I'll try to tell you as much as I can about what it's like to be a zoologist. I was very interested in marine biology and marine animals. Most of us did our research at the Smithsonian Museum of Natural History. Then, we take our specimens back to a laboratory to look at them more closely.
Zoologists tend to be experts on a very specific group.
I worked on crustaceans, and knew a lot about that group in general, but I worked on a very specific kind of shrimp, about which I knew very much in detail. Zoologists are doing that on a much more detailed scale. A cladogram looks like a family tree - and that's just about exactly what it is. If you look at a geneaological tree of your family, you find yourself and your siblings at the bottom of the tree, but you're all joined together going back to an immediate ancestor - your parents. Likewise, your father and his siblings go back to an immediate ancestor - your paternal grandparents.