Two Origins of Life? What a New Metabolism Map Suggests About Bacteria, Archaea, and Earth’s First Cells

Source attribution: This post is a curated breakdown of Scientists find evidence for two origins of life on Earth, with additional scientific context and philosophical analysis from Species Universe.

What if “life on Earth began once” is only half the story? A new line of research argues that even if all modern organisms share one genetic code, the first truly free-living cells might have emerged twice—once on the bacterial branch and once on the archaeal branch.

That idea matters beyond curiosity about the distant past. It reshapes how we think about the earliest ecosystems, how metabolism (the chemistry of living) could have taken off before modern enzymes and ATP dominated, and what “origin of life” even means in practice. It also has implications for astrobiology: if free-living life can arise more than once under similar conditions, then life elsewhere might be more plausible—though not guaranteed.

Why this matters (in plain terms)

When people say “life began,” they often picture a single dramatic moment: one first cell that then diversified into everything else. But origin-of-life research is increasingly about stages: networks of reactions, mineral catalysts, protocells, genetic coding, energy capture, and finally the ability to survive away from a particular geochemical setting.

The new work highlighted in the source focuses on that last part—how early systems might have moved from being “vent-dependent chemistry” to being independent, free-living cells. If bacteria and archaea made that transition separately, then the origin of life could be less like one spark and more like a shared “pre-life platform” that enabled multiple launches.

What the source says

The source describes an international team led by researchers at Heinrich Heine University Düsseldorf. Their work—reported as published in Science Advances—reconstructs aspects of early metabolism by comparing genomes, protein structures, and the chemical reaction network that modern cells use to build key components like amino acids, RNA bases, and vitamins.

1) They analyze a full “metabolic network” (420 reactions)

Rather than choosing a few famous pathways, the researchers reportedly examine a complete set of 420 interconnected reactions that (in modern organisms) convert simple inputs such as hydrogen gas, ammonia, and CO₂ into biological building blocks. The source emphasizes that many of these reactions are extremely ancient and broadly shared across life.

2) A key surprise: reactions look ancient, but enzymes don’t match across the bacteria–archaea split

One headline claim in the source is that while the reaction network is deeply conserved, the enzymes performing many of those reactions are not conserved in the same way between bacteria and archaea. The source reports the team’s inference that LUCA (the last universal common ancestor of all modern cells) possessed enzymes for only about half of the metabolic reactions in the network, while the remaining reactions could have been catalyzed by metals in the environment.

This is an interpretive reconstruction, not a direct observation of LUCA. The underlying idea is that if two lineages use different enzymes to achieve the same metabolic job, that might indicate independent invention after their split—or extensive replacement over time.

3) A proposed sequence: from metal-only catalysis → hybrid LUCA → separate bacterial and archaeal enzyme evolution

The source describes four “stages” in the early evolution of catalysis. The basic storyline is:

• Stage 1: early reactions catalyzed by metals (inorganic catalysis).
• Stage 2: a hybrid state (associated with LUCA) where metals and enzymes both contribute.
• Stage 3–4: after bacteria and archaea diverge, each lineage evolves enzymes that increasingly replace environmental catalysts.

Crucially, the source claims the team found examples where bacteria and archaea appear to have evolved structurally distinct enzymes that perform the same essential reaction—suggesting parallel solutions rather than shared inheritance of a single enzyme type.

4) An energy question: before ATP, what powered phosphorylation-like steps?

The source also highlights an energy puzzle. Modern metabolism leans heavily on ATP, but ATP itself requires elaborate enzymatic systems. The team reportedly identifies a possible alternative: phosphite (a reduced form of phosphorus) reacting with organic compounds in the presence of palladium, producing phosphorylation-like reactions in water under lab conditions. The source frames this as a plausible pre-ATP energy mechanism relevant to hydrothermal vent settings.

5) The big conclusion in the source: one genetic code, two “origins of life”

The source’s most provocative synthesis is that bacteria and archaea may have made the transition to free-living cellular existence independently. In that framing, there could be one origin of the genetic code (shared ancestry) but two origins of free-living life (two separate “launches” from a vent-dependent state).

How to interpret “two origins” without losing the plot

At Species Universe, we find this kind of claim exciting precisely because it forces better definitions. Here are three distinct questions that often get blurred together:

• Origin of organic chemistry: how nonliving environments produced or accumulated life-relevant molecules.
• Origin of heredity / coding: how information-bearing systems emerged and stabilized (leading toward something like the genetic code).
• Origin of autonomous cells: how systems became robust enough to live away from a particular geochemical “power outlet.”

The source is mainly about the third question (autonomous, free-living cells), using metabolism as the lens. That’s a legitimate focus, but it means the headline can sound bigger than what’s strictly being tested.

What the evidence type likely is (and isn’t)

• Not a fossil or direct observation of first cells (none exists for ~4 billion years ago).
• Yes to comparative inference from modern biology: enzyme families, protein structures, pathway coverage, and how these patterns differ between bacteria and archaea.
• Yes to experimental chemistry support: showing certain metal-catalyzed reactions can substitute for steps that are enzyme-driven today.

