One of Marx's materialist discoveries is that the working class is the only revolutionary class under capitalism, being its gravedigger. This applies to humans and any other form of life on this planet that becomes sentient through evolution as well as sentient aliens around the universe. Marx's conception of dialectical materialism and historical materialism is scientifically based, the only reason it's not recognised as such is because we are ruled by the bourgeoisie ideologically and economically in the capitalist system, the ruling ideology is the ruling class ideology and it's not in the interest's of the bourgeoisie to label Marxism as science.