Exam 31: Protostome Animals

Use the following information when answering the corresponding questions). Many terrestrial arthropods exchange gases with their environments by using tracheae, tubes that lead from openings called spiracles) in the animal's exoskeleton or cuticle directly to the animal's tissues. Some arthropods can control whether their spir opened or closed; opening the spiracles allows the carbon dioxide produced in the tissues to travel down the tracheae and be released outside the animal. Klok et al. measured the carbon dioxide emitted over time represented by VCO₂) by several species of centipedes. Figure 31.2 presents graphs of their results for two species, Cormocephalus morsitans and Scutigerina weberi. C. J. Klok, R. D. Mercer, and S. L. Chown. 2002. Discontinuous gas- exchange in centipedes and its convergent evolution in tracheated arthropods. Figure 31.2 -Look at the graph for Cormocephalus morsitans. What is the best interpretation of these results?

In arthropods, the hemocoel performs which of the following functions?

The presence of a lophophore in a newly discovered species would suggest which of the following?

What is the only group of Mollusca that does not have a radula?

If you wanted to identify an unfamiliar protostome with a limbless, wormlike body, which characteristic would not be helpful in differentiating one species from another?

Which one of these groups does not molt?

The protostome developmental sequence arose just once in evolutionary history, resulting in two main subgroups-Lophotrochozoa and Ecdysozoa. What does this finding suggest?

How could you tell a millipede apart from a centipede?

The common ancestor of the protostomes had a coelom. What does this suggest?

What is not true of all arthropods?

Which mollusc group can be described as having several calcium carbonate plates along their dorsal side?

The body cavity type for arthropods and molluscs can best be described as

Which adaptation is unique to insects among all protostomes?

Use the following information when answering the corresponding questions). Many terrestrial arthropods exchange gases with their environments by using tracheae, tubes that lead from openings called spiracles) in the animal's exoskeleton or cuticle directly to the animal's tissues. Some arthropods can control whether their spir opened or closed; opening the spiracles allows the carbon dioxide produced in the tissues to travel down the tracheae and be released outside the animal. Klok et al. measured the carbon dioxide emitted over time represented by VCO₂) by several species of centipedes. Figure 31.2 presents graphs of their results for two species, Cormocephalus morsitans and Scutigerina weberi. C. J. Klok, R. D. Mercer, and S. L. Chown. 2002. Discontinuous gas- exchange in centipedes and its convergent evolution in tracheated arthropods. Figure 31.2 -Compare the graphs in Figure 31.2 of CO₂ emission for Cormocephalus morsitans and Scutigerina weberi. What hypothesis can you make about each centipede's habitat?

On which body segment are arthropod wings attached?

As stated in the text, "DNA sequence data indicated that two major subgroups existed within the protostomes." This finding contradicts the long- held hypothesis that the protostomes are a monophyletic group.

A cephalopod's tentacles are modified from its

You find what you believe is a new species of animal. Which of the following characteristics would enable you to argue that it is more closely related to a flatworm than it is to a roundworm?