Impromptu is an unrehearsed speech. Not rehearsing would not allow speakers to gather 100% of their thoughts.
The answer is: it is about evolution.
Darwin himself characterized his seminal book, <em>On the origin of the species, </em>as “one long argument”. There is still debate as to what exactly did he mean by that characterization, but it is agreed upon that he evidently was referencing his theory of evolution based on common ancestry between species and natural selection as the process of differentiation between them, which, all in all, tells a story that took millions of years, or, in more poetic terms, it summarizes a very long argument.
It's in inverted order. Natural order would say "A quiet little toad sat in the middle of the road."
B. life long love...........: )
