Ok kiddo, so you know how we have different types of animals like cats, dogs, and birds? Well, sometimes scientists want to study a whole group of animals that are really similar to each other, but not exactly the same. It's kind of like how we have different types of dogs, but we also have things called breeds, like poodles, golden retrievers, and bulldogs.
When scientists want to study a group of animals that are really similar but not the same, they call it a "species aggregate." This means that they are looking at a bunch of animals that are almost the same species, but not quite.
It's like if we were looking at a room full of golden retrievers, but some of them were bigger, some were smaller, some had longer fur, and some had shorter fur. Even though they're not all exactly the same, we can still lump them together as a species aggregate of golden retrievers.
Scientists use species aggregates to study similarities and differences between different types of animals, so they can learn more about how they evolved and how they interact with their environment. It's kind of like putting puzzle pieces together to see the bigger picture of how all these animals fit into the world around us.