Using signal processing, we wish to gain knowledge about biological complexity, as well as using this knowledge to engineer better technology. Three areas are identified as critical to understanding bio-complexity: 1) understanding DNA, 2) understanding protein pathways, and 3) evaluating overall biological function subject to external conditions. First, DNA is investigated for coding structure and redundancy, and a new tandem repeat region, an indicator of a neurodegenerative disease, is discovered. Second, the way a single-cell mobilizes in response to a chemical gradient, known as chemotaxis, is examined. Inspiration from chemotaxis receptor clustering is shown to improve sensor array performance of a gradient-source (chemical/thermal) localization algorithm. Implementation of the array is evaluated in diffusive and turbulent environments. We also show how to improve sensor array localization in turbulence by using the cross-correlation method. The work illustrates how signal processing is a tool to reverse engineer complex biological systems, and how our better understanding of biology can improve sensor network localization.