‘Non-Progression’, the interpretation of life-history launched by Lyell in 1830 and defended by him for over twenty years, can be summarized as follows. Palaeontologists, Lyell contended, should assume that at every period of the earth's recoverable past, each class of plants and animals has been represented somewhere on earth. Species have been created solely as responses to perpetually shifting environmental conditions, and not as temporally conditioned stages in the unique unrolling of a grand plan. If certain environments are especially suited (...) to reptiles, then the Creator tailors collections of beautifully adapted terrestrial, aquatic, and even aerial reptiles for them—as He did, for example, for the environments recorded in the British Jurassic; as He did, much more recently, for the Galapagos Islands; and as He will do again, if conditions somewhere on earth ever force mammals into extinction, leaving ecological niches which can more suitably be filled by reptiles. If, for example, changes in the topography and climate of the Sussex Weald eventually lead to the re-establishment of an environment that particularly suits iguanodons, then iguanodons will assuredly appear there again. The essential point about Lyell's interpretation is that time does nothing to determine a particular flora and fauna. When designing a new animal, the Creator, according to Lyell's view, has to take into account only the creature's or plant's destined environment: He has to consult no timetable, or lineage, governing the production of new forms. In notes for a speech given in 1852 Lyell reduced his interpretation to the epitome, ‘Adaptation to geographical circumst5 not progressive develop the real history of past changes’. (shrink)