Marine Biology 10th Edition by Peter Castro,Michael Huber

Exercise 2

Cephalopods, the squids, octopuses, and allies, show a much higher degree of structural and behavioral complexity than the other groups of molluscs. What factors triggered the evolution of these changes? A rich fossil record among cephalopods shows that once they were very common and even dominant in some marine environments. Now there are only about 650 living species of cephalopods, far fewer than gastropods. In the end, were cephalopods successful? What do you think happened along the way?