Part 1 of this note dealt with Sewall Wright's Shifting Balance theory of evolution (the SBT) in its original form, as propounded between 1929 and 1931. This final part deals with subsequent developments in the theory. These include refinements and elaborations, some changes of emphasis, one major addition, and one major change of substance. In particular I will cover: 1. The role of new mutations 2. The concept of selective peaks 3. The effect of changes in environment 4. The adaptiveness of evolution 5. The process of intergroup selection 6. The three phases of the shifting balance. I will throw in a few remarks about Fisher and Haldane as well.
Related:Sewall Wright & the Shifting Balance Theory, Notes on Sewall Wright: the Adaptive Landscape, Notes on Sewall Wright: Migration, Notes on Sewall Wright: Population Size, Notes on Sewall Wright: the Measurement of Kinship, Notes on Sewall Wright: Path Analysis and On Reading Wright.