Drinking regular milk will not only give kittens diarrhea, but will also cause them to slowly starve to death if their diet isn't properly supplemented [source: Kitten Rescue]. The ratio of caseins and whey in cow's milk is nowhere near sufficient to support a growing kitten [source: Fries].
One of the significant adaptions occurred in one strain of E. coli. In general, this bacteria is known for not being able to use citrate in an aerobic environment as an energy source, even though it could use citrate under anaerobic conditions because it already has the machinery to process citrate.
Escherichia coli is a rod-shaped bacterium. Each bacterium measures approximately 0.5 Î¼m in width by 2 Î¼m in length. E. coli is a Gram-negative bacterium. E. coli cells stain Gram negative because they have a thin cell wall with only 1 to 2 layers of peptidoglycan. E. coli is a facultative anaerobe, which means it does not require oxygen, but grows better in the presence of oxygen.