Question 1A. Mussels, like the Mytilus californianus, are commonly found in the mid to high zone of the intertidal. As dominant competitors in their ecosystem, they are able to take over space claimed by other sessile organisms like barnacles or even macroalgae. Why are they generally not found higher with the barnacles? Why do they not venture into the low zone? Give at least one reason for each question.
Question 1B. Much of intertidal photosynthesizers face special challenges compared to their animal neighbors in regards to the tides: too much time above water, and they risk desiccation; yet too little time above water, and they may not get the sunlight they need to photosynthesize. Give examples of two potential adaptations for algae to live in high intertidal zones, as well as two potential adaptations for living in the lower zones.