Dr. Jonathan Zehr is the distinguished professor at the University of California, Santa Cruz, Institute of Marine Sciences.  He and his colleagues have discovered the possibility of a eukaryote with a nitrogen-fixing organelle derived from endosymbiosis, which is called a nitroplast. Studying a marine alga with a cyanobacterial endosymbiont, Coale et al. used soft x-ray tomography to visualize cell morphology and division of the alga, revealing a coordinated cell cycle in which the endosymbiont divides and is split evenly, similar to the situation for plastids and mitochondria in these cells.  What they witnessed is evolution in actions.  Dr. Zehr will share with us how such a revolutionary discovery was made.