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.
E. coli is the type species of the genus (Escherichia) and in turn Escherichia is the type genus of the family Enterobacteriaceae, where the family name does not stem from the genus Enterobacter + i (sic.) + aceae, but from enterobacterium + aceae (enterobacterium being not a genus, but an alternative trivial name to enteric bacterium).