Better cultures benefit their host more than older ones on the long run. I will first talk about biological evolution, then, not because it is the only or best way to see this process, but because it's the one we are the most familiar with, and the one that has the most precise concepts and terms. As a form of adaptation, the object of biological evolution is lifeforms. Its most important mechanisms are natural selection and mutations. We must also take into account the phenomenon of environmental change, since organisms adapt to their environment as well as to other organisms.
Natural selection is the simplest concept of the three.
Only the most adapted survive, or in terms of genes, only the most adapted genes survive and have the possibility of being propagated. Most are neutral, from the point of view of the fitness of the mutated organism, most of the remaining are harmful, and of course the rest are beneficial. Mutations are the main way in which genetic variety increases, and therefore represent the random-like natural way of adding stock to the process. Environmental changes are not part of evolution, but of its context. For example, when, we suppose, a meteor crashed on this planet at the age of the dinosaurs, it gave rise to a whole new ecosystem, which in turn evolved in such a manner that finally gave rise to homo sapiens .