View Full Version : Anatomy question

08 August 2002, 12:57 AM
I have a sci-fi story in which mankind is destroyed on Earth, and a few on the Moon survive. They freeze their bodies for millions of years in order to allow an experiment of Biosphere Generation to proceed, something like the Genesis Project of one of those Star Trek movies.
The thing is that mankind survives, suffering unexpected mental outcomes because of their long-term sleep. They lose all faculties of language and basic motion behavior, they basically have to learn to walk and talk all over again. So they go thru an evoultion process for thousand of thousands of years.

Here's my anatomy question:
Since the Moon's gravity is lower than that of Earth, how would their muscles look like and behave like after their evolution there?
The air density should be the same as that of Earth, there are new plants and animals.
I figured that they would just be three times taller than us, but maybe there are other muscular issues I haven't been aware of.

My story is called "Virtuality" by the way.

Please help me on this one...

08 August 2002, 01:17 AM
Oh, that's a nice question.
So there's an atmosphere on the Moon, fine, and the moon is now around the sun's orbit instead of the earths, ok.

I think muscles would become weaker, and the bones (and joints) frail. I think you would get these very fragile long and thin humans.
They will propably be able to move with greater precision (and acceleration) because of the lower gravity. (there's less "slowness")
I'm not sure how the temperature would be. The heat and cold on the Moon is pretty harsh as it is now. The atmosphere would prolly soften it all up a bit (like on Earth now). So skin and hair would differ little.
Hmm, maybe they would hear and talk at greater frequencies :D
That's how I see it, I'm not Darwin but I hope it helps :)

08 August 2002, 01:32 AM
That's very interesting Joril.
Thanks for the reply.

The Moon will still be revolving around Earth, because planet Earth still exists, it's not blown up like in Titan A.E., instead everyone is killed and the cities are buried under crumbing mountains.

I like the fact that humans would be faster ans more fragile, I thought of the fragility, but I never thought how fast they could be.
They'd be descendants of the scientific community on the Moon that survived, so their behavior would be very scientifically inclined. Perhaps one side of their brain evolves faster than the other. I like the frecuency issue as well.

The animals and plants are not the same as the ones we have, because they are from a collection of experimental DNA banks, of new species produced out of genetic engineering on the Moon. So there will be no dogs or cats, instead other pets. And no cows or chickens, instead other apecies. But that's just some other deatils about the tory.
I am greatly interested in developing the "Moonlings".

10 October 2004, 01:35 AM
Personaly, though I don't belive in evolution, a low gravity enviroment would make people apear to age slower (because the skin would not be as heavy and thus produce less wrinkles). Furthermore, in addition to being taller, people's hair might actually be longer. They might not actualy appear more fragile, because although thinner they would not neccisarily be skinny (so their bodyfat levels would be roughtly the same) good luck, hope this was helpfull

10 October 2004, 09:10 AM
Hey. I see two ways now. First if humans would wear some heavy weight shoes with some strong legs. Second, if not, some skinny legs, not bony (skeletal) ones would be adequate. In both situations I see them tall, maybe with a bigger cranium. Also I agree with theswardsman about wrinkles and gravity. But please note that I donít think that would be enormous changes in actual shape.


10 October 2004, 04:20 PM
Not sure how "scientifically" accurate you want this to be. Just in case it's important to you, there are some big (not saying this meanly) misconceptions on evolution you'll have to overcome.

Just being in an environment wouldn't cause offspring to change. Natural Selection (through death), or Sexual Selection would be the driving forces that are easily understood you could use. If your creatures were starting at ground zero, you'd have things well adapted to a low grav environment. Starting with humans though, you're going to continue to get "normal" humans. Only traits that help or hinder their breeding in this new environment will alter them. I don't think you're going to get humans much different from what you have on earth unless you place them on the moon in an environment where they're being "hunted" for those evolutionary years.

If you do that, you can start to really push the advantages in certain mutations to a low grav enivornment. Give your evolutionary period plenty of time, and you can have some wildly different humans. Remember that in low grav environments, momentum is more difficult to control as you don't have as much gravity helping to slow you down to a stop. You'd come out, more than likely, with animals and humans that are much more agile than they are here, and much thinner/lighter so that they carry less momentum. If the air density on the moon is the same as it is on earth, but just lower gravity, flying becomes much much easier and more likely to become a feature through mutation.

Just some notes from a bio guy. :)

11 November 2004, 07:59 AM
Given enough generations in a low grav environment you'd almost certainly have to have your characters using exo-skeletons where they to visit another "earth like" (in terms of gravity) planet.

One would imagine that in a low grav enironment the tendency for older members of the population to have increased curvature in their spines might be reduced. So you might have to find some other visual clue to differenciating the ages.

