Question 1

Multicellular organisms must keep their cells awash in an "internal pond" because
A)their membranes will crystallize if not in contact with interstitial fluid.
B)an aqueous medium is needed for the cellular exchange of nutrients, gases, and wastes.
C)this prevents the loss of water due to osmosis.
D)their cells need to be protected from dissolved nitrogen gas in the blood.
E)terrestrial organisms have not adapted to life in dry environments.

Accepted Answer

Multicellular organisms need an aqueous medium for cellular exchange of nutrients, gases, and wastes. The interstitial fluid serves as that medium.

Question 2

The similar fusiform body shape of diverse animals, such as sharks, penguins, and aquatic mammals, has evolved because
A)natural selection typically has no limits when different organisms face the same challenge.
B)respiration through gills is enhanced by having a fusiform shape.
C)this is the body shape that makes it possible for aquatic animals to swim rapidly.
D)the fusiform shape is coded by the same genes in all three types of aquatic animals.
E)all three types evolved from the same ancestral form, which flew in air rather than swam in water.

Accepted Answer

The fusiform body shape of aquatic animals is due to its effectiveness in swimming rapidly through water. This shape reduces drag and allows for efficient movement through the water. Natural selection may favor this shape when different organisms face the same environmental challenge of moving through water, but this is not the only factor in the evolution of this body shape. Respiration through gills may be enhanced by having a streamlined body shape, but this is not the primary reason for the evolution of the fusiform shape. The fact that these different types of aquatic animals share a similar body shape suggests convergent evolution, rather than a common ancestral form that evolved from flying in air. There may be some overlap in the genetic basis for the fusiform shape in these different groups, but this is not a major factor in the evolution of this shape.

Question 3

When the temperature of the outside air exceeds their internal body temperature, jackrabbits living in hot, arid lands will
A)dilate the blood vessels in their large ears to transfer more body heat to the environment.
B)constrict the blood vessels in their large ears to reduce transfer of external heat to the blood in their ears.
C)increase motor movements to find a sunny area to maximize heat transfer into their bodies.
D)increase pigmentation in their ears, darkening them to maximize their capacity to take up heat.
E)begin involuntary shivering of their skeletal muscles in order to generate more metabolic heat.

Accepted Answer

Jackrabbits will constrict the blood vessels in their large ears to reduce transfer of external heat to the blood in their ears in order to prevent overheating. This is a common adaptive response to high temperatures in many desert-dwelling animals.

Question 4

Animals with a complex body plan can maintain homeostasis in a changing environment by using all of the following except
A)sensory organs that provide information about the animal's environment.
B)internal digestive organs that break down food gradually.
C)an external skeleton that provides protection against predators.
D)a gastrovascular cavity that opens directly to the external environment.
E)filtration system that can change the composition of the interstitial and circulatory fluid.

Accepted Answer

A gastrovascular cavity that opens directly to the external environment does not contribute to maintaining homeostasis in a changing environment, as it is primarily involved in digestion and distribution of nutrients rather than regulating internal conditions.

Question 5

To increase the effectiveness of exchange surfaces lining the lungs and the intestines, evolutionary pressures have
A)increased the exchange surface area with folds and branches.
B)increased the thickness of the membranes in these linings.
C)increased the number of cell layers in these linings.
D)decreased the metabolic rate of the cells in these linings.
E)increased the volume of the cells in these linings.

Accepted Answer

Increasing the exchange surface area with folds and branches allows for more surface area for exchanging gases or nutrients, increasing the efficiency of the exchange. This is demonstrated in the alveoli of the lungs and the villi of the small intestine, which have extensive folds and branches to increase surface area. Options B, C, D, and E are not supported by the evidence and would actually decrease the effectiveness of the exchange surfaces.

Question 6

Which choice best describes a reasonable mechanism for animal structures becoming better suited over evolutionary time to specific functions?
A)Animals that eat the most food become the most abundant.
B)Animals that restrict their food intake will become less abundant.
C)Animals with mutations that give rise to effective structures will become more abundant.
D)Animals with inventions that curtail reproduction will become more abundant.
E)Animals with parents that continually improve their offspring's structures will become more abundant.

Accepted Answer

Mutations that create effective structures will provide a selective advantage to the individual possessing them, allowing them to better survive and reproduce. Over time, this can lead to the spread of the beneficial mutation throughout the population, resulting in better-suited animal structures. Choices A, B, D, and E do not accurately describe the process of natural selection and the evolution of animal structures.

Question 7

All animals, whether large or small, have
A)an external body surface that is dry.
B)a basic body plan that resembles a two-layered sac.
C)a body surface covered with hair to keep them warm.
D)the ability to enter dormancy when resources become scarce.
E)each living cell in contact with an aqueous medium.

