There are ecological energy cycles. And there are energy cycles in organisms and Cells. Like the TCA cycle, Calvin cycle. The same principles applied in macro and micro.
The organism is full of cycles because cycles make thermodynamic sense. Cycles involve perpetual returns to the same states, they give dynamic stability as well as autonomy to the organism. Cycles also enable the activities to be coupled, or linked together, so that those yielding energy can transfer the energy directly to those requiring energy, and the direction can be reversed when the need arises. These symmetrical, reciprocal relationships are most important for sustaining the system. That's how our metabolism and physiology is organised: closing the cycle and linking up.
I have drawn a diagram to represent the nested cycles that span all space-time scales, the totality of which make up the life cycle of the organism.
The life cycle has a self-similar fractal structure, so if you magnify each cycle, you will see that it has smaller cycles within, looking much the same as the whole.
The system effectively stores and mobilises energy over all space-times that are coupled together, so energy can get from any space-time compartment to every other, from the local to the global and vice versa. This complex dynamical structure is the secret of how the system can sustain itself as a whole. Minimum dissipation means, in one sense, that energy (as well as material) going into the system is used many times over before it is exported to the outside. Intuitively, one can see that the more complex the dynamical structure, the more cycles there are, the longer the energy remains in the system, and the least amount is dissipated. In other words, increase in space-time differentiation leads to increase in the energy that can be stored in the system. 1[/size]
Cell division is a process that had to emerge prior when life began since it is an essential process to perpetuate life. It requires the coordinated generation of energy for multiple processes, including the synthesis of the machinery required for DNA replication and mitosis. 2 The regulation of OXPHOS and glycolysis is under the control of major cell-cycle regulators such as cyclin–Cdk complexes and cell-cycle ubiquitin ligases. The relationship between energy and the cell cycle is bidirectional, and several cell-cycle checkpoints sense energy deficits in the cell, thus leading to cell-cycle arrest or exit. Autophagy and particularly mitophagy are crucial pathways that link energy availability to cell-cycle progression.