Bivalves are often used as indicators of environmental quality. Based on your knowledge of bivalve gills, describe why bivalves are useful environmental indicator organisms.

Given that the ligament holding valves together readily decays, how do you expect to find intact bivalves in the fossil record? What do you expect their valve orientation with the substrate to look like? How might this affect morphometric studies-- i.e. is it always possible to take measurements in three dimensions?

Clown fish are often found swimming within the tentacles of sea anemone whereas other fish avoid them at almost all cost. Which statement below is the best explanation for this observation? The spicules of the sea anemone cannot penetrate a slime layer surrounding a clown fish but other fish do that have that neutralizing slime layer. Clown fish are good at maneuvering between the spines of the sea anemone and use them for camouflage. Clown fish are attracted to the cnidocytes of the sea anemone as their source of food. Clown fish are immune to the sting of the nematocyst of the sea anemone but other fish are not.

Distinguish each of the following from each other: fringing reefs; barrier reefs; atolls; patch or bank reefs