Thomas Guy “Tom” Hallam, Sr., of Boise, Idaho, passed from this world on April 3, 2025, surrounded by family, friends, and grandchildren. Tom was born to Norman and Helen (Jarvey) Hallam in Chicago, Illinois, on September 3, 1937. Basketball took Tom to Southern Illinois University, where he earned B.A. degrees in Chemistry and Mathematics in 1959 and an M.A. degree in Mathematics in 1961.
More importantly, prior to the first day of class in 1959, Tom met his love, Rachel Edell (McCallen) Hallam, at a Methodist Youth Camp where he was a counselor, welcoming new students to Southern Illinois. After Tom and Rachel met, their love carried them through a lifetime of travel and adventures. They married on August 8, 1964, and celebrated their 60 th anniversary last year!
Tom received his Ph.D. degree in Mathematics from the University of Missouri in 1965, which led Tom and Rachel to stops at Florida State University, the University of Rhode Island, and University of Georgia, before finding a home in Knoxville, Tennessee, at the University of Tennessee in 1977. Go Vols. While in Knoxville, Tom developed a love for the Tennessee Lady Vol Basketball team which he would happily discuss with you, no matter whether it was basketball season or not.
Tom’s research evolved over the years, from his early publications on stability and asymptotic behavior of ordinary differential equations to later work related to mathematical ecology. Tom is considered to be a founder of the field of mathematical eco-toxicology, with some of his research measured as “seminal” work on population and community dynamics. Tom founded Tennessee’s Institute for Environmental Modeling, served as the Head of the Department of Ecology and Evolutionary Biology, and was instrumental in building Tennessee’s mathematical biology program to be one of the best in the world. His favorite professional accomplishments included his eighteen years of jointly organizing workshops at the International Centre for Theoretical Physics in Trieste, Italy (with his good friends Lou Gross and Simon Levin), and advising and collaborating with students and colleagues around the world, including mentoring 34 master’s students, training 21 PhD students, and 7 postdoctoral students. Shortly before his death, Tom commented that his colleagues and students inspired him because it was always exciting to see the paths they would go down that he would have never thought of trying.
Tom retired for the first time in 2008, with his final credited co-publication in 2015 about the importance of natural habitat for bats. In total, Tom is credited with approximately 150 publications. Post retirement, Tom wrote and self-published a work of fiction, entitled The Gards, Transitions , an adventure fantasy involving a group of Viking youth.
Tom and Rachel traveled extensively for both work and pleasure. He really enjoyed beach time on St. George Island, Florida, when the children were young. Noteworthy international trips for Tom included living in Grado, Italy for 3 months (twice!), along with visits to Brazil, Peru, China and India. Tom’s favorite wildlife sighting trips were to Kangaroo Island, Australia, and Katmai National Park, Alaska. In total, Tom visited 33 different countries over the years!
In 2019, Tom and Rachel moved to Boise, Idaho. In Idaho, Tom enjoyed attending the sporting events of his grandchildren, cooking impressive specialty desserts and lasagnas, riding his bike and other outdoor activities with Rachel, and rock-hounding with his good friend, Barry.
Tom was preceded in death by his parents, Helen and Norman Hallam, and is survived by the love of his life, wife Rachel, siblings Joanne Shrout and Mick Hallam (Betty), children Guy Hallam (Shannon) of Boise, ID, Bethany Hallam (Wade Davies) of Knoxville, TN, and Julie Jolly (Sean) of Knoxville, TN, along with grandchildren Evan Davies, Elijah Davies, Breana Hallam, Benjamin Hallam, Simon Jolly, and Kate Jolly.
The family would like to thank the St. Luke’s Hospice team and caregivers from Angels Among Us HomeCare for the kind and compassionate care they delivered to Tom and Rachel.
Tom’s memorial service will be held on Saturday, April 26, 2025, at 2:30 p.m. MT, at the Cathedral of the Rockies, 717 N. 11th st., Boise, Idaho. A reception celebrating Tom’s life will immediately follow.
To attend the service virtually please visit https://boxcast.tv/view/tom-hallam-memorial-service-uzrii4mzvvfsmaubnnca
In lieu of flowers, please consider contributing to The Thomas G Hallam Fellowship Fund at https://giving.utk.edu/Hallam_EEB which continues Tom’s work by helping support deserving graduate students in the Ecology & Evolutionary Biology program at the University of Tennessee, or to the Local Missions of the Cathedral of the Rockies (FUMC) at https://secure.myvanco.com/L-ZA1K/campaign/C-ZT01 .