The path cannot be followed smoothly in reverse, going from a knowledge of ecology into a knowledge of biology into a knowledge of chemistry and so on. The smaller the sub-category of knowledge you have, the less it can be generalized. The more general the knowledge, the more it can be applied to specific situations. The fundamental knowledge of physics would be the most useful scientific knowledge as such, in case someone had to pick which areas to study. And because physics is the study of matter, energy, space and time, without which there would be nothing in existence to react or thrive or live or die, all of this makes sense. The entire universe is built upon of the principles revealed by a study of physics. I suppose I should also point out that the opposite argument holds just as strongly: someone who is studying science needs to be able to function in society, and this involves understanding the entire culture (not just the techno-culture) involved while on the subject of well rounded education. The beauty of Euclidean geometry is not inherently more beautiful than the words of Shakespeare ... it's just beautiful in a different way.

More about why study physics

Scientists (and physicists especially) tend to be fairly well rounded in their interests in their experience. The classic example is the violin-playing virtuoso of physics, Albert Einstein. Perhaps medical students, who lack diversity more due to time constraints than lack of interest is one of the few exceptions. A firm grasp of science, without any grounding in the rest of the world, provides little understanding of the world, let alone appreciation for it. Political or cultural issues do not take case in some sort of scientific vacuum, where historical & cultural issues need not be taken into account.  The fact is that important issues in society never involve purely scientific questions while many scientists who feel that they can objectively evaluate the world in a rational, scientific manner. The Manhattan Project, for example, was not purely a scientific enterprise, but also clearly triggered questions that extend far outside of the realm of physics. This energy can take the form of motion, light, electricity, radiation, gravity . . . just about anything, honestly. Physics deals with matter on scales ranging from sub-atomic particles (i.e. the particles that make up the atom and the particles that make up those particles) to stars and even entire galaxies. Physics utilizes the scientific method to test and formulate such hypotheses that are based on observation of the natural world. The goal of physics is to use the results of these experiments to formulate scientific laws. They are usually expressed in the language of mathematics, which can then be used to predict other phenomena.