Flagellate phylogeny: an ultrastructural approach
Traditionally, morphological characteristics have been almost the sole source of information in determining the possible evolutionary relationships of flagellates. With the advent of electron microscopy in 1960s, much more detailed and reliable information became available. A combination of diverse and conservative structures have been found. The latter have been used to construct evolutionary rows of homologous elements, which probably reflect the evolution of organelles and other cell structures.