Linking scaling laws across eukaryotes.

Area of Science:

• Ecology
• Evolutionary Biology
• Theoretical Biology

Background:

• Universal scaling laws link body mass to species characteristics in biology.
• Metabolism, abundance, growth, and mortality often follow power laws, typically attributed to metabolic constraints.
• Existing theories lack cross-eukaryote testing and formal links between these four variables.

Purpose of the Study:

• To test metabolic scaling theories across all eukaryotes.
• To examine the links between metabolism, abundance, growth, and mortality.
• To determine if observed scaling patterns support theoretical expectations.

Main Methods:

• Utilized comprehensive datasets covering all eukaryotes.
• Analyzed scaling laws for metabolism, abundance, growth, and mortality against body size.
• Tested for reciprocal scaling and energetic equivalence across species.

Main Results:

• Metabolism and abundance exhibit reciprocal scaling with body size (exponents near ±3/4 within groups, ±1 across groups), supporting energetic equivalence.
• Growth and mortality rates show similar scaling (exponents near ±1/4) both within and across taxonomic groups.
• Findings contradict a purely metabolic basis for growth and mortality scaling.

Conclusions:

• Energetic equivalence is supported across eukaryotes through reciprocal metabolism-abundance scaling.
• Growth and mortality scaling patterns are inconsistent with prevailing metabolic theories.
• Metabolism may adjust to growth needs, suggesting growth dynamics as a basis for biological scaling.