Hey there, before I start I just want to point out that I'm a statistician and doesn't know much about biology. I've worked with artificial neural networks, which required a minor understanding of some biological concepts, but apart from that, my level of knowledge in biology is very limited. I was thinking about the theory of evolution and landed on a confusing thought. I will write down a series of assumptions I made which lead to what seems to be a paradox, or just a counter-intuitive conclusion. Now I know it isn't totally true, therefore it implies that some of the assumptions I made are false, and I would just like to know which. Here are my assumptions : 1. Although diversity can arise through other mechanisms than mutation, mutation remains the most important one. 2. The more evolved (and therefore complex) a species is, the more mutations it requires to evolve again. 3. There are three important types of mutations: beneficial, neutral, or harmful. I have read that most mutations that occur are either neutral or harmful, making the probability of having a good mutation at most 1 in 10,000. 4. Since the large majority of mutations are harmful, evolution help species evolve mechanisms to protect themselves from them. A human cell is less likely to mutate than a less-evolved species' cell. Which leads to my conclusion : Evolution requires mutation, but evolution evolves mechanisms to help species protect themselves from mutations. Since the probability of having a benefical mutation is reasonably low, and that the more evolved the species are the more mutations they need to evolve, and that the more evolved they become the less likely their cells are to mutate, then is evolution slowing down? Thanks!