My story takes place in dense woodland on highly uneven terrain in a temperate climate on Earth as we know it (e.g. central Europe), except a certain sort of magic is in operation.

In this woodland, there are a few very small objects which magically cause life around them to evolve extremely rapidly within a short radius, 1-5 metres. The mutation rate is higher than normal and there is no intelligence guiding this process, although I am happy to play god and guide the process a bit for the sake of interesting results.

I am imagining this would kill complex life forms since the mutation rate would be too high to allow seeds, fetuses etc develop normally. The main effect is on unicellular organisms which can sustain having large numbers of cells mutate themselves to death, the survivors will simply take their space in a short time.

This effect has been in place for a few decades, and as a result, there are these small pockets of life in the woods which are dominated by highly evolved and highly over-specialized unicellular life forms.

For example, if a fungus is growing on a rotting log, this fungus will be better than any other fungus on Earth at making use of rotting logs. However, after the log has rotted completely away, the fungus might perish since it has over-specialised.

The weather is relatively stable. Annual frosts, a few hot weeks, nothing extreme by our standards. Let's say that significant changes in the life forms takes a couple of years or more, so some (but not all) mutations will survive the cycle of the seasons.

Wind, rain, and the passage of animals will disrupt the edges of these pocket ecosystems, so these modified life forms will spread somewhat.

What absurdly over-specialised features might we observe after a few decades, and how might they interact with each other and the surrounding normal ecosystem?

  • $\begingroup$ What do you understand under "evolving"? Just rapid random mutations or truly everything is beneficial to the organism at that time? And is is continuously evolving during living or only at certain growth stages, like mitosis? $\endgroup$
    – Trioxidane
    Aug 22 '20 at 13:43
  • 2
    $\begingroup$ I'm willing to fudge those details a bit for the sake of story. Magic exists, after all. $\endgroup$
    – spraff
    Aug 22 '20 at 13:51
  • 4
    $\begingroup$ What is the evolutionary pressure? There are unicellular organisms on Earth that have not evolved much since before atmospheric oxygen. $\endgroup$
    – Mary
    Aug 22 '20 at 14:05
  • 1
    $\begingroup$ @spraff "Because magic", the fantasy version of this infamous cartoon: flickr.com/photos/jpallan/4633000725 $\endgroup$ Aug 23 '20 at 12:36
  • 1
    $\begingroup$ "dense woodland" and "kill complex life forms since the mutation rate would be too high to allow seeds, fetuses etc develop normally" are incongruous. How did you get a forest if nothing more than unicellular organisms can develop? $\endgroup$
    – Frostfyre
    Aug 24 '20 at 12:35

Given the selective pressure in this environment, I think they would evolve resistance to mutagenic magic. Maybe they would evolve better DNA repair mechanisms, or something like that. There are radiation-resistant bacteria, for example, which have improved DNA repair. I would expect mutations like these in your forest.

A short explanation of my answer: Natural selection works on random mutations. Those mutations which are advantageous (in the particular environment where the organisms live) increase the fitness of their bearers, and they have a higher probability to leave offspring in the population. In the long run, they are more likely to increase in frequency, relative to other similar organisms, and eventually, they could dominate the population. In this case, the high mutation rates are probably more harmful than beneficial, for example, because of the high number of inviable offspring (offspring is costly to produce). In real microorganisms, mutation rates have been fine-tuned by natural selection; too much causes unreliable reproduction and too little hampers adaptation to changing environmental conditions (by limiting the mutations availiable for evolution). Therefore, in your forest, I believe natural selection would favor those microorganisms which can avoid mutations as much as possible. Maybe they cannot avoid the magic directly, but they can try to repair the introduced mutations.

  • $\begingroup$ An easy way to make this happen is by increasing the amount of "useless" DNA in your organism. Most plants have high ploidy, which allows them to keep one viable set of genes around and have another set that can mutate without too much negative consequence. $\endgroup$
    – Whitehot
    Feb 8 '21 at 10:40

Microbes already can evolve extremely rapidly.

Consider the generation time of a bacterium. It can be a few days. Consider the bacteria which would like to eat the resources of a redwood tree. The redwood tree is 1000 years old. During the time of the tree there have been hundreds of thousands of generations of bacterium. How can they not have evolved around the defenses of the tree? Bacteria evolved resistance to penicillin in just a few decades. It is an interesting question to ponder.

For the sake of the fiction, here is how this might play out.

  1. Multicellular life is excluded from the region for the reasons you mention.

  2. There ensues a pitched battle between unicellular autotrophs which can produce their own food from light, and heterotrophs which want to take those resources for themselves. This battle will shift back and forth. Autotrophs with evolved defenses will spread in a green circle on the bare ground. When a heterotroph line evolves a way around those defenses the circles will die back as they are devoured. A new green circle will spring up with resistant autotrophs and spread, possibly overrunning the autotroph circles that have been there before.

Occasionally new organisms will happen into this realm by chance, blown by winds. They and their descendants will enter the battle. Sometimes a line of organisms will be pushed to extinction. If it is the autotrophs, the heterotrophs will follow and the region will be lifeless until new spores happen in.

  • $\begingroup$ Since the heterotrophs can consume all the available resources, might this turn into an unbounded expanding ring of death, the centre of which could be repopulated? $\endgroup$
    – spraff
    Aug 24 '20 at 10:01
  • $\begingroup$ @spraff - interesting idea. If the autotrophs had a spore / seed form which was uneatable that could happen. The center would fill back out and until it hit the expanding heterotroph ring which would then head back in. Hmm.. sounds like a math simulation waiting to happen! $\endgroup$
    – Willk
    Aug 24 '20 at 22:33

Hidden selection outside the frame of view.

Making evolution go faster is tough. You could increase the mutation rate, but then the load of undesirable mutations increases, and without a reduction in life span you can have "mutational meltdown". You could have a hidden single-celled generation undergo a desperate footrace for survival of the fittest, but spermatozoa already do that. You could have modular construction of genes for enhanced odds of creating useful new proteins, but we do that too.

The key to making super fast evolution, then, is to cheat. Three options:

a) The Objects scan the genome of surrounding organisms and upload it to a lab, where many duplicates of the environment are created and minor genetic variations tested; then the winning possibilities are used to modify the original organisms.

b) The world is actually a simulation on a quantum computer. The quantum computer generates an output that optimizes the "success" of the organisms surrounding the reference Objects.

c) The Objects randomly cause swaps of small segments of genetic information with very closely related parallel universes. Because these parallel universes have sometimes developed more effective genes, organisms near the Objects occasionally receive a genetic advantage nothing else in their world has.


You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .