Chapter 33 Questions Flashcards
The phylum Cycliophora was discovered in 1995. They are tiny organisms that live in large numbers on the outsides of the mouthparts and appendages of lobsters. The feeding stage permanently attaches to the lobster via an adhesive disk and collects scraps of food from its host’s feeding by capturing the scraps in a current created by a ring of cilia. The body is saclike and has a U-shaped intestine that brings the anus close to the mouth. Cycliophorans are coelomates, do not molt (though their host does), and their embryos undergo spiral cleavage.
Which of these, if discovered among cycliophorans, would cause the most confusion concerning our current understanding of cycliophoran taxonomy?
a. if embryos are diploblastic
b. if the organisms show little apparent cephalization
c. if the ciliated feeding ring is a lophophore
d. if the body cavity is actually a pseudocoelom
a. if embryos are diploblastic
Which of the following is most likely to be aquatic?
a. mass feeder
b. fluid feeder
c. deposit feeder
d. filter feeder
d. filter feeder
Healthy corals are brightly colored because they ___.
a. secrete colorful pigments to protect themselves from ultraviolent light
b. host symbionts with colorful photosynthetic pigments
c. build their skeletons from colorful minerals
d. secrete colorful pigments to attract mates
b. host symbionts with colorful photosynthetic pigments
An elementary school science teacher decided to liven up the classroom with a saltwater aquarium. Knowing that saltwater aquaria can be quite a hassle, the teacher proceeded stepwise. First, the teacher conditioned the water. Next, the teacher decided to stock the tank with various marine invertebrates, including a polychaete, a siliceous sponge, several bivalves, a shrimp, several sea anemones of different types, a colonial hydra, a few coral species, an ectoproct, a sea star, and several herbivorous gastropod varieties. Lastly, she added some vertebrates - a parrot fish and a clown fish. She arranged for daily feedings of copepods and feeder fish.
One day, Tommy, a student in an undersupervised class of 40 fifth graders, got the urge to pet Nemo (the clown fish), who was swimming among the waving petals of a pretty underwater “flower” that had a big hole in the midst of the petals. Tommy giggled upon finding that these petals felt sticky. A few hours later, Tommy was in the nurse’s office with nausea and cramps. Microscopic examination of his fingers would probably have revealed the presence of ___.
a. nematocysts
b. spicules
c. spines
d. teeth marks
a. nematocysts
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 that it is to a roundworm?
a. It has no coelom.
b. It is shaped like a worm.
c. It has a mouth and an anus.
d. It is a suspension feeder.
a. It has no coelom.
Against which hard structure do the circular and longitudinal muscles of annelids work?
a. hydrostatic skeleton
b. endoskeleton
c. cuticle
d. shell
a. hydrostatic skeleton
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.
The nematocysts of sea slugs should be most effective at protecting individual sea slugs from predation if the predators ___.
a. consume entire sea slugs in one gulp and have no long-term memory
b. consume entire sea slugs in one gulp and have long-term memory
c. remove small bites of flesh from sea slugs and have long-term memory
d. remove small bites of flesh from sea slugs and have no long-term memory
c. remove small bites of flesh from sea slugs and have long-term memory
The sea slug Elysia chorotica has no nematocysts or dinoflagellates but, rather, has “naked” chloroplasts in its skin. The chloroplasts are all that remain of the seaweed (Vaucheria sp.) that Elysia feeds upon. The chloroplasts are transferred to the skin; consequently, this slug is green. It spends most of its time basking in shallow water on the surface of seaweeds. How should we expect its chloroplasts to benefit the Elysia sea slug?
a. provide Elysia with a bright color that warns away potential predators
b. provide Elysia with fixed oxygen
c. provide Elysia with fixed carbon dioxide
d. provide Elysia with fixed nitrogen
c. provide Elysia with fixed carbon dioxide
Parasitism is one of the most widespread lifestyles ever to evolve. Which of the following is consistent with this finding?
a. Parasites almost always predigest their hosts’ tissues and, therefore, spend less energy and require fewer structural adaptations.
b. Parasites, unlike predators, feed on almost all the tissues of their host.
c. Parasites generally kill their host and can feed for a very long time because they are much smaller than their host.
d. Parasites do not generally kill their hosts; thus they can feed on the same host throughout the host’s normal life span and do not have competition from decomposers.
d. Parasites do not generally kill their hosts; thus they can feed on the same host throughout the host’s normal life span and do not have competition from decomposers.
Molecular studies have changed many of the phylogenetic relationships previously identified by morphological studies. These changes indicate that ___.
a. molecular studies add additional information to morphological studies and improve our understanding of evolutionary history
b. molecular and morphological studies rarely agree
c. molecular studies are less reliable than morphological studies
d. molecular studies are extremely time consuming and expensive and really don’t add additional information to our understanding of evolutionary history
a. molecular studies add additional information to morphological studies and improve our understanding of evolutionary history
Toilets are a modern convenience that people often take for granted. In fact, they are helpful in preventing spread of disease because ___.
a. many parasites release fertilized eggs in the feces of humans and other animals
b. disease-causing insects die quickly in fecal-contaminated water
c. many diseases are transmitted by flying insects
d. toilets disinfect human feces
a. many parasites release fertilized eggs in the feces of humans and other animals
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?
a. sea wasps
b. mussels
c. lobsters
d. trematodes
b. mussels
Whiteflies are common pest insects found on cottom, tomato, poinsettia, and many other plants. Nymphs are translucent and mostly sessile, feeding on their host plant’s phloem (sap) from the undersides of leaves. They undergo incomplete metamorphosis into winged adults. Because whitefly nymphs cannot escape predation by moving, you hypothesize that their translucent bodies make them hard to spot by predators. How could you directly test this hypothesis?
a. Compare rates of predation on whitefly nymphs versus whitefly adults.
b. Compare rates of predation on whitefly nymphs coated with a nontoxic dye versus undyed whitefly nymphs.
c. Compare rates of predation on whitefly nymphs on plant leaves of different colors (for example, red versus green poinsettia leaves).
d. Compare rates of predation on whitefly nymphs by predators that are translucent versus predators that are not translucent.
b. Compare rates of predation on whitefly nymphs coated with a nontoxic dye versus undyed whitefly nymphs.
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?
a. a body cavity
b. a mantle
c. a heart
d. a filter-feeding apparatus
b. a mantle
A farm pond, usually dry during winter, has plenty of water and aquatic pond life during the summer. One summer, Sarah returns to the family farm from college. Observing the pond, she is fascinated by some six-legged organisms that can crawl about on submerged surfaces or, when disturbed, seemingly “jet” through the water. Watching further, she is able to conclude that the “mystery organisms” are ambush predators, and their prey includes everything from insects to small fish and tadpoles.
If the pond organisms are larvae, rather than adults, Sarah should expect them to have all of the following structures, except ___.
a. an open circulatory system
b. sex organs
c. antennae
d. an exoskeleton of chitin
b. sex organs
