The Bilbao conference "Palaeontology and Evolution: Extinction Events": A big step forward in understanding exceptional global changes

Abstract

An important precondition to master the problems ofmankind's future is to understand evolution in respect to evolutionary mechanisms, including the manifold interactions between abiotic parameters and the biota, which means the complex interplay between biosphere, hydrosphere, atmosphere and geosphere. The contribution of the palaeontological science to approach this aim is to investigate and to analyze those cases in earth history in which such abiotic iníluences on the biota have to be supposed. That is the case with one certain kind of the so-called global biological events, namely the extinction events. Before discussing the extinction events it should be noticed that there aré two additional, differing patterns ofbio-events: biological innovation events and radiation events. The first one is either independent of abiotic in íluences or at least dominated by pure biological parameters and processes. Radiation events occur subsequent to innovation events (Rp; = post-innovation radiation), but also after extinction events (Rp, = post-extinction ra diation). The Rp, mirrors the relatively short-termed occupation ofthose niches which occured dueto the extinc tion event. Between the latter and the Rp, normally exists a certain time interval in which the s~lectional stress is more or less strongly reduced. This causes a relatively rapid evolution and enables the concerned taxa to enlarge their potency to intrude into the adjacent niches. In this sequence -extinctions, interval, radiations- the causing global event leads not only to extinctions, i.e. to an interruption of the evolution within certain phyletic lines, but it triggers also an acceleration of the evolution, visible in the subsequent radiations. Extinction events are characterized by a relatively high rate of extinction within a relatively short time. "Re latively" means in comparison with the long intervals of relatively stable conditions, in which the rate of back gr ound extinctions equals more or less the originating rate. Thus, extinction events are characterized by short termed floral and/or fauna! changes which are globally traceable.