The article "Toward a unified view of cellular and ecosystem processes" by James J. Elser, Dean R. Dobberfuhl, Neil A. MacKay, and John H. Schampel explores the integration of ecological and evolutionary biology through the lens of elemental stoichiometry. The authors argue that while energy has been the primary focus in ecology, elemental stoichiometry offers a complementary framework to understand the relationships between species and ecosystems. They highlight the importance of nitrogen-to-phosphorus (N:P) ratios in modulating secondary production and nutrient cycling in ecosystems. The article reviews the biochemical and cellular composition of key biomolecules and structures, such as proteins, nucleic acids, and cellular membranes, and how these contribute to the overall N:P ratio of organisms. It discusses how variations in N:P ratios are linked to life history traits, growth rates, and ontogenetic development. For example, rapid-growing organisms like Daphnia have lower N:P ratios due to higher RNA content, while slower-growing organisms like calanoid copepods have higher N:P ratios. The authors also explore the allometric variation in N:P ratios across different organism sizes, from bacteria to large vertebrates. They predict that larger organisms will generally have higher N:P ratios, which has implications for their efficiency in recycling nutrients and their impact on ecosystem processes. The article concludes by emphasizing the potential of stoichiometry to bridge the gap between evolutionary biology and ecosystem science, providing a new tool to understand the causal mechanisms linking cellular, ecosystem, and evolutionary processes.The article "Toward a unified view of cellular and ecosystem processes" by James J. Elser, Dean R. Dobberfuhl, Neil A. MacKay, and John H. Schampel explores the integration of ecological and evolutionary biology through the lens of elemental stoichiometry. The authors argue that while energy has been the primary focus in ecology, elemental stoichiometry offers a complementary framework to understand the relationships between species and ecosystems. They highlight the importance of nitrogen-to-phosphorus (N:P) ratios in modulating secondary production and nutrient cycling in ecosystems. The article reviews the biochemical and cellular composition of key biomolecules and structures, such as proteins, nucleic acids, and cellular membranes, and how these contribute to the overall N:P ratio of organisms. It discusses how variations in N:P ratios are linked to life history traits, growth rates, and ontogenetic development. For example, rapid-growing organisms like Daphnia have lower N:P ratios due to higher RNA content, while slower-growing organisms like calanoid copepods have higher N:P ratios. The authors also explore the allometric variation in N:P ratios across different organism sizes, from bacteria to large vertebrates. They predict that larger organisms will generally have higher N:P ratios, which has implications for their efficiency in recycling nutrients and their impact on ecosystem processes. The article concludes by emphasizing the potential of stoichiometry to bridge the gap between evolutionary biology and ecosystem science, providing a new tool to understand the causal mechanisms linking cellular, ecosystem, and evolutionary processes.