Cumulative 1

Question 1

Penguins, seals, and tuna have body forms that permit rapid swimming, because ________.
A) all share a recent common ancestor
B) all of their bodies have been compressed since birth by intensive underwater pressures
C) the shape is a convergent evolutionary solution, which reduces drag while swimming
D) this is the only shape that will allow them to maintain a constant body temperature in water

Answer 1

C) the shape is a convergent evolutionary solution, which reduces drag while swimming

Question 2

As animals have evolved large body size, they have also evolved adaptations to improve exchange of energy and materials with the environment. For example, in many larger organisms, evolution has favored lungs and a digestive tract with ________.
A) more branching or folds
B) increased thickness
C) larger cells
D) decreased blood suppl

Answer 2

A) more branching or folds

Question 3

Much of the coordination of vertebrate body functions via chemical signals is accomplished by the ________.
A) respiratory system
B) endocrine system
C) integumentary system
D) excretory system

Answer 3

B) Endocrine system

Question 4

Compared with a smaller cell, a larger cell of the same shape has ________.
A) less surface area
B) less surface area per unit of volume
C) a smaller average distance between its mitochondria and the external source of oxygen
D) a smaller cytoplasm-to-nucleus ratio

Answer 4

B) less surface area per unit of volume

Question 5

Both the endocrine and nervous systems transmit information around an animal’s body. Which of the following is a characteristic of nervous system signals?
A) allow gradual changes to take place in the body
B) travel quickly, allowing rapid transmission of signals
C) usually impact the entire body
D) a voltage change must occur

Answer 5

B) travel quickly, allowing rapid transmission of signals

Question 6

Some animals have no gills when young, but then develop gills that grow larger as the animal
grows larger. What is the reason for this increase in gill size?
A) The young of these animals are much more active than the adult, which leads to a higher
BMR (basal metabolic rate) and, therefore, a higher need for oxygen.
B) Relative to their volume, the young have more surface area across which they can transport
all the oxygen they need.
C) The young have a higher BMR.
D) Relative to their surface area, the young have more body volume in which they can store
oxygen for long periods of time.

Answer 6

B) Relative to their volume, the young have more surface area across which they can transport all the oxygen they need.

Question 7

Evolutionary adaptations that help some animals directly exchange matter between the cells of their body and the environment include ________.
A) a gastrovascular cavity, 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) an unbranched internal surface, a small body size, and thick covering

Answer 7

B) an external respiratory surface, a small body size, and a two-cell-layered body

Question 8

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) most of their cells in contact with an aqueous medium

Answer 8

D. most of their cells in contact with an aqueous medium

Question 9

Interstitial fluid is ________.
A) the internal environment inside animal cells
B) identical to blood in composition.
C) a site of exchange between blood and body cells
D) found only in the lumen of the small intestine

Answer 9

C) a site of exchange between blood and body cells

Question 10

Generally, epithelial cell layers are responsible for separating two fluids. For example, the
epithelium of blood vessels in animals separates the blood from the interstitial fluid. What
characteristic would you expect to see in an epithelium that was specialized for passive diffusion
of materials from one fluid to another?
A) a single layer of flattened cells
B) many layers of cells stacked together
C) large, cube-shaped cells
D) loosely connected cells surrounded by an extracellular matrix

Answer 10

A) a single layer of flattened cells

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

Answer 11

D) Epithelial Tissue

Question 12

Connective tissues typically have ________.
A) little space between the membranes of adjacent cells
B) the ability to transmit electrochemical impulses
C) the ability to shorten upon stimulation
D) relatively few cells and a large amount of extracellular matrix

Answer 12

D) relatively few cells and a large amount of extracellular matrix

Question 13

In mammals, GH (growth hormone) is an endocrine signal that stimulates repair and growth
of various tissues. Which of the following would be required for a tissue to respond to growth
hormone?
A) the presence of a growth hormone receptor on the responding tissue
B) the responding tissue must be muscle
C) nerve cells must attach to the responding tissue for growth hormone to work
D) a voltage change must occur

