Invention by evolution: functional analysis in paleobiology

Functional analysis of fossils is and should remain a key component of pale obiological research. Despite recently expressed doubts, conceptual and met hodological developments over the past 25 years indicate that robust and te stable claims about function can be produced. Functional statements can be made in at least three different hierarchical contexts, corresponding to th e degree of structural information available, the position in the phylogene tic hierarchy and the degree of anatomical specificity The paradigm approac h, which dominated thinking about function in the 1960s and 1970s, has been supplanted with a methodology based on biomechanics. Paleobiomechanics doe s not assume optimality in organismal design, but determines whether struct ures were capable of carrying out a given function. The paradigm approach c an best be viewed as a way of generating, rather than testing, functional h ypotheses. Hypotheses about function can also be developed and supported by well-corroborated phylogenetic arguments. Additional functional-evidence c an be derived from studies of trace fossils and of taphonomy. New computer techniques, including "Artificial Life" studies, have the potential for pro ducing far more detailed ideas about function and mode of life than have be en previously possible. Functional analysis remains the basis for studies o f the history of adaptation. It is also an essential component of many pale oecological and paleoenvironmental studies.