Under global change, populations have four possible responses: ‘migrate, acclimate, adapt or die’ (Gienapp et al. 2008 Climate change and evolution: disentangling environmental and genetic response. Mol. Ecol. 17, 167–178. (doi:10.1111/j.1365-294X.2007.03413.x)). The challenge is to predict how much migration, acclimatization or adaptation populations are capable of. We have previously shown that populations from more variable environments are more plastic (Schaum et al. 2013 Variation in plastic responses of a globally distributed picoplankton species to ocean acidification. Nature 3, 298–230. (doi:10.1038/nclimate1774)), and here we use experimental evolution with a marine microbe to learn that plastic responses predict the extent of adaptation in the face of elevated partial pressure of CO2 (pCO2). Specifically, plastic populations evolve more, and plastic responses in traits other than growth can predict changes in growth in a marine microbe. The relationship between plasticity and evolution is strongest when populations evolve in fluctuating environments, which favour the evolution and maintenance of plasticity. Strikingly, plasticity predicts the extent, but not direction of phenotypic evolution. The plastic response to elevated pCO2 in green algae is to increase cell division rates, but the evolutionary response here is to decrease cell division rates over 400 generations until cells are dividing at the same rate their ancestors did in ambient CO2. Slow-growing cells have higher mitochondrial potential and withstand further environmental change better than faster growing cells. Based on this, we hypothesize that slow growth is adaptive under CO2 enrichment when associated with the production of higher quality daughter cells.
Data for Figure 1
Description: columns in csv file contain data as follows: ecotype - lineage of Ostreococccus. Initial plasticity - plasticity as measured at t0. Response - fitness response as measured at t400. for calculation see main manuscript and SI. whichresp - indicates whether response was measured in ancestral or selection environment. sdini and sdresp are standard deviations for plasticity at t0 and fitness response at t400 respectively. Here, they are pooled for 3 biological and 3 technical replicates. clade - clade A,B,C,D based on ITS sequences. year and culturing for year of isolation and culturing method at the Roscoff culture collection respectively. wherefrom: sampling depth as factor. Pst0 and growtht0 - are photosynthesis and growth rates at t0 (foldchange PS and foldchangegrowth are foldchanges thereof). Figure legend: (a–d) Lineages with higher ancestral plasticity evolve more. Direct and correlated responses to selection plotted as a function of plasticity in oxygen evolution rates before evolution (ancestral plasticity). For all panels (a–d), different shapes represent mean values for each lineages ± 1 s.e. For each lineage n = 3. Dashed line indicates no response to selection. Panel (a) (selection in FH, assay at 1000 ppm CO2): ancestral plasticity in FH evolved lineages predicts up to 47% of the evolutionary response (F2,13 = 210.67, p < 0.001). FH populations evolve slow growth in response to high pCO2. Panel (b) (selection in SH, assay at 1000 ppm CO2): with no selection for plasticity, a linear relationship using ancestral plasticity as the only explaining variable is not statistically significant (p = 0.63). Still, most lineages evolve lower growth rates (range from −0.31 to −0.08, mean −0.15 ± 0.12). Panel (c) (selection in FH, assay at 430 ppm CO2): ancestral plasticity is a significant nonlinear predictor of the correlated response to selection (F2,13 = 563.38, p < 0.0001). Lineages from FH increased their growth rate at ambient pCO2 the most when their ancestral plasticity was high (increase in growth of 0.12–0.30, mean 0.19 ± 0.05). Panel (d) (selection in SH, assay at 430 ppm CO2): lineages selected in SH had a negative correlated response, and the relationship between ancestral plasticity and the correlated response to selection was significant (F2,13 = 22.28, p < 0.01), though best described by a nonlinear fit (p-values and r2 reported on the panels are for linear regression).
evolvedresponsescolumns - Figure 1.csv
Data for Figure 2
Columns in data file contain - evoplas (evolved plasticity), iniplas (initial plasticity), as well as - evoplassd and - iniplassd (standard deviations pooled here for three biological and three technical replicates). clade - A,B,C,D - clade as found by ITS sequences.
inievo4panel - Figure 2 condensed for data dryad.csv
data for Figure 3
Data in columns is organised as follows: growthdif - foldchange difference of growth rate in selection environment compared to control environment. selected assay - selection environment and assay environment, e.g. 1000fluc 1000ppm lineages have been selected at fluctuating 1000ppm CO2 (FH in main manuscript) and were measured at 1000ppm CO2 (mean ppm in their selection environment). ecotype - lineage of Ostreococcus . forwhat - trait considered. Here, growth rate. hl - high or low pCO2. ls - long term or short term response.
growthdiffdetail - Figure 3.csv