Answer 13

A) the presence of a growth hormone receptor on the responding tissue

Question 14

Blood is best classified as connective tissue because ________.
A) its cells are separated from each other by an extracellular matrix
B) it contains more than one type of cell
C) its cells can move from place to place
D) it is found within all the organs of the body

Answer 14

A) its cells are separated from each other by an extracellular matrix

Question 15

Most types of communication between cells utilize ________.
A) the exchange of cytosol between the cells
B) the movement of the cells
C) chemical or electrical signals
D) the exchange of DNA between the cells

Answer 15

C) chemical or electrical signals

Question 16

All types of muscle tissue have ________.
A) striated banding patterns seen under the microscope
B) cells that lengthen when appropriately stimulated
C) a response that can be consciously controlled
D) interactions between actin and myosin

Answer 16

D) interactions between actin and myosin

Question 17

Cardiac muscle cells are both ________.
A) striated and interconnected by intercalated disks
B) smooth and under voluntary control
C) striated and under voluntary control
D) smooth and under involuntary control

Answer 17

A) striated and interconnected by intercalated disks

Question 18

Muscle cells are organized to perform specific types of contractions within a tissue. Which of
the following is a characteristic of smooth muscle?
A) many cells fused together
B) intercalated discs
C) spindle-shaped cells with a single nucleus
D) striations with sarcomeres

Answer 18

C) spindle-shaped cells with a single nucleus

Question 19

Food moves along the digestive tract as the result of contractions by ________.
A) cardiac muscle
B) smooth muscle
C) striated muscle
D) skeletal muscle

Answer 19

B) smooth muscle

Question 20

In many animals, fat is stored in specialized cells in the ________.
A) bone
B) muscle
C) adipose tissue
D) blood

Answer 20

C) adipose tissue

Question 21

Bone consists of ________.
A) a mixture of hardened collagen and minerals.
B) chondroitin sulfate secreted by chondrocytes.
C) many columnar epithelial cells packed together.
D) hardened fibrous connective tissue.

Answer 21

A) a mixture of hardened collagen and minerals

Question 22

What is the name of the epithelial cell surface that faces the outside of an organ?
A) apical
B) basal
C) interstitial
D) lumen

Answer 22

B) Basal

Question 23

Which organ system is responsible for protection against injury, infection, and dehydration?
A) Reproductive system
B) Excretory system
C) Skeletal system
D) Integumentary system

Answer 23

D) Integumentary System

Question 24

Which of the following is a true statement about body size and physiology?
A) The amount of food and oxygen an animal requires and the amount of heat and waste it
produces are inversely proportional to its mass.
B) The rate at which an animal uses nutrients and produces waste products is independent of its
volume.
C) Small and large animals face different physiological challenges because an animal’s body
mass increases cubically while its surface area increases as a squared function.
D) The wastes produced by an animal double as its volume doubles and triple as its surface area
triples.

Answer 24

C) Small and large animals face different physiological challenges because an animal’s body mass increases cubically while its surface are increases as a squared function

Question 25

An elephant and a mouse are running in full sunlight, and both overheat by the same amount above their normal body temperatures. When they move into the shade and rest, which animal will cool down faster?
A) The elephant will because it has the higher surface-area-to-volume ratio.
B) The elephant will because it has the lower surface-area-to-volume ratio.
C) The mouse will because it has the higher surface-area-to-volume ratio.
D) They will cool at the same rate because they overheated by the same amount.

Answer 25

C) The mouse will because it has the higher surface-area-to-volume ratio

Question 26

You have a cube of modeling clay in your hands. Which of the following changes to the shape of this cube of clay will decrease its surface area relative to its volume?
A) Pinch the edges of the cube into small folds.
B) Flatten the cube into a pancake shape.
C) Round the clay up into a sphere.
D) Stretch the cube into a long, shoebox shape.

