Andrew Herbert Knoll (born 1951) is an American paleontologist and paleobotanist, who is the Fisher Research Professor of Natural History and of Earth and Planetary Sciences, Emeritus, at Harvard University. Born in West Reading, Pennsylvania, in 1951, Andrew Knoll graduated from Lehigh University with a Bachelor of Arts in 1973 and received his Ph.D. from Harvard University in 1977 for a dissertation titled "Studies in Archean and Early Proterozoic Paleontology." Knoll taught at Oberlin College for five years before returning to Harvard in 1982 and teaching there until 2022. At Harvard, he served in the departments of Organismic and Evolutionary Biology and Earth and Planetary Sciences.

Scientific work Andrew Knoll is best known for his contributions to Precambrian paleontology and biogeochemistry. He has discovered microfossil records of early life in Spitsbergen, East Greenland, Siberia, China, Namibia, western North America, and Australia, and was among the first to apply principles of taphonomy and paleoecology to their interpretation. He has also elucidated early records of skeletonized animals in Namibia and remarkable fossils of the Ediacaran Doushantuo Formation, China, preserved in exceptional cellular detail by early diagenetic phosphate precipitation. Knoll and colleagues authored the first paper to demonstrate strong stratigraphic variation in the carbon isotopic composition of carbonates and organic matter preserved in Neoproterozoic (1000–539 million years ago) sedimentary rocks, and Knoll's group also demonstrated that mid-Proterozoic carbonates display little isotopic variation through time, in contrast to both older and younger successions.

Knoll has longstanding interests in biomineralization, paleobotany, plankton evolution, and mass extinction. Among other things, Knoll and his colleagues were the first to hypothesize that rapid build-up of carbon dioxide played a key role in end-Permian mass extinction, 252 million years ago. More generally, Knoll uses physiology as a conceptual bridge to integrate geochemical records of environmental change with paleontological records of biological history. He has also served as a member of the science team for NASA's MER rover mission to Mars.

Honors include membership in the US National Academy of Sciences, the American Academy of Arts and Sciences, the American Philosophical Society, the American Academy of Microbiology, and Foreign Membership in the Royal Society of London and the National Academy of Sciences, India, as well as the Paleontological Society Medal, the Wollaston Medal of the Geological Society (London), the Moore Medal of the Society for Sedimentary Geology, the Oparin Medal of the International Society for the Study of the Origin of Life, the Sven Berggren Prize of the Royal Physiographic Society, Sweden, the Penrose Medal of the Geological Society of America, the Garrels Award of the Geobiology Society, and both the Walcott and Thompson medals of the US National Academy of Sciences. He received the Phi Beta Kappa Book Award for "Life on a Young Planet: The First Three Billion Years of Evolution on Earth". In 2018, Knoll received the International Prize for Biology, conferred in Tokyo in the presence of the Emperor and Empress of Japan. In 2022, he received the Crafoord Prize in Geosciences.

Knoll criterion In astrobiology, the Knoll criterion says that "to be evidence of life, an observation has to not just be explicable by biology; it has to be inexplicable without it".

Books 2004 – Life on a Young Planet: The First Three Billion Years of Evolution on Earth. Princeton University Press, Princeton NJ, 277 pp., 2007 – The Evolution of Primary Producers in the Sea. Falkowski, P. and A.H. Knoll, Eds. Elsevier, Burlington MA, 441 pp., 2012 – Fundamentals of Geobiology. Knoll, A.H., D.E. Canfield and K. Konhauser, Eds. Wiley-Blackwell, Chichester UK, 443 pp., 2013 – Biology: How Life Works. Morris, J., D. Hartl, A.H. Knoll, R. Lue, and others. Macmillan. 2nd Edition 2016: ; 4th Edition 2022. 2021 – A Brief History of Earth: Four Billion Years in Eight Chapters. Knoll, A.H. Custom House, New York NY, 272 pp., 2026 – Earth and Life: A Four Billion Year Conversation. Princeton University Press.

Selected papers

Sperling, E.A., C.A. Frieder, P.R. Girguis, A.V. Raman, L.A. Levin, and A.H. Knoll (2013) Oxygen, ecology, and the Cambrian radiation of animals. Proceedings of the National Academy of Sciences, USA 110: 13446–13451.

Honors 1967 – Eagle Scout 1987 – awarded Charles Schuchert Award, presented to a promising paleontologist under 40 1987 – awarded Walcott Medal for contributions to the study of Precambrian life, in particular the microbial roots of plant evolution 1996 – awarded honorary doctorate from Uppsala University, Sweden 1998 – awarded honorary doctorate from Lehigh University 2003 – awarded Phi Beta Kappa Book Award in Science for Life on a Young Planet 2005 – awarded Paleontological Society Medal 2005 – awarded Raymond C. Moore Medal 2007 – awarded Wollaston Medal , the highest award granted by the Geological Society of London; previous recipients include Charles Darwin and Louis Agassiz 2012 – awarded Thompson Medal for meritorious research in paleontology and geology 2013 – foreign fellow, National Academy of Sciences, India 2014 – awarded honorary doctorate from the University of Chicago 2014 – awarded the Oparin Medal from the International Society for the Study of the Origin of Life 2014 – awarded honorary doctorate from the University of Southern Denmark 2015 – elected a Foreign Member, Royal Society (ForMemRS) of London 2017 – awarded honorary doctorate from the American Museum of Natural History 2018 – awarded the Sven Berggren Prize, Royal Physiographic Society, Sweden 2018 – awarded the Geological Society of America's Geobiology and Geomicrobiology Division Award 2018 – awarded the International Prize for Biology 2022 – awarded the Crafoord Prize 2024 – awarded the Penrose Medal of the Geological Society of America 2025 – awarded the Garrels Award of the Geobiology Society

References

External links Knoll lab webpage Harvard webpage America's Best 2001: Paleontologist Time.com: Fossil Finder PBS NOVA Origins: How Did Life Begin? Interview with Dr. Knoll on his role in Voyage of Time