Evolutionarily stable disequilibrium: endless dynamics of evolution in a stationary population

Area of Science:

• Evolutionary Biology
• Systems Biology
• Theoretical Biology

Background:

• Evolution is typically defined as population-level changes over generations.
• Life's hierarchical organization allows for evolution at multiple, potentially conflicting, levels.
• Existing models may not fully capture the complexity of multilevel evolutionary processes.

Purpose of the Study:

• To explore a novel mode of evolution driven by conflicting multilevel selection.
• To investigate if evolution can occur without apparent population-level change.
• To model the dynamics of protocells with internal replicating molecules.

Main Methods:

• Development of a minimal mathematical model of multilevel evolution.
• Simulation of protocell populations with internal catalytic molecules.
• Analysis of evolutionary dynamics at both the individual (protocell) and sub-individual (molecule) levels.

Main Results:

• Demonstrated a mode of evolution where individuals continuously modify phenotype and fitness along their lineages.
• Observed that conflicting selection pressures between protocells and internal molecules lead to oscillations in fitness.
• Showed that these oscillations, occurring independently in different lineages, result in a seemingly stationary population.

Conclusions:

• Population-level stasis can mask ongoing, lineage-specific evolutionary change.
• Conflicting multilevel selection is a viable mechanism for generating hidden evolutionary dynamics.
• The traditional view of evolution solely as population change may be incomplete.