Take comparative verte. physiology. You will be thanking me. The concepts you learn will never leave you and you'll have much appreciation for how humans do it (you do talk ab humans too). For instance, insects make hyperosmotic urine just as we do, the principle is the same: Countercurrent multiplier - transport ions next to the fluid you want to become concentrated and increase the permeability to let water leave. I was studying with my friends in Human A&P for our finals and we talked about things they never heard of AND they had no idea WHY the body is the way it is. In comparative you understand the WHY. WHY do humans produce concentrated urine and freshwater fish don't?