I would collect DNA samples from every species of bat on the world, measurements on all their body shapes, and 3D scans of each one, and combine them all to have the most advanced understanding of their evolution we possibly could. Plus, I would finance a lot of fossil-collecting trips to discover more extinct species!
I would find a solution for global climate change. There are billions of organisms that are affected by it, and many species will go extinct. The rate of extinction now is almost as fast as when the asteroid whipped out the dinosaurs. Its also hurting millions of people by casing floods and droughts and spreading deadly mosquito born diseases. The best way to protect The greatest number of humans and other organisms is to stop climate change.
If I had ALL the money in the world, I think I would actually work on the origins of consciousness and work on how best to communicate with the other life on earth. It seems odd to me that we’re always looking to outer space to communicate with intelligent life when there’s so much of it here on earth! We’re even really bad at understanding what other humans are feeling, so I think finding ways to communicate more effectively, using evolutionary cognitive neuroscience would be a priority.