System-dependent Selection, Ecological Feedback and the Emergence of Functional Structure in Ecosystems

Area of Science:

• Evolutionary biology
• Ecology
• Systems theory

Background:

• Traditional natural selection models assume static or unrelated environmental fluctuations.
• Ecological feedback, where organism phenotypes influence environmental parameters, is often overlooked.
• This feedback loop can modify selection pressures in response to evolving phenotypes.

Purpose of the Study:

• To investigate evolutionary dynamics when ecological feedback is incorporated.
• To introduce and define the concept of 'system-dependent selection'.
• To explore how system-dependent selection can lead to functional organization and environmental regulation.

Main Methods:

• Utilized James Lovelock's Daisyworld model to simulate system-dependent selection dynamics.
• Applied a similar modeling approach to analyze an ancient Balinese wet-rice farming system.
• Investigated system stability by examining conditions for mutant phenotype invasion in Daisyworld.

Main Results:

• System-dependent selection can produce stable phenotypic diversity that regulates environmental parameters.
• This regulation increases mean population fitness and reduces fitness variance among phenotypes.
• Models accurately predicted functional organization in Balinese river systems, demonstrating real-world applicability.

Conclusions:

• System-dependent selection generates functional organization at the system level, not just the individual.
• Phenotypic diversity and organization are maintained when environmental parameters vary over evolutionary time.
• Ecological feedback is a crucial factor in understanding complex evolutionary and ecological systems.