Question 1

Bilateral symmetry is advantageous primarily because it allows for the development of
A) duplicate body parts in case of injury.
B) limbs for the infant to attach to a parent.
C) a specialized head and posterior.
D) a specialized body cavity.
E) a hydrostatic skeleton.

Accepted Answer

Bilateral symmetry is advantageous because it allows for the development of a specialized head (cephalization) and posterior, enabling more complex movement and sensory processing directed towards the environment ahead of the organism.

Question 2

Figure 30.2
-Which morphological trait evolved more than once in animals, according to the phylogeny based on DNA sequence data found in Figure 30.2 above?
A) bilateral symmetry
B) coelom
C) protostome development
D) segmentation
E) tissue

Accepted Answer

According to the phylogeny based on DNA sequence data found in Figure 30.2, segmentation evolved more than once in animals. Segmentation is found in both the arthropod and annelid lineages, which are two separate branches on the phylogenetic tree. Bilateral symmetry, coelom, protostome development, and tissue are all features that evolved only once in animal evolution.

Question 3

Lophotrochozoans differ from ecdysozoans in that
A) lophotrochozoans grow their skeletons continuously, while ecdysozoans shed their external skeletons to grow.
B) lophotrochozoans exhibit segmentation, while ecdysozoans do not.
C) lophotrochozoans have pseudocoeloms, while ecdysozoans have coeloms.
D) lophotrochozoans undergo protostome development, while ecdysozoans undergo deuterostome development.

Accepted Answer

Lophotrochozoans and ecdysozoans are both major clades of protostome animals, but they differ in their growth and development strategies. Lophotrochozoans typically grow their skeletons continuously throughout their lives, while ecdysozoans undergo molting or ecdysis to shed their external skeletons and grow. This difference is reflected in the different anatomical features of the two groups, such as the presence or absence of body segments and the type of body cavity they possess. Therefore, choice A is the best answer.

Question 4

Suppose a researcher for a pest- control company developed a chemical that inhibited the development of an embryonic mosquito's endodermal cells. Which of the following would be a likely mechanism by which this pesticide works?
A) The mosquito would have trouble with respiration and circulation, due to impaired muscle function.
B) The mosquito would develop a weakened exoskeleton that would make it vulnerable to trauma.
C) The mosquito wouldn't be affected at all.
D) The mosquito would have trouble digesting food, due to impaired gut function.

Accepted Answer

Endodermal cells are the cells that differentiate into the gut or digestive tract of an organism. Therefore, inhibiting their development would result in impaired gut function, which would make it difficult for the mosquito to digest food. This would likely lead to reduced growth and ultimately death.

Question 5

The text describes four ways, or tactics, of feeding. Which of the following is NOT one of those ways?
A) suspension feeding
B) herbivory feeding
C) deposit feeding
D) food- mass feeding
E) fluid feeding

Accepted Answer

Herbivory feeding is not one of the four ways of feeding described in the text.

Question 6

The evolution of animal species has been prolific the estimates go into the millions and tens of millions). To what does the text attribute much of this diversity?
A) a large variety of methods for capturing and processing food
B) a large variety of body plans
C) novel reproductive strategies
D) the development of multiple tissue types
E) a complex nervous system providing the intelligence for survival in difficult times

Accepted Answer

The text attributes much of the diversity in animal species to a large variety of methods for capturing and processing food, which allows different species to exploit different ecological niches.

Question 7

Why might researchers choose to use molecular data such as ribosomal RNA sequences) rather than morphological data to study the evolutionary history of animals?
A) Some phyla vary too widely in morphological characteristics to be classified accurately.
B) Sequence data can be gathered faster than morphological data, and morphological data can lead to wrong conclusions.
C) Molecular data can be gathered in the lab, while morphological data must be gathered in the field.
D) Morphological changes usually don't result from molecular changes.

Accepted Answer

The answer of Why might researchers choose to use molecular...

Question 8

Which of the following species would you not classify as an animal?
A) sponges
B) blue whales
C) choanoflagellates
D) horses

Accepted Answer

Choanoflagellates are actually protists, not animals. The other options are all animals.

Question 9

The embryo doesn't grow larger during the stage known as cleavage. What is going on in the embryo during this process?
A) Cleavage is the process by which the polarity of the cell is established; that is, the anterior is distinguished from the posterior.
B) The cells are dividing at this stage, but all the cytoplasm is being split between resulting cells without the formation of new cytoplasm.
C) Cleavage is just the stage at which cells begin to differentiate; that is, endodermal cells start to look different from ectodermal and mesodermal cells.
D) Cleavage is the formation of the gastropore that is used to differentiate protostomes and deuterostomes.

