This is a second question about the same world described in this question about human reaction to an alien world.

So here's the idea: human beings travel to and land on an Earth-like world with the intention of colonizing it.

This world is remarkably Earth-like: gravity close to 1G, oxygen-nitrogen atmosphere with very close to the same proportions as Earth, similar climate, and similar life forms. So, in principle, a human could walk around unprotected on this world.


The life on this planet, while at a similar level of development to that of Earth, is not based on the same DNA/RNA bases or the same amino acids in proteins. In short, the lifeforms on this planet resemble Earth life, but the chemistry is different.

Would our familiar Earth plants grow in such an environment?

It seems unlikely to me that alien bacteria, viruses, etc. would attack our plants - after all, the genetic material and proteins are different.

But what about the soil? My first thought is that humus on this planet would be made up of organic material from decomposing alien life (decomposed by alien bacteria), and therefore wouldn't provide a medium in which Earth plants could get the nutrients they need. But is that correct? I guess to some extent it depends on how much the humus is decomposed (ie. just down to proteins & amino acids, or broken down even further).

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    $\begingroup$ You'll probably be interested in my old question Would humans be able to derive nutrition from foodstuffs found on alien planets? $\endgroup$
    – user
    Oct 8, 2018 at 16:44
  • $\begingroup$ Do the lifeforms on this planet use similar building blocks even if they don’t use the same DNA/RNA? I.e., can we assume that they also use PO4(3-) phosphate and NH3 ammonia molecules, or will they need to synthesize those from the atoms? $\endgroup$
    – Dubukay
    Oct 8, 2018 at 17:20

2 Answers 2


Scientifically speaking, plants are Autotrophs, and they do not require life to thrive. They don't need DNA, proteins, or anything else produced by life.

After all, life must have begun with something that required no prior life to exist. Those things were molds, algae, perhaps others, and those things evolved into plants (that still require no prior life).

The only thing you might have to worry about is some toxic chemical in the soil (like salt or some metals) to which the native life is immune.

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    $\begingroup$ Plants do need various bacteria for nutrients, like cobalamin. $\endgroup$
    – jaxad0127
    Oct 8, 2018 at 21:07
  • $\begingroup$ @jaxad0127 Not vascular plants. Algae uses a bacterium to synthesize it, that's all I find. Land plants do not require B12. See researchgate.net/publication/… $\endgroup$
    – Amadeus
    Oct 8, 2018 at 21:22

I am not an expert on the matter, but I would think that so long as earth plants can get access to the nutrients and sunlight they need to survive they will thrive. Bacteria and fungi are not important for plants to grow, they're important to decompose dead organice matter (including plants).

I think the danger will be that earth plants won't be able to decompose eventually leading to the native plans being covered by dead organic matter from the earth plants. There was a period called the Carboniferous that is pretty well known due to the fact most coal formations happened during that time as a result of the decomposing problem.

Basically can your plants get nutrients on some way or not? If yes, they can thrive.

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    $\begingroup$ There are important exceptions to microorganisms not being important to plant growth. Mycorrhizae are fungi that inhabit the roots of a plant, helping it extract nutrients from the soil: en.wikipedia.org/wiki/Mycorrhiza And nitrogen-fixing bacteria in legumes &c are important for extracting nitrogen from the air: en.wikipedia.org/wiki/… But savvy colonists would take a supply of both... $\endgroup$
    – jamesqf
    Oct 8, 2018 at 17:21
  • $\begingroup$ I think part of the question is whether or not plants could extract the nutrients they need from soil on an alien planet. $\endgroup$
    – Kat
    Oct 8, 2018 at 22:47
  • $\begingroup$ Well, the Earth plants would have Earth bacteria on them capable of breaking them down. $\endgroup$ Oct 8, 2018 at 23:32

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