Origins of Plastids looks at symbiosis and symbiogenesis as a mechanism of evolution. This theory of endosymbiotic evolution postulates that photosynthetic prokaryotes living as endosymbionts within eukaryotic cells gradually evolved into the organelle structures called chloroplasts. The theory is controversial but has been strongly advocated by Lynn Margulis. Based on a colloquium held at the Bodega Bay Marine Laboratory of the University of California at Davis, Origins of Plastids reviews recent data on this most basic problem in plant evolution. In it, leading researchers in the field...

Ralph A. LewiQand Lanna Cheng In physics, the discovery of new (more properly, hitherto undetected) particles has often resulted from a search: like the discovery of America, their existence had been postulated but their actual existence awaited confirmation. In biology, new discoveries are rarely made in this way. The existence of an alga like Prochloron, as a putative ancestor of chloro- plasts, had been postulated, but in fact its discovery was a consequence of fortuitous events. Green algal symbionts in didemnid ascidians had been known for decades to a few marine zoologists who had...