I have been working my way through a fascinating book by Professor Geoffrey Hodgson, Economics in the Shadows of Darwin and Marx.  They were the two great theorists of structural change in complex systems in the nineteenth century, and I've been looking for new ideas on how their theories have been applied and adapted in modern economic scholarship.  This sentence, in a chapter comparing their worldviews, was too interesting and amusing to keep to myself:

Marx and Engels characterized Darwin's doctrine as an inappropriate extension of the norms of capitalist competition to the natural world.

Enjoy!