I have been spending quite a bit of time in my senior Biology class allowing students to explore these two games. They are now all addicted to Pocket Frogs, and we had a really good discussion about inheritance, heritable characteristics and the 'flaws' in the Pocket Frogs model when compared to some of the human inheritance we know of.
Selective breeding was also a small part of it as students tried to breed particular coloured frogs to meet requests, or just meet their own goals of getting a certain colour combination.
Now the students are exploring Plague Inc, next week we will have the discussion about selective pressures and evolutionary theory. I still think that Plague Inc is a great way to introduce the topic and get students thinking about it. Within a couple of hours of game play (2 lessons or so of my class time) students have a pretty good base to make some inferences about evolution, its effects and what some of the key terms may mean.
Now if I can manage to tie these 2 games together when we talk about selective breeding and its impact on evolution I will be very happy.
The great thing about using these games as a learning tool/introduction is that students will play at home, not only in my class. Then when we get together in class we can discuss their findings as a group and they can share their ideas with others, which of course will impact on the way they play afterwards.