Diversity of Life through Time
Published Online: 15 NOV 2010
Copyright © 2001 John Wiley & Sons, Ltd. All rights reserved.
How to Cite
Simpson, C. and Kiessling, W. 2010. Diversity of Life through Time. eLS. .
- Published Online: 15 NOV 2010
Global diversity is the total number of taxa living in the present day or at any time in the geological past. Reconstructing the trajectory of global diversity by compiling data from the fossil record has been a major research agenda for palaeontologists for decades. The goal is to produce an accurate reconstruction of the pattern of global diversity that will ultimately allow us to understand the causes of diversity increases, decreases and transitions in the composition of the biota. The Paleobiology Database, a new large-scale database based on individual collections of fossil taxa, allows palaeontologists to standardise sampling, thereby controlling for vagaries of the fossil record. Collection-level data also allows researchers to identify any asynchrony of changes in diversity among regions of the globe, with the ultimate goal of identifying the habitats or environments that support biodiversity growth.
Biodiversity is the number of taxa alive in any interval of time.
Given that not all taxa are readily preserved in the fossil record and not all taxa can be counted, trajectories of interpolated changes in biodiversity are more relevant than estimates of extrapolated diversity.
Ancient biodiversity patterns are biased in multiple ways; extreme care must be taken to adjust for biases.
Diversification can be positive and negative; mass depletions of biodiversity are caused by severe and rapid environmental changes, whereas major increases of diversity are more gradual being governed by recoveries from mass extinctions and evolutionary innovations.
Evidence for limits of diversity is increasing in the fossil and molecular records.
Different taxa dominated at different times.
New taxa tend to originate in shallow tropical reef environments.