The fossil record reveals that living things do not change, as long as they remain in existence. The 95-million-year-old catshark pictured is one of those life forms that have not altered over millions of years. This means that evolution—which maintains that living things are in a constant state of change and progress from the primitive to the more developed—is invalid. In actuality, evolution"s claims regarding the origin of life do not reflect the facts, as is expressed in the book Integrated Principles of Zoology, jointly authored by three evolutionist biologists: "Many species remain virtually unchanged for millions of years, then suddenly disappear to be replaced by a quite different . . . form. Moreover, most major groups of animals appear abruptly in the fossil record, fully formed, and with no fossils yet discovered that form a transition from their parent group." (C.P. Hickman [Professor Emeritus of Biology at Washington and Lee University in Lexington], L.S. Roberts [Professor Emeritus of Biology at Texas Tech University], and F.M. Hickman, Integrated Principles of Zoology, St. Louis: Times Mirror/Moseby College Publishing, 1988, p. 866)