A theory about One Piece comes to my mind recently: the series contain a lot of impossible, non-existent and "fairy tale"-like elements, such as various giant animals, bizarre cross-species, giant or simply impossibly tall humans, sapient but animal-shaped species, and such.

Despite all these facts, the series tends to be much more realistic than actual fairy tales, making it surprisingly consistent and believeable. Moreover, a lot of similarities to actual human history and culteres also appear, implying that civilizations in this world developed near identically to some Earth countries, which is, I think, extremely unlikely.

Thus, I started wondering if One Piece takes place on Earth, but millions or even billions of years later.

In this question, I'd like to be interested only in the biological, to be precise: the genetic aspects. 65 million years was enough to evolve from rats to humans and enormous amount of other mammals, so evolution is pretty strong at making exotic species into existence, but what about such extreme results? Also, what about humans?

Is it possible that during either a natural or a supervised evolution, giant humans, giant animals, other intelligent species and other similar "fairy tale"-like beings form and live? Or is there a boundary for genetic recombination?

  • $\begingroup$ Hey! I am in no way evolved from rats! $\endgroup$ – Xandar The Zenon Mar 23 '16 at 19:49
  • $\begingroup$ I think this is too broad because we don't know enough about the different species. I reccomend looking at the anatomically correct series of questions and other similar ones, then making a world where all of these can evolve. As it stands, we just don't know enough, and if we did it would still be too broad. $\endgroup$ – Xandar The Zenon Mar 23 '16 at 19:55
  • $\begingroup$ "Also, what about humans?" -- What about them? Do you want to know if humans can evolve over the course of 65 million years? That's kind of trivial to answer... $\endgroup$ – Frostfyre Mar 23 '16 at 20:46
  • $\begingroup$ In just a few tens of thousand years, our real Earth produced the great diversity of the caucasoid, mongoloid, and negroid varieties in Homo sapiens (sorry, I don't know the modern PC equivalents of these terms). Had the globalization of the last couple centuries not happened, is it that hard to imagine the process continuing for next million years into elvoid, drawfoid, gnomoid, etc.? $\endgroup$ – cobaltduck Mar 23 '16 at 21:45

I think you might be able to get away with some of this...perhaps not all...by altering the world to include much greater climate variations and extreme isolation.

Giants are actually one of the more challenging aspects to justify...the size of a species is directly realted to the environment they are in. Rich oxygen environements are much more likely to produce gigantic creatures (small creatures actually perish to oxygen toxicity. For source. ). How exactly you could get concentration high enough to giant size some but not others is beyond me. Giants would require increased oxygen levels just to live.

That said, extreme isolation between populations will created diverting evolutionary traits...what is good on one island might be disastrous on another. Such badly isolated populations are your best bet in arriving at such mixed variations on life.

Editting to add:

Im not a fan ofnthe cross species, such as the centaur and other such creatures. The centaur either has the digestive track of a horse, in which case this includes flat teeth and the ability to gnash prior to eating and would require the jaw and muscle structure to support that (horse face much?) or reversely, its a carnivore....and then you get into the questions of how it feeds and gets enough energy to support its horse self (remeber, functionality of the brain requires a huge amount of digestion support) and why itd have several traits favorable to a herbavore and not a carnivore? This really gets rid of the potential of them naturally evolving to such. However this does not exclude some mad scientist successfully combining the two (sew a pigeon to a rat and call it the first ratbird?). Whether or not these are sustainable is a bit out there...frankenstien was sustainable enough for a story, no? Especially if there is some degree of 'magic' present.

  • $\begingroup$ Yes, I've heard about the thing of giants: volume and mass increased exponentially with height, and neither human heart or human brain is able to support extreme height, not even talking about the legs. $\endgroup$ – Zoltán Schmidt Mar 22 '16 at 23:11
  • 2
    $\begingroup$ Yes, it's hard to upsize...square cube rule, Giants become hard to justify quickly. That's not to say humans are a little undersized as is....our average height is increasing, odd are with proper diet and health care we should be averaging 7 to 8 feet in the semi distant future...and who knows what a microgravity-4-life human would look like $\endgroup$ – Twelfth Mar 22 '16 at 23:48
  • $\begingroup$ @zoltanschmidt - i editted in a comment to the cross species. They are quite hard to come about naturally as many of the cross species are crossing carnivores and herbavores....they have very distinct traits that are advatageous to them. A used centaur as an example....would a carnivore 'horse' grow claws instead of hoovers? $\endgroup$ – Twelfth Mar 23 '16 at 21:49

Evolution will produce organisms based on the parameters you give it to work with. Earth's evolutionary process produced humans - we're perfectly adapted for the terranean environment. That means

  • 101kPa mean surface pressure
  • 0-30oC temperature (with modern materials and techniques we can survive more)
  • 78% nitrogen, 16% oxygen, 4% carbon dioxide, 0.04% argon atmosphere
  • 9.81ms-2 gravitational acceleration
  • No major predators

If you supply a different environment, you will get a creature out with very different adaptations.