Accepted Answer

During cleavage, the zygote undergoes rapid cell division without an increase in overall size, so the cytoplasm is split between resulting cells without the formation of new cytoplasm. This creates smaller and smaller cells called blastomeres. Therefore, choice B is the correct answer.

Question 10

Which of the following is not a feature of the tube- within- a- tube body plan in most animals?
A) The inner tube consists of digestive organs.
B) Typically, the mouth and anus form the ends of the inner tube.
C) The two "tubes" are separated by mesoderm tissue.
D) Typically, the outer tube consists of a hard exoskeleton.

Accepted Answer

Typically, the outer tube consists of a hard exoskeleton is not a feature of the tube-within-a-tube body plan in most animals. This is because not all animals have an exoskeleton, and many animals have a soft outer layer that is not a tube.

Question 11

Figure 30.1
-As you are on the way to Tahiti for a vacation, your plane crash- lands on a previously undiscovered island. You soon find that the island is teeming with unfamiliar organisms and, as a student of biology, you decide to survey them with the aid of the Insta- Lab Portable Laboratory you brought along in your suitcase). You select three organisms and observe them in detail, making the notations found in Figure 30.1.
Which organism would you classify as an animal?
A) organism A
B) organism B
C) organism C

Accepted Answer

The answer of 
 Figure 30.1
-As you are on the...

Question 12

Which of the following statements concerning animal taxonomy is/are true?
1) Animals are more closely related to plants than to fungi.
2) All animal clades based on body plan have been found to be incorrect.
3) Kingdom Animalia is monophyletic.
4) Animals only reproduce sexually.
5) Animals are thought to have evolved from flagellated protists similar to modern choanoflagellates.
A) 3 and 5
B) 5 only
C) 1 and 2
D) 2 and 4
E) 3, 4, and 5

Accepted Answer

Statement 1 is false, as animals and plants are in different kingdoms and not closely related. Statement 2 may have some inaccuracies, as taxonomy is always evolving based on new information, but it is generally true that some previous classifications have been revised. Statement 3 is true; Kingdom Animalia is considered monophyletic because all animals share a common ancestor. Statement 4 is false, as some animals can reproduce asexually. Statement 5 is true; the most widely accepted theory is that animals evolved from choanoflagellates, a type of protist that resembles the collar cells found in sponges.

Question 13

From the information provided in the figure above, how would you classify the feeding strategy of organism C?
A) suspension feeding
B) predation
C) parasitism
D) A and B
E) B and C

Accepted Answer

Organism C is shown to utilize both suspension feeding and predation as feeding strategies, making both A and B correct. Suspension feeders capture food particles suspended in the water, and predators feed on other organisms.

Question 14

Which tissue type, or organ, is not correctly matched with its germ layer tissue?
A) stomach-endoderm
B) skin-ectoderm
C) muscular-mesoderm
D) nervous-mesoderm
E) skeletal-mesoderm

Accepted Answer

Nervous tissue is derived from the ectoderm, not the mesoderm.

Question 15

Use Figure 30.3 and the following information when answering the next question.
In a review paper published in 2000, Adoutte et al. examined some animal phylogenies generated by comparing the ribosoma rRNA) of animals from many different phyla. They then integrated these independently created phylogenies into one phylog best fit all the data.
Figure 30.4 compares a traditional phylogeny based on morphological characteristics A) to the new molecular- based phylog described by Adoutte et al. B).
Note that platyhelminthes, nemerteans, and entoprocts, which do not have coeloms and are classified as acoelomates in the morphological phylogeny, are reclassified as lophotrochozoans in the molecular phylogeny. Similarly, groups classified as pseudocoelomates in the morphological phylogeny are reclassified as either lophotrochozoans or ecdysozoans in the molecula phylogeny; other lophotrochozoans and ecdysozoans have coeloms. 
A. Adoutte, G. Balavoine, N. Lartillot, O. Lespinet, B. Prud'homme, and R. de Rosa. 2000. The new animal phylogeny.
 Figure 30.3
-What does this reclassification based on molecular data imply about the evolution of acoelomates, pseudocoelomates, and coelomates?
A) Pseudocoelomates can be seen as an intermediate stage between acoelomate and coelomate development.
B) Some pseudocoelomates and acoelomates have evolved from coelomates.
C) Although acoelomates and pseudocoelomates evolved only once, coelomates evolved multiple times in different lineages.
D) Only the animals that evolved earliest are acoelomates.

Accepted Answer

The reclassification based on molecular data suggests that the traditional view of body cavity evolution as a linear progression from acoelomates to pseudocoelomates to coelomates is overly simplistic. Instead, it indicates that some organisms traditionally classified as pseudocoelomates or acoelomates may have actually evolved from ancestors that had a true coelom, suggesting a more complex pattern of evolutionary changes.

