Pimm and Redfearn (1988) showed that ln abundance N of animals also follows a power law, and since the ln variance of ln N is equivalent to ln this implies that the variance of realized growth rate increases indefinitely over time, apparently with exponent 0.36 ( Inchausti and Halley 2002). This environmental variability may drive changes in the growth and abundance of populations. Pelletier (1997) obtained z = 0.75 for ice-core samples for periods between 1 month and 2000 years. They found that plots of log V E on log elapsed time are almost perfectly linear with slope z = 0.65. (1998) analysed deviations of daily maximum temperature from their seasonal average values, estimated with very voluminous and exact data taken at weather stations around the world over a period of more than a century. This means that the log difference in physical conditions at a site increases with log elapsed time at a rate z/2. This is often adequately described by a power law, V E = at z, where the exponent z expresses the rate of increase of variance over time. The rate of increase in environmental variance over time provides a quantitative measure of variability. We hope, and we believe, that evolutionary biology is the key to predicting how the world will change, and we see this as the principal task of evolutionary biologists in the next few decades.Ī physical factor changes on all time scales, and at any given time scale varies by some characteristic amount. The emphasis throughout is quantitative and experimental. The final section describes how phytoplankton populations may adapt to the prime mover of change, the increase in atmospheric concentration of carbon dioxide. The second is concerned with whether or not populations can adapt to a novel and severe stress before being extinguished by it. The first deals with the variability that is commonly experienced by natural populations, and how they respond to it. Our account is organized into three sections. We shall instead try to sketch the main tasks that we think that evolutionary biologists should undertake to contribute to our understanding of the future. In this opening article of a new journal, we shall not attempt to offer a review of the whole field, which would be too intricate and extensive to fit within the confines of a short paper. The greatest of these experiments is now under way: the alteration of the atmosphere and climate of the Earth, with consequences for every living thing. The transformation of environments by agriculture and industry has created, and continues to create, a wide range of unintentional experiments in which populations are exposed to severe and novel perturbations, and either adapt to them or cease to exist. Global change presents a clear, immediate and urgent challenge for evolutionary biology.

Living earth elm hill pike