Hopefully this isn't two separate questions - I do feel like they are interconnected enough that they can be counted as one. I'm wondering if it would be possible for primitive human ancestors.
Let's say around 6 million years ago, a species similar to the Orrorin tugenensis (which from what I understand can be considered one of our earliest ancestors), decided to move into the water for reasons (competition from other species, some kind of natural disaster at surface level, whatever it is). The assumption is that the water would be safer and just overall better for them than the surface would be.
How would this primitive species adapt and build a civilization underwater? SOme thoughts I had:
- Maybe they live near hydrothermal vents, their "fire" underwater and build their civilization around those
- Maybe they actually found a network of underground tunnels that have pools that provide deeper access to the sea
Anything else that could exist that would allow such a civilization to flourish? (both in terms of physiological changes over millions of years as well as infrastructure)