...kill every protohuman who tries to leave the African continent.

This comment made me think about one question.

Suppose you have robot guards, like futuristic lasers, who just shoot at any landing animal who tries to approach the coast and fries him.

If those robo-guards stay indefinitely and have infinite energy, will fauna and flora adapt to coexist with this technology through the ages?

Are there real or similar cases on our world?

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    $\begingroup$ Some population of moths which was mostly white became mostly black due to smoke from factories staining walls and flora black - suddenly the darker moths were better camouflaged. If I recall that was one example Darwin used regarding natural selection. $\endgroup$ – Renan Feb 14 at 15:27
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    $\begingroup$ @Renan That's the peppered moth and is a classic example :) another interesting example is that it's been observed that the wingspan of small birds (robins, tits, finches etc.) seems to be reducing in areas with heavy traffic. Shorter wings are less efficient, but better for fast manoeuvring allowing birds to escape oncoming cars. $\endgroup$ – Ynneadwraith Feb 14 at 15:36
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    $\begingroup$ I edited your question for grammar, etc, and added the quote. If I got the wrong quote or if I changed the meaning of your question, please change it back. I had a very hard time understanding the "If" sentence especially. Hopefully I got it right. But if I didn't, please don't hesitate to fix it. $\endgroup$ – Cyn Feb 14 at 15:45
  • $\begingroup$ It's ok. Thanks! $\endgroup$ – Malkev Feb 14 at 15:47
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    $\begingroup$ What is the cost/benefit ratio? Antarctica is a very desolate place, guaranteed to kill anything that come close, more effective than your robot weapons. Flora and fauna has not adapted, because there are no resources. Cost/benefit is negative. Is there evolutionary pressure that 'squeezes' them into this territory? $\endgroup$ – Justin Thyme Feb 14 at 15:52


A continued cause of death in an area is a strong selection pressure regardless of its cause. Over a significant enough timescale life will evolve in response to that pressure.

The textbook case of evolution in response to man-made pressures is the peppered moth, which changed colour in response to air pollution during the industrial revolution.

Another interesting case is the evolution of small birds to have shorter wings in order to better avoid collisions with cars. There are also examples mentioned in the linked article of fish maturing quicker in response to commercial fishing, and two diverging populations of finches in the Galapagos combining back into a single population in response to bird feeders.

The evolution of antibiotic resistance in bacteria such as MRSA, CDiff and TB is another, very worrying example.

In order to predict what adaptations we might see from the immortal killer robots we'd need to know a little more about how they function, which would be an interesting follow-up question!

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    $\begingroup$ It is technically incorrect to say that the peppered moth evolved or changed color. There were always black moths and white moths. What happened, was that previously the white moths were less eaten than the black moths, and therefore the white gene was more prevalent, percentage wise, as a result of natural selection. When the background darkened, the white moths were eaten, so the black gene became more prevalent. But the black gene did not evolve, it was always there. Not ALL the black gene moths were eaten before procreating, just MOST of them. $\endgroup$ – Justin Thyme Feb 14 at 16:01
  • $\begingroup$ There is a very big difference between 'selection pressure' and actual gene evolution. In the first, the genes are already there. I the second, the gene is truly modified. The second is VERY slow, due to the 'splat' factor (the original single unique prototype carrier of the new gene is killed before procreating. That is, the single gene mutation has to be procreated to become established). $\endgroup$ – Justin Thyme Feb 14 at 16:09
  • $\begingroup$ @JustinThyme Very good point. They didn't actually change, only the proportion changed. I'll edit that now :) you're also right that there is a very big difference between selection pressure and gene evolution, but the former is thought to directly influence the latter and considering the robots remain indefinitely with infinite energy the pressure is guaranteed to be around for long enough to influence evolution. $\endgroup$ – Ynneadwraith Feb 14 at 16:44
  • $\begingroup$ @Ynneadwraith If you want the example causing the bigest headache in healthcare: MRSA, because of the sheer parallel numbers of bacterial population involved, gene evolution was over decades, brute force attack on bacteria resulted in genome adaptation - resulted in antibiotics becoming increasingly irrelevant. (I don't have time to make an answer at this point.) $\endgroup$ – Don Qualm Feb 14 at 17:15
  • $\begingroup$ @Agrajag Excellent (and frankly terrifying) example. I'll add that in. $\endgroup$ – Ynneadwraith Feb 15 at 16:49

