This book raises and attempts to answer the following thought experiment: ‘For any planet with carbon-based life, which persists over geological time-scales, what is the minimum set of ecological processes that must be present?’. The main intention of this book is to use an astrobiological perspective as a means of thinking about ecology on Earth. Its focus on processes contrasts with the commoner focus in ecology textbooks on entities such as individuals, populations, species, communities, ecosystems, and the biosphere. The book suggests that seven ecological processes are fundamental (not including natural selection and competition, which characterize all of life rather than only ecology): energy flow (energy consumption and waste product excretion), multiple guilds (autotrophs, decomposers, and parasites), tradeoffs (specialization versus generalization, leading to biodiversity within guilds), ecological hypercycles (cycles within cycles), merging of organismal and ecological physiology (as life spreads over the planet, biotic and abiotic processes interact so strongly as to be inseparable), photosynthesis (which it suggests likely in most biospheres but not inevitable), and carbon sequestration. These fundamental processes lead to the emergence of nutrient cycling. The integration of Earth System Science with ecology is vitally important if ecological science is to successfully contribute to the massive problems and future challenges associated with global change. The book is heavily influenced by Lovelock's Gaia hypothesis.