MODELS FOR THE DIVERSIFICATION OF LIFE

The diversification of life through geological time suggests a rise fr om presumably one species to many millions today. The diversification of marine families in the past 600 million years (Myr) appears to have followed two or three logistic curves, with equilibrium levels that l asted for up to 200 Myr. In contrast, continental organisms clearly sh ow an exponential pattern of diversification, and although it is not c lear whether the empirical diversification patterns are real or are ar tefacts of a poor fossil record, the latter explanation seems unlikely . Perhaps marine and continental organisms diversified in different wa ys, or perhaps the appearance of equilibrium patterns for marine organ isms is an artefact of taxonomic structures.