U7 Practice FRQ 3/20

Read the excerpt and answer the questions below using your understanding of unit 7. Be sure to pay attention to what the task verb is asking of you.

One summer you begin noticing ants in your kitchen. It starts off as just a few here and there, but pretty soon you begin noticing more and more appearing each day. Before long, it is apparent you have an ant infestation. While you wait for an exterminator to come to your house, you observe their behaviours. You notice that some ants seem to be congregating near crumbs, while other ants seem to avoid the crumbs and, instead, are eating the plant you have in the kitchen. You try to clear the ants away from the food, and when you do, you notice a strong, unpleasant scent. You then try to clear the ants away from the plants, and when you do, you observe no unpleasant odors. When the exterminator arrives, you ask him about these strange observances. Upon closer look at the ants, the exterminator concludes that you have an infestation of two different species, Crematogaster ashmeadi (acrobat ants) and Linepithema humile (Argentine ants).

Propose the most probable type of speciation that occurred between C. ashmeadi and L. humile. and Justify your response.

Identify one potential postzygotic isolating mechanism that reduces the fitness of the fitness of hybrid individuals and explain how that mechanism works.