Catagenesis is a somewhat archaic term from evolutionary biology referring to evolutionary directions that were considered "retrogressive." It was a term used in contrast to anagenesis, which in present usage denotes the evolution of a single population into a new form without branching lines of descent.
The earliest written reference to catagenesis comes from Edward Drinker Cope[1], in his article, On Catagenesis, published in The American Naturalist in 1884. In this article, he defines the "primitive energy", which evolution through time has specialized. He defines catagenesis as a return to the "primitive energy"[2] .