Some Details

Suppose an Earth-like world with the following changes:

  • Atmosphere: 67% nitrogen, 31% oxygen, 2% other
  • Average surface temperature: 16.7° C (62° F)
  • Day/night cycle: 20 hours
  • Gravity: 0.86 g

This world is inhabited by genetically diverse creatures that are equipped with sugar-laden cells to power seemingly supernatural abilities. In order to support the ever-increasing needs of these creatures throughout their evolution, the native flora has grown to harbor increasing amounts of starch in an attempt to acquire more attention from the sugar-dependent fauna.

Additionally, as the creatures became more genetically diverse, the flora required a means to adapt their own genetics to the variability of their consumers. To this end they developed a symbiotic zombie fungus that can take over one unfortunate species of minute flying creature. Like O. unilateralis, this fungus has the ability to direct the actions of the host until its death. The target species is very similar to Earth's female mosquitoes: the creature feeds on the blood of its victims.

The fungus, however, interprets the consumed blood to extract DNA sequences. It then directs the host to fly to as many plants as it can, usually the generating species of flora, where it then releases spores the plant is capable of retrieving and realigning its DNA to match. This enables the plant to continue to be a producer for individual members of the victim's species. The genetic shift is mostly minor, so it can only expand the plant's ability to feed the native fauna.

The Problem

Humans arrive at the planet with a desire to colonize it. After witnessing the abilities of the native fauna, they want to settle the planet without completely terraforming it. The zombie fungus defined above will allow the native flora to rapidly adapt to H. sapiens, but there is no such adaptability for the environmental concerns.

The Questions

  • Given the planetary details defined above, what precautions would humans need to take upon first arriving on the planet?
  • How long would it take for humans to adapt to the planetary conditions to no longer require those precautions?
  • $\begingroup$ Is the adapting of the flora so that humans can eat them safely? Does this adapting trickle over to the fauna? $\endgroup$
    – AndyD273
    Commented Jan 18, 2016 at 18:55
  • $\begingroup$ @AndyD273 Yes to the first, but haven't decided on the latter. $\endgroup$
    – Frostfyre
    Commented Jan 18, 2016 at 19:09
  • 1
    $\begingroup$ I am a little unclear on what you are asking Frost, are you worried about the impact of the zombie fungus on humans or the impact of humans on the ecosystem? Either way I think we need to understand how the bug impacts an infected human. $\endgroup$
    – James
    Commented Jan 18, 2016 at 19:47
  • $\begingroup$ @James I'm concerned about the impact of the atmosphere and gravity on humans. $\endgroup$
    – Frostfyre
    Commented Jan 18, 2016 at 19:54
  • $\begingroup$ @James I included the portion about the fungus so answerers wouldn't focus on the ecosystem, as its adaptation/impact is already defined. $\endgroup$
    – Frostfyre
    Commented Jan 18, 2016 at 19:56

2 Answers 2


Once the humans figure out that the zombie fungus will help make the planet more hospitable, they'd want to get the process started as quickly as possible.

They might not want to start the process with themselves though.
Biologically speaking, earth mice and other lab animals are close enough that a plant that is adapted to one of them will be edible to us.
This is why we use them as lab animals.

This is useful for a couple reasons:

  1. It acts like a buffer. If there was something that could harm humans on the planet, it would be better if it happened to some animals first.
  2. We don't have to be annoyed with the bug bites. Kind of speaks for itself.

One of the bigger dangers on an alien planet isn't the weather or large animals, it's the really really tiny things that would see humans as large bags of salty water and minerals.

Humans would want to quarantine themselves from the planet until those things could be found and studied to see what effects they would have on us.

As to the environment, that gravity is a little lighter, but significantly so. People returning to earth after several years would be uncomfortable.
Earths average surface temperature is 15°C, so the planet would be a little warmer over all, but not excessively so, and there would be hot places and temperate places and really cold places, just like here.
It's a little more oxygen rich, but not enough to cause oxygen toxicity. It might just make it easier to work out, as your body wouldn't have to work as hard.
Found a few other effects of higher oxygen. Mostly good, but there would be more free radicals, which is bad.
Things like fires might need a little more care.

The hardest part might be the day length, but 4 hours shorter is probably better than 4 hours longer. It would take a little time, but people would adapt to it eventually.

During the quarantine period you'd have plenty of time to model the weather and learn where a good place for a permanent base would be. There's a lot that goes into a decision like that, and you'd want to see the possible areas in all seasons to really get a feel for it.

  • $\begingroup$ But how long would it take to adapt, so precautions weren't required anymore? $\endgroup$
    – Frostfyre
    Commented Jan 18, 2016 at 19:42
  • 1
    $\begingroup$ @Frostfyre That's a really good question, it it really depends, since it's partly a question on what is living there and how it works, which the humans don't know. You'd want to expose a large number of animals. Some you'd expose to captured biters in the lab, and then biopsy the bite marks instantly. Some you'd put out in mesh cages to be bitten to start the adaptation process. Eventually you'd let some forage in a contained area to see if getting exposed to the plants makes a difference. $\endgroup$
    – AndyD273
    Commented Jan 18, 2016 at 19:49
  • 1
    $\begingroup$ Probably you'd want to wait a couple generations of your lab animals so you can see how they die and autopsy all of those, how they are born and sample some from each period of gestation, plus test a random number from each generation. You also need to find out how quickly the plants adapt to our biology, and sample some of the animals after they eat the plants to check for any weird effects. $\endgroup$
    – AndyD273
    Commented Jan 18, 2016 at 19:54
  • 1
    $\begingroup$ A big part of it is what kind of diagnostic equipment they have available too. Having some kind of super advanced detection equipment could help lift the quarantine faster. $\endgroup$
    – AndyD273
    Commented Jan 18, 2016 at 20:10
  • 1
    $\begingroup$ @Frostfyre See my edit. Sorry, was focusing on the first part because of the title and large part of the text was focusing on that. $\endgroup$
    – AndyD273
    Commented Jan 18, 2016 at 20:21

There have been a few times when oxygen levels were that high on Earth. That was the time in Carboniferous Era with really big insects. Higher oxygen allowed permeation deeper into the bugs.

But higher oxygen also means far more intense fires. One graph showed combustion rate initially linear with increasing O2 up to about 35-40%, then raising abruptly to a slope close to twice that.

Most metals will burn in a pure oxygen atmosphere.


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