If nobody is around to know, why does it matter? We've barely been here five minutes in the great scheme of things. I really don't understand the mantra that it's so important that our specific species lives on for millennia.
You can bet nobody is going to suggest taking creatures we don't find useful with us, so there's going to be millions of species that will disappear.
What is so vitally important about us as a species that we survive? Given the mess we have made of this planet, I have little hope that if we did find another home that could sustain our life without us needing to rely on a lot of tech, we'd look after that one any better.
In just the time since we have been here, how many species have become extinct? We are just another species. We are no more likely to survive forever than any other, especially given how much our survival beyond this planet will depend upon a very small handful of people. The species who have already greater longevity than us are simpler organisms that have been able to physically adapt to their surroundings.
We can't build, or tech our way out of this environment with any hope of permanence. Apart from anything else, given that this latest mission hasn't really got us much further than we went in 1969, we aren't progressing fast enough towards reaching a habitable planet, or one we might be able to build an artificial environment on to beat the effects of the changes happening here on us as a species.
There's too much change happening too quickly. If it makes people feel better to faff about trying to build an ark, fine. But let's not kid ourselves we are on a pathway to eternal survival every time a rocket goes up. We really aren't.