If you were going to build an ark and put two of every animal on it, in these modern times, you would have to consider ectogenesis. Basically, you would freeze embryos, which is a 100% viable existing technology, and build robots with some kind of reliable renewable power source to thaw them out and raise them after you are long dead. You could fit a lot of this on an ark, or a spaceship, and they wouldn’t eat or drink or poop as long as you kept them frozen. One conundrum, which the article does go into, is whether or not to include humans, or just see if some other species evolves intelligence. I would bet on crows/ravens personally. Dolphins have had their chance, and they are perpetually stuck at toddler level, although they seem to have fun. Whatever it is, then they could use their intelligence to develop planet-killing weapons and energy sources, along with ethical consciousness, ark building technology, and the ability to freeze embryos and build robots to hatch and raise them.