A laboratory-created autocatalytic reaction network in a continuous-flow reactor is a controlled origin-of-life model in which chemical species mutually catalyze one another while fresh reactants flow in and waste flows out. Inspired by Eigen and Schuster’s hypercycle theory and related to Szostak’s protocell research, such systems explore how nonliving chemistry can become self-amplifying, self-maintaining, and selectively persistent. From a covolutionary viewpoint, the ARN and reactor together form a quasi-living symvironmental system: the network is not merely acted upon by its environment, but begins to bias, constrain, and direct its own future chemical state-space.

 

Autocatalytic Reaction Networks in Continuous-Flow Reactors

An autocatalytic reaction network, or ARN, is a chemical system in which reaction products help catalyze the production of themselves or of other members of the network.

A continuous-flow reactor is a laboratory vessel where fresh reactants continuously enter and products or waste continuously leave.

Together, these form a useful origin-of-life model:

A chemical network is kept far from equilibrium so that it can persist, amplify itself, and show primitive selection-like behavior.

This is not life yet, but it is more organized than ordinary chemistry. It is a model of quasi-living chemistry.

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1. The basic idea

The simplest autocatalytic reaction is:

A + X → 2X

Here, X helps make more X.

A network form would be:

A helps make B
B helps make C
C helps make A

In this case, no single molecule has to be a perfect self-replicator. The network as a whole becomes self-maintaining.

This is why ARNs are important for origin-of-life theory.
Early life may not have started as one perfect gene-like molecule.
It may have started as a chemical network that could maintain and reproduce its own organization.

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2. Eigen and Schuster: the hypercycle

Manfred Eigen and Peter Schuster developed the concept of the hypercycle, especially in their 1979 book The Hypercycle: A Principle of Natural Self-Organization.
A hypercycle is a theoretical model in which self-replicating molecules are connected in a cyclic autocatalytic network. (PMC)

A simplified hypercycle looks like this:

I1 helps replicate I2
I2 helps replicate I3
I3 helps replicate I4
I4 helps replicate I1

The point of the hypercycle was to explain how early molecular systems could store and maintain more information than a single short, error-prone molecule could manage alone.

So Eigen and Schuster’s contribution was mainly this:

They showed mathematically how early molecular replicators could become linked into a cooperative, self-amplifying system.

This was important because it suggested a bridge from chemistry to evolution.

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3. Jack Szostak and protocell research

Jack Szostak’s work is closer to experimental origin-of-life chemistry.
His research program asks how primitive chemical systems could combine:

RNA-like information
membrane compartments
chemical energy
growth
division
competition

In a 2016 discussion of the origin of life, Szostak emphasized that RNA replication requires chemical energy, that vesicle division can be driven by physical or mechanical energy, and that plausible origin-of-life environments must support concentration, replication, membrane formation, and division. (medicinabuenosaires.com)

So Eigen and Schuster give the network theory.
Szostak’s tradition asks how such chemistry could become physically embodied in protocells.

A good way to contrast them is:

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4. Why continuous flow matters

A closed flask is usually a poor model of life. The system uses up its reactants, waste accumulates, and the chemistry stops.

A continuous-flow reactor is different:

fresh reactants enter
the reaction network operates
products and waste leave
the system remains far from equilibrium

This is much closer to life.

Living systems also persist by continuous flow:

nutrients in
energy transformed
waste out
organization maintained

Autocatalytic flow chemistry is therefore important because autocatalysis is a major mechanism of nonequilibrium self-organization, and it is often considered relevant to origin-of-life research. Recent work also shows that autocatalytic networks under flow can display dynamic behaviors such as bistability and propagating fronts. (PubMed)

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5. What life-like properties does an ARN have?

The important point is that an ARN has some properties of life, but not all.

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6. Is an ARN alive in terms of covolution?

No.

A laboratory ARN is not a living organism. It usually lacks:

robust heredity
membrane-bounded individuality
regulated reproduction
repair
autonomous metabolism
open-ended evolution
genotype-phenotype mapping

But it is not merely passive chemistry either.

A better term is:

quasi-living chemistry

It is chemistry that has begun to show self-maintenance, self-amplification, and primitive directionality.

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7. Covolutionary interpretation

From the viewpoint of covolution theory, an ARN in a continuous-flow reactor is important.

It shows that directionality can begin before genes, cells, brains, or organisms.

Once autocatalytic closure appears, the system begins to bias its own future.
Some reactions become more likely because the network has already produced the catalysts that favor them.

So the ARN is not just a mixture of chemicals.
It is a primitive chemical system that begins to constrain and redirect its own future state-space.

In covolutionary language:

An ARN is a quasi-living network that converts chemical feedback into primitive control information.

The continuous-flow reactor is also important.
It is not just a container. It acts as the ARN’s artificial symvironment.

The real unit is not:

ARN alone

but:

ARN + flow + substrate supply + dilution + waste removal + reactor conditions

That whole coupled system determines whether the ARN persists or collapses.

This fits covolution theory very well because covolution does not treat the organism, or proto-organism, as separate from the environment. It treats life-like systems as network-symvironment complexes.

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8. Why this matters for the origin of life

The standard Darwinian story often begins with heritable variation and selection.

But ARNs suggest that before full biological evolution, there may have been a more primitive process:

chemical feedback
network closure
self-amplification
persistence under flow
primitive selection-like stability
compartmentalization
heredity
life

This is important because it means the earliest step toward life may not have been “random molecule plus external selection.” It may have been:

a chemical network that began to maintain and direct itself.

That is a very covolutionary idea.

Life may have emerged when chemistry crossed a threshold from passive reaction to self-referential network control.

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9. Short definition

A laboratory-created autocatalytic reaction network in a continuous-flow reactor is a controlled chemical system in which reaction products help regenerate the network while fresh substrates flow in and waste flows out. Inspired by Eigen and Schuster’s hypercycle theory and related to Szostak’s protocell research, it models how nonliving chemistry could become self-amplifying, persistent, and eventually evolvable. From a covolutionary viewpoint, it is a quasi-living network-symvironment system that begins to convert chemical feedback into primitive directionality.