The Asian shore crab invaded parts of the aastarn coast of the United States about 15 years ago. The Asian shore crab preys on blue mussets. in the time since the Asian shore crab arrived, the avorage shell thiekness has increased in the blue mussel population. Which of the following ts the most likely reason that this increase in shell thickness has occurred? a) Blue mussels with thick shells attract more crabs than mussels without thick shells. b) Blue mussels with thick shells grow in larger colonies than mussels without thick shells. c) Blue mussels with thick shells catch more food per day than mussels without thick shells. d) Blue mussels with thick shells survive and reproduce more successfully than mussels without thick shells.

The increase in average shell thickness among blue mussels is likely due to the pressure exerted by the Asian shore crab predation. Over time, mussels with thicker shells have a better chance of surviving attacks from crabs. As a result, these mussels become more prevalent in the population, allowing them to pass on their thicker shell trait to future generations. This illustrates natural selection in action! In terms of real-world observation, we can see similar dynamics across other ecosystems. When invasive species like the Asian shore crab introduce new predation pressures, native species can adapt morphologically, such as growing thicker shells or evolving different strategies for survival. This showcases the balance and interconnectedness of ecosystems, where every species plays a role in shaping the traits of others!