Speciation Rates Decline through Time in Individual-Based Models of Speciation and Extinction

Authored by Shaopeng Wang, Anping Chen, Jingyun Fang, Stephen W Pacala

Date Published: 2013

DOI: 10.1086/671184

Sponsors: Chinese National Natural Science Foundation

Platforms: No platforms listed

Model Documentation: Other Narrative Mathematical description

Model Code URLs: Model code not found

Abstract

A well-documented pattern in the fossil record is a long-term decline in the origination rate of new taxa after diversity rebounds from a mass extinction. The mechanisms for this pattern remain elusive. In this article, we investigate the macroevolutionary predictions of an individual-based birth-death model (BDI model) where speciation and extinction rates emerge from population dynamics. We start with the simplest neutral model in which every individual has the same per capita rates of birth, death, and speciation. Although the prediction of the simplest neutral model agrees qualitatively with the fossil pattern, the predicted decline in per-species speciation rates is too fast to explain the long-term trend in fossil data. We thus consider models with variation among species in per capita rates of speciation and a suite of alternative assumptions about the heritability of speciation rate. The results show that interspecific variation in per capita speciation rate can induce differences among species in their ability to resist extinction because a low speciation rate confers a small but important demographic advantage. As a consequence, the model predicts an appropriately slow temporal decline in speciation rates, which provides a mechanistic explanation for the fossil pattern.

Tags

Dynamics Diversity Biodiversity Ecological communities Marine fossil record Neutral-theory Species abundance Mass extinctions Protracted speciation Molecular phylogenies