Adolf Seilacher

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Adolf "Dolf" Seilacher (b. 24th February 1925) is a German palaeontologist who has made remarkable contributions to many areas of evolutionary and ecological palaeobiology in a career stretching over 60 years. He won the Crafoord Prize in 1992. He is best known for his contributions to the study of trace fossils; constructional morphology and structuralism; biostratinomy (including "aktuopaläontologie") exceptional preservation and the Ediacaran biota.

[edit] Career

Seilacher started his career with his doctoral work under Otto Heinrich Schindewolf, professor of palaeontology in Tübingen. Gaining his doctorate in 1951 on trace fossils, he moved to the University of Frankfurt (1957) and then the University of Baghdad, before taking up a chair in palaeontology in Göttingen. He returned to Tübingen in 1964 as the successor to Schindewolf. Since 1987 he has held an Adjunct Professorship in Yale, New Haven and currently splits his time between Yale and Tübingen.

[edit] Significant work

Seilacher's publications are numerous (well over 200) and cover a wide range of topics. His studies on trace fossils are perhaps his most well-known contributions, especially in his 1967 work on the bathymetry of trace fossils. Here he established the concept of ichnofacies; distinctive assemblages of trace fossils controlled largely by depth (this characterisation has later been expanded to include the influence of substrate, oxygen, salinity and so on). In addition, he analysed many trace fossils in terms of the behaviour they represent, leading to such work as early computer simulation of trace fossil morphology (wth David Raup, in 1969).

In 1970 he announced his programme of "Konstructions-Morphologie". Herein, he stressed the importance of three factors in determining the form of organisms: ecological/adaptive aspects; historical/phylogenetic aspects; and architectural/constructional aspects. The latter two factors are important sources of biological constraints; both acknowledging that both past history and constructional principles place limits on what may be achieved in at least the short term of evolution. Such a view was influential on later workers such as Gould and Lewontin, such as their famous paper on "spandrels" that criticized panadaptionist accounts of evolution and form.

Seilacher's interest in pattern formation led him to espouse self-organisation models for the origin of certain types of form, the most famous of which are "pneu" structures. These are fluid-filled structures under tension whose form is broadly determined by the need to distribute the tension across the surface. Seilacher may thus be squarely considered to be a structuralist.

Seilacher has published several important papers on fossil Lagerstätten, including one of 1985 that proposed a widely-accepted scheme for their classification; indeed, much of his work has been concerned with preservation and taphonomy in general.

His most controversial contributions have come in his work on the Ediacaran assemblages, which he suggested, based on their constructional morphology, to be pneu structures completely unrelated to modern metazoans. While this view has been steadily opposed by many workers, it has gained some ground in recent years as the affinities of many of these organisms has remained resistant to analysis. More recently, Seilacher has considered many of these taxa to be giant xenophyophores, ie large rhizopodal protists.

Seilacher has presented his work over the years with a unique mixture of an indomitable personal style, a gift for coining terminology, and an unmistakable style of diagrams and drawings that have been present in almost all of his publications.

[edit] References

• Anonymous (1995). Laudatio: Tribute to Adolf Seilacher. Geologische Rundschau 84, 435-436.
• Briggs, D. E. G. (2005). Seilacher on the science of form and function. In Evolving form and function: fossils and development. Proceedings of a symposium honoring Adolf Seilacher for his contributions to paleontology, in celebration of his 80th birthday, pp. 3-24 [includes a bibliography of Seilacher up to 2005].