Published online by Cambridge University Press: 01 May 2009
An attempt is made to correlate the concept of the fossil lineage with our knowledge of polytypic species. The influence of changing environmental conditions in the geological succession and the relationship between geographical and chronological sub-species is analysed on a theoretical basis. The fossil lineage is considered to be the resultant of combined evolutionary and environmental change. Phenotypic modifications in response to environmental conditions are discussed in relation to the study of variation in fossil communities.