Loop-Centric Perspective on Life’s Origin, Evolution and Functions
From a systems engineering perspective, I am conducting personal research on the origins of life.
In this article, while revisiting the system-theoretical hypothesis on the origins of life, built from a process loop-centered perspective as demonstrated in previous articles, we will consider the functions and mechanisms needed by the process loop to enhance its robustness.
It’s important to note that I’m not pondering how the known functions of organisms are realized; rather, I’m focusing on how to systemically bolster the robustness of something termed a “process loop”. Despite this approach, it’s evident that the functions we know in organisms naturally emerge.
This realization is intriguing for two reasons:
First, it implies that the functions deemed essential when viewed from a systems engineering standpoint are naturally acquired by organisms. Whether it’s biological evolution driven by DNA or chemical evolution predating DNA’s appearance, these functions emerge merely by abiding by the rule that those suited to their environment survive.
Secondly, beyond conventional approaches to understanding the purpose of an organism’s functions, by considering the necessary functions for the system of life phenomena to persist, we can also discern the significance of biological functions. If there are functionalities within an organism whose purpose is elusive, this perspective might provide an explanation.
Let’s delve deeper into the main content below.
Hypothesis on the Origin of Life from a Process Loop-Centered Perspective
In previous articles, we presented a viewpoint that conceptualizes life based on a loop structure of chemical reactions facilitated by catalytic chemicals, terming this basic structure a “process loop”.
Broadening our perspective, this process loop can also be understood as one of the chemical reactions, which when integrated, creates another chain of reactions potentially forming another loop structure.
It’s postulated that the initial process loops formed by leveraging the Earth’s water cycle for material transfer. Successive integrations of these process loops would lead to chain-like dependencies. Eventually, the interdependence between these loops can form a cyclical structure, allowing groups of process loops to become independent of the initial ones.
Furthermore, when these independent process loop structures can realize the material transfer each requires without relying on the Earth’s water cycle, they achieve autonomy from this external force.
At this juncture, we can say the first phase of life’s formation has been realized. Groups of catalytic chemicals create a looped chain of chemical reactions, with these loops cyclically dependent on each other. As long as each looped chain can incorporate external input materials and energy, they can maintain their reactions. My hypothesis posits that once these looped chemical reactions can sustain themselves without external aids like the Earth’s water cycle or terrain, relying solely on the group of catalytic chemicals, they transition from mere natural phenomena to what we can term “life phenomena”.
The Importance of Resource Rectification
For these processing loops, each chemical reaction and the movement of materials that don’t rely on the Earth’s water cycle require energy.
If a consistent supply of energy is always provided from the external environment, there would be no issue. However, usually, the energy provided varies. Additionally, other concurrent chemical reactions might also consume the available energy.
To ensure that the necessary energy is available when required, a mechanism is essential to store energy acquired from the external environment and then supply it based on demand.
For instance, in the case of storing energy in sugars, it involves mechanisms like photosynthesis to produce the sugar and glycolysis to utilize it. For lipids, it refers to lipid metabolism. At the origin of life, energy might have been stored in forms other than sugars and lipids.
Besides energy, inputs in the form of other materials are also required for the processing loops. Primarily, these would be acquired from the external environment. A mechanism to store them and supply when needed is vital.
Let’s simply refer to these necessary energies and materials from the external world as “resources”. I’d like to term the mechanism that consistently provides these resources to the processing loops as “resource rectification”.
Mechanism of Resource Rectification
Resource rectification requires mechanisms for resource collection, storage, and supply.
Resource collection in its primitive form likely consisted of passively waiting for materials or energy to be provided, then capturing them. As it evolved, mechanisms to actively attract resources or movement to enhance collection opportunities might have developed.
Resource storage might involve converting resources into forms like sugars or fats, storing them in confined spaces, or adsorbing them onto a core substance.
In a basic supply mechanism, stored resources would be released at regular intervals. In more advanced systems, resources would be supplied precisely when the processing loop demands them.
In this way, the mechanism of resource rectification can provide a stable supply of resources to the necessary processing loops, even if there are fluctuations in external supply or overlapping timings with other loops. This makes the group of processing loops robust against environmental changes.
Importance of Maintenance and Purification
For the processing loop to function properly, the condition of the environment in which the process occurs is crucial, in addition to the resources. Typically, the processing occurs in water. For unicellular organisms, it’s the cytoplasm, and before the emergence of cell membranes in the origin of life, it would have been places like ponds or lakes.
Key conditions of the water in which these processing loops operate include temperature and pH levels. Moreover, the absence of unnecessary substances in that environment is essential.
Thus, mechanisms to maintain the water conditions, such as temperature and pH level, and purification mechanisms to remove excess substances are vital.
Maintenance is essentially a mechanism to stabilize conditions, like maintaining temperature or pH within a certain range. Purification involves mechanisms to filter out, expel, or break down unwanted substances.
Additionally, it’s essential not to intake unnecessary substances from the external environment when obtaining resources. This can be likened to “screening” or immunity, but for our purposes, we’ll categorize it as part of the purification mechanism.
Mechanisms of Maintenance and Purification
Initial maintenance mechanisms activate when the target parameters deviate from a baseline state. This involves a processing loop that provides feedback opposite to the deviation from the baseline. For instance, if the pH level becomes acidic, the processing loop is triggered to eventually produce a substance that shifts the pH towards alkalinity. If the pH goes beyond the baseline towards alkalinity, the loop works to make it more acidic.
