.The belt is subdivided into four main volcanic zones that are separated from each other by volcanic gaps. The volcanoes of the belt are diverse in terms of activity style, products and morphology.t is one of the four volcanic zones of the Andes. The Central Volcanic Zone extends from Peru to Chile and forms the western boundary of the Altiplano plateau. The volcanic arc has formed due to subduction of the Nazca Plate under western South America along the PeruâChile Trench.