Non-equilibrium phase transitions from survival to extinction have recently been observed in computational models of evolutionary dynamics. Dynamical signatures predictive of population collapse have been observed in yeast populations under stress. We experimentally investigate the population response of the budding yeast Saccharomyces cerevisiae to biological stressors (temperature and salt concentration) in order to investigate the system's behaviour in the vicinity of population collapse. While both conditions lead to population decline, the dynamical characteristics of the population response differ significantly depending on the stressor. Under temperature stress, the population undergoes a sharp change with significant fluctuations within a critical temperature range, indicative of a continuous absorbing phase transition. In the case of salt stress, the response is more gradual. A similar range of response is observed with the application of various antibiotics to Escherichia coli, with a variety of patterns of decreased growth in response to antibiotic stress both within and across antibiotic classes and mechanisms of action. These findings have implications for the identification of critical tipping points for populations under environmental stress.

最近在进化动力学的计算模型中观察到从生存到灭绝的非平衡相变。在压力下的酵母种群中观察到了预测种群崩溃的动态特征。我们通过实验研究了出芽酵母酿酒酵母对生物应激源（温度和盐浓度）的群体反应，以研究系统在群体崩溃附近的行为。虽然这两种情况都会导致种群数量下降，但种群反应的动态特征根据压力源的不同而显着不同。在温度胁迫下，种群发生急剧变化，在临界温度范围内出现显着波动，表明发生了连续的吸收相变。在盐胁迫的情况下，反应更加渐进。在对大肠杆菌应用各种抗生素时观察到了类似的反应范围，在抗生素类别和作用机制内部和之间，响应抗生素应激而出现多种生长减少模式。这些发现对于确定处于环境压力下的人群的关键临界点具有重要意义。