Sounds like our sources on communist theory disagree. Let me guess, yours is from a pro-Darwin source, attempting to separate Darwinism from Marxism.
My source is actual History, you might want to learn some sometime.
“Lysenko and the tragedy of Soviet Science”, a book by a former Molecular Genetics teacher of mine from the Soviet Union - a man who thanked Ronald Reagan in his prayers every day for getting him the hell out of the Soviet Union.
Lysenko and Stalin separated Darwin’s theory from Marxism - they threw anyone who espoused Darwin’s theory (or modern Genetics) out of their job, to Siberia, and even execution.
Hard to find a more draconian separation than that.
His source is from history itself: The soviets rejected Darwin’s theory and implemented Lamarckianism instead, with Lysenko at the helm. The results were unbelievably disastrous.