I have heard and read the word “evolution” used to describe what I believe is development in game design. Evolution, in biology, is descent with modification. A bird that evolved from another kind of bird looks like their ancestor but they are modified. You could say that about games that have multiple editions. The tendency is toward greater complexity in follow on editions. The most important difference between development and evolution is intent.
Evolution of species is a random event. Every generation of living beings has some slight mutation and that mutation is a random occurrence. If that particular mutation makes the offspring more successful in its environment, that trait may be inherited by the offspring of that animal and over succeeding generations that mutation gets spread around. This is all junior high biology class stuff. The most important bit here is that this process is random.
The process of development in game design is not random. It is intentional. There is an agent; the game designer, the publisher, the editor who has an intention to change the game for some purpose. It is not random. There is a reason why they chose to go from a single save to multiple saves and then to saves based on a category of ability rather than the category of threat. No one picked up a twenty sider and consulted a chart to see what change they would try this time.
When I heard people talk about the “evolution” of a particular game or RPG’s in general, it is often assumed this is progress toward something better. This assumption is wrong. One need only look at the history of TSR in the 90’s to see that the intent, at least on the part of management was, “more money.” Lorraine Williams didn’t care at all if 2nd edition was “better” than 1E. We must, if we are to have a grown up conversation about game design, set aside this notion that game companies, which are for profit entities, always put out something that is “better” than what came before. What they are putting out is something that they feel will put food on the table. Sometimes, “better” and “profitable” are the same thing but not always. Intent of the designer and publisher matters. Evolution and development are two different things.