As the maintenance mechanism becomes more sophisticated, it can adjust the baseline state according to circumstances. The mechanism that raises body temperature when one catches a cold is an example.
Purification can involve continuously circulating water and filtering out excess substances through a filter, or it can be triggered when an excess substance appears. In the latter case, there might be mechanisms to expel the substance externally or to produce substances that break down the target.
By developing advanced maintenance and purification mechanisms, a system becomes less susceptible to external environmental changes or influences from its internal processing, making the system more robust.
Importance of Membranes as Barrier
For the processing loop groups to function stably, it’s crucial that the necessary catalysts don’t scatter. When considering the need to purify interactions between processing loops so that they are not interfered with by other entities, and to maintain them for smooth operation, having some form of barrier becomes advantageous.
This is where membranes become significant. Within the membrane, the catalysts required for the processing loop groups are enclosed, and the maintenance and purification primarily target the inside of this membrane.
Membrane Mechanism
The membrane itself seems to form relatively easily, similar to soap bubbles, if lipids can be produced.
When a membrane forms and efficiently encloses the necessary catalysts, as mentioned earlier, the processing loop operates stably, and the mechanisms for maintenance and purification also work effectively.
This implies that if the processing loops necessary for membrane generation operate stably, it becomes easier for the membranes to form. In this manner, the formation of membranes can be considered a self-reinforcing feedback loop.
Mystery of Membrane Formation and Cytoskeleton
It is known that cell membranes can form spherical structures due to lipids exhibiting both hydrophobic and hydrophilic ends. However, assuming that when these membranes appeared, the catalysts necessary for various processing loops just conveniently got encapsulated inside seems quite serendipitous. How precisely the necessary catalysts got encapsulated inside the cell membrane remains a mystery.
Before encapsulation within a membrane, it’s believed that various catalysts were present in ponds or lakes, with material exchange between them facilitating processing loops. If we assume material exchange solely depended on water currents and diffusion at this stage, the formation of membranes must have been heavily reliant on chance.
However, if we hypothesize that even before being encased in a membrane, various catalysts were linked by some structural entities, with materials exchanged along these entities for the processing loops to function, the narrative changes. This suggests a scenario where aggregates with various catalysts attached to structures existed even before being encased by membranes. If such structures existed, there would be no need to rely on chance when lipids encase and encapsulate the necessary catalysts.
Indeed, within cells, there are various fibers and tubes of different widths, known as the cytoskeleton. It’s plausible to think that they existed in ponds or lakes like micro bundles of cotton before being enclosed by lipid membranes. It seems more logical to think that the aggregates of cytoskeletal fibers and tubes existed before the membranes.
The development of small computer devices integrated into electronic products also follows a similar pattern. Initially, prototypes are developed without casings, much like the exposed fiber bundles and group of catalysts. Even without being encased in a membrane, they function by exchanging power and information through circuits on the base.
And, just as when a device is manufactured as a product, it is encased in a hard shell, enclosing it in a membrane protects the internals from damage and unwanted entities disrupting their operation.
Importance and Mechanism of Catalyst Production
For mechanisms such as resource rectification, maintenance and purification, and membrane formation to function, efficient catalysts are essential. Therefore, the production of catalysts becomes crucial.
Each of these mechanisms can be viewed as a type of processing loop. And for a processing loop to persist over time, it needs to evolve as a self-reinforcing feedback loop during chemical evolution.
There are several directions for this feedback loop’s self-reinforcement. For example, it might involve the processing loop acquiring more necessary resources or ensuring that chemical reactions within the loop smoothly occur in optimal conditions. Another direction is for the processing loop to produce its own required catalyst.
A processing loop capable of producing its own catalyst is more robust as a self-reinforcing feedback loop. Thus, it would have a higher survival likelihood during natural selection. With this in mind, it wouldn’t be surprising if many of the processing loops that survived chemical evolution had the ability to produce their necessary catalysts.
To DNA
Eventually, DNA forms and enters the membrane, becoming something we can refer to as a cell due to its self-replicating ability.
How DNA came into existence remains unknown.
I believe the state where the processing loop produces its catalysts likely existed before the emergence of DNA. And based on the mechanism where the processing loop produces its own catalysts, this foundation probably led to the birth of DNA. However, these are speculative thoughts, and the mechanism behind the origin of DNA is a topic I’d like to delve deeper into in the future.
In Conclusion
By considering the origins of life from a loop-centered perspective, shaped in the form of a “process loop,” we’ve been able to more vividly visualize the hypothesis.
In this article, based on that premise, we reflected on mechanisms that enhance life’s robustness: resource rectification, maintenance and purification, membrane creation, and skeletal formation. While life boasts a myriad of intricate functions, by sequentially ensuring the robustness of the process loop, we discern that these functions are logically essential.
As mentioned at the outset, viewing life phenomena as a system and pondering the functions and mechanisms it should inherently possess might offer a fresh perspective on the functionality of organisms.
Additionally, in this article, we also shared thoughts on the creation of catalysts and DNA.
Admittedly, there remain aspects that are not yet clearly delineated and need more concrete contemplation. However, by organizing these concepts grounded on a loop-centered viewpoint, I believe we can gain novel insights. The process of DNA formation remains a significant mystery at this juncture, but I aspire to explore effective approaches to this enigma.
