Exam 33: An Introduction to Invertebrates

All insects ________.

Use the following information and figure to answer the question. Aphids are Hemiptera that suck phloem liquid from plants. Ants are often seen tapping the posterior end of the aphid and collecting the liquid that is released from the aphid's digestive system. In an effort to understand this interaction, several researchers measure the survival rates of aphid populations when ants were present and when they were excluded. Their results are shown. Imagine that you wished to discover if the ants protect the aphids from flying predators. You would exclude ants from the plants and count aphid population size under two conditions. Which of the following experiments would best help answer this question?

Healthy corals are brightly colored because they ________.

Use the information and figure to answer the following question. The sea slug Pteraeolidia ianthina can harbor living dinoflagellates (photosynthetic protists)in its skin. These endosymbiotic dinoflagellates reproduce quickly enough to maintain their populations. Low populations do not affect the sea slugs very much, but high populations (> 5 × 10⁵ cells/mg of sea slug protein)can promote sea slug survival. Percent of sea slug respiratory carbon demand provided by indwelling dinoflagellates. In the graph, the percent of the oxygen demand contributed by the dinoflagellates is greater than 100% during much of the year. What is the fate of this "excess" energy?

Use the information and figure to answer the following question. The sea slug Pteraeolidia ianthina can harbor living dinoflagellates (photosynthetic protists)in its skin. These endosymbiotic dinoflagellates reproduce quickly enough to maintain their populations. Low populations do not affect the sea slugs very much, but high populations (> 5 × 10⁵ cells/mg of sea slug protein)can promote sea slug survival. Percent of sea slug respiratory carbon demand provided by indwelling dinoflagellates. If the dinoflagellate-containing sea slug P. ianthina preys on coral animals, then it would be most surprising to find that ________.

Use the information to answer the following question. The nontaxonomic term sea slug encompasses a wide variety of marine gastropods. One feature they share as adults is the lack of a shell. One might think, therefore, that they represent defenseless morsels for predators. In fact, sea slugs have multiple defenses. Some sea slugs prey on sponges and concentrate sponge toxins in their tissues. Others feed on cnidarians, digesting everything except the nematocysts, which they then transfer to their own skins. Whereas the most brightly colored sea slugs are often highly toxic, others are nontoxic and mimic the coloration of the toxic species. Their colors are mostly derived from pigments in their prey. There are also sea slugs that use their coloration to blend into their environments. This nudibranch, a type of sea slug, has many reddish cerata on its dorsal surface, as well as two white-tipped rhinophores located on the head. Which structure do sea slugs use to feed on their prey?

What would be the most direct effect of removing or damaging an insect's antennae? The insect would have trouble ________.

Use the following information and figures to answer the question. 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 spiracles are 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. The figures present graphs of their results for two species, Cormocephalus morsitans and Scutigerina weberi. How would a terrestrial centipede most likely benefit from the ability to close its spiracles? Closing spiracles would ________.

In Figure 33.8, assume that the two medusae shown at step 4 were produced by one polyp colony. Review Concept 12.1 and Concept 13.3, and then use your understanding of mitosis and meiosis to evaluate whether the following sentence is true or false; if false, select the answer that provides the correct reason. Although the two medusae are genetically identical, a sperm produced by one will differ genetically from an egg produced by the other.

Which one of these mollusc groups can be classified as suspension feeders?

Compared to insects with incomplete metamorphosis, insects with complete metamorphosis ________.

Against which hard structure do the circular and longitudinal muscles of annelids work?

Soft-shell crab is a prized dish in many ocean-side resorts. Why are the crabs' shells soft?

The water vascular system of echinoderms ________.

In a tide pool, a student encounters an organism with a hard outer covering that contains much calcium carbonate, an open circulatory system, and gills. The organism could potentially be a crab, a shrimp, a barnacle, or a bivalve. The presence of which of the following structures would allow for the most certain identification of the organism?

Parasitism is one of the most widespread lifestyles ever to evolve. Which of the following is consistent with this finding?

Imagine that you are a research chemist who wishes to develop a chemical adhesive that will work under water. Which of the following organisms might give you a clue about where to start?

Which of the following can be found in the mesohyl of a sponge?

Planarians lack dedicated respiratory and circulatory systems. This deficiency does not cause a problem because ________.

Which of the following statements about bryozoans (ectoprocts)is correct?