"When two closely related species are found to be living in the same area in close association, members of each invariably specialize in slightly different foodstuffs, breed in different seasons or otherwise behave in minor but consistently different ways."

"Wherefore come out from among them, and be ye separate, saith the Lord, and touch not the unclean thing; and I will receive you, and will be a Father unto you, and ye shall be my sons and daughters, saith the Lord Almighty."