Aspects of evolutionism are perfectly consistent with Marxism. The explanation of the origins of humankind and of mind by purely natural forces was, and remains, as welcome to Marxists as to any other secularists. The sources of value and responsibility are not to be found in a separate mental realm or in an immortal soul, much less in the inspired words of the Bible. Marxism is a 'this worldly' rather than an 'other-worldly' philosophy. It is also a materialism with a definition of matter and its potential which is much richer than the impoverished idea of matter left over in the mind-body dualism which puts all meaning and purpose in the minds of God and people.
Labour is neither nature nor culture but their matrix.
So, while the naturalism, materialism and this-worldliness of Darwinian evolution are acceptable to Marxists, this does not mean that natural explanations take over from historical ones. Put another way, in Marxist approaches to humanity, genetics doesn't replace human labour. There has been a recent revival of advocacy of close attention to the biological limits of human nature among some Marxists. It has been pointed out that we need to root our conceptions of the human species in biological givens. This is a salutary warning against the romantic belief that we are free spirits and can decide our futures by free choice and by just trying harder.