It’s the birthday of paleontologist Stephen Jay Gould (1941-2002), known for his many popular science essays published in Natural History magazine and collected in volumes such as Ever Since Darwin (1977), The Panda’s Thumb (1980), and Bully for Brontosaurus (1991). Gould was also known for his “punctuated equilibrium” theory, which posited that evolutionary change occurs in fits and starts rather than slowly and steadily—a radical idea that cheesed off all the slow, steady evolutionary biologists, some of whom have referred to Gould’s theory as “evolution by jerks.”

(Okay, that’s hilarious.)

Gould was born in Queens, New York, the son of a court stenographer and an artist. At the age of five, he visited the American Museum of Natural History, where the Tyrannosaurus rex skeleton inspired him to become a paleontologist, as Tyrannosaurus rex skeletons are wont to do. He studied geology at Antioch College in Ohio (1963), got his PhD in paleontology from Columbia University (1967)—this was where he and another grad student, Niles Eldredge, came up with punctuated equilibrium—and then settled into a life-long teaching career at Harvard.

Gould was often controversial and always interesting. His challenge to certain aspects of Darwinian evolution was decried as assisting creationists; at the same time, he was called creationism’s greatest opponent. He was credited with reinvigorating his entire field yet accused of promoting loosey-goosey theories that couldn’t be proved. He was firmly agnostic, rooted for the New York Yankees, and if you needed to know anything about Cerion land snails in the Bahamas, Gould was your man.

In the year of his death, Gould published what he considered his magnum opus, The Structure of Evolutionary Theory (2002), about which he said, “It is to me a great consolation because it represents the putting together of a lifetime of thinking into one source.” (My gosh. If I can just finish the grocery list I’m happy.) Gould also had several books published posthumously, including Triumph and Tragedy in Mudville: A Lifelong Passion for Baseball (2003).

Gould died at 60 of cancer.

Have a bright green Tuesday warming into the 80s and stay scrupulously honest to the data.