Pop Culture and Special Topics in Evolution
Many sci-fi films talk about the "next stage of human evolution." This is used to segue into explanations of mutant or alien creatures that are trying to wipe out humanity, or are trying to live peacefully with humanity while we try to wipe them out.
These common tropes in movies depict evolutionary theory in a nutshell. If you imagine that humans evolved some extra feature, these neo-humans will either be better suited for survival and will lead to reduction of humans in the population, or they will be weaker and we will try to wipe them out (either actively or passively). Mutant humans will struggle for survival against regular humans, and those best suited to their environment will survive.
This has already happened in human evolution, where Homo sapiens wiped out (or outbred) Neanderthal man (Homo neanderthalensis). We could expect that if there is ever evolution that leads to X-men, it would be at the expense of humans. The specific acquisition of teleportation, adamantium claws, or shooting lasers out of one's eyes doesn't appear to have a place in the gradualism of Darwinian evolution, but it sure is cool to watch.
Other movies such as Species and Planet of the Apes talks about how evolution of life that is superior to humanity will eventually lead to the subjugation of humans. While this is a frightening idea, this would only happen if we continue to hog all of the resources. As humans, we happily destroy natural habitats to build high-rise condos or private resorts. If there were super apes or some other species that was smarter than us, we can expect that they would demand the same resources that we currently use. Since we'd be fighting over the same environment and resources, we'd lose to the super apes.
Finally, if you think you'd like to try out natural selection for yourself, there are several games where you can wipe out some species. The most popular of which is the 2008 game Spore. In this game, you get to start from microbial life and evolve into beings capable of interplanetary life. Good thing this chapter's over. Go play.