Stickleback Fish Exhibit Variation in a Morphological Trait Known as Gill

Multiple Choice

Stickleback fish exhibit variation in a morphological trait known as gill rakers. Fish with long gill rakers are very good at eating plankton, and fish with short gill rakers are good at eating deep-water invertebrates. However, fish with intermediate-length gill rakers are poor at eating either type of food. Fish that are better at consuming food have higher survival and reproduction rates than poorer consumers. Based on this information, what type of selection is likely acting on stickleback gill raker length?

A) no natural selection
B) stabilizing selection
C) disruptive selection
D) directional selection