Palaeotaxonomy, Biogeography, Evolution and Extinction

Abstract

Under appropriate circumstances, animals, plants and even microorganisms can leave remarkably good traces in rocks. In many cases the actual substance of the fossilized organism may have been replaced by minerals or at least have been greatly changed chemically but exceptions do occur, and fossils are sometimes formed under conditions that permit preservation of antigenic materials (Westbroeket al.1979) or even DNA that can be isolated and put to systematic use (Golenberget al.1990). Some fossil taxa are described not from their own remains but from changes they have brought about around themselves when they were alive, for example, fossil animals can be described from their tracks, burrows or nests. Clearly, the organisms that created these ichnofossils will virtually never be known with any great certainty and so concepts of species or even genera and families in such cases may be very hazy. However, other better preserved taxa provide a historic record — albeit an incomplete one — of life on earth and thus provide a window into the past. Fossils therefore have a potentially important role to play in taxonomy and phylogenetics, but their interpretation and use is not without its pitfalls and contentious issues.

ArticleNote

… the fossil record demonstrates, albeit incompletely, the actual course that evolution has taken. Until recently it was also taken for granted that fossils had a vital role to play in phylogenetic reconstructions...

(Hallam, 1988)