Karnani Mahesh, Annila Arto
Department of Biosciences, University of Helsinki, FI-00014 Helsinki, Finland.
Biosystems. 2009 Jan;95(1):82-7. doi: 10.1016/j.biosystems.2008.07.003. Epub 2008 Jul 29.
The ideas of the Gaia hypothesis from the 1960s are today largely included in global ecology and Earth system sciences. The interdependence between biosphere, oceans, atmosphere and geosphere is well-established by data from global monitoring. Nevertheless the theory underlying the holistic view of the homeostatic Earth has remained obscure. Here the foundations of Gaia theory are examined from the recent formulation of the 2nd law of thermodynamics as an equation of motion. According to the principle of increasing entropy, all natural processes, inanimate just as animate, consume free energy, the thermodynamic driving force. All species, abiotic just as biotic are viewed as mechanisms of energy transduction for the global system to evolve toward a stationary state in its surroundings. The maximum entropy state displays homeostasis by being stable against internal fluctuations. When surrounding conditions change or when new mechanisms emerge, the global system readjusts its flows of energy to level newly appeared gradients. Thus, the propositions of Gaia theory and holistic understanding of the global system are recognized as consequences of thermodynamic imperatives.
20世纪60年代盖亚假说的观点如今在很大程度上已被纳入全球生态学和地球系统科学之中。全球监测数据充分证实了生物圈、海洋、大气和岩石圈之间的相互依存关系。然而，支撑地球稳态整体观的理论仍不明朗。在此，我们从作为运动方程的热力学第二定律的最新表述出发，审视盖亚理论的基础。根据熵增原理，所有自然过程，无论有无生命，都消耗自由能，即热力学驱动力。所有物种，包括非生物和生物，都被视为全球系统向其周围环境中的稳态演化的能量转换机制。最大熵状态通过对内部波动保持稳定来展现稳态。当周围条件变化或新机制出现时，全球系统会重新调整其能量流，以消除新出现的梯度。因此，盖亚理论的命题以及对全球系统的整体理解被视为热力学必然结果。
