Like all other living things, sturgeon fish, which belong to the order Acipenseriformes, have no evolutionary forebears in the fossil record. Throughout geologic history, they have always existed as sturgeon. This fact once again dramatizes the "intermediate form" dilemma, one of the major problems facing Darwinists. The paleontologist Colin Patterson revealed the absence of any intermediate forms that might be proposed by Darwinists, by not referring to such forms at all in his book Evolution. He made the following admission in a letter to those people wondering why this was so: "I fully agree with your comments on the lack of direct illustration of evolutionary transitions in my book. If I knew of any, fossil or living, I would certainly have included them. As a paleontologist myself, I am much occupied with the philosophical problems of identifying ancestral forms in the fossil record. You say that I should at least "show a photo of the fossil from which each type of organism was derived." I will lay it on the line—there is not one such fossil for which one could make a watertight argument." (From a letter dated 10 April, 1979, quoted in L. D. Sunderland"s Darwin"s Enigma: Fossils and Other Problems, 4th edition, Master Books, 1988)