The earth and its life: Systems perspective

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Abstract
From the planetary point of view, the Earth can be imagined as a system comprised of interwined natural populations propagated through time via recycling. This recycling, or ‘birth/death’ process, imposes age patterns on natural populations of the solid earth, hydrosphere, atmosphere and living entities. Mathematically, the concept is analogous to that of population dynamics in living systems. The populations of the Earth system form a hierarchical structure. The hierarchy of geological tectonic realms contains populations of ≤1024−1026 gr in size, with half-lives in the 107−109 yr time range. The approximate parameters for the oceans are ≤1024 gr and 102−107 yr, for the atmosphere ≤1021 gr and 10−2−107 yr, and for living systems ≤ 1014−1019 gr and 10−3−102 yr, respectively. In this perspective, and in departure from the GAIA hypothesis, the subordinate populations, such as those of living systems, are constrained to operate within limits imposed by the larger, and slower, hierarchies. They can overstep the imposed limits only on time scales shorter than the response time of the dominant populations. Isotopic record of past sea water shows that on time scales of 107 yr the solid earth, hydrosphere, atmosphere and life act as a unified system controlled by tectonics, that is by the hierarchy of the solid earth.