The relative importance of directional change, random walks, and stasis in the evolution of fossil lineages.

ABSTRACT: The nature of evolutionary changes recorded by the fossil record has long been controversial, with particular disagreement concerning the relative frequency of gradual change versus stasis within lineages. Here, I present a large-scale, statistical survey of evolutionary mode in fossil lineages. Over 250 sequences of evolving traits were fit by using maximum likelihood to three evolutionary models: directional change, random walk, and stasis. Evolution in these traits was rarely directional; in only 5% of fossil sequences was directional evolution the most strongly supported of the three modes of change. The remaining 95% of sequences were divided nearly equally between random walks and stasis. Variables related to body size were significantly less likely than shape traits to experience st

SUBMITTER: Hunt G 

PROVIDER: S-EPMC2141789 | biostudies-literature | 2007 Nov

REPOSITORIES: biostudies-literature