title: Biogenesis as an evolutionary process [letter].
abstract: The earliest fossil stromatolites present evidence of a complex ecosystem of photosynthetic organisms.  Because the origin of present life can be dated within a few hundred million years prior to these fossils, their complexity poses a problem.  A heuristic model outlines the first radiation leading to the universal ancestor.
authors.affiliation: Biology Department, George Mason University, Fairfax, VA 22030, USA.
authors.forename: H J
authors.initials: HJ
authors.lastname: Morowitz
authors.forename: D W
authors.initials: DW
authors.lastname: Deamer
authors.forename: T
authors.initials: T
authors.lastname: Smith
mesh_terms: D005075:Biological Evolution; D002477:Cells; D005580:Fossils; D046911:Macromolecular Substances; D008962:Models, Theoretical; D000069497:Origin of Life
chemical_list: D046911:Macromolecular Substances