It depends on the 'sighting method' used by the robotic guards, the nature of the weapon, and the already available genes in the animal population.

There is a very big difference between 'natural selection' and 'genetic evolution'.

If, for instance, the robots use infrared, then if there were already a gene in the animal population that reduced the infrared footprint (thicker insulating fur, more capillaries in the belly than the back, heat dissipated by paws on the ground, heat dissipated by vapor from the mouth - therefore the IR footprint was not the center of mass but in front of the center of mass, leading to targeting inaccuracies) then over time these genes would be 'selected' and thus the animals that had these genes and survived would result in a greater representation of these genes in the population, and in turn a greater probability of survival.

Or if the weapon were laser, did this animal already have a gene in the gene pool that produced in some animals a fur or skin that was more reflective to the laser (like pigment in the skin allows some people to stay out in the sun longer)?

But if the animal species did not ALREADY have a gene in the gene pool that produced some trait, skill, or factor that resulted in superior survivability to the robotic guards, then there is no trait that can be selected for. At that point, it is a crap shot that some random gene mutation might result in a greater survivability factor, and that mutation actually survives every other hazard to being reproduced, and that gene's 'offspring' live to reproduce. But that hope rests on ONE individual surviving long enough to reproduce. Unless you believe in 'evolution by intelligent design'.

That's what extinction events are all about. Failure to already have a suitable gene in the gene pool in sufficient numbers to assure enough survivors.

  • $\begingroup$ How many genes/traits/alleles are we actually talking about here? I'm guessing billions, maybe trillions. But even if it's only thousands, what are the chances that out of such a huge selection of possibilities, not one of them would provide some usefulness? I suspect the probabilities are astronomically in favor of some useful gene being present. A lucky mutation would just be an added boost to speed up the process. $\endgroup$ – Dalila Feb 15 at 19:13
  • $\begingroup$ @Dalila If your reasoning were true, then over millions of years of random gene mutation the likelihood of some animal ALREADY able to avoid the robots and being able to survive from injury from a laser weapon would be a certainty. In that case, it would be genetic selection and not gene evolution. But if it hasn't happened in millions of years of genetic evolution, I fail to see why the probability of it happening in the future are astronomically high. They would be the same, I posit, as they have always been. $\endgroup$ – Justin Thyme Feb 15 at 21:49
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    $\begingroup$ Whoa, I just said "some usefulness". I got no where near "able to avoid the robots" or "survive injury from a laser weapon". Also, the question asked about robot "guards", not robot assassins or hunters, and the question asked about "adapt to coexist", not adapt to be invulnerable to the robots or adapt to be able to evade them entirely 100% of the time. I'm just suggesting that what has happened over the millions of years, is that some useful traits already exist, and putting animals in this situation would lead to their prominence, whereas they are not as prominent currently. $\endgroup$ – Dalila Feb 15 at 22:01
  • $\begingroup$ @Dalila - I agree, especially since that trait of "some usefulness" need not be a straightforward anti-laser adaption. Since OP mentions guarding a coastline, something like increased territoriality (to avoid the danger zones) or more social behavior, (to warn others "don't go that way") would be traits that are not so uncommon, and can have some usefulness. $\endgroup$ – Megha Feb 16 at 3:23
  • $\begingroup$ @Dalila I seem to be missing the phrase 'some usefulness' in the original question.. Perhaps you can clarify where it is? $\endgroup$ – Justin Thyme Feb 16 at 15:44

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