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From Human “Colonizers” to Cosmic “Stomachs”: Microbial Life, the Spark Toward Humans, and Darwin-Like Selection in Quantum Physics
Abstract
This article synthesizes a set of linked questions: (i) how many species live on or in humans and which “living beings” are closest to us as constant colonizers; (ii) whether anything sits alone atop Earth’s food chain; (iii) what kind of alien life we’re most likely to detect; (iv) whether meteorites such as Murchison could plausibly represent a pivotal “event” for life’s emergence; (v) what, specifically, could count as the “spark” that makes a human possible; and (vi) whether physics—especially quantum entanglement and decoherence—contains processes analogous to Darwinian evolution. The central unifying thread is information: in biology, information is copied and selected (Darwinian evolution); in physics, information can be preserved, dispersed, redundantly recorded, or filtered by stability, but not necessarily in a Darwinian way.
1) What does “living on/in humans constantly” even mean?
You asked for all identified species, ordered “most to least,” that live on or in humans constantly. The immediate scientific complication is definitional:
“All identified” is not a closed set; metagenomics keeps expanding catalogs (especially for viruses and uncultured microbes).
“Constantly” can mean “in every human,” “in most humans,” or “in humans as a species (the global pool).” Those differ dramatically.
“Species” is straightforward for animals, less so for microbes and especially viruses (often defined by sequence clusters rather than classical species concepts).
A practical compromise is to distinguish:
(A) the global human-associated pool vs (B) what a typical individual hosts at a time, and to treat viruses separately because many people do not consider them “alive.”
2) How many microbial species are human-associated (and which groups dominate by
species count
)?
2.1 Global pool (across humans, multiple body sites)
A widely cited NIH/HMP framing is that humans are hosts to roughly 10,000 bacterial species globally, while an individual hosts on the order of ~1,000 species at a time.
Beyond that headline number, modern reference catalogs show why “all identified” keeps moving:
Gut bacteria/archaea (prokaryotes): The UHGG catalog reports 4,644 gut prokaryote species (species-level groups) from large-scale genome collection work.
Gut viruses (mostly bacteriophages): A large metagenomic survey reported >140,000 gut viral “species” (sequence-defined groups), with many novel.
Fungi (mycobiome): Reviews note >390 fungal species identified across human niches.
Archaea: Archaeal diversity is smaller than bacterial diversity but increasingly characterized; large genome-based surveys show substantial archaeal genome diversity in humans.
2.2 “Most to least” by species richness (global, human-associated)
If you include viruses as “living,” then viruses likely dominate by species-level group counts in current catalogs; if you exclude them, bacteria dominate among cellular life. The rough ordering by identified diversity is:
Viruses (if counted) — extremely high diversity in gut virome catalogs.
Bacteria — thousands globally; ~10,000 species framing in NIH/HMP.
Fungi — hundreds identified across human body sites.
Archaea — fewer than bacteria, but nontrivial and better cataloged than historically appreciated.
3) If we restrict to “things with a brain and a heart,” what are the closest human colonizers?
You proposed simplifying to organisms “closer to humans” (animals with nervous systems and a heart-like pump). That essentially shifts the discussion from microbiomes to ectoparasites and skin-associated arthropods. Here, “constant colonizer” becomes narrow: the most “normal” long-term residents are mites; lice and scabies are obligate human parasites but not universal; others (bed bugs, botflies, sand fleas) are human-associated but usually not permanent residents.
Top 10 animal colonizers / human-associated “resident-like” parasites (with one-sentence rationale)
(Ordered roughly from “most commonly present as a long-term resident” → “less common / more regional / more episodic.”)
Demodex folliculorum (face mite) — common on humans, living in hair follicles (notably eyelashes/face) often without symptoms.
Demodex brevis (face mite) — commonly found on humans, tending to inhabit sebaceous (oil) glands and follicles.
Head louse (Pediculus humanus capitis) — a blood-feeding parasite that lives on the scalp and lays eggs on hair shafts.
Body louse (Pediculus humanus humanus/corporis) — typically resides and lays eggs in clothing seams, migrating to skin to feed; can persist with ongoing exposure conditions.
Pubic louse (Pthirus pubis) — a crab-like louse inhabiting coarse hair (usually pubic region), feeding on blood.
Scabies mite (Sarcoptes scabiei var. hominis) — fertilized females burrow into the top skin layer and lay eggs, enabling sustained colonization without treatment.
Common bed bug (Cimex lectularius) — not a body resident, but a persistent human-associated blood feeder that lives near sleeping areas and repeatedly feeds on humans.
Tropical bed bug (Cimex hemipterus) — similarly human-associated, repeatedly feeding on people while residing in the environment (beds/furniture).
Sand flea / chigoe (Tunga penetrans) — adult females can burrow into skin (often feet) and remain embedded during egg production (tungiasis).
Human botfly (Dermatobia hominis) larvae — larvae can develop in human skin (furuncular myiasis) for weeks, but this is geographically limited and episodic.
Key caveat: only a few of these are plausibly “constant colonizers” in ordinary, healthy adults (notably Demodex). The rest are better described as parasites/infestations that can become persistent in the right social/ecological conditions.
4) Who is “the ultimate master of Earth” at the top of the food chain?
You asked for a single being “on top of the food chain alone,” not getting eaten “like humans.” Ecologically, there’s a mismatch in the framing: apex predators can be hard to prey upon while alive, but no organism escapes being consumed by decomposers eventually.
A useful reframing is your later “stomach of the world” idea: the organisms that ultimately digest everything. In that framing, the closest answer is:
Decomposers—especially fungi and bacteria—complete food webs by breaking down dead organic matter and recycling nutrients.
So if “master” means “final consumer / the biosphere’s stomach,” it’s microbial decomposers.
If “master” means “dominant shaper of Earth’s surface right now,” you can argue for humans, but that’s a statement about technology and global impact—not immunity from being consumed in the long run.
5) What’s the most likely alien life we’ll find?
Your intuition that the first aliens are likely microbial is consistent with mainstream astrobiology strategy: microbes are simpler, more robust, and can exploit chemical energy in dark environments (e.g., subsurface oceans). NASA discussions of Europa/Enceladus life-detection commonly emphasize biosignatures compatible with microbial life and the plausibility of sampling for such signatures.
A second point you implicitly raised: we may detect biosignatures (chemical/isotopic/mineral patterns) before we ever “see” a cell. That’s why sample return and in situ life-detection are major priorities in Mars and ocean-world exploration.
6) Is there a single “event” in world history like the Murchison meteorite delivering life’s building blocks?
You proposed something like: a carbonaceous meteorite delivers amino acids and other organics, seeding Earth with the building blocks for microbes. Murchison is a good symbol because we have strong evidence it contains abundant organics, including many amino acids, with isotopic signatures supporting extraterrestrial origin.
Examples of the evidence:
Isotopic and enantiomeric analyses support that many Murchison amino acids are extraterrestrial rather than terrestrial contamination.
Reviews note dozens of amino acids identified in Murchison, with many more detected across carbonaceous meteorites.
However: this is best viewed as one input stream, not “the origin event.” Early Earth likely received organics from multiple sources (endogenous synthesis + many impacts), across many environments.
7) “Good luck explaining the origin of life”: a more specific, non-handwavy path to humans
You pressed for a concrete “spark” rather than “billions of years happened.” The scientifically useful “spark” is not “a random amino acid,” but:
7.1 The earliest spark that makes humans possible
A self-copying system with heredity and variation capable of Darwinian evolution—often discussed as an RNA-like replicator (information storage + catalysis) coupled to compartments (protocells). This is the point where chemistry becomes an evolutionary process, not just reactions.
Work on fatty-acid vesicles encapsulating genetic polymers is one experimentally grounded line for how protocell-like systems could arise and couple growth with division.
RNA-world literature motivates why RNA (or an RNA-like polymer) is attractive: it can carry information and catalyze reactions, enabling a bridge from chemistry to heredity.
7.2 The later spark “closest to a human”
You also asked what’s “the spark of a human,” not just life. A strong candidate for the pivotal transition enabling complex multicellular life is:
Eukaryogenesis with mitochondria: mitochondria derive from an ancestral endosymbiotic alphaproteobacterium, and this event is tightly coupled to the rise of complex eukaryotic cellular architecture.
From there, the path to humans is “standard” evolutionary history: multicellularity → animals → vertebrates → mammals → primates → hominins.
8) Your physics analogy: chain reactions, heat mixing, and “matter competing to be the same”
You proposed that physical processes—nuclear chains, fusion/fission transformations, even warm/cold air exchange—look like “competition,” “variation,” and “information preservation,” suggesting an RNA-like information flow in matter itself.
A careful synthesis is:
Many physical systems show amplification (e.g., chain reactions) and pattern formation (e.g., convection), and they can preserve information at the microscopic level.
But Darwinian evolution requires a special ingredient: high-fidelity template-based copying with heritable variation, enabling cumulative adaptation.
Turbulent mixing and thermal equilibration typically erase usable macroscopic information (even if microscopic dynamics remain reversible in principle), which is the opposite of what genomes do.
So your analogy works best if interpreted as: far-from-equilibrium physics can generate persistent structures, but open-ended Darwinian evolution needs templated heredity.
9) Entanglement: “If A changes, B changes—so why doesn’t B’s environment change?”
This was the core conceptual knot you kept returning to. The resolution is that there are two different things people call “state change”:
9.1 What does change instantly (in the joint description)
If A and B are entangled, a measurement on A lets you update the conditional state you assign to B given the outcome at A.
9.2 What does
not
change locally at B (without classical communication)
Local physics at B is governed by B’s reduced state. The no-communication (no-signaling) principle says local operations/measurements on A cannot be used to transmit information to B faster than light; B’s local outcome statistics remain unchanged unless a classical signal arrives.
9.3 How entanglement is experimentally
proven
You asked: “How do we influence it and prove it—do we need to change both sides at the same time?” A standard approach:
Choose measurement bases independently on each side,
record outcomes,
show the correlations violate a Bell inequality (e.g., CHSH), ruling out local hidden-variable explanations under the experiment’s assumptions.
