David Severin Dennison86, passed away on March 10, 2019 at his home in Hanover. David was born in Ann Arbor, Michigan on March 19, 1932 to David Mathias Dennison and Helen (Johnson) Dennison.

David grew up in Ann Arbor, where his father was a professor of Theoretical Physics at the University of Michigan. He attended University High School in Ann Arbor, graduating in 1950. David attended Swarthmore College from 1950 to 1954, earning a Bachelor of Arts in Physics.

While at Swarthmore, David met Mary Lois Eckler, whom he married in Washington DC in 1954. Following their wedding, David and Mary moved to Pasadena, California, where David entered the graduate program in Biology at the California Institute of Technology.

In 1958, after being awarded the PhD in Biology from Caltech, David and Mary moved to Hanover, where David joined the faculty at Dartmouth, spending the remainder of his professional career there. David's passion at Dartmouth was his students. He introduced generations of undergraduates to the biological sciences, teaching both the introductory "Bio 5" class, as well as a popular freshman seminar.

David was an active skier, hiker, and sailor, and he enjoyed spending time outdoors with his family. David traveled widely, spending a sabbatical year at the Max Planck Institute in Tübingen Germany in 1963 and 1964, and traveling to the Soviet Union in the early 1970s. David also traveled for pleasure, crossing the country by car, both as a newlywed and later with his children.

David loved order and precision in all things. He trained himself as a clockmaker and photographer, and throughout his life he maintained an interest in precision machinery.

David was a thoughtful and caring man in his relations with others. He was devoted to his children and grandchildren, Benjamin, David, Haley and Charlotte. Above all and always, David cherished his life with Mary, remaining by her side throughout her prolonged illness. He was deeply loved by his family and he will be missed by them.

David is survived by his two sons, Edward Dennison of Dover, MA and Eric Dennison of Strafford, VT.

Memorial services will be held privately at a future date.