Obviously the timelines are insane but just as a thought experiment, I would suspect we would get different answers depending on who you ask, and thus the study, understanding and conservation of other life that shows a form of intelligence becomes much more important to some, whilst human preservation at the expense of all else is more important to others.
(I also recognise you aren't saying that by the way, but it's what came to mind when I read your comment. I personally think we have more than enough resources to do both. I'd also imagine we will learn more about ourselves and what's possible in medicine by studying other species.)
Second, what people know is often valued more. If you can tell people about the environment then you can create a fascination and make them value their surroundings more, maybe causing them to think twice before dumping trash mindlessly in the forest or voting for the next guy who wants to expand fracking operations. And in order to tell them, you first need to understand it.
Third, it can give you material for creating useful tools or medicine which then improves lives, like vaccines or airplanes (which we wouldn't have without curiosity about birds).
Apart from that, it's empathy too. Animals can suffer and causing them suffering is usually against empathy people feel. More understanding helps with that. (It's not too long ago that the prevailing view of "that's just a fish, they don't feel anything, so I can eat them even though I'm vegetarian" was challenged and slowy overturned.)
And finally, beauty. Nature is just beautiful. Compared to a dead rock like mars, it's absolutely amazing what we have around us.
I hope these five reasons give you some perspective as a biology student.
I wonder, what made you choose that field of study?
Let’s raise them humanely, kill them swiftly, and use they wholly letting nothing go to waste.
This is an entirely reasonable ethic.