There is virtually no connection between Darwin and Marx, other than that they were contemporaries. They never met. In fact, Marx was an active socialist agitator, who had written and published virtually all of his work, before 1859, when Darwin first published Origin of Species. The only work Marx published after that was Das Capital, which makes no mention of Darwin or evolution. Nor did Darwin's work make any mention of Marx, or his works. So there is no intellectual connection between the two.
Although Marx had never met Darwin, he knew that Darwin had become one of the most famous scientists of the time, so Marx sent him a copy of Das Capital, and requested permission to dedicate it to him. Darwin declined, saying that he knew nothing about the subject, and appears never to have read the book.
A source that most creationists accept, the Institute for Creation Research, has this article posted at their website:
Darwin's Influence on Ruthless Laissez Faire Capitalism. Yes, ICR links Darwin to good ol' capitalism.
Do these facts (which have been posted many times) ever stop creationists from claiming a "connection" between Darwin and Marx? No, of course not.
Darwinism was condered to be "bourgeois science" by the communists, just as relativity was considered to be "Jewish science."