In “The Columbian Exchange: Biological and Cultural Consequences of 1492,” a wide-ranging book published in 1972, Professor Crosby examined in pithy, sometimes wry prose how disease had devastated indigenous populations after Columbus landed.
He also described a parallel development that transformed global ecology forever: the transoceanic movement of plants and animals, in which Europeans shipped staple crops like wheat, oats and fruit stock along with horses, goats and pigs to the Americas, where they were not known, and transported back to Europe New World cultivars like maize, potatoes and beans.
On Oct. 12, 1492, the “two worlds” on either side of the Atlantic, “which were so different, began on that day to become alike,” Professor Crosby wrote.
“That trend toward homogeneity,” he concluded, “is one of the most important aspects of the history of life on this planet since the retreat of the glaciers.”
When asked in an interview in 2011 with Smithsonian magazine why his scholarly approach had not been pursued before, he said, “We were thinking politically and ideologically, but very rarely were historians thinking ecologically, biologically.”
He expanded on that idea in 1994 in “Germs, Seeds and Animals: Studies in Ecological History,” a collection of essays. He wrote that a venture into epidemiology had led him to “a more general subject: ecological history, the history of all organisms pertinent to human history and their (our) environment.”
“Yes, germs were important,” he continued, “and so, it turned out, were insects, fungi, weeds, crops and domesticated and wild animals. Humanity turned out to be the purposeful but often drunken ringmaster of a three-ring circus of organisms.”
In 1986, with “Ecological Imperialism: The Biological Expansion of Europe, 900-1900,” Professor Crosby, in his words, “took ‘The Columbian Exchange’ up another notch in scope and abstraction.”
In this book he posited the existence of “neo-Europes,” areas and countries where Europeans settled, especially between 1820 and 1930, after they had “leapfrogged across the globe.” These settlers became so successful at food production and food export that they easily dominated indigenous cultures and then nearly decimated them.
He traced the rise of these “neo-Europes” to a kind of environmental competition that the invading Europeans won. Flora and fauna native to the Americas were so different from the plants and animals that Europeans brought with them, and so acclimated to specific growing conditions, that they couldn’t compete biologically. What Professor Crosby called “the companions of the conquistadors” conquered as well.
At the same time, catastrophically, native peoples increasingly died of diseases, usually smallpox, that had moved from domestic animals to humans. Descendants of the European settlers, by contrast, had acquired immunity.
The books had wide impact. The author Charles Mann’s well-regarded 2011 best-seller, “1493: Uncovering the New World Columbus Created,” was an effort, encouraged by Professor Crosby, to update “Ecological Imperialism.”
“Al was an exceptionally independent thinker whose work pioneered half a dozen new genres,” Mr. Mann wrote in an email. “Scores, if not hundreds of writers — me among them — have scribbled their works in the margins of ‘The Columbian Exchange’ and ‘Ecological Imperialism.’ ”
Alfred Worcester Crosby Jr. was born in Boston on Jan. 15, 1931, and grew up in Wellesley, Mass., to Alfred Sr. and the former Ruth Coleman. He graduated from Wellesley High School.
He told an interviewer in the journal “The Americas” in 2015 that comic strip superheroes and historical events like “rockets vaulting the English Channel” during World War II, and “then rockets on their way to the Moon and Mars,” had seized his imagination when he was young. But he nevertheless concluded, he said, that “Columbus stumbling on an unexpected continent seemed more suitable an object for my focus than even the all-powerful Clark Kent.”
He graduated from Harvard in 1952 with a degree in history and then served in the Panama Canal Zone as a sergeant in the Army, becoming exposed to a Latin American culture that he had known little about, he said. After the service, he obtained a doctorate in history from Boston University.
Professor Crosby taught at the University of Texas in Austin for 22 years and retired in 1999 as professor emeritus of geography, history and American studies.
Before that, while teaching at Washington State University, he was involved in a student strike that led to his becoming a co-founder, with the anthropologist Johnetta Cole, of the school’s first black studies department. He taught there for 11 years.
He also came to know the labor and civil rights leaders Cesar Chavez and Dolores Huerta when Professor Crosby pitched in to help build a medical center for the United Farm Workers in California.
In addition to his wife, Ms. Karttunen, his survivors include his son, Kevin; his daughter, Carolyn Crosby; his stepdaughters, Jaana Karttunen and Suvi Aika; and two grandchildren. His previous marriages, to Anna Bienemann and Barbara Stevens, ended in divorce.
Professor Crosby’s other books include “The Measure of Reality: Quantification and Western Society, 1250-1600” (1997), which he called “an essay on the essential characteristic of civilization: mathematics,” and “Children of the Sun: A History of Humanity’s Unappeasable Appetite for Energy” (2006).
“The Columbian Exchange” might not have been published at all if Greenwood Press, a small publisher of academic books in Westport, Conn., had not agreed to take it on. Dr. Crosby had found no takers among mainstream publishers
In the preface to “The Columbian Exchange,” Professor Crosby addressed his interdisciplinary method and what may be considered his scholarly legacy. He expressed hope that the book was “an unpretentious one, but I am the first to recognize that historians, geologists, anthropologists, zoologists, botanists and demographers will see me as an amateur in their particular fields.”
He said he would partly agree with them if they thought so, but he also concluded that “although the Renaissance is long past, there is a great need for Renaissance-style attempts at pulling together the discoveries of the specialists to learn what we know, in general, about life on this planet.”