Assembling the universal Tree of Life is an ambitious project that intends to provide a framework for what scientists interpret as the genealogy of life on planet Earth. The branch of biology involved in this tree-building processs is called phylogenetics, and it combines efforts from all areas of organismal biology together with mathematics and computer science. Phylogeneticists reconstruct phylogenetic trees (hypothetical genealogies of organisms) which are primarily derived from analyses of morphological, anatomical, physiological, developmental, behavioral, and molecular attributes assembled in data matrices. Molecular attributes include primarily deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) sequence data, but also include the structure of proteins or genomes. Although molecular sequence data are at the forefront of assembling the Tree of Life, more traditional morphological data are still important, especially for fossils and extinct or rare species, as these are the only data available.