SA2a. (3 pts) Scenario 2: Carcinus maenas (The Green Crab)…

SA2a. (3 pts) Scenario 2: Carcinus maenas (The Green Crab) is native to Europe where it typically consumes European periwinkles snail species.  In recent decades the green crab has invaded the North American Pacific coast during the last few decades where it now successfully feeds on North American periwinkle snails that differ markedly from their European cousins in terms of size, shape, and shell strength. Name three things that you would need to show in order to demonstrate that natural selection is happening in periwinkle populations?

SA2b. (3 pts)  Scenario 2 continued: Imagine you have two cr…

SA2b. (3 pts)  Scenario 2 continued: Imagine you have two crabs. You feed one only thick-shelled snails and the other you feed only thin-shelled snails.  Over the course of its life, the crab fed only thick-shelled snails develops larger claws than the crab fed only on thin-shelled snails.  Is this evolution in action? Why or why not?