Question 1

In a tide pool, a student encounters an organism with a hard outer covering that contains a large amount 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 definitive identification of the organism?

Accepted Answer

A mantle is a characteristic feature of bivalves, which distinguishes them from crabs, shrimp, and barnacles.

Question 2

The heartworms that can accumulate within the hearts of dogs and other mammals have a hemocoel, an alimentary canal, and an outer covering that is occasionally shed. To which phylum does the heartworm belong?

Accepted Answer

Heartworms belong to the phylum Nematoda, characterized by their elongated, cylindrical bodies that are often referred to as roundworms. The presence of an alimentary canal and an outer covering that is occasionally shed are features consistent with nematodes, distinguishing them from the other options listed.

Question 3

Which of the following senses would be most directly affected by removing or damaging an insect's antennae?

Accepted Answer

Insects primarily use their antennae for detecting chemical signals in the environment, which is related to the sense of smell.

Question 4

Which of the following characteristics do all insects exhibit?

Accepted Answer

Insects, like all arthropods, have an exoskeleton or cuticle that provides structural support and protection. Choices A, B, and D include characteristics that are not universal to all insects or are incorrect (e.g., radula is a feature of mollusks, not insects; spicules are associated with sponges; not all insects undergo complete metamorphosis).

Question 5

Sexual reproduction leads to increased genetic variation, but male bdelloid rotifers have never been observed. Which of the following are correct statements with regard to evolution in bdelloid rotifers?

Accepted Answer

Bdelloid rotifers are known to gain genetic variation by absorbing DNA from their environment, a process known as horizontal gene transfer, which compensates for the lack of sexual reproduction.

Question 6

Which of the following characteristics of parasites explains how parasitism has become so widespread among living organisms?

Accepted Answer

Parasites typically do not kill their hosts immediately, allowing them to exploit the host for an extended period. This strategy enhances their survival and spread, making parasitism a widespread interaction among organisms.

Question 7

Which of the following statements applies to both nematodes and arthropods?

Accepted Answer

Both nematodes and arthropods undergo ecdysis, which is the process of molting or shedding their exoskeleton to allow for growth.

Question 8

Which of the following characteristics is shared by both cnidarians and flatworms?

Accepted Answer

Both cnidarians and flatworms have a digestive system with a single opening that serves as both mouth and anus.

Question 9

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

Accepted Answer

The answer of Which of the following statements about bryozoans...

Question 10

Why do large animals need specialized organs for gas exchange?

Accepted Answer

C) As an animal's size increases, its volume grows more rapidly than its surface area. This means that the surface area available for gas exchange (like oxygen and carbon dioxide) does not increase as quickly as the volume of tissues that require oxygen. Therefore, larger animals need specialized organs (like lungs or gills) to efficiently manage gas exchange to meet the needs of their larger volume of tissues.

Question 11

Which of the following characteristics of their exoskeletons is exhibited by both arthropods and molluscs?

Accepted Answer

Both arthropods and molluscs benefit from their exoskeletons in terrestrial habitats, as these structures help in retaining moisture, which is crucial for their survival outside aquatic environments.

Question 12

Which of the following statements best explains how planarians can survive and thrive without respiratory or circulatory systems?

Accepted Answer

Planarians can survive without specialized respiratory or circulatory systems because their flat bodies allow all cells to be in close proximity to the external environment or the gastrovascular cavity, facilitating direct diffusion of gases and nutrients.

Question 13

Our understanding of many of the evolutionary relationships among animals changed after those phylogenies were based on morphological and molecular data (as opposed to only using morphological data).What do these changes indicate?

Accepted Answer

Molecular studies, which include DNA and genetic analysis, have provided new insights that complement and sometimes correct interpretations based on morphology (physical structures). This has led to a more accurate understanding of evolutionary relationships by revealing connections not apparent through morphology alone.

Question 14

Our understanding of many of the evolutionary relationships among animals changed after those phylogenies were based on morphological and molecular data (as opposed to only using morphological data). Which of the following groups represents an example of this change?

Accepted Answer

The group "Lophotrochozoa" (correct spelling) was identified as a major clade of protostome animals based on molecular data, which was not evident from morphological data alone.

Question 15

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

Accepted Answer

Mussels secrete a type of adhesive to attach themselves to surfaces underwater, making them an excellent model for developing underwater adhesives.

Question 16

You find a multi-legged animal in your garden and want to determine if it is a centipede or a millipede. Which of the following characteristics would allow you to make this distinction?

Accepted Answer

Centipedes have a pair of venomous claws (forcipules) behind their head, which they use to paralyze their prey, a feature that millipedes lack. Millipedes, in contrast, are generally detritivores and do not possess venomous claws.

Question 17

Whiteflies are common pest insects found on cotton, tomato, poinsettia, and many other plants. Whitefly 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. Which experimental approach is best for testing your hypothesis?

Accepted Answer

B) This approach directly tests the hypothesis by altering the visibility of the nymphs and observing the effect on predation rates, allowing for a clear assessment of whether their translucency provides a protective advantage.

Question 18

Which one of these mollusc groups is classified as suspension feeders?

Accepted Answer

Bivalves are known as suspension feeders because they feed by filtering small particles from water. This group includes clams, oysters, and mussels, which use their gills to capture food particles suspended in the water.

Question 19

Which of the following statements correctly describes one difference between nematodes and arthropods?

Accepted Answer

Arthropods have an open circulatory system, where blood is not always enclosed within blood vessels, but nematodes do not have a circulatory system at all, relying instead on diffusion to transport nutrients and waste.

Question 20

A terrestrial animal species is discovered with the following larval characteristics: exoskeleton, system of tubes for gas exchange, and modified segmentation. What other characteristic is most likely present in this organism?

Accepted Answer

The characteristics described (exoskeleton, system of tubes for gas exchange, and modified segmentation) are typical of arthropods. Among arthropods, an open circulatory system is a common feature, where blood is not entirely contained within blood vessels but flows freely through cavities in the body, facilitating nutrient and gas exchange.

Quiz 33: Invertebrates