That's a really interesting article, and shows that nature can indeed adapt very quickly to new conditions. Gives me better hope for the human race to survive once we destroy our planet.Yes, two thousand years doesn't seem like much time in evolutionary terms, but when we're dealing with populations living in different environmental conditions, the process of adaptation can happen rather quickly. For instance, Tibetans diverged from Han Chinese only about 3000 years ago but have already experienced massive divergence in a number of genes that improve their ability to survive in oxygen-poor conditions.
On topic, it seems plausible that there were no ground-based battles during the Earth-Romulan War since it was an ideological war. The Romulans would just destroy everything from orbit as stated above. The Romulans were probably using the Remans as shock troops in their own empire, putting down rebellions or subjugating other races.