Communism is an historicist (historically deterministic) theory, whereas evolution is a contingent (non-deterministic) process in the historical dimension.
Communism is a collectivist theory, where mass historical forces are the determinative factor. Darwinian evolution is an individualist theory, where the trial and error success or failure of individuals (to reproduce) is determinative.
Communism is a finalistic theory, where history is (allegedly) progressing to a definite and culminative goal. Evolution is just a process that occurs due to the nature of living things (variation, heretibility, reproduction, death) and will continue so long as there are living things.
Evolutionary theory was (predominately) initially formulated and developed by individuals who embraced Western liberalism, modernization, the growth of markets, industrialism and the prosperity it created, and who saw these forces as positive and good in themselves. Communism was formulated and advanced by individuals who rejected the liberal society, and saw the forces of modernization as creative only in so far as their "internal contradictions" would lead to strife, suffering, and self destruction (leading to the communist utopia).