Even if the reported enzyme “non-conservation” holds up, there are multiple pathways to explain it. Parallel enzyme invention is one; widespread enzyme replacement is another; horizontal gene transfer (gene sharing across lineages) can complicate any simple tree; and different ecological constraints could push each lineage toward different biochemical hardware.

Practical steps: how to read this claim like a careful science reader

If you’re not a specialist, you can still evaluate what’s being argued—without either dismissing it or turning it into certainty.

1) Track the level of the claim

• Strongest level (often testable): “Many metabolic reactions are shared, but the enzymes differ between bacteria and archaea in specific steps.”
• Interpretive level: “Those differences imply independent invention of enzymes after divergence.”
• Big-picture synthesis: “Therefore, free-living life originated twice.”

It’s normal for papers to move up that ladder. As readers, we just keep the rungs separate.

2) Ask what would change the conclusion

Here are fair, concrete “what would convince me otherwise?” checks:

• If more shared enzyme ancestry is discovered (missed homologs, new structural links), the case for independent invention could weaken.
• If geochemical constraints make the proposed metal-catalyzed network less plausible at scale, the vent-dependence story might need revision.
• If alternative early habitats (not vents) can explain the same enzyme patterns, the “two vent launches” emphasis could soften.

3) Connect it to the bigger evolutionary picture (without conflating topics)

This is origin-of-life research (abiogenesis and early cellular evolution), not “evolution by natural selection” in the familiar population-genetics sense—though once stable reproduction exists, evolutionary mechanisms take over quickly.

If you want a grounded refresher on what evolutionary explanations do well (and what they don’t claim), the University of California, Berkeley’s educational hub is a reliable starting point: Understanding Evolution.

4) Use Species Universe as a map for related questions

• For our broad hub on how evolutionary thinking scales from genes to ecosystems, visit Evolution & Species Development at Species Universe.
• For how we frame scientific knowledge in a larger worldview (and how to keep evidence and interpretation distinct), see the Species Universe Framework.
• For a systems perspective on change, constraints, and multi-level dynamics, explore our guide to evolutionary systems thinking.
• For a curated on-ramp to evolution basics and common misconceptions, use our Evolution Understanding library.

Common misunderstandings to avoid

“Two origins” does not mean “two unrelated trees of life”

The source explicitly gestures toward a shared genetic code and deep common ancestry. The “twice” claim is about how two lineages might have independently achieved autonomy from a particular environment.

This is not evidence that life is “easy” everywhere

Even if Earth saw two transitions to free-living cells, those transitions may have depended on very specific constraints: hydrothermal chemistry, sustained gradients, availability of certain metals, and long time spans. None of that guarantees the same outcomes on other planets.

This does not imply consciousness is fundamental

Origin-of-life chemistry is fascinating—and philosophically evocative—but nothing in the source (as summarized) demonstrates that observation, information, or “measurement” makes life happen, or that mind is a basic ingredient of physics. Those are separate debates requiring separate evidence.

Bottom line

The source reports a bold but specific argument: when you map a very large swath of metabolism and compare bacteria to archaea, you may see signs that early life relied heavily on environmental metal catalysts—and that bacteria and archaea later evolved distinct enzyme solutions to the same core metabolic problems. From that pattern, the researchers infer that the leap to fully free-living cellular life could have happened independently on both branches.

Whether the scientific community ultimately embraces “two origins of life” as the best framing will depend on how robust the enzyme reconstructions are, how alternative explanations fare (including enzyme replacement and gene transfer), and how well the proposed pre-ATP energy chemistry scales to realistic early-Earth settings. The most durable takeaway right now is simpler and still profound: life’s beginning may have been less like a single invention and more like a long negotiation between geology and biology—until cells could finally carry their own chemistry with them.

Q&A

Does “two origins of life” mean there were two completely separate beginnings on Earth?

Not necessarily. In the source’s framing, the genetic code can still have a single shared origin, while the transition to fully free-living cellular life (away from vent-dependent chemistry) could have occurred twice—once in the bacterial lineage and once in the archaeal lineage.

What is the evidence type behind the claim?

It’s largely comparative inference: patterns in genomes, protein structures, and which enzymes perform which metabolic steps in bacteria vs archaea, combined with origin-of-life chemistry showing that metals can catalyze some reactions that enzymes handle today. It is not a direct observation of first life.

What role do hydrothermal vents play in this story?

Hydrothermal vents are proposed as settings where natural metal catalysts and strong chemical gradients could support early metabolic networks. The source suggests early life may have been vent-dependent at first, then gradually evolved enzymes that allowed cells to live independently of that environment.

Does this research prove life is likely everywhere in the universe?

No. Even if Earth experienced two transitions to free-living cells, those transitions could still depend on specific geochemical conditions and long time spans. The work may expand what we consider plausible, but it doesn’t provide probability estimates for life elsewhere.

Does any of this imply consciousness is fundamental to reality?

No. The source concerns early metabolism, catalysis, and energy sources for pre-ATP chemistry. Philosophical reflections are possible, but this type of evidence does not demonstrate that observation or information alone generates life, nor that consciousness is a fundamental physical ingredient.