Gut Infection. Gastroeteritis or the stomach flu can be caused by a virus, bacteria or parasites and causes inflammation of the lining of the digestive tract. Besides white poop, this infection can also cause chills, fever, vomiting, achiness, diarrhea or abdominal pain.
Last Updated: Human evolution, the process by which human beings developed on Earth from now-extinct primates. Viewed zoologically, we humans are Homo sapiens, a culture-bearing, upright-walking species that lives on the ground and very likely first evolved in Africa about 315,000 years ago.
Evolution refers to any genetic change in a population, whereas natural selection specifies one particular way in which such changes are brought about. Natural selection is the most important agent of evolutionary change simply because it results in adaptation of an organism to its environment. Other possible mechanisms of evolution besides natural selection include gene flow, meiotic drive, and genetic drift.