Adaptive radiation from resource competition in digital organisms.

Area of Science:

• Ecology
• Evolutionary Biology
• Theoretical Biology

Background:

• Species richness often exhibits a hump-shaped relationship with productivity, peaking at intermediate levels.
• The underlying mechanisms driving this pattern, particularly in resource-driven systems, are not fully understood.
• Environmental heterogeneity has been proposed as a key factor, but its necessity is debated.

Purpose of the Study:

• To investigate the mechanisms generating intermediate species richness.
• To determine if environmental heterogeneity is essential for the hump-shaped productivity-richness relationship.
• To explore the role of resource diversity and frequency-dependent selection in driving adaptive radiation.

Main Methods:

• Utilized experiments with evolving digital organisms in a controlled, spatially homogeneous environment.
• Manipulated resource availability and diversity to simulate varying productivity levels.
• Employed population genetics and ecological modeling to analyze species dynamics and evolutionary trajectories.

Main Results:

• Maximum species richness was observed at intermediate productivity levels, consistent with empirical observations.
• This pattern emerged even in the absence of spatial environmental heterogeneity.
• Frequency-dependent selection on a diverse pool of limiting resources was identified as the primary driver.
• Adaptive radiation, characterized by the emergence of distinct phenotypes and lineages, was observed.

Conclusions:

• A diverse array of limiting resources is sufficient to drive adaptive radiation and maintain high species richness.
• Frequency-dependent selection, rather than environmental heterogeneity, can explain the peak in species richness at intermediate productivity.
• These findings provide a mechanistic understanding of biodiversity patterns in resource-driven ecosystems.