The Structure of Evolutionary Theory The Structure of Evolutionary Theory The Structure of Evolutionary Theory (2002) is Harvard paleontologist Stephen Jay Gould's technical book on macroevolution and the historical development of evolutionary theory. The book was twenty years in the making, published just two months before Gould's death. Aimed primarily at professionals, the volume is divided into two parts. The first is a historical study of classical evolutionary thought, drawing extensively upon primary documents; the second is a constructive critique of the modern synthesis, and presents a case for an interpretation of biological evolution based largely on hierarchical selection, and the theory of punctuated equilibrium
Neutral theory of molecular evolution Neutral theory of molecular evolution The neutral theory of molecular evolution holds that at the molecular level most evolutionary changes and most of the variation within and between species is not caused by natural selection but by genetic drift of mutant alleles that are neutral. A neutral mutation is one that does not affect an organism's ability to survive and reproduce. The neutral theory allows for the possibility that most mutations are deleterious, but holds that because these are rapidly removed by natural selection, they do not make significant contributions to variation within and between species at the molecular level.