Adaptive evolution shapes the present-day distribution of the thermal sensitivity of population growth rate

• DOI: 10.1371/journal.pbio.3000894
• Publication Date: 2020-10-16T17:39:29Z
• Authors: Dimitrios—Georgio...; Thomas P. Smith; Timothy G. Barrac...; Samraat Pawar
• Keywords: Ectotherm; Trait; Convergent evolution; Rate of evolution

Developing a thorough understanding of how ectotherm physiology adapts to different thermal environments is crucial importance, especially in the face global climate change. A key aspect an organism's performance curve (TPC)-the relationship between fitness-related trait and temperature-is its sensitivity, i.e., rate at which values increase with temperature within typically experienced range. For given trait, distribution sensitivities across species, often quantified as "activation energy" values, right-skewed. Currently, mechanisms that generate this are unclear, considerable debate about role thermodynamic constraints versus adaptive evolution. Here, using phylogenetic comparative approach, we study evolution sensitivity population growth phytoplankton (Cyanobacteria eukaryotic microalgae) prokaryotes (bacteria archaea), 2 microbial groups play major carbon cycle. We find these moderately phylogenetically heritable, shaped by repeated evolutionary convergence throughout parameter space. More precisely, detect bursts increasing amount overlap among distributions clades. obtain qualitatively similar results from analyses physiological rates underlying rate: net photosynthesis respiration plants. Furthermore, episodes consistent opposing forces: decrease due environmental fluctuations adaptation stable environments. Overall, our indicate can lead large relatively rapid shifts microbes for occur short timescales. Thus, more attention needs be paid elucidating implications organismal ecosystem functioning.