How the mass of a planet affects the evolution of life on that planet

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Summary:: Specifically, how earth and life on it would have evolved if our planet was twice as massive but with the same composition of building elements?

Could humans or sentient, upright walking creatures appear in the evolutionary scale in a twice as strong gravitational field? How that would affect geophysical processes and evolution? I hypothesize it would turn them more violent and chaotic and it would render the chances of life happening much slimmer.
 

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  • #2
berkeman
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Summary:: Specifically, how earth and life on it would have evolved if our planet was twice as massive but with the same composition of building elements?

Could humans or sentient, upright walking creatures appear in the evolutionary scale in a twice as strong gravitational field? How that would affect geophysical processes and evolution? I hypothesize it would turn them more violent and chaotic and it would render the chances of life happening much slimmer.
Welcome to the PF. :smile:

We don't allow personal hypotheses or speculation here. Please see if you can find a scientific paper that covers this type of influence on evolution, then post a link here so that we can discuss it. Thanks.
 
  • #3
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I moved your thread to the Science Fiction forum as it could be an interesting though not so scientific premise for a story.

With respect to your question, I don't think it would make a species more or less aggressive being raised in a heavier environment to Earth. All species strive to survive and use whatever means available to them to do so.

Some popular stories with differing gravities:
- John Carter of Mars where the lighter gravity gave John Carter superhuman abilities
- Superman also came from a heavier gravity planet
 
  • #4
BillTre
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Aspects of biophysics deal with differences in body shapes under different conditions.
As land animals get larger, their mass will increase in a somewhat cubic manner, but their supports (such as legs) will increase disproportionately because the amount of weight they can support depends on the leg cross section , an area, which works more on a square function.
Animals in the water can get larger (such as blue whales, the largest known animals ever) due to their neutral buoyancy.
Birds have to maximize light weight and therefore have much lighter and more fragile bones.

Affects upon behavior:
Large size does not necessarially have to go aggressive action.
They often don't need it. Many predators are often not a threat to large animals (although their young may be endangered) and large animals are often not predators.

The basic rules of building a functioning ecology would still have to hold. How the ecology is made would be modified to the specific situation.
 
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256bits
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it would render the chances of life happening much slimmer.
Are you basing that on substance separation by artificial means such as with a centrifuge.
 
  • #6
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I think life would be based around a squatter, short-legged frame to reduce the need to pump blood against gravity - sort of crocodilian in nature. You wouldn't get many giraffes.
Cell structures would be different, they would probably evolve to strengthen the walls. I don't know if they might be smaller/larger t oachieve stronger bonds, or if that is even necessary in 2G.
 
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If they were quadrupedes, evolving into bipeds would be less likely. Likewise avians.

So, centaurs.
 
  • #8
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If they were quadrupedes, evolving into bipeds would be less likely. Likewise avians.

So, centaurs.
Centaurs would also necessitate the blood being pumped up the body. In high-G, I would expect any land creatures to be fairly flat and squat to reduce the amount of overcoming gravity involved.
I also think that this sort of evolution would lend itself to predators which can "get the drop" on prey, by being above them. Though the prey might have rotating eyes to see further around, that sort of thing.
 

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