NEW YORK — Carl Woese, a biophysicist and evolutionary microbiologist whose discovery 35 years ago of a ‘‘third domain’’ of life in the vast realm of microorganisms altered scientific understanding of evolution, died Sunday at his home in Urbana, Ill. He was 84.
Dr. Woese spent his entire career at the University of Illinois. He spent years comparing genetic sequences of protein-building structures in cells.
He studied Archaea, a category of single-cell microbes initially believed to exist only in extreme environments. In the years since Dr. Woese’s initial research, they have been found in many places.