Oh no, Earth has exploded!

Luckily, we have a backup plan: a single space station and enough storage to keep DNA samples of:

  • Humans,
  • 5 plant species,
  • 5 vertebrate species,
  • 5 invertibrate species

Purpose of the Question

A thought experiment mainly. To determine what species would be most important to ensure human survival in a small, closed "world in a bottle" sort of situation.

Note that the important part of the question is human survival. This means that just creating a self sustaining ecosystem isn't enough, it has to be populated by organisms which will benefit us, and fulfill as many niches to human civilization as possible.

The Space Station

This is just a thought experiment. How the Space Station works is irrelevant, but to keep the question specific I will include a few details:

The structure is a Stanford Torus - or, a large ring that rotates to generate gravity. It has a livable interior surface area of 10,000 square kilometers - or, slightly larger than Sardinia.

The interior is large enough to generate weather such as rain and wind. Sunlight is directed into the habitat via mirrors.

Colonists inside have the option to generate electricity in any way they choose, as long as it is within the bounds of modern technology.

In terms of abiotic building materials, they have a limited supply of every element, but cannot rely entirely on metal, etc. to build every structure.

How much water is on board, what sort of biome you want the interior to resemble, temperature, etc. is all up to you and can be customized to fit whatever species you decide to bring.

In terms of the soil and ground, there is enough material to cover every 10,000 square kilometers in 100m of ground. What that ground is made of, whether it is shaped like picturesque mountains and valleys or a great archipelago amidst an artificial ocean is all up to you.

The ship will have to be 100% self-sufficient, so we'll need something to keep the soil nutrient rich and generate oxygen, something to break down any woody plants you decide to bring along, and so on.

The Brave Colonists

And, of course, the humans on board will have to eat, build stuff, etc.

As for their culture and creed, it hardly matters: only that they are simple humans as we know them today and need to develop a hardy, well rounded civilization to survive for as long as possible without access to outside resources.

Of course, the human element can affect ecology: there will (hopefully) be plenty of manpower to manage things like animal populations, sowing forests, etc. How effectively they will be able to manage and live off their quaint little 10,000km is entirely dependant on what species they have to leverage.

Extra Considerations

  • Yes, I know it makes no sense that a 10,000 square km Stanford Torus only has room for 15 DNA samples. This isn't important and isn't meant to be a "how would we do this?" question as much as it is to highlight which plants and animals would be the best space companions over exceptionally long, isolated missions.
  • The colonists do not know how to genetically modify their plants and animals, at least not from the start of the mission. What they have is what they are stuck with. They can use run-of-the-mill selective breeding, of course.
  • in terms of different animal breeds, we'll keep it simple by saying you only get one.
  • Microorganisms would complicate things far too much for the scope of the question. So, for some reason, while the spacecraft only has enough space for 15 DNA samples, it does have enough room to keep cultures of whatever microorganisms the colonists and other species may need, including algae. So no, your flock of space sheep aren't all going to die because they have no stomach bacteria. This does open up the ability to use algae alone to keep the air breathable, but do keep in mind you only have max 10,000 square km of 100m deep ocean, and people do need to live somewhere.

Note: this is the first question I'vd asked here in some time. I spent a few hours trying to account for as much as possible while trying not to go too crazy on the length. I hope I did a good job, but I'm no English major.

