I've read the following context which mentions the word "course of evolution" and I don't think that the meaning is in the simple meaning of course, like a course in the university. It seems to me something like "part of time" or period, but I am not sure even though I checked the definition in the dictionary, but to be honest it's not clear to me (probably because I'm non Native English speaker)
"Our starting point for exploring the nervous system is the neuron, a cell type exemplifying the close fit of form and function that often arises over the course of evolution"