Which part of the biological sciences specifically deal with the theoretical part biology?

@Chinmay, thanks for a nice question. I found some discussions on it. One is-

“Theoretical biology is the study of biology from first principles. The goal for me is to make a full mathematical model of the behavior of a cell which is capable of predicting the behavior in a general situation, at least statistically (meaning, the range of possible behaviors).”

– Ron Maimon

To understand biology, computational and statistical data analysis, mathematical modelling, even philosophical arguments are part of theoretical biology.

Developmental Biology. Evolution-these are quite relevant to theoretical Biology -I guess. In addition, Computational Biology or Statistical modelling probably terms to Applied Biosciences.