David Baum


Department of Botany

David Baum is Professor of Botany and Director of the James F. Crow Institute for the Study of Evolution at UW–Madison. He grew up in London, England and obtained an undergraduate degree in Botany from Oxford University. He then obtained a PhD in Population and Evolutionary Biology at Washington University in St. Louis and obtained his first teaching appointment as a professor at Harvard University. He has been on the UW–Madison faculty since 2001 and teaches biology, botany, and advanced classes in evolutionary biology. He has published more than 80 papers and one book (Tree thinking: An introduction to phylogenetic biology) on a variety of topics concerned with plant evolution and evolutionary theory. Awards include a National Science Foundation Career Award, Sloan Foundation Young Investigator in Molecular Evolution award, a Guggenheim fellowship, and election as Fellow to the American Association for the Advancement of Science.


  • Origin of Cell Complexity
  • The metaphor of a tree of life, showing the evolutionary relationships among species, was developed by Charles Darwin over 150 years ago, and served as a key element in his theory of evolution. Until about 20 years ago, however, scientists’ ability to reconstruct this evolutionary tree, or phylogeny, were very limited. One of the greatest triumphs of modern biology has been in using molecular and genomic data to build an ever more detailed picture of evolutionary history. The resulting phylogenetic trees provide insights into such diverse topics as the origins of novel traits, the appearance of new diseases, the movement of species around the globe, and the assembly of ecological communities.

    Approximate length of talk: Depends

  • Professor Baum will share some of his experiences as a graduate student studying the exotic pollination biology of baobab trees in Madagascar and Australia and then try and explain how this foundation serves him even today as he conducts research in such modern fields as molecular phylogenetic, genomics, and evolutionary developmental genetics. As a field scientist he learned theessence of scientific inquiry – thoughtful questioning and careful and self-critical observation and experimentation. Furthermore, the field setting provided him abundant opportunities to develop his own theoretical perspectives that provided the basis of his scientific accomplishments. This is not to say that field research is the only route to success in laboratory science. But what it does show is that science benefits when scientists come from different backgrounds and have diverse career paths.

    Approximate length of talk: Flexible

  • The core of the origin of life problem is to explain the emergence of systems that can grow and evolve adaptively. This poses the ultimate chicken-and-egg problem: Adaptive evolution is needed to explain complexity, but evolving adaptively requires reproduction which, in all life that we know of, is very complicated. A resolution to this paradox is suggested by recent advances in evolutionary theory, which point to the surfaces of minerals as a location where a kind of selection, which I call neighborhood selection, can occur and could eventually result in the origin of cells. Excitingly, this insight suggests that it might be possible to create new evolving chemical systems, “life” in a very generic sense, in the laboratory.  I will describe these experiments and any progress we have made at the time.

    Approximate Length of Talk: Variable

  • Arguably the most important evolutionary event in the history of life on earth was the origin of complex, eukaryotic cells, such as found in animals, plants, and fungi. These cells have various internal membrane-bound structures, including the nucleus, which houses the DNA, and mitochondria, which generate most of the cell’s energy supply.  Biologists have long puzzled over the origin of these cellular features. Many theories have been proposed, all of which assume that an ancestral, simple cell internalized membranes and evolved the nucleus and other structures inside the original cell body. As an undergraduate student I dreamt up an alternative theory which, literally, turns the existing model “inside out.” Instead of creating a nucleus within the ancestral cell, I think that an ancestral cell, corresponding to the nucleus, created an outer compartment in the course of interacting with extracellular bacteria. I recently began working with a cell biologist on this theory and find that it fits the available information surprisingly well. This well illustrates the principle that sometimes naive individuals can have valuable scientific insights.

    Approximate Length of Talk: Variable

  • In 1819 the baobab tree was said to be “the most monstrous of all productions of the vegetable kingdom. It is the most admirable, because, by its nature, it longest resist the action of time; because by its organisation, and the vigor of its constitution, it attains an unmeasurable size; because, with the faculty of existing for thirty centuries, the heart of its wood is still light and tender…This astonishing vegetable production, which holds the same rank amongst vegetables as the elephant does amongst quadrupeds, or the whale amongst fish, undoubtedly deserves to be spoken of in detail.” This talk, built upon more that 30 years of research, including many months of research in the tropics, will do just that. I will introduce all 8 species of baobab, describe what is known about their ecology (with a special focus on their remarkable pollination ecology), and summarize current understanding of their evolutionary history and conservation status.