To me, there are only five divisions of natural science: Physics, Chemistry, Biology, Astronomy, and Geology. The subdivisions within those branches and the connections between them illustrate the futility of essentialism.

http://en.wikipedia.org/wiki/Essentialism

Physics and chemistry are the “parent” sciences and biology, astronomy, and geology are the “children” sciences that are built on the first two. Parent sciences do not have a historical element, but children sciences do because the physical and chemical laws are applied to deep time to produce natural history. The scientific method is used to define and confirm all physical and chemical laws.

http://en.wikipedia.org/wiki/Deep_time

http://en.wikipedia.org/wiki/Scientific_method

Having a holistic view of the universe, it seems to me that one can only understand it properly by looking at all its component parts and the various ways they can interact, and thus boundaries between different branches of science must ultimately become meaningless. To become an expert in astronomy, for example, without studying geology or chemistry is a waste of time because you would miss the connections between them and thus limit the scope of your research.

http://en.wikipedia.org/wiki/Holism