Today, scientists' perception of what constitutes life on Earth has changed drastically. In his talk, Dr. Nealson will discuss the new definition of life, how its distinctive signatures might be detected, and strategies that might be used to find extraterrestrial life. Today, the nature of life on Earth has been redefined in terms of genetic diversity. Living organisms are now classified into three kingdoms. Two of these kingdoms, bacteria and archaea, are prokaryotes - cellular organisms that have no distinct nucleus.
Protists are eukaryotes, organisms with organized nuclei.
The prokaryotic organisms are extremely hardy and genetically diverse life forms capable of inhabiting niches that were not considered habitable even a decade ago. Thus, new methods to find extraterrestrial life would take into account the tenacity and toughness of these life forms. Dr. Nealson earned a B.S. in biochemistry in 1965, and a Ph.D. in microbiology in 1969, both from the University of Chicago. After taking a postdoctoral position at Harvard University, Dr. Nealson joined the faculty of the Scripps Institution of Oceanography at the University of California, San Diego, in 1973. In 1985, he took on the title of Distinguished Professor at the University of Wisconsin, Milwaukee, Center for Great Lakes Studies.