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An evolutionary tipping point in a changing environment
Author(s) -
Osmond Matthew M.,
Klausmeier Christopher A.
Publication year - 2017
Publication title -
evolution
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.84
H-Index - 199
eISSN - 1558-5646
pISSN - 0014-3820
DOI - 10.1111/evo.13374
Subject(s) - biology , inflection point , tipping point (physics) , selection (genetic algorithm) , extinction (optical mineralogy) , population , maxima and minima , fitness landscape , trait , fitness function , evolutionary biology , mathematics , mathematical optimization , genetic algorithm , computer science , paleontology , mathematical analysis , geometry , electrical engineering , demography , artificial intelligence , sociology , engineering , programming language
Populations can persist in directionally changing environments by evolving. Quantitative genetic theory aims to predict critical rates of environmental change beyond which populations go extinct. Here, we point out that all current predictions effectively assume the same specific fitness function. This function causes selection on the standing genetic variance of quantitative traits to become increasingly strong as mean trait values depart from their optima. Hence, there is no bound on the rate of evolution and persistence is determined by the critical rate of environmental change at which populations cease to grow. We then show that biologically reasonable changes to the underlying fitness function can impose a qualitatively different extinction threshold. In particular, inflection points caused by weakening selection create local extrema in the strength of selection and thus in the rate of evolution. These extrema can produce evolutionary tipping points, where long‐run population growth rates drop from positive to negative values without ever crossing zero. Generic early‐warning signs of tipping points are found to have little power to detect imminent extinction, and require hard‐to‐gather data. Furthermore, we show how evolutionary tipping points produce evolutionary hysteresis, creating extinction debts.