Pure Darwinism takes a "sterile" view of biology, one omitting microorganisms, says Jan Sapp of York University in Toronto, Ontario, Canada, one of several speakers who honored Carl Woese, recipient of the Abbott-ASM Lifetime Achievement Award, during a special session of the 109th ASM General Meeting, held last May in Philadelphia, Pa. Woese, whose health is described as "delicate," did not attend the meeting, but Sapp and other participants ignored that fact when they occasionally seemed to address Woese directly, as if he were sitting at the center of the same stage. 

"Darwin didn't like microorganisms or microscopes," Sapp says. Even though subsequent evolutionary biologists and microbiologists found ways to incorporate microbes into evolutionary schemes, those arrangements were "based on ecology and were not phylogenetic." The latter approach to classifying species "was not possible for bacteriology during the 20th century"-or at least not until its final decades when Woese put forward his three-domain Tree of Life, which came to be widely, if not universally, accepted. Indeed, some biology textbooks either ignore it or include it merely as one of several options for classifying organisms.

In developing a scheme that fits all organisms into three distinct biological domains, Woese provided "experimental grounding to our perspective on evolution," says Norman Pace of the University of Colorado, Boulder. Before that systematic development, "we had mere anecdotes." Pace also emphasizes that those developments, "in the main [were] a solo job." Yes, Woese had close collaborators. However, the "arcane nature of his data made it difficult for others to appreciate" what that information implies, Pace notes. "Biologists weren't used to looking at it"-with "it" being comparisons of DNA sequence information for 16S ribosomal RNA genes. Moreover, those data were being collected and analyzed well before DNA sequencing was automated, could be done rapidly and repeated readily, and then analyzed via elaborate software options.

"The ‘Woesean' world is very complex, and [nonexperts] sometimes have to step aside," Sapp says, explaining why the general public and others fall short of understanding the Woese view of biology. "Evolution is finally being taken seriously as an experimental science. Darwin's theory didn't do that. It didn't have hopes of predictability until we got to phylogenetics." Adds Pace, "Even among scientists, inertia is enormous."

Although the Woese scheme is phylogenetic, it masterfully accommodates microbial ecology, according to Edward DeLong of Massachusetts Institute of Technology in Cambridge, Mass. Although not known for barnstorming the country to convince the scientific community of his views, Woese is "not shy about voicing his opinions," DeLong says. "He is very provocative."

Moreover, the three-domain framework continues to provide many ways for formulating hypotheses, and lends itself to a "global understanding of the microbial world," DeLong says. Because it embraces the basics of how the "planet functions," that framework offers more than a way of understanding the "tree of life, but also an understanding of the planet. Carl [Woese] recognized this in a very deep way . . . and we owe him a very great debt."

Jeffrey L. Fox