Extinction dataThis data file contains the extinction dynamics. For each culture, at each time point in the experiment, it says whether the culture is alive or extinct. The 'plate' column contains an identifier for the 96-well plate on which the culture was propagated; 'Environment' describes the assay environment; 'Well' is the well in which the culture was propagated; 'Selection' is the selection history of the culture; 'Line' is the line number out of 5 from each selection history; 'Spore' is the spore number out of 4 from each line; 'Replicate' is the replicate out of 3 for each spore; 'State' is a brief description of the density of the culture as observed under a microscope; 'Time' is the cycle number of the experiment; 'Extinct' is whether the culture is alive (1) or extinct (0).extinction.data.csvYield dynamicsThis data file contains the yield dynamics. For each culture at each time point it contains the optical density ('absorbance') read at 750 nm. The 'Plate' column contains the identifier of the 96-well in which the culture was propagated; 'Environment' is the assay environment; 'Well' is the well in which the culture was propagated; 'Selection' is the selection history of the culture; 'Line' is the line number out of 5 from each selection history; 'Spore' is the spore number out of 4 from each line; 'Replicate' is the replicate number out of 3 from each spore; 'Time' is the cycle number of the experiment; 'absorbance' is the optical density reading at 750 nm, a proxy for yield.yield.data.csv

Environments rarely remain the same over time, and populations are therefore frequently at risk of going extinct when changes are significant enough to reduce fitness. While many studies have investigated what attributes of the new environments and of the populations experiencing these changes will affect their probability of going extinct, limited work has been directed toward determining the role of population history on the probability of going extinct during severe environmental change. Here we compare the extinction risk of populations with a history of selection in a benign environment, to populations with a history of selection in one or two stressful environments. We exposed spores and lines of the green alga Chlamydomonas reinhardtii from these three different histories to a range of severe environmental changes. We found that the extinction risk was higher for populations with a history of selection in stressful environments compared to populations with a history of selection in a benign environment. This effect was not due to differences in initial population sizes. Finally, the rates of extinction were highly repeatable within histories, indicating strong historical contingency of extinction risk. Hence, information on the selection history of a population can be used to predict their probability of going extinct during environmental change.