Question 1

What do all sponges have in common?

Accepted Answer

All sponges are aquatic animals and live on the bottom of a body of water, whether it be in fresh or salt water.

Question 2

Due to its unusual habitat (inside the digestive tracts of other animals),the tapeworm lacks _____.

Accepted Answer

Tapeworms lack both a mouth and a digestive tract because they absorb nutrients directly through their skin from the host's partially digested food.

Question 3

What would you expect to happen if,in the experiment outlined in Figure 32.19,researchers supplied an enzyme that blocked the expression of the Dll gene?

Accepted Answer

The Dll gene is responsible for the formation of appendages in developing embryos. If an enzyme is supplied that blocks the expression of the Dll gene, this would result in the developing embryo having no appendages. Therefore, option C is the best choice.

Question 4

Comb jellies may not be the most familiar animal to you,but they are critical in the food chain because they make up a significant portion of the planktonic biomass.Their feeding strategy is predatory and involves adhesives or mucus on their tentacles or other body parts.What feeding tactic do these animals use?

Accepted Answer

Comb jellies use their tentacles as a sieve to capture small organisms from the water column, which is characteristic of a suspension feeding strategy.

Question 5

All of the following are true about choanoflagellates except _____.

Accepted Answer

Choanoflagellates are not animals; they are considered the closest living relatives of animals.

Question 6

Most cnidarians are known to produce toxins.In fact,it has been claimed that one particular species produces the most deadly of all toxins on the planet.What feature of this group most likely evolved simultaneously with the development of these toxins?

Accepted Answer

Cnidarians are either sessile or slow-moving in their adult form, and their toxins are used for defense and prey capture. The development of toxins was likely an evolutionary response to their sedentary lifestyle and a way to protect themselves from predators.

Question 7

Why are healthy corals brightly colored?

Accepted Answer

Healthy corals are brightly colored because they host symbiotic algae called zooxanthellae within their tissues. These photosynthetic pigments give corals their bright colors, and this symbiotic relationship is crucial for the coral's survival by producing the majority of their food.

Question 8

Which of the following would most strongly support your hypothesis that an animal you are observing is an ectoparasite?

Accepted Answer

The answer of Which of the following would most strongly...

Question 9

To reproduce,many plants produce seeds-structures containing embryonic offspring along with nutrients inside a tough case.These offspring develop after being released by the parent plant.To which animal reproductive strategy is seed production most comparable?

Accepted Answer

Seed production is most comparable to oviparous reproduction, where the offspring develops outside the parent's body, like birds laying eggs. The seed is similar to an egg, as it contains an embryonic offspring along with nutrients inside a tough case, and develops after being released from the parent plant.

Question 10

Which of the following feeding tactics is consistent with this list of features:
Two-part stomach capable of breaking down tough food particles;simple mouthparts;the ability to burrow through,and consume,indigestible fecal material to get to hidden food?

Accepted Answer

The two-part stomach capable of breaking down tough food particles is indicative of deposit feeders, which consume organic matter found in mud, sand or detritus. The ability to burrow through and consume indigestible fecal material further supports the deposit feeding strategy. The simple mouthparts also suggest a deposit-feeding strategy, as filter and fluid feeders tend to have more complex mouthparts for capturing small prey, while food-mass feeders have specialized teeth or jaw structures to manipulate and consume large food items.

Question 11

Most fish deposit fertilized eggs,but some sharks keep the fertilized egg inside the female until she gives birth to a relatively well-developed pup.These sharks would thus be characterized as _____.

Accepted Answer

Sharks that keep the fertilized egg inside the female until she gives birth to a relatively well-developed pup are called ovoviviparous. This term refers to animals that produce eggs that develop and hatch inside the female's body, but are not fed by the mother's body like in viviparity. Instead, the young are sustained by the yolk sac inside the egg.

Question 12

If humans were characterized as undergoing metamorphosis,human development from infant to adult would be better described as _____,and human infants would be described as _____.

Accepted Answer

Humans undergo gradual development without a pupal stage, similar to hemimetabolous metamorphosis, where nymphs resemble smaller versions of the adult form.

Question 13

Which of the following groups of terms best describes the acoelomorpha?

Accepted Answer

Acoelomorpha are triploblastic, bilaterally symmetric, have simple digestive tracts, and are mobile. Therefore, option C best describes them. Option A is incorrect because acoelomorphs have simple digestive tracts, not complex ones. Option B is incorrect because acoelomorphs are bilaterally, not radially, symmetric. Option D is incorrect because acoelomorphs are mobile, not immobile.

Question 14

A radula is a specialized feeding organ,used to scrape material off of food for ingestion,much like a cheese grater scrapes shreds off of a block of cheese.Snails,which have this structure,are thus which kind of feeder?

Accepted Answer

Snails use their radula to scrape material off their food, which qualifies them as mass feeders, meaning they ingest chunks of food rather than small particles or fluids.

Question 15

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

Accepted Answer

The statement that parasites do not generally kill their hosts is consistent with the idea that parasites can feed on the same host throughout its normal lifespan, avoiding competition from decomposers. This also allows parasites to expend less energy and require fewer structural adaptations as they do not need to locate new hosts. Option A is incorrect because parasites do not always predigest their hosts' tissues, and may instead obtain nutrients and energy from various tissues in the host's body. Option B is incorrect because parasites can feed on specific tissues, organs, or fluids within a host's body, rather than all tissues. Option D is incorrect, as parasites that kill their hosts would not be able to feed on them for a prolonged period.

Question 16

Suppose you came across a novel organism you suspected belonged to one of the following animal phyla:
Porifera,Cnidaria,Ctenophora,or Acoelomorpha.Which of the following characteristics would not be helpful in placing the organism into the correct phylum?

Accepted Answer

The presence or absence of a coelom is a key characteristic that distinguishes the phyla Porifera, Cnidaria, Ctenophora, and Acoelomorpha. Therefore, whether the organism has a coelom would be helpful in placing it in the correct phylum. However, the feeding strategy, habitat, presence of a gut, and whether the adults are sessile or motile are all characteristics that can provide additional clues to help identify the organism's phylum.

Question 17

Following the fusion of gametes in Obelia,the resulting cell divides via mitosis to become a _____.

Accepted Answer

Following the fusion of gametes in Obelia, the resulting cell divides via mitosis to become a larva. This is part of the life cycle of Obelia, which includes both asexual and sexual phases. The larval stage is crucial for dispersal and settlement before developing into a polyp.

Question 18

Figure 32.4
 
-Dll is a gene known to direct limb development in the fruit fly.Researchers studying this gene have found that it is also expressed in developing appendages in animals from many other phyla as well,supporting the hypothesis that all animal appendages may be homologous.However,suppose researchers looking at Dll activity had instead found the results shown in Figure 32.4.What would these results suggest?

Accepted Answer

The figure shows that Dll is expressed in the developing appendages of a sea urchin, which is a deuterostome. This suggests that the role of Dll in limb development may have evolved separately in protostomes and deuterostomes, rather than being a shared ancestral trait.

Quiz 32: An Introduction to Animals