Henry Cowles was one of the  founders  of the American school of ecology that has been labelled "Dynamic Ecology".  He came to the conclusion that ecological succession was a dynamic event through his work on the vegetation of the sands dunes that lie at the southern end of Lake Michigan.  From his field work on those dune systems he determined that the vegetation at any one point in the system is related to the distance the point lies from the lake, the kind of soil present at the location, and the time period over which seeds, spores, etc. have had a chance to germinate.  He later compared his work on those dunes with dune ecosystems from other parts of the world.  These comparisons showed similar causative agents at work.
Cowles did not start out as an ecologist.  He was born at Kensington, Connecticut, 27 February 1869.  He attended the local public schools and graduated from New Britain High School.  He went to Oberlin College and graduated from there in 1893.  In 1894-95 he taught natural science at Gates College in Nebraska.  He came to Chicago to study geology under the tutelege of Thomas C. Chamberlin and Rollin D. Salisbury, both of whom were strong advocates of the dynamic approach.  Salisbury had bring brought to Chicago by William Rainy Harper, the President of the University of Chicago, to organize the geography department.  He was attracted to botany by John MerleCoulter.
	Coulter had come to Chicago to initiate a program in botany.  He introduced Cowles to the work of Warming, a pioneer European plant ecologist.  Cowles then brought his geological background to bare on the problem of ecological succession on the nearby sand dunes.  The presence of an interurban line gave him direct access to these dunes for the purposes of his field research.  He completed his Ph.D. in 1898 and published in 1899 his classic paper "The ecological relations of the vegetation of the sand dunes of Lake Michigan" in the Botanical Gazette.  He expanded that research to other areas in the Chicago vicinity and published additional papers in 1901 in the Botanical Gazette and the Bulletin of the Geographic Society of Chicago.   In his 1903 paper he compared the Lake Michigan dune floras to those of Cape Cod.

"A man may be a great scientist and a great teacher and yet inspire in his colleagues and students little affection or none at all.  With Cowles, it is far otherwise. . .  And yet, merely because it is a joy to do so, we make mention of a few of his many lovable traits—his unfailing good humor, his far-famed ability in the telling of a story, he readiness to give ungrudgingly of time and effort in the service of students and friends, his eagerness to discover and commend whatever is meritorious in the work of a fellow scientist or admirable in the man himself.  . . . .Fortunate and happy is the man with a record of accomplish so throughly satisfying.  Such good fortune and such happiness are undoubted right and privilege of Henry Chandler Cowles.

In science reputations are determined by the papers you publish or the students you produce.  Cowles concentrated on the former early and the latter group in the second half of his career.