I am pondering a world, where life very early on took a slightly different turn. First some background sketch, to explain what I mean:

Current theories state that life first evolved as protocells: little pores or similar, in which certain chemicals got concentrated and electro-chemical potentials could build up in a natural way; later on, primitive, single celled organisms, like bacteria and archaea arose, which could live independently of thise environment. At some point an archaeon somehow engulfed a bacterium and learned to live with it; the bacterium became the mitochondrion, and the result was the eukaryotic cell, which over time evolves into us, among other things.

Bacteria and archaea have at an early stage evolved to form biofilms; to do this they have had to learn to cooperate and communicate, in some primitive sense, by means of chemicals and electric signals (they do this even in our reality) - and they exchange bits of DNA. Imagine now, that instead of eukaryotes arising, these biofilms evolved ever higher complexity, specialisation and organisation, so that they in effect became multicellular lifeforms, but consisting of large numbers of different species of bacteria and archaea.

What would they be like? Could they evolve intelligence? And what would happen if they one day learned interstellar travel and came across these bizarre monocultures called humans?

  • $\begingroup$ Hi j4nd3r53n. I edited the title of your question to try to better summarize what you're asking; feel free to Edit further if you feel I got your intent wrong. $\endgroup$
    – user
    Sep 21, 2018 at 11:02
  • 1
    $\begingroup$ How is this different from the real life animals and plants which are formed of many different tissues consisting of many different varieties of specialized cells? In our biosphere the cells in multicellular organisms must share one common genetic code because our reproduction mechanism starts with one totipotent cell; in the fictional world described in the question reproduction would by necessity have to be vegetative. But even in our world many multicellular organisms, mostly plants and fungi but also some animals, reproduce vegetatively. $\endgroup$
    – AlexP
    Sep 21, 2018 at 11:03
  • $\begingroup$ "What would they be like?" is not a question that can be answered. Please try to ask an answerable question. This is a Q&A and not an online forum. Also you've noticed that life is not static and you cannot really expect anyone to predict anything on the timescales of billions of years unless it is a very simple problem. Life is the most complex system we know, we can't even model and predict anything with reasonable accuracy on a biochemical level - that's where we are at with your question - not even for a second. Perhaps a couple of femtoseconds in model systems with crude approximations $\endgroup$
    – Raditz_35
    Sep 21, 2018 at 11:06
  • $\begingroup$ Ah, and for the new title: look up slime molds for an example of complex behavior arising from deceptively simple structure. $\endgroup$
    – AlexP
    Sep 21, 2018 at 11:07
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    $\begingroup$ My guess is that they would be slower since signal paths are longer in an essentially 2 dimensional matrix. $\endgroup$
    – ShadoCat
    Sep 21, 2018 at 17:41

2 Answers 2


Short answer: Yes.

It’s evolution, this doesn’t break any of the laws of physics, with suitable stimuli intelligence could form in a colonial biofilm organism.

Long answer: Yes, but I can’t see a reason it wouldn't be outcompeted by more efficient “Y’know what, let’s mash our energy generating bacteria into our other bacteria, maybe come up with some common blueprints for how a whole colony should reproduce and grow, hey, wouldn’t it be great if we all shared one big resource network with specialised cells to transport oxygen and sugar” organisms.

So sure: you can say it happened, but there’s nothing stopping someone else from pointing out how lucky your slime molds got.

PS: I’m focusing purely on the title question, as the other questions should be... well, other questions.

  • $\begingroup$ You got your chocolate in my peanut butter!! $\endgroup$
    – RonJohn
    Sep 21, 2018 at 18:47
  • $\begingroup$ Perhaps the evolutionary pressures involved might make multi-celled life impossible or inefficient. I'm imagining a Super-Earth with a considerably higher gravity than our own planet; large creatures with endoskeletons would be infeasible. Now imagine that this planet has a lot of water and is overall very humid (which, correct me if I'm wrong, is a good environment for biofilms and bacterial mats). Now you have a planet that is unfriendly towards large multi-cellular creatures, but is friendly towards distributed bacterial colonies, biofilm, and archaea. $\endgroup$
    – AugustDay
    Sep 21, 2018 at 20:00
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    $\begingroup$ @AugustDay: even in that scenario it still makes more sense to have a ‘mitochondria’ wrapped inside a cell than having the two separate, and it makes more sense to have one shared ‘code’ amongst various different species to control the growth of the various colonies etc, even unto the point the different species start to very much resemble one species, and the different colonies start to resemble individual creatures. Then you have a situation where you have multicellular life, it’s just very flat $\endgroup$
    – Joe Bloggs
    Sep 21, 2018 at 21:39

There's no reason they couldn't. But one of the reasons for that is that we don't have the foggiest clue what actually makes something intelligent. Even defining criteria for being intelligent is an enormously tricky question.

If you use the Integrated Information Theory of Consciousness (IIT), it looks quite clear that you can assign a Φ value to your biofilm, which means it can be treated as being, in some way, conscious. IIT is nice to use here because it's based in cold hard mathematics. You may not agree that having a high Φ value means you are conscious, but at least you can agree that that thing has a high Φ and that people objectively agree with you. It makes for a very nice framework to answer questions about the consciousness/awareness or even intelligence of things we don't usually think of as conscious or aware.

My opinion is that intelligence is not far off from consciousness. I find "intelligence" seems to be a discrete aspect of consciousness, where "true" and "false" are distinct things. Thus talk of the consciousness level of your biofilm should relate to intelligence.

The biggest issue will be its ability to integrate the processing of its subcomponents. The human brain has a massive advantage: it's hanging out in a nice bone box, protected from the world. It has a bloodstream to provide it supplies, and an entire ecosystem of white-matter cells whose purpose in life is to do nothing but tend to the grey-matter neurons that make our brain think. Biofilms are not so well protected. It's easier to scratch them, or impact them, tearing them apart. If you scratch a brain, it's called a lobotomy. If you impact a brain, it's called a concussion.

If you did evolve a consciousness this way, it would likely lead your biofilm to act in ways related to the Ood from Dr. Who. The particular reason is a spoiler for Planet of the Ood (episode 191):

The Ood evolved with an external brain which supports their intelligence. The brain in their head was responsible for the more emotional decisions. They would hold their "hindbrain" in their hands, connected by bundle of neural fibers to their head. Accordingly, their species was one of the most peaceful in existence. It's very hard to get into conflict when you literally hold your brain in your hand. You learn to be peaceful.

I expect your biofilm would elect to be peaceful as well.

  • $\begingroup$ Why wouldn't a biofilm be well protected? Couldn't some of the species evolve to produce skin, or maybe scales and bones? $\endgroup$ May 12, 2020 at 9:37
  • $\begingroup$ @IchthysKing It may just be the way I read the question. At some point the entity stops earning the term "biofilm" and starts to become something else, like a creature. I think you're talking about how it might evolve after that point, while I only focused on the time where it still had biofilm properties. Once it passes that point, I think a biofilm evolving into a thinking being would be as indistinguishable from any other sort of creature as we are from whatever single-celled organism we grew from. $\endgroup$
    – Cort Ammon
    May 12, 2020 at 16:46
  • $\begingroup$ It would still be identifiable as a biofilm by the structure and arrangement of its cells, just as we are identifiable as eukaryote colonies by structure and arrangement of our cells $\endgroup$ May 12, 2020 at 20:38

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