The Effect of Rare and Novel Temperature Regimes on The Release of Cryptic Variation in The Fathead Minnow, Pimephales Promelas

Abstract

Climate change has led to (and will continue to lead to) more pronounced temperature variation, exposing organisms to new extremes (IPCC 2013)

The increase in extremes may ‘break’ previously canalized phenotypes, leading to an increase in variation (Ghalambor et al. 2007). This is a critical component of the adaptive capacity of a population, as the rate of evolution is proportional to the additive genetic variance (Lande 2009).

However, empirical evidence for these predicted changes is quite limited and it is unclear whether variance actually increases in novel conditions (i.e., whether the fanning out really occurs; McGuigan and Sgrò 2009, Ledón- Rettig et al. 2014).