Research Highlights

• Subject Category:
  • Ecology & evolution

Published online: 8 October 2008 | doi:10.1038/nchina.2008.236

Competition: Distinct extinction

Tim Reid

Introduction

© (2008) istockphoto.com/Michael Dodd

Competition between species is one of the crucial forces in natural selection, but under what conditions can it lead to the extinction of a species? Jian Zu at Southwest Petroleum University in Chengdu and co-workers¹ have shown that the chances of evolutionary suicide — the process in which a viable population adapts in such a way that it can no longer persist — may depend on exactly what the individual species are competing for.

The researchers simulated the population dynamics of two competing species each with one variable trait — the organism size — to determine the outcome of disputes. Their model took into account the effects of random mutations and population density, and was assessed under two common types of competition — symmetric and asymmetric.

In symmetric competition, resources are divided up equally among the two competing species. For example, birds with larger beaks would eat the same amount of seeds as those with smaller beaks. In asymmetric competition, however, two species compete for a limited resource and one will receive more. For example, taller plants get more light in a forest than shorter plants.

The researchers' model showed that evolutionary suicide is impossible when the only form of competition is symmetric, but can occur when species compete asymmetrically. However both types of competition are more likely to produce stable evolutionary cycles in which both species survive.

The authors of this work are from:
School of Sciences, Southwest Petroleum University, Chengdu, China; School of Mathematics and Statistics, Southwest University, Chongqing, China; Department of Systems Engineering, Faculty of Engineering, Shizuoka University, Hamamatsu, Japan; School of River and Ocean Engineering, Chongqing Jiaotong University, Chongqing, China; Department of Computer Sciences, Third Military University, Chongqing, China.

Reference

1. Zu, J., Wang, W., Takeuchi, Y., Zu, B. & Wang, K. On evolution under symmetric and asymmetric competitions. J. Theor. Biol. doi: 10.1016/j.jtbi.2008.06.001 (2008).  | Article |