  • 1
    $\begingroup$ 5000 kW per day on a surface like Sardinia? At 5 kw per house, that would be barely enough for a neighborhood of 1000 houses. Sardinia counts 1.6 million inhabitants, thus about 400000 houses. I think you need to check your math. $\endgroup$
    – L.Dutch
    Apr 14, 2021 at 12:56
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    $\begingroup$ If this is a constructed environment, why do they need to smelt their materials to build? Wouldn't they have made them available for ready use? Also I would take the word ideal out of the title, you have a constrained ecosystem. $\endgroup$
    – Allan
    Apr 14, 2021 at 13:02
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    $\begingroup$ What is your actual question? By the way, determining an eco-system is a gargantuan task. Even describing one in enough detail to put it on a space ship would be a huge task. $\endgroup$
    – puppetsock
    Apr 14, 2021 at 13:26
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    $\begingroup$ Bunnies, cuz they are cozy and grass. Also thye are good meat and they have interesting genetic mechanisms which diverisfy them in span if decades, there is an island/place in japan which inhabited by bunnies living in wild and they are descendants of few pairs or something like that, do not recall all the details, quite healthy population. A bee, fly, chicken, cow, predator fish(any), a flower(any) - and u set for hapy life, lol. But yeah a hard question u ask, really. $\endgroup$
    – MolbOrg
    Apr 14, 2021 at 15:02
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    $\begingroup$ Fungi are not animals, they are in a separate kingdom $\endgroup$
    – Allan
    Apr 14, 2021 at 16:43

2 Answers 2


If this space station is just for Humans - assuming that all the micro-organisms I will just list the 5 species for plants, vertebrates & invertebrates and the reasons I chose them.

I would have the land form be a terraced mountain falling into the ocean with the terraces randomly holding freshwater ponds/springs.


  1. Bees - pollinators of many plants & creators of wax/royal jelly/pollen/etc. - Also if you can create cultures of the micro-organisms needed for the area to be self-sufficient then they can harvest & enhance bee poison from the stingers.
  2. Earthworms - they decompose the material in the soil & they can be a good source of protein if processed correctly - also fish bait.
  3. Beetles - they held material on top of the soil decompose & they can also be a good source of protein & entertainment.
  4. Shellfish - they can live in any body of water, they filter the water so that it is cleaner & they are good sources of protein
  5. Grasshopper/Crickets (iffy about this one but...) - Good source of protein, they can be fish bait, they can be entertainment & they they can evolve into locust! Inbuilt drama/disaster


  1. FISH! They are sources of food/minerals/vitamins/fun, you can also use the carcasses to feed the plants
  2. Rabbit - fiber, leather, meat, fertilizer & pet material - they can dig tunnels for you or they can just graze on grass - depends on how you construct their courtyard
  3. Chicken - These birds give eggs, meat, they eat any bugs they can find, they can pick at and dislodge any unwanted seedlings, they can fertilize the soil with their droppings.
  4. Goat - they can give fiber, leather, milk, meat, graze and eat anything to they can tame any 'wild' land & they leave great fertilizer behind!
  5. Pig - Meat, fertilizer, Smart- they can be trained and they have a very good sense of smell, they can also plow the land - also if they get loose and breed wild you can have a feral hog problem (drama!)


  1. Grass - these plants can live on land or underwater - both fresh and salt, they feed all the invertebrates (except maybe the shellfish) and they can feed most of the vertebrates (except the pigs/humans), they also produce a tremendous amount of oxygen given their size
  2. Moringa oleifera - This is a tree that is fast growing (wood and oxygen), you can eat the leaves, roots, seeds and bark! It also has all the vitamins/minerals you'll ever need. - feed the pigs with it too 3 & 4 & 5 ) are basically the 3 sisters - the Maize Corn, the Squash and the Legume - complete meal for forever and can feed all the vertebrates & invertebrates.

Assuming all the micro-organisms can be cultivated & assuming that the fungi hitched a ride I would want to add 1 more plant - Azadirachta indica (this neem tree is known as the pharmaceutical tree and basically does everything...)

That would be my short list - if I absolutely had to name the species (do not ask me to do cultivators, I will not be able to...)

