Research

Theoretical size distribution of fossil taxa: analysis of a null model

William J Reed¹ and Barry D Hughes²

¹  Department of Mathematics and Statistics, University of Victoria, Victoria, British Columbia V8W 3P4, Canada

²  Department of Mathematics and Statistics, University of Melbourne, Parkville, Victoria 3010, Australia

author email corresponding author email

Theoretical Biology and Medical Modelling 2007, 4:12doi:10.1186/1742-4682-4-12

Published:	22 March 2007

Abstract

Background

This article deals with the theoretical size distribution (of number of sub-taxa) of a fossil taxon arising from a simple null model of macroevolution.

Model

New species arise through speciations occurring independently and at random at a fixed probability rate, while extinctions either occur independently and at random (background extinctions) or cataclysmically. In addition new genera are assumed to arise through speciations of a very radical nature, again assumed to occur independently and at random at a fixed probability rate.

Conclusion

The size distributions of the pioneering genus (following a cataclysm) and of derived genera are determined. Also the distribution of the number of genera is considered along with a comparison of the probability of a monospecific genus with that of a monogeneric family.