The singular origin of complex life

Nick Lane

All complex life on Earth shares a common ancestor that arose just once in four billion years of evolution. That common ancestor had a large number of complex traits, from the nucleus to sex, none of which is known in bacteria. Nick argues that the common ancestor of complex life was a chimeric cell, in which a simple host cell engulfed a bacterium, the ancestor of mitochondria. This endosymbiosis changed the basic architecture of cells, ultimately giving them orders of magnitude more energy per gene. He will discuss the singularity of complex life: why mitochondria enabled the evolution of enormous genomic complexity, while simultaneously forcing the evolution of so many curious traits.