  • 3
    $\begingroup$ grass is very broad, from lawns to grains to bamboo. Fish also, what species? and what does it eat? $\endgroup$
    – Allan
    Apr 19, 2021 at 16:24
  • $\begingroup$ I agree that grass is very broad and if I had to chose I would start with sea grass and then they can the micro-organism technology to evolve/mutate the original to grains/bamboos/everything else! In an ideal position $\endgroup$
    – Lusalma
    Apr 19, 2021 at 16:55
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    $\begingroup$ The Fish would start with Parrot-fish (shellfish might include coral? Also eat the sea grass & can grow pretty big) then differentiate into other fish that can live in both the freshwater to be food/recyclers/entertainment $\endgroup$
    – Lusalma
    Apr 19, 2021 at 17:00
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    $\begingroup$ dropping rabbits to get a second variety of fish, specifically a cleaner fish like tilapia might be worth it. also you will need a grain for all the livestock. $\endgroup$
    – John
    Apr 19, 2021 at 18:11
  • $\begingroup$ An excellent answer. If I may ask, what influenced your choice of a a terraced mountain landscape? Its certainly an evocative image, but what sorts of advantages does it bring? Also, yes, beetles are very 'entertaining', aren't they? :) $\endgroup$
    – Armok
    Apr 20, 2021 at 19:18

To start, you should identify the human needs, then find species that support those needs while keeping each other alive as well. In order of how long you can go without them before dying, humans need: air, water, and food. Shelter and sanitation can be structural, without dedicating species slots to them. Psychological needs can be met by other humans, so they don't require a slot, either.

Air The good news is that pretty much all plants are good at converting carbon dioxide into oxygen via photosynthesis. This is a great symbiosis, and it means that you can get all of your energy needs via solar power as absorbed by plants. The great thing about plants is that many of them can pull their weight in other categories by providing additional benefits.

Water All animals and plants need water to live. Therefore, you must have a way to filter wastewater. Fortunately, plants can once again come to the rescue: Woody plants can be turned into charcoal, which can be used to filter water, before being returned to the soil. Therefore, we should include at least one kind of tree.

Food Humans (and other animals) need food to eat. This will be the hardest category to satisfy, since humans are omnivores and should eat a wide variety of foods if possible, in order to ensure good health. Plants are useful for this as well: We can make our tree a fruit tree to provide necessary vitamins. We should also include a staple crop to provide calories. Maize Corn is especially well suited for this role, since it provides a plethora of vitamins and minerals as well. Chickens are great for providing eggs and meat, and can be fed from the Maize. Brassica oleracea is an excellent choice because it provides a lot of variety, since it takes many different forms.

Bonus: Medicine Some plants also have medicinal uses. Aloe is a solid choice, as it is hardy and can be used to treat many injuries and afflictions.

Support: Pollinators In order to maintain flowering plants, you will likely want pollinators, although this is not necessary for all flowering plants. However, bees produce honey and wax, which can be very useful.

Support: Decomposers You may find it useful to devote one or more of your animal slots to decomposers. This is in addition to the bacteria and fungi, and will help nutrients to continue cycling through the ecosystem.

  • 2
    $\begingroup$ pollinators arent needed in an underwater ecosystem as long as the humans provide strong enough artificial water currents to the ecosystem. $\endgroup$
    – zackit
    Apr 14, 2021 at 17:33
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    $\begingroup$ In theory, it probably wouldn't be too hard to use a purely aquatic environment but with a few islands. You could probably achieve higher total biomass. You'd still want trees, though... Perhaps mangroves? $\endgroup$
    – Armok
    Apr 14, 2021 at 17:43
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    $\begingroup$ @Armok Bamboo is one of the best choices for plants: It can be eaten (bamboo shoots), can be used as timber, grows fast, can be selectively bred, etc. It is just a matter of picking the correct species. $\endgroup$
    – Otkin
    Apr 17, 2021 at 3:30
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    $\begingroup$ Maize is notably short or several major nutrients. It also requires other crops to prevent soil degradation. $\endgroup$
    – John
    Apr 19, 2021 at 18:08
  • $\begingroup$ @Otkin Bamboo is an excellent choice, especially since it is the Chickens original food source. $\endgroup$
    – Jafego
    Apr 20, 2021 at 17:30

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