Rarely have I ever encountered someone in real life who genuinely has an issue supporting evolution as an explanation for how and all other life on our planet arrived in the present day. As the Internet has reminded me, there are people who cannot properly understand and appretiate evolution.
To give credit to my high school's science department, or at least my biology teacher, they have done an excellent job of teaching evolution to the students. For the most part, I have not come across anyone in my classes that displayed a blatant ignorance or stubborn misunderstanding of evolution during my high school years.
Of course, my perspective does not include everyone who might not have done really well academically, and it's not as though I regularly discussed evolution with my more religious classmates.
On the national landscape, it seems that the theory of evolution has trouble penetrating the minds of particular individuals and demographics, especially the majority of the presidential candidates vying for the Republican nomination. One major stumbling block may be a failure to properly understand "theory" in the scientific context. As important side note if you every come across someone who decries evolution because it's "only a theory," remind them that a scientific theory is an explanation of a phenomena that has been verified experimentally — otherwise it is little more than a hypothesis.
More importantly, you should be properly armed with useful knowledge and tidbits when encountering those who cannot grasp evolution, whether it is grounded in religion or a general misunderstanding of evolution. I recently came across a little feature dubbed "15 Evolutionary Gems" in the journal Nature put together by Henry Gee, Rory Howlett and Philip Campbell. Their goal back in 2009 was to highlight some key examples of research supporting evolution that had been published in Nature over the prior decade, intending for this particular noodle of knowledge to be rapidly disseminated.
I will leave it to you to find this particular article on your own, especially since you don't need to access it through campus internet (unlike most articles on Nature). However, I do want to highlight a very visual example they mention: the land-based origins of whales.
Basically, whales have many similarities to land mammals in that they also breathe air and suckle their young with maternal milk. If you ever saw a whale swim, you would recognize how they flap their tail fins in a vertical motion rather than horizontally as fish do. That up and down motion parallels the way four-legged animals, such as dogs and tigers, run on land. Keep in mind that the proper way to explain this is that whales did not come from other land animals like dogs or tigers, rather they descended from a common ancestor of whales and land animals.
That common ancestry may be the raoellids, a now-extinct group identified in a 2007 Nature study. Raoellids do not have the extensive whale features found in other parts of the whale fossil record that span millions of years, including whale/land-mammals hybrids, but they do fill a critical gap between land mammals and whale precursors.
Whales aside, there are plenty of examples you can rely on to convince the skeptics. If you want something explained by a professional, try searching "flightless cormorant" and "Richard Dawkins."
