You have now learned the basics of classification, including taxonomy and binomial nomenclature. Cladograms illustrate visually how different organisms share common ancestors, similar to a family tree. Dichotomous keys help the user identify the names of species by observing characteristics of specimens. In order to understand the relationships between diverse organisms, you explored how molecular evidence and homologous structures reveal the hidden evolutionary history of species. Even in embryonic development, you can understand how different vertebrates evolved from the same types of cells. Finally, you took a look at characteristics of different domains and kingdoms of organisms. Taxonomy is a work in progress that continues to evolve as more knowledge about species is discovered.