In the anime Vandread, the antagonists (earthlings) had a goal that I find interesting. So I am going to use them as the premise and hopefully expand it well enough to work for a world I am working on.


There are earthlings and their are settlers. Settlers are basically humans that have left Earth to settle other planets and earthlings are humans that didn't. I know that's pretty complicated but bear with me.

The earthlings, being that they are from earth and have the name of the planet in their names, feel that they are above the settlers and, over the generations, pull their best impersonation of European royal families circa formation of European royal families to the Red Revolution and wind up inbred and lacking in genetic diversity. Also since this is the far-ish future, humans have since learned that building their civilization based on lighting dead dinosaurs on fire to boil water to cook their flatulating bovines raised entirely on fields of grains grown the way nature intended them to be grown complete with natural selection and non-human intervention was not a great way to maintain said civilization.

Luckily, their version of Rasputin, who shall be known as Space Rasputin, was something of a mad scientist/possible space ghoul. He figured that the settlers were human and earthlings were humans but better so the settlers would be more than happy to help out the Earthlings survival.


Space Rasputin, not being the worlds most diplomatic thinker but the self-titled world's greatest evolutionary biological humanist, figured that they should just sort of take the settlers' organs from them and attach them to the earthlings' bodies. Because that's how genetics works.

But continuing forward on that path to its "logical" conclusion: he figured they should take the best organs from the best settlers. And since natural selection is probably a thing on other planets too, they should harvest the organs from the settlers who have the best organs because evolution and natural selection. Even if they had to tweak the whole natural part.

For this reason, his merry band of human harvesters went out into space to collect body parts from the best human planets for those body parts. For example, they harvested skin from a planet that was basically just slowly and painfully poisonous to humans, the thinking being that the skin would get stronger as humans survived and mated and managed to live into their thirties. They harvested sex organs from planets that only contained that sex, because that makes sense somehow. So basically all earthlings are Frankenstein's monster.

The Question (tl;dr)

So basically, given some amount of terraforming to make alien planets liveable and apply tweaks to the environment but otherwise no other earthling interference, is it possible to raise a population of humans to have one organ that is super fitted to its purpose even at the expense of some or all of their other organs?

You can assume enough time has passed that the settlers have forgotten that they are settlers and believe they are "X-Planet"-lings and have no real knowledge of earth. However, they must still look at least mostly human. The idea is that those harvested are still considered human.

Science-based is good enough, but hard science is better.

Edit for clarity: by super fit organ I mean an organ that does the task it is designed for extremely well. Like a liver that is highly resistant to damage caused by poisons it tries to filter out and processes them very fast or a heart that is super efficient and able to do in 1 heart beat what the average human heart might do in 5 or 6. However, things like lungs that breathe water or a spleen that makes you fly and plays the banjo are not considered "super" fit. And you can limit it to human organs.

  • $\begingroup$ Comments are not for extended discussion; this conversation has been moved to chat. $\endgroup$ – Monica Cellio Nov 12 '17 at 3:51


Terraforming is the process of making a planet habitable. Just because a planet is habitable does not mean it is entirely conducive to life. This is where mutation and evolution come in. If there are factors that make reproducing difficult then mutations that overcome those challenges will propagate more till eventually you have evolution.

One reason the human liver is so good at metabolizing alcohol is because we have been drinking it for 10k years, so that trait has been refined and passed on. However, not all humans are efficient at metabolizing alcohol because it isn't a total barrier to reproduction and some communities didn't need or use it.

So going back to your 'world':

If there was a planet with semi toxic water, mutations could evolve creating superior kidneys and livers.

If there was a habital planet with a thin dusty atmosphere, mutations could evolve creating superior lungs.

A planet with thin ozone and primitive humans running through scraggly bushes would likely require tough resilient skin.


This process isn't fast however it is sped up by 'selection'. There is a sweet spot between maintaining just enough genetic diversity and culling the heard of counter productive traits. It takes many 10s of generations to develop and refine these traits all the while 'selection' is playing a critical role. Make no mistake these aren't happy conditions. For selection to play this big a role means life is hard with people not reproducing or living long enough to reproduce.

This can be sped up by an intelligent emotionless race capable of resolving themselves to refine these traits in a form of pseudo selective breeding.

NOTE: I do not believe an intelligent species can technically "selectively breed" itself. Selective breeding is a process where an outside influence determines what traits are 'desirable' and manually influences the genepool to proliferate that trait. Man cannot selectively breed man because man is a member of man and not an outside influence. If anything it would be an adapted quirk of mans mating habits.

| improve this answer | |

Any time you separate a species into groups long enough to specialize a single organ, you run the real risk of the sub-group becoming genetically incompatible with parent group. This is how specification happens.

reference: https://en.wikipedia.org/wiki/Darwin%27s_finches

This could be a plotline. Also, "self"-selective-breeding is called eugenics. It's a real thing, it's been done, it's generally considered evil.

| improve this answer | |

Selective Breeding is your solution

If you make the society in a way that they value one specific attribute much more than anything else than you can force breeding in the same way we do with animals. When only people with incredibly great eye sight are allowed to breed we'll have great improvements in the matter of a few generations. If we were to continue something like this over the period of a hundred generations we'd end up with a population of people with great eye sight, but all the other stuff regarding health, strength, etc. was not part of the selective pressure (besides that the minimum of a ability to survive has to be given). Therefore all the other traits might have been weakened over the generations.

You would need a strict enforcement of this by society, though. Humans tend to breed with whomever they want (with the built-in biological criteria of attractiveness). You would need to override these "normal" behaviours and force humans to be very selectively breeding with the desired criteria.

Natural Selection

The only reason why something like this would occur naturally if your enviroment would be pushing very strong selective pressures on your population.

If you have a constant level of toxic stuff in your air or in your food you would have a high selective pressure on people's ability to sustain their bodies despite the toxins. This would result in the specific attacked becoming very resistent to toxins and/or your liver very good at filtering toxins out of your body.

| improve this answer | |

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.