Question 16

In examining an unknown animal species during its embryonic development, how can you be sure what you are looking at is a protostome and not a deuterostome?
A) There is a well- developed coelom.
B) The mouth develops first, and the anus develops later.
C) There is evidence of cephalization.
D) The animal is triploblastic.
E) The animal is clearly bilaterally symmetrical.

Accepted Answer

In protostomes, the mouth develops first in the embryonic development, whereas in deuterostomes, the anus develops first.

Question 17

While looking at some seawater through your microscope, you spot the egg of an unknown animal. Which of the following tests could you not use to determine whether the developing organism is a protostome or a deuterostome?
A) See whether the coelom is formed from a split in the mesoderm or from mesodermal pockets pinched off the gut.
B) See whether the animal exhibits spiral cleavage or radial cleavage during early development.
C) See whether the pore formed during gastrulation becomes the mature animal's mouth or its anus.
D) See whether the ectoderm forms the mature animal's skin/exoskeleton or nervous system.

Accepted Answer

The distinction between protostomes and deuterostomes is not based on whether the ectoderm forms the mature animal's skin/exoskeleton or nervous system, as both groups can have these structures derived from the ectoderm. The key differences involve patterns of cleavage, coelom formation, and the fate of the blastopore.

Question 18

Which one of the following objects most closely resembles the pattern of the tube- within- a- tube body plan?
A) a bowling ball with finger holes drilled)
B) a pipe with a straw inside
C) a soda can with the tab removed
D) a cup with a straw in it

Accepted Answer

The tube-within-a-tube body plan consists of an inner digestive tube (the gut) that is surrounded by an outer body wall. Option B, a pipe with a straw inside, best represents this body plan. The pipe can be thought of as the outer body wall and the straw inside as the inner digestive tube, both nested within each other. The other options do not have this clear differentiation between an inner and outer structure.

Question 19

If you think of the tube- within- a- tube body plan as a pipe with a straw inside, where would you expect to find most of the ectodermal, mesodermal, and endodermal germ layers, respectively?
A) straw; space between pipe and straw; pipe
B) pipe; straw; space inside of straw
C) space inside of straw; straw; space between pipe and straw
D) pipe; space between pipe and straw; straw

Accepted Answer

The outer layer, or ectoderm, would be represented by the pipe, while the inner layer, or endoderm, would be the straw. Mesoderm, which is located between the ectoderm and endoderm, would be represented by the space between the pipe and straw. Therefore, the best choice is D - pipe; space between pipe and straw; straw.

Question 20

Which of the following combinations of embryonic features is common in the deuterostomes?
A) spiral cleavage and the gastrulation pore or gastropore) becomes the anus
B) spiral cleavage and the absence of gastropore formation
C) radial cleavage and the gastropore becomes the mouth
D) radial cleavage and the gastropore becomes the anus
E) absence of cleavage and gastropore becomes the anus

Accepted Answer

Deuterostomes typically exhibit radial cleavage and the gastropore becomes the anus. This includes organisms such as echinoderms and chordates.

Quiz 30: An Introduction to Animals

Bilateral symmetry is advantageous primarily because it allows for the development of

Figure 30.2 -Which morphological trait evolved more than once in animals, according to the phylogeny based on DNA sequence data found in Figure 30.2 above?

Lophotrochozoans differ from ecdysozoans in that

Suppose a researcher for a pest- control company developed a chemical that inhibited the development of an embryonic mosquito's endodermal cells. Which of the following would be a likely mechanism by which this pesticide works?

The text describes four ways, or tactics, of feeding. Which of the following is NOT one of those ways?

The evolution of animal species has been prolific the estimates go into the millions and tens of millions) . To what does the text attribute much of this diversity?

Why might researchers choose to use molecular data such as ribosomal RNA sequences) rather than morphological data to study the evolutionary history of animals?

Which of the following species would you not classify as an animal?

The embryo doesn't grow larger during the stage known as cleavage. What is going on in the embryo during this process?

Which of the following is not a feature of the tube- within- a- tube body plan in most animals?

From the information provided in the figure above, how would you classify the feeding strategy of organism C?

Which tissue type, or organ, is not correctly matched with its germ layer tissue?

In examining an unknown animal species during its embryonic development, how can you be sure what you are looking at is a protostome and not a deuterostome?

While looking at some seawater through your microscope, you spot the egg of an unknown animal. Which of the following tests could you not use to determine whether the developing organism is a protostome or a deuterostome?

Which one of the following objects most closely resembles the pattern of the tube- within- a- tube body plan?

If you think of the tube- within- a- tube body plan as a pipe with a straw inside, where would you expect to find most of the ectodermal, mesodermal, and endodermal germ layers, respectively?

Which of the following combinations of embryonic features is common in the deuterostomes?