Plants compared to animals: the broadest comparative study of development.

If the last common ancestor of plants and animals was unicellular, comparison of the developmental mechanisms of plants and animals would show that development was independently invented in each lineage. And if this is the case, comparison of plant and animal developmental processes would give us a truly comparative study of development, which comparisons merely among animals, or merely among plants, do not-because in each of these lineages, the fundamental mechanisms are similar by descent. Evidence from studies of developmental mechanisms in both kingdoms, and data from genome-sequencing projects, indicate that development evolved independently in the lineages leading to plants and to animals.