I'm wondering how many people it would take to start a new civilization. I'm thinking generally speaking in the following scenarios:
Scenario A) A group of people are exiled from their home. They are forced out into the wilderness [let's assume for the sake of argument that it's a pretty temperate and mild wilderness] and the population settles and thrives. They farm and reproduce (at an steady or exponential rate) how many people would you need to prevent crippling lack of genetic diversity? If there was an insufficient number, how many generations approximately would it be before crippling lack of genetic diversity set in?
Scenario B) In a post-apocalyptic scenario or future scenario wherein humans had to populate a planet either through colonization or through post-apocalyptic repopulation, how many humans would it take to repopulate?
Scenario C) If humans knew that they were facing an extinction crisis, what population control measures/laws could be feasibly adopted by governments to try and make sure that even though the initial genetic pool may be small. For example, would requiring every family to have a certain number of children and approving marriages to ensure that they allow for the greatest genetic diversity impact it at all?
Thank you so much!