ABSTRACT
Beginning with the depths of space and the regions of remotest nebulae, we will gradually descend through the starry zone to which our solar system belongs, to our own terrestrial spheroid, circled by air and ocean, there to direct our attention to its form, temperature, and magnetic tension, and to consider the fullness of organic life unfolding itself upon its surface beneath the vivifying influence of light [Alexander von Humboldt, Cosmos, vol. 1 (1997), pp. 79–80, original German edition (1845), p. 80]. The outer layer of the Earth must, therefore, not be considered as a region of matter alone but also as a region of energy and a source of transformation of the planet [Vladimir Vernadsky, The Biosphere (1998), p. 44, original Russian edition (1926)]. Living things profoundly influence and are influenced by Earth’s physical processes. They have played a major role in shaping and recording planetary history from time immemorial. The mutual feedbacks between life and its physical surroundings – biospheric and biogeologic processes – can never be far from our thoughts as we attempt to reconstruct that history (Preston Cloud, Oasis in Space: Earth History from the Beginning (1988), p. 42). No one ought to feel surprise at much remaining as yet unexplained in regard to the origin of species and varieties, if he makes due allowance for our profound ignorance in regard to the mutual relations of all the beings which live around us. […] Still less do we know of the mutual relations of the numerous inhabitants of this world during the many past geological epochs of its history (Charles Darwin, On the Origin of Species (1859), Introduction, p. 6.).
