You evolutionists are being disingenuous in pretending that evolutionism starts in 1859 with Charles Darwin.
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So which evolutionist did Marx use as the foundation of his beliefs? Surely you can tell us that. And maybe you can point to the relevant passages in Marx’s writings (prior to Darwin) that demonstrate this belief in evolution as the necessary foundation for his theory.
Any response other than bibliographical would be disingenuous.
He was a philosopher. As such it was ideas, not people, upon which his thinking was based. So you ought to have asked which version of evolutionism.
At that time I don't think it is necessary to subdivide evolutionism and say Marx favored one above another. Though since his time, punk eek has clearly been identified with Marxism, over and against gradualistic evolutionism. (I.e, as reflected in the writings of the late Stephen J. Gould and Niles Eldredge.)
One could also mention the Soviet reliance on Lysenko and his strange allegiance to Lamarkism, with persecution of dissenters, such that Soviet biology research and prestige suffered lasting damage. But again that is after the fact - I can't think offhand why Marx would have wedded himself to Lamarck over and against other evolutionary theories. The key point, for Marx, was the denial of a Creator God and the assumption that 'morality' is a creation of whomever happens to be in power.