4. Like Bear Paw Lake, nearby Kalmbach Lake is an Alaskan la…

4. Like Bear Paw Lake, nearby Kalmbach Lake is an Alaskan lake that historically had no native predatory fish. The Alaska Department of Fish and Game started introducing rainbow trout into Kalmbach Lake in 1982. Prior to these introductions, the pelvic reduction was common in this stickleback population. The rainbow trout are known to prey on stickleback. What would you hypothesize has happened to the stickleback population in the more than 30 generations that have elapsed since the trout was introduced?  

3. One of the functions of pelvic spines in the ocean is to…

3. One of the functions of pelvic spines in the ocean is to protect stickleback from larger fish predators. Based on this knowledge, which statement might be a possible explanation for the differences in pelvic spines between Bear Paw Lake and Frog Lake sticklebacks?