Answer 26

C) Round the clay up into a sphere

Question 27

The metabolic rate of an animal is most accurately determined by ________.
A) the amount of work done by an animal
B) the amount of food consumed during a meal
C) the amount of carbon dioxide produced by an animal in a given time.
D) the amount of energy used by an animal in a given time

Answer 27

D) the amount of energy used by an animal in a given time

Question 28

The migratory eel, Anguilla rostrata, is born and lives the juvenile (immature) part of its life
in a freshwater environment, but then migrates thousands of miles through the ocean as an adult
in order to breed. These eels are known to regulate their internal water and salt balance. What
adaptations would you expect this eel to have in order to transition from fresh water to salt water
at these two life stages?
A) The juvenile eels would be better at removing salt from their bodies compared to adults.
B) The adult eels would be better at removing salt from their bodies compared to juveniles.
C) The juvenile eels would spend energy keeping water in their bodies.
D) The adult eels would spend energy keeping salt in their bodies.

Answer 28

B) The adult eels would be better at removing salt from their bodies compared to juveniles

Question 29

The metamorphosis of a tadpole to an adult frog involves a thorough reconstruction of the animal’s body. All of the structural and physiological changes must be complete or the frog will not survive this transformation. Which type of regulation would ensure that the animal
completed its transformation?
A) positive feedback
B) negative feedback
C) feedback inhibition
D) enzymatic catalysis

Answer 29

A) positive feedback

Question 30

When the body’s blood glucose level rises, the pancreas secretes insulin and, as a result, the blood glucose level declines. When the blood glucose level is low, the pancreas secretes glucagon and, as a result, the blood glucose level rises. Such regulation of the blood glucose level is the result of ________.
A) catalytic feedback
B) positive feedback
C) negative feedback
D) protein-protein interactions

Answer 30

C) negative feedback

Question 31

The body’s automatic tendency to maintain a constant and optimal internal environment is termed as ________.
A) balanced equilibrium
B) physiological chance
C) homeostasis
D) static equilibrium

Answer 31

C) homeostasis

Question 32

An example of a properly functioning homeostatic control system is seen when ________.
A) the core body temperature of a runner rises gradually from 37°C to 45°C
B) the kidneys excrete salt into the urine when dietary salt levels rise
C) a blood cell shrinks when placed in a solution of salt and water
D) the blood pressure increases in response to an increase in blood volume

Answer 32

B) the kidneys excrete salt into the urine when dietary salt levels rise

Question 33

If a person were to travel to a time zone that was several hours ahead of their own, they may experience tiredness known as jet lag. Jet lag is due to a disruption of ________.
A) homeostasis
B) circadian rhythm
C) body temperature
D) nerve impulses

Answer 33

B) Circadian Rhythm

Question 34

What would be an advantage for an animal that conforms to a changing environmental condition, such as temperature?
A) The animal’s internal temperature would remain constant, even though the external temperature had changed.
B) The animal’s internal temperature would change opposite to the change in the external temperature.
C) The animal would spend more time looking for food.
D) The animal would spend less energy regulating its internal temperature.

Answer 34

D) The animal would spend less energy regulating its internal temperature

Question 35

You discover a new species of bacteria that grows in aquatic environments with high salt levels. While studying these bacteria, you note that their internal environment is similar to the salt concentrations in their surroundings. You also discover that the internal salt concentrations of the bacteria change as the salt concentration in their environment changes. The new species
can tolerate small changes in this way, but dies from large changes because it has no mechanism for altering its own internal salt levels. What type of homeostatic mechanism is this species using to regulate its internal salt levels?
A) conformation
B) regulation
C) integration
D) assimilation