A landmark “loophole-free” Bell test with separated systems is one example of this experimental strategy.
Answer to your timing question: you do not need to “change both sides simultaneously.” You need measurements on both sides and a correlation analysis; spacelike separation is used to prevent ordinary causal coordination.
10) Is entanglement only “spin 0/1”? And does spin matter for fusion/fission?
You asked whether entanglement is limited to two-state “spin up/down,” and whether spin has real physical consequences in nuclear processes.
10.1 Entanglement degrees of freedom
Entanglement can involve many degrees of freedom (polarization, path, energy/time bins, orbital angular momentum, etc.), and systems are not limited to two levels—qudits and continuous-variable entanglement exist in principle and practice.
10.2 Does spin matter in fusion?
Yes: reaction probabilities can depend on spin configurations. In particular, spin-polarized fusion is studied because aligning spins of reactants can increase cross sections.
First-principles nuclear calculations and fusion research discussions report that fully aligned D–T polarization can increase the D–T fusion cross section by ~50% (≈ factor 1.5) under ideal polarization assumptions.
This is a local effect: spin influences nuclear reaction channels and cross sections. It is not an example of “remote entanglement making distant matter behave differently.”
11) Your goal: an experiment where entanglement triggers a “Darwinistic reaction” on both sides
You asked for the closest experiment where two entangled systems each interact with their local environments in a way that looks Darwinian—i.e., persistence + competition + emergence of stable “winners.”
The closest well-developed framework is Quantum Darwinism:
Decoherence filters out fragile superpositions.
A small set of stable pointer states survives interaction with the environment (environment-induced superselection, “einselection”).
The environment then stores many redundant records of the pointer-state information, enabling multiple observers to agree on the same “classical reality.”
A recent superconducting-circuit experiment reports a comprehensive demonstration consistent with these Quantum Darwinism signatures (branching structure, redundancy / mutual information plateau behavior).
11.1 A concrete “two-sided” design that matches what you proposed
Step 1: Prepare A and B in an entangled state.
Step 2: Couple A to a local environment E_A (many ancilla qubits or photonic modes), and couple B to an independent local environment E_B.
Step 3: Engineer the coupling so that each environment “monitors” its system, selecting pointer states and imprinting redundant copies of the system’s classical information into many environment fragments.
Step 4: Verify Darwinism-like behavior by showing that small fragments of E_A (and separately E_B) each reveal essentially the same pointer-state information (redundancy / plateau), while the underlying quantum coherences are suppressed.
This is “Darwin-like” in a precise, limited sense:
Selection: pointer states are the stable survivors under decoherence.
Replication: the environment stores many copies (redundant records) of those survivors.
What it is not: biological evolution’s open-ended adaptation via heritable variation across generations.
12) Your universe-scale extension: black holes, expansion, and distant “chaos”
You suggested a speculative extrapolation: if distant systems are entangled (e.g., black hole interiors entangled with Hawking radiation or other cosmological degrees of freedom), perhaps “one side” could create changes or chaos elsewhere in a Darwin-like way.
A careful statement consistent with known constraints is:
Black holes and Hawking radiation raise deep questions about entanglement and information (the black hole information paradox, Page curve, etc.).
There are speculative ideas linking entanglement and geometry (e.g., ER=EPR as a conjectured relationship between wormholes and entanglement).
But entanglement alone does not provide a controllable causal channel: it reshapes correlations, not local dynamics in a way you can use to force distant environmental effects (no-signaling remains the operational constraint).
So your “black hole ↔ expansion ↔ creation” picture is best treated as a research-level speculation about global correlations, not as a mechanism for remote Darwin-like causal influence.
Conclusions (the shortest faithful summary of the whole arc)
Humans host vast biodiversity, especially microbial; global catalogs suggest ~10,000 bacterial species associated with humans, ~1,000 per person at a time, gut prokaryote catalogs at 4,644 species, gut viromes at >140,000 viral groups, and mycobiomes at >390 fungal species.
If you restrict to animals with “brain + heart,” the closest “colonizers” are mainly Demodex mites, plus lice and scabies as persistent parasites; others are more episodic or environment-dwelling (bed bugs, sand fleas, botfly larvae).
No organism is “not eaten” in an ultimate sense; decomposers (bacteria/fungi) are the biosphere’s final digesters.
The most likely first alien life is microbial, and we may detect biosignatures before organisms.
Meteorites like Murchison plausibly contributed organics (including amino acids) to early Earth, but they’re likely one part of a broader chemical supply chain.
The most defensible “spark” for life is a templated, self-copying system capable of Darwinian evolution, plausibly in protocell-like compartments; the most defensible “spark” for human-level complexity is eukaryogenesis with mitochondria.
Entanglement creates strong nonclassical correlations, verified via Bell tests, but does not allow remote causal control of a distant environment (no-signaling).
The closest thing to “Darwinism in physics” is Quantum Darwinism: decoherence selects stable pointer states and the environment replicates their information redundantly.