Okay kiddo, so "Requiem for a Species" is actually a book that talks about how humans are hurting the Earth and the animals living on it. You know how we need clean air to breathe and water to drink? Well, some people are doing things that make the air and water not clean anymore, like burning lots of fossil fuels and dumping things into rivers. And because of this, some animals are losing their homes and some are even dying out.
The author of the book wants people to realize what we're doing and start making changes, like using cleaner energy and not wasting so much stuff. It's like if we were playing a fun game, but we realized that we were actually hurting some of our friends while we played. We would want to stop the game and make sure everyone was okay, right? That's kind of what the book is about- trying to make sure our world and the creatures on it stay healthy and happy.