Earth Clock I：Biological Nitrogen Fixation and the Evolution of Complex Life

Biological nitrogen fixation is one of the greatest innovations in Earth's history. It transformed an atmosphere dominated by inert nitrogen into a biosphere capable of sustaining complex life, agriculture, and ultimately human civilization.

In The Earth Clock I, Qi Cheng presents a new scientific framework that connects molecular biology, evolution, Earth system science, and planetary time. Through the concept of the Earth Clock, the book reveals how nitrogen fixation became the hidden engine driving biological complexity over billions of years.

Combining modern research with an accessible narrative, this volume explores the origin of nitrogenase, the evolution of photosynthesis, the emergence of multicellular life, and the future of biological innovation. It also introduces new concepts such as the Light-Utilizing Nitrogenase (LUN) hypothesis and synthetic nitroplast systems.

As the opening volume of the Earth Clock Library, this book provides a comprehensive vision linking life, time, and the future of civilization.