  • To get giants, you would likely need to reduce surface pressure and gravitational acceleration. People would naturally be taller. You could also put all the major food sources in tall trees, so that survival of the fittest kicks in and only those who can reach the best food survive.

Supervised evolution is known as selective breeding - you have a population, and you select the individuals with the traits you're looking for to breed with each other. Eventually, those traits prosper and you evolve the population to have that trait intrinsically. To get giants, don't let anyone shorter than the 95th percentile of height reproduce.

  • $\begingroup$ Oh, nevermind. I get it now. 9.81 meters per second squared = 9.81m/s^2 = 9.81m*s^-2. Thanks for clearing that up in my mind. $\endgroup$ – Xandar The Zenon Mar 23 '16 at 21:20

Yes, it is possible, in a world of abundance

When humans, elephants, bats and dolphins have all evolved from some lemur-like proto-mammal, it seems that there are nearly unlimited possibilities with the same starting DNA. The problem is whether the species survive in the long run.

Survival of the Fittest

On our planet, the plants and animals most optimized to their environment are the most successful. A plant may grow flowers and fruits, but only big and energy-rich enough to be just a little more attractive than its neighbors to the insects or animals it uses to spread its seeds.

A plant that puts all its energy into huge fruits would likely lose out to a plant that puts more energy into strong/healthy seeds or reserves for bad seasons. For animals, it is the same. Using up too much energy on non-essential features makes an animal vulnerable to competition from more efficient species, especially when conditions turn bad for a while and there are resource shortages.

Survival of the Coolest

Many of the fantastical features (giant growth, winged humanoid, etc) you ask about are essentially inefficient or sub-optimal in our environments on Earth, which is likely why we don't see them. If the planet/ecology was much richer in resources, and rarely affected by droughts/freezes/plagues, efficiency would not be as strong a factor in the evolution of species, since more varieties can survive and thrive. Instead, species could be selectively breeding according to their own criteria, be they height, pointy ears or ability to glide from tree to tree (fairies).

The ideal environment would probably be a (sub)tropical paradise, seeing how rainforests on Earth also house the widest varieties of species.

Maintaining the Balance

However, there would need to be one more factor that is not present on Earth: Some process or entity that prevents single species from crowding out all the rest.

The most likely candidate would be a sapient species that's maintaining the balance (very unlike what humans are doing).

Another way could be that the "have few offspring, invest a lot in each of them" strategy has been universally adopted for some reason.

Finally, some kind of endemic virus common to all species may be fairly benign, even helpful, but turn deadly if a critical mass of creatures is reached in one location. This would weed out rapidly breeding creatures, but also prevent the formation of cities until the species finds a way to prevent triggering the virus's deadly reaction.


As twelfth has already mentioned, genetic modification is not your only concern here.

To answer your question: yes, you can alter a creature's genes to make it look the way you want it. However whether that creature will be able to sustain its life in its ecosystem is a completely other thing. It is quite complex and difficult to play around with the anatomy of a creature and then get away with it. Most of the time you would end up with a creature which would die very soon due to one reason or the other. In some cases your subject would survive but with some long term consequences.

A very tall human would have issues with bones (specially backbone). Most very tall humans have had these issues which required surgical procedures. Feeding issues might also be present. Then there is hormone balance. The endocrine system is very sensitive and hormones affect each other too, besides facilitating an organ-related action.

So all in all, creating very tall or bizarre creatures is not only limited to making them appear so tall or bizarre but also involves some very complex structuring and math about how to balance things internally which would enable the subject to function properly.


Over millions of years it's certainly possible to see a massive range of genetic variations, just look at the various species of great apes but then consider that voles, elephants, dolphins and moles are all mammals too.

Creating the variation isn't the problem, the only thing that is a problem is giving those variations a reason to exist and to stay separate. Great height comes with a cost in calories, in bone strength, etc. If there is a big advantage you would expect everyone to become giant. If there is no advantage you would expect a normal range in sizes.

So you need to separate the populations for long enough that they become different enough that the genes are unlikely to mix back into each other again when they do meet.

Explaining giants and trolls are easy enough though. Even explaining dwarves and elves could be done.

If you want literal fairies with wings on their back able to fly around then almost certainly you can't get that through standard evolution and even if you could they don't really add up in terms of being able to fly.


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