You might be able to get some movement ideas from that species of generic engineers in Star Wars Episode II (the ones that create the drone army). Here you've got very tall characters with lots of nice wave like secondary movements. I'm not suggesting they look like this - but their weight / height dynamic is very well done.

11 November 2004, 02:12 PM
Given the low gravity perhaps flaps of skin would appear attached between the arms and the back, similar to a flying fox? Humans would be less heavily built, as muscles need to carry less weight, and therefore we could also glide from place to in high canopies....

Not sure that we wouldmove faster in a low gravity enviroment though, astronauts always move slowly and its not just the suits!?


11 November 2004, 04:44 PM
Cool idea. I've written alot of sci fi over the years from hard science to space opera so here are a few ideas you can play with. I usually start with the environment, then explore the life then how it all fits together.

The atmosphere on the moon would be thinner I think. Even if you have something replenishing the atmosphere continuously it would be leaking away at a pretty fast rate. Depending on how space opera your going you may have a glittering ring in the orbit of the moon around the earth. Anyway you have to explore something that keeps adding the atmosphere back to the moon.

Despite the thinness I like the idea of flaps of skin as wings since a good jump could push you pretty far and it would be nice to have something to guide yourself back to the ground without going off a clift.

Now the biggest problem you will face is that the moon has a rotation from day to night of 656 hours (27.3 days)(some text uses 29.5 from new moon to new moon but since the new moon takes into account the sun also moving in relation it is not correct for this purpose) So even with an atmosphere you will have long cold nights and hot sweltering unending days with days of twilight inbetween. Think of Alaska which has months of night and day. Anyone from alaska or a similar extreme could probably add more to this idea.

How much water is there on the moon? 10%?, 50%? in any case a lack of the concentrations of salts like we have on earth means that during the night the entire body of water will freeze over allowing animals to get to/off islands or other remote locations. Maybe a particlarly dangerous animal shows up during these periods. I may be wrong about salt concentrations but it is sci fi anyway so make up something fun.

The core of the moon is cold so there will be no earthquakes, volcanos or other such problems. The low gravity and the presence of earth also makes flooding an big problem so anphibians and related life like aligators, hippos etc will thrive in this environment. Any dwellings will need to be far from water or on stilts.

Much of the life on the planet would have some kind of wings/membranes and preditors would be sleek jumpers who pounce on prey or low scramblers who hug the ground for more manueverability.

With such a short timeframe and with the moon being so small I would think the diverity of life would be less than Earth.

fat-lean-thin debate is a hard one. From all my investigation fat is more based on temperature than gravity. So if it is always cold life forms will tend to be fatter or furrier. Warm makes them lean and light. In any case gravity will makes the bones thinner and the muscles smaller so overall the animals may be a bit lighter. I wonder if bears and related hibernating life would thrive since their bones don't weaken from lack of use, in this case weak gravity.

Without diverging into a theological debate on evolution the way I see life on the moon is this way. Traits that don't help the animal survive are lost and ones that help appear, animals better suited to an environment will kill off those that don't. So on the moon you would have lots of birds and other flyers. monkeys, rodents and other animals with hands would thrive. hoofed animals may still exist but tend to move slow since a wrong jump can get them into trouble. Many furred animals would grow out fur during the night and shed it during the day.

More on bears. since they swim, don't have weak bones, have enough fur to deal with hot and cold extremes and have enough of a hand to grip they may out pace most other preditors.

So lets evolve all this base life over a few million years. the bears,etc and aligators,etc would form the top of the food chain. I am just worrying about preditors since they are most likely to be invloved in the action of a story. Bear like life forms may get prehistoric in size because of the light gravity, grow longer legs and break up into several new life forms. some smaller, long limbed and faster others giants and still others that may break off into alot of other smaller groups. Aligator like life forms may get longer limbs some may get fatter, giant and break up into more groups. reptiles as a whole I think would not survive all the cold weather and would not make any great showing on the moon.

The gravity of the moon is something like 15% of earth so a reperator as well as the exoskeleton may be needed on earth.

Humans would be lighter in build unless they did something genetically to make their bones thicker/stonger. Now one thing to keep in mind is that because of the light gravity you can have jabba the hutt sized fat humans since it won't crush them to death. People who hit 6-800lbs on earth could still get around on the moon. Maybe some boss or political body may be made up of these guys that never leave and are over 1000 lbs of fat. Gives all new meaning to fat cats. :)

Anyway because of water the cities will be up higher or water proofed on the first floor with stairs/exit on the 2nd floor going down to ground level. stilt towns/cities or something like venice may be normal in coastal areas

In the end take a look at all the reference and everyones ideas and pick what you think are cool ideas and stuff that excites you even if it may not be scientifically realiastic.

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