The difference between living on earth and living I'm space is that oxygen is at a miniscule levels thus leading to not being able to breathe. Also if you don't have oxygen you can't have plants because we need oxygen to breathe out carbon dioxide.
If we lived in space, we would need a planet that could have enough gravity for us to live on and also a water source. Even if there wasn't oxygen we could live there with oxygen masks but animals wouldn't be able to survive.
Without a water source we wouldn't be able to grow food. even though we couldn't grow plants and vegetables, we couldn't go out and hunt a deer or two. To be able to live in space we would need oxygen, water and the right amount of gravity.
Hope that helped!