Accepted Answer

All animal cells require water to carry out their essential functions such as gas exchange, nutrient transport, and waste elimination. Therefore, all animals have each living cell in contact with an aqueous or water-based environment. Choices A, B, C, and D are incorrect as they do not apply to all animals.

Question 8

If thermoregulation is considered to be a secondary function of the large ears of jackrabbits, then the primary function of the ears is
A)to optimize nutrient intake through the thin, permeable surfaces on the ears.
B)to alter the rate of gas exchange, based on the adjustable radius of the ears' blood vessels.
C)to detect predators by using the large size and flexible positioning of the external ears to channel sound waves into the ear canal.
D)to protect offspring from bright sunlight by the positioning the ears to cast maximum shadows.
E)to protect against pathogens by having a thick, waxy surface on the ears.

Accepted Answer

The large size and flexible positioning of jackrabbit ears allow them to detect predators by channeling sound waves into the ear canal. While thermoregulation may be a secondary function of their ears, it is not the primary function. The other choices do not accurately describe the function of jackrabbit ears.

Question 9

Tissues are composed of cells, and tissues functioning together make up
A)organs.
B)membranes.
C)organ systems.
D)organelles.
E)organisms.

Accepted Answer

Tissues working together create the various organs in the body. Therefore, choice A is the correct option. Membranes and organ systems do not accurately describe the relationship between tissues in the body. Organelles are not composed of tissues. E is incorrect because it refers to entire living beings, which are not made up of organs working together.

Question 10

Penguins, seals, and tuna have body forms that permit rapid swimming, because
A)all share a common ancestor at some point in the past.
B)all of their bodies have been compressed since birth by intensive underwater pressures.
C)flying, pregnancy, and gill-breathing all require similar adaptations in form.
D)the shape is a convergent evolutionary solution to the need to reduce drag while swimming.
E)this is the only shape that will allow them to maintain a constant body temperature in water.

Accepted Answer

The question asks about the body forms of penguins, seals, and tuna, which all have a streamlined shape that reduces drag while swimming. This shape is likely a convergent evolutionary solution to the need for rapid swimming in aquatic environments. The other answer choices are not supported by scientific evidence or are not relevant to the question.

Question 11

Most of the exchange surfaces of multicellular animals are lined with
A)connective tissue.
B)smooth muscle cells.
C)neural tissue.
D)epithelial tissue.
E)adipose tissue.

Accepted Answer

The exchange surfaces of multicellular animals, such as the alveoli in the lungs and the villi in the small intestine, are lined with epithelial tissue. This type of tissue is composed of tightly packed cells that form a barrier between different environments, and it is responsible for functions such as absorption, secretion, and protection. Connective tissue, smooth muscle cells, neural tissue, and adipose tissue may all be present in and around these exchange surfaces, but they are not the primary tissue type lining these surfaces.

Question 12

Of the following choices, the epithelium with the shortest diffusion distance is
A)simple squamous epithelium.
B)simple cuboidal epithelium.
C)simple columnar epithelium.
D)pseudostratified ciliated columnar epithelium.
E)stratified squamous epithelium.

Accepted Answer

Simple squamous epithelium has a single layer of flattened cells, making it the thinnest of all the epithelial tissues, thus providing the shortest diffusion distance for substances to diffuse through it.

Question 13

Interstitial fluid is
A)the fluid inside the gastrovascular cavity of Hydra.
B)the internal environment inside animal cells.
C)identical to the composition of blood.
D)the route for the exchange of materials between blood and body cells.
E)found only in the lumen of the small intestine.

Accepted Answer

Interstitial fluid is the fluid that surrounds and bathes the cells of the body. It is the route for the exchange of materials between the blood and body cells, allowing nutrients, gases, and waste products to be exchanged. It is not the fluid inside the gastrovascular cavity of Hydra (A), the internal environment inside animal cells (B), or identical to the composition of blood (C). It is also not found only in the lumen of the small intestine (E).

Question 14

The specialized structures of complex animals have evolved because
A)the environment imposes identical problems regardless of where the animals are found.
B)the development of the specialized structures in an animal is influenced by the animal's ability to learn.
C)the simplest animals are those with the most recent appearance among the biota.
D)they permit adjustments to a wide range of environmental changes.
E)the most complex animals are the ones with the most ancient evolutionary origin.

Accepted Answer

Specialized structures in animals have evolved to allow them to adapt to a variety of environmental changes. Animals need to be able to adjust to changes in temperature, food availability, predator pressure, and more. Therefore, the development of these specialized structures allows for greater flexibility in an organism's ability to survive in different environments.

Question 15

The specialized function shared by the cells that line the lungs and those that line the lumen of the gut is that both types of cells
A)receive their oxygen directly from inhaled air and ingested foods.
B)provide abundant exchange surface.
C)have exceptionally high numbers of cellular organelles in the cytoplasm.
D)offer greater protection due to increased membrane thickness.
E)have a lowered basal metabolic rate due to cooperative exchange between cells.

