Michod's talk was the perfect lead-in for the penultimate lecture of the conference by the acknowledged star of the weekend, Lynn Margulis, famous for her pioneering research on symbiogenesis. Margulis began graciously by acknowledging the conference hosts and saying, "This is the most wonderful conference I've ever been to, and I've been to a lot of conferences." She then got to work, pronouncing the death of neo-Darwinism. Echoing Darwin, she said "It was like confessing a murder when I discovered I was not a neo-Darwinist." But, she quickly added, "I am definitely a Darwinist though. I think we are missing important information about the origins of variation. I differ from the neo-Darwinian bullies on this point." She then outlined the basis of her theory of the origin of the cell nucleus as a fusion between archaebacteria (thermoplasma) and Eubacteria (Spirochaeta). "We live on a bacterial planet," she reflected. "The cell is the fundamental unit of life. A minimal cell has DNA, mRNA, tRNA, rRNA, amino acylating enzymes, polymerases, sources of energy and electrons, lipoprotein membranes, and ion channels, all contained within a cell wall, and is an autopoietic (self-regulating feedback) system." The biggest break in life, she explained, was between the prokaryotes (cells with nucleoids: monera, prokaryota; archaebacteria, eubacteria) and eukaryotes (cells with nuclei: protoctista, fungi, plantae, animalia).

In this framework, Margulis continued, all of life's history can be divided into three major eons: Archean (3,500 to 2,500 million years ago), Proterozoic (2,500 to 540 mya), and Phanerozoic (540 to 0 mya). "Most evolutionary biologists deal with the Phanerozoic, which is like saying that history began in 1909 when the Ford Motor Company opened shop in Dearborn, Mich," Margulis quipped. The major steps in evolution involved symbiogenesis, which Margulis described succinctly as "the inheritance of acquired genomes" and more formally in its relationship to symbiosis, "the long-term physical association between members of different types (species)." The problem with neo-Darwinism, Margulis concluded, is that "Random changes in DNA alone do not lead to speciation. Symbiogenesis--the appearance of new behaviors, tissues, organs, organ systems, physiologies, or species as a result of symbiont interaction--is the major source of evolutionary novelty in eukaryotes--animals, plants, and fungi."

There were no direct challenges to Margulis in the discussion period that followed, so I once again queried a number of the experts in this area after the lecture. The overall impression I received was that Margulis goes too far in her rejection of neo-Darwinism, but because she was right about the role of symbiogenesis in the origin of the first eukaryote cells, they are taking a wait-and-see approach. One scientist added that since Margulis was to receive an honorary doctorate that afternoon, it seemed inappropriate to challenge her in this venue.

The final talk was delivered by evolutionary biologist Joan Roughgarden, from Stanford University. Evolutionary skepticism must have been in the air, for on the heals of Margulis' pronouncement of the death of neo-Darwinism, Roughgarden proclaimed the death of Darwin's theory of sexual selection. Darwin said that males have stronger passions than females, that females are coy, and that females choose mates who are more attractive, vigorous and well-armed. "People are surprised to learn how much sex animals have for purely social reasons (including same-sex sexuality in over 300 species of vertebrates)," Roughgarden explained, "and how many species have sex-role reversal in which the males are drab and the females are colorfully ornamented and compete for the attention of males, and that most plants and perhaps a quarter of all animal species have individuals that cannot be classified as male or female." In response, University of Georgia evolutionary biologist Patricia Gowaty noted that Roughgarden is right in identifying the exceptions to Darwin's theory and that there is much we still do not know, but added that since Darwin's time much has been learned about mate selection and competition that should not be dismissed.