"The Earths past has seen periods of distinct states determined by new biological evolutionary innovations (such as oxygenic photosynthesis): the planets history consists of a dynamic between the evolution of its crust and atmosphere and that of biological evolution - there has been an interrelated co-evolution of life and planet. Further, each of these planetary states is separated by a critical transition that is geologically brief (millions of years) compared the length of these states duration (generally on the order of a billion years). All these critical transitions (tipping points) are driven by a major biological innovation (such as the rise of multi-cellularity) and all have a distinct set of characteristics (such as the creation of new mineral species): other critical transitions (such as that connected with the K/Pg [dinosaur] extinction) do not have all these characteristics. That all these characteristics can be seen today suggests that the planet is about to cross a critical transition and enter a new state: the present day is part of an on-going process stretching back billions of years. That all but one of the major biological evolutionary innovations driving these transitions have arisen multiple times suggests that not only are these common but also easy evolutionary steps. That a technology-wielding species has arisen so late in the Earths habitable lifetime is less to do with it being a difficult evolutionary step but that each of the previous evolutionary steps has to take place first and in sequential order. If this co-evolution of life and planet narrative has merit, then it should speak to the nature of life, and the exobiological probability, on other worlds. It might also explain the Fermi paradox"-- Provided by publisher.