The greatest symphony is found in the composition of life. A large-scale consonance of sounds, an arrangement of different shapes and sizes. Within the symphony are many foundational players. Populations make up each movement and follow their own structure and format. Proteins compose the melody that confer this structure and this melody must harmonize the notes of DNA and RNA to avoid dissonance. Darwin diligently studied each measure within a movement to try and piece together their origins. His theory of natural selection realized how the harmonizing of consonance notes of a melody will be favored, survived, and thrive while the dissension of sound will be phased out and cease to exist. Mendel listened and observed how these notes are sung and inherited from one generation to the next and how the variation in alleles lead to different chord progressions. Evolved differences among organisms serve as an arrangement: a musical reconceptualization of a previously composed work. It may differ from the original work by means of reharmonization, melodic paraphrasing, orchestration, development or regeneration of the formal structure. The resulting organism is similar but also different in many ways. Almost a century later, Huxley reprised these ideas into the Modern Synthesis, the changes in chord progression, or allele frequency, within a movement, or population. Not much later Watson, Crick, and Franklin identified the notes that make up genes and alleles as DNA. This dissertation aims to describes just a few of the instruments responsible for regulating how and when these melodies are played. All living things have certain characteristics in common: we have cellular organization, the ability to reproduce, grow, develop, respond and adapt to our environment. Chapter One will provide a brief overview of the field of evolutionary biology past and present. It will review the origins of teeth, why they make an excellent model system for studying evolution and the relationships they share with other regenerating epithelial appendages in morphology and genetic regulation. It will describe how small changes in the notes of non-coding regions of DNA can lead to large phenotypic differences and defend why these regions are the source for driving evolution and melodic diversity among living things. It will also explain why the threespine stickleback fish, Gasterosteus aculeatus, is the model organism of choice to gain a better understanding of the greater symphony. Chapter Two will play the instruments of genetic regulation, pleiotropy, and transcriptional enhancers. We investigated the pleiotropy of an intronic enhancer of the stickleback Bmp6 gene, previously shown to regulate evolved changes in tooth number and tooth regeneration. Transgenic analysis and site-directed mutagenesis experiments both deleting and scrambling highly conserved notes in the binding site for a predicted Foxc1 transcription factor revealed that this binding site is required for enhancer activity in both teeth and fins throughout embryonic, larval, and adult development. Collectively these data support a model where the melody of this enhancer depends on the very specific notes of this binding site in order to be played in more than one tissue from the embryo to the adult. Finally, Chapter Three will reveal arranged evolutionary differences on a cellular measure, assessing proliferation dynamics and cell cycling kinetics. Cell division is a vital process for long-term renewal of organs but the tempo of proliferation rates of slow cycling cells can vary greatly based on cell type, tissue, sex, age, health and organism. Exploiting the natural variation between marine and freshwater stickleback populations and the dynamic variations of slow cycling, label-retaining cells (LRCs), we reveal evolved reductions in LRCs in the adult pharyngeal dentitions of a high-toothed, freshwater population relative to an ancestral low-toothed marine population. These findings are some of the first to demonstrate the evolved differences in tempo of proliferating cells which give rise to evolved regeneration differences between populations. Together these completed works are a score in the greater musical work of the symphony of life and aims to amplify the sound of evolution and developmental biology.