Accepted Answer

Both lung cells and gut cells line surfaces where there is a need for efficient exchange of substances (oxygen and carbon dioxide in the lungs, nutrients and waste products in the gut). Their specialized function is to provide an abundant exchange surface where this can occur.

Question 16

An exchange surface in direct contact with the external environment is found in the
A)lungs.
B)skeletal muscles.
C)liver.
D)heart.
E)brain.

Accepted Answer

The lungs are responsible for gas exchange, with oxygen entering the body and carbon dioxide being expelled. This exchange surface is in direct contact with the external environment through breathing. Skeletal muscles, liver, heart, and brain do not have exchange surfaces in direct contact with the external environment.

Question 17

In a multicellular animal, the circulatory system exchanges materials with the external environment using specialized exchange surfaces. Which of the following is not an example of such an exchange surface?
A)lung
B)muscle
C)skin
D)intestine
E)kidney

Accepted Answer

Muscles are not specialized exchange surfaces, as they do not directly exchange materials with the external environment. Instead, they receive nutrients and oxygen from the circulatory system through blood vessels that run alongside or within the muscles.

Question 18

The absorptive epithelia in the gut are considered "polarized" because
A)thick and thin filaments are present.
B)they pump wastes into the lumen while pumping nutrients toward the blood.
C)the colours seen on the top and bottom of the cells are different.
D)they must fire action potentials to absorb most nutrients.
E)the structures on the apical surface are different than those on the basal surface.

Accepted Answer

The statement "the structures on the apical surface are different than those on the basal surface" is the correct explanation for why the absorptive epithelia in the gut are considered polarized. In polarized epithelial cells, the apical surface (facing the lumen) has microvilli and specific transporters for nutrient uptake, while the basal surface (facing the blood) has different types of transporters for nutrient release into the bloodstream. This differentiation of structures allows for efficient absorption and transport of nutrients in one direction.

Question 19

Evolutionary adaptations that help diverse animals directly exchange matter between cells and the environment include
A)a gastrovascular activity, a two-layered body, and a torpedo-like body shape.
B)an external respiratory surface, a small body size, and a two-cell-layered body.
C)a large body volume; a long, tubular body; and a set of wings.
D)complex internal structures, a small body size, and a large surface area.
E)an unbranched internal surface, a small body size, and thick covering.

Accepted Answer

The external respiratory surface allows for efficient exchange of gases between cells and the environment. A small body size allows for a larger surface area to volume ratio, allowing for more efficient exchange. A two-cell-layered body allows for direct exchange of materials between cells and the environment.

Question 20

As body size increases in animals
A)there is a decrease in the surface-to-volume ratio.
B)reproduction becomes limited to terrestrial environments.
C)there is greater variability in metabolic rate.
D)migration to tropical areas becomes necessary for thermoregulation.
E)it becomes more difficult to conserve body warmth in cold environments.

Accepted Answer

As body size increases, the volume of an animal's body increases at a greater rate than its surface area. This results in a lower surface-to-volume ratio, which affects a range of physiological processes, including gas exchange, heat loss, and nutrient uptake.

Quiz 40: Basic Principles of Animal Form and Function

Multicellular organisms must keep their cells awash in an "internal pond" because

The similar fusiform body shape of diverse animals, such as sharks, penguins, and aquatic mammals, has evolved because

When the temperature of the outside air exceeds their internal body temperature, jackrabbits living in hot, arid lands will

Animals with a complex body plan can maintain homeostasis in a changing environment by using all of the following except

To increase the effectiveness of exchange surfaces lining the lungs and the intestines, evolutionary pressures have

Which choice best describes a reasonable mechanism for animal structures becoming better suited over evolutionary time to specific functions?

All animals, whether large or small, have

If thermoregulation is considered to be a secondary function of the large ears of jackrabbits, then the primary function of the ears is

Tissues are composed of cells, and tissues functioning together make up

Penguins, seals, and tuna have body forms that permit rapid swimming, because

Most of the exchange surfaces of multicellular animals are lined with

Of the following choices, the epithelium with the shortest diffusion distance is

Interstitial fluid is

The specialized structures of complex animals have evolved because

The specialized function shared by the cells that line the lungs and those that line the lumen of the gut is that both types of cells

An exchange surface in direct contact with the external environment is found in the

In a multicellular animal, the circulatory system exchanges materials with the external environment using specialized exchange surfaces. Which of the following is not an example of such an exchange surface?

The absorptive epithelia in the gut are considered "polarized" because

Evolutionary adaptations that help diverse animals directly exchange matter between cells and the environment include

As body size increases in animals