My advice, start off with a simple definition of evolution: the change in allele frequency in a population over time. That means certain genetic traits become more or less popular in the population. Nobody will have trouble accepting that.
Then you could give a brief mention of natural selection, the main driver of evolutionary change over time. Don't use "survival of the fittest," because that's bullshit. Emphasize that it's "survival of the FIT." Good enough is good enough for evolution, and even if the solution to the problem is sloppy, a sloppy solution is better than no solution at all. Organisms that develop some trait for surviving better tend to have more of their offspring survive into the next generation, lather rinse repeat.
You could then mention that scientific theories have to tell us what we should expect to find, and whether or not we find them determines how good the theory is. For evolution, we expect to find many different things depending on where we look:
-Based on anatomy, if evolution is true we'd expect organisms that are closely related to be more similar than organisms that are not closely related. Then point out that this is exactly what we DO find, and that we have been classifying plants and animals this way long before we knew that things evolved.
-Based on genetics, evolution tells us that organisms sharing a recent common ancestor should have more genes in common than organisms with a common ancestor from long ago in the past. It turns out that this is exactly what happens, and we can check the results of genetic studies against the results of taxonomy (the first point about anatomical similarity). To a large extent they match up almost exactly as we predicted they would. Contrary to what some people may say, we are NOT more closely related to bananas than chimps. That's an urban legend.
-Based on fossils, we should expect to see gradual transitions from sea life to land animals, and from early types of land animals into more and more different types. We should NOT find human bones and dinosaur bones together. It turns out that we can use this theory to predict when and where to look for fossils of certain animals, like the first fishes to grow legs and move onto the land. We also have such "transitional forms" for amphibians->reptiles, reptiles->mammals, and dinosaurs->birds. We also expect humans and modern apes to share a recent common ancestor, and over the last hundred years we have found more and more transitional forms between ancient apes and modern humans.
I think if you can pare those down a bit to fit in one point per sentence or so, you should be able to squeeze that much into a 2 minute presentation.