Why are interactions between biological components important in systems biology?

In systems biology, interactions between biological components are essential because they give rise to "emergent properties"—critical system-wide behaviors that cannot be predicted or understood by examining individual parts in isolation.1

As noted by biologists Linus Pauling and Emil Zuckerkandl, "Life is a relationship among molecules and not a property of any one molecule". Because biological organisms are highly complex, their functions—such as memory in the human brain or gene expression—depend on the collective, coordinated activity of many components acting together.12

Unlike engineered systems designed with known specifications, biological systems must be understood through "systems reverse engineering," where researchers identify individual components and then infer how their interactions create observable biological behaviors. Consequently, focusing on these interactions and the information they transmit provides the necessary framework to understand how living systems function, evolve, and maintain stability.31