Virgo Nathaniel, Ikegami Takashi, McGregor Simon
University of Tokyo and Tokyo Institute of Technology.
University of Tokyo.
Artif Life. 2016 Spring;22(2):138-52. doi: 10.1162/ARTL_a_00195. Epub 2016 Mar 2.
Life on Earth must originally have arisen from abiotic chemistry. Since the details of this chemistry are unknown, we wish to understand, in general, which types of chemistry can lead to complex, lifelike behavior. Here we show that even very simple chemistries in the thermodynamically reversible regime can self-organize to form complex autocatalytic cycles, with the catalytic effects emerging from the network structure. We demonstrate this with a very simple but thermodynamically reasonable artificial chemistry model. By suppressing the direct reaction from reactants to products, we obtain the simplest kind of autocatalytic cycle, resulting in exponential growth. When these simple first-order cycles are prevented from forming, the system achieves superexponential growth through more complex, higher-order autocatalytic cycles. This leads to nonlinear phenomena such as oscillations and bistability, the latter of which is of particular interest regarding the origins of life.
地球上的生命最初必定起源于非生物化学过程。由于这种化学过程的具体细节尚不为人所知，我们总体上希望了解哪些类型的化学过程能够导致复杂的、类似生命的行为。在此我们表明，即使是热力学可逆体系中非常简单的化学过程也能够自我组织形成复杂的自催化循环，催化作用源自网络结构。我们用一个非常简单但热力学合理的人工化学模型来证明这一点。通过抑制反应物到产物的直接反应，我们得到了最简单的自催化循环类型，从而实现指数增长。当这些简单的一级循环无法形成时，系统通过更复杂的高阶自催化循环实现超指数增长。这导致了诸如振荡和双稳性等非线性现象，其中双稳性对于生命起源尤其令人关注。
