Hello to all. I work with someone who is majoring in Biology who hopes to become a medical doctor in time. I believe that at least at my school, calculus is not a part of the biology curriculum. I would like to know from those of you who know biology and calculus: 1) How much of a role does calculus play in biology? Are there some biological systems which are most properly modeled by calc or differential equations? 2) What about chains of biological interactions, especially those of medicines or different chemicals of the body? My intuition tells me that absorption rates and various chemical reaction rates are probably governed by differential equations. 3) Is calc eventually required to study how medicines interact with the body? I'm just a curious engineer.