Answer 35

A) conformation

Question 36

Chum salmon (Oncorhynchus keta) are born in freshwater environments and then migrate to the sea. Near the end of their lives, they return to the freshwater stream where they were born to spawn. In fresh water, water constantly diffuses into the body and ions are lost from the body. In
salt water, body water diffuses out of the body and excess ions are gained from the water. A salmon’s gills have special cells to pump salt in or out of the body to maintain homeostasis. In response to the salmon’s moves between fresh water and salt water, some cells in the gills are produced and others are destroyed. These changes made in the cells of the gills during the lifetime of an individual salmon are an example of which of the following?
A) evolution
B) trade-off
C) acclimatization
D) adaptation

Answer 36

C) acclimatization

Question 37

To prepare flight muscles for use on a cool morning, hawkmoths ________.
A) relax the muscles completely until after they launch themselves into the air
B) decrease their standard metabolic rate
C) rapidly contract and relax these muscles to generate metabolic warmth
D) reduce the metabolic rate of the muscles to rest them before flight

Answer 37

C) rapidly contract and relax these muscles to generate metabolic warmth

Question 38

In a cool environment, an ectotherm is more likely to survive an extended period of food deprivation than would an equally sized endotherm because the ectotherm ________.
A) maintains a higher basal metabolic rate
B) expends more energy per kilogram of body mass than does the endotherm
C) invests little energy in temperature regulation
D) has greater insulation on its body surface

Answer 38

C) invests little energy in temperature regulation

Question 39

Elephants can often be observed cooling off by spraying water over their bodies with their trunks. What type of heat exchange is occurring?
A) conduction
B) convection
C) radiation
D) evaporation

Answer 39

D) evaporation

Question 40

An example of an ectothermic organism that has few or no behavioral options when it comes to its ability to adjust its body temperature is a ________.
A) sea star living deep in the ocean
B) bass living in a farm pond
C) hummingbird flying through a prairie
D) honeybee in a hive on a rural farm

Answer 40

A) sea star living deep in the ocean

Question 41

The panting responses observed in overheated birds and mammals dissipate excess heat by ________.
A) countercurrent exchange
B) acclimation
C) vasoconstriction
D) evaporation

Answer 41

D) Evaporation

Question 42

Most land-dwelling invertebrates and all of the amphibians ________.
A) are ectothermic organisms with variable body temperatures
B) alter their metabolic rates to maintain a constant body temperature of 37°C
C) are endotherms but become thermo-conformers when they are in water
D) become more active when environmental temperatures drop below 15°C

Answer 42

A) are ectothermic organisms with variable body temperatures

Question 43

The temperature-regulating center of vertebrate animals is located in the ________.
A) thyroid gland
B) hypothalamus
C) subcutaneous layer of the skin
D) liver

Answer 43

B) hypothalamus

Question 44

The metabolic breakdown of specialized brown fat deposits in certain animals is
substantially increased during ________.
A) acclimatization
B) torpor
C) nonshivering thermogenesis
D) shivering thermogenesis

Answer 44

C) nonshivering thermogenesis

Question 45

The use of brown fat to generate metabolic heat is mostly limited to small mammals. What is the basis of this adaptation?
A) Small mammals cannot grow enough fur to insulate their bodies.
B) Because of their large surface area to volume ratio, heat loss across the body surface is higher in small animals.
C) Small mammals do not have enough muscle to generate heat by shivering.
D) Large mammals have lost their brown fat through the course of their evolution.

Answer 45

B) Because of their large surface are to volume ratio, heat loss across the body surface is higher in small animals

Question 46

Which of the following would increase the rate of heat exchange between an animal and its environment?
A) feathers or fur
B) vasoconstriction
C) wind blowing across the body surface
D) blubber or fat layer

Answer 46

C) wind blowing across the body surface

Question 47

You are studying a large tropical reptile that has a high and relatively stable body
temperature. How would you determine whether this animal is an endotherm or an ectotherm?
A) You know from its high and stable body temperature that it must be an endotherm.
B) You know that it is an ectotherm because it is not a bird or mammal.
C) You subject this reptile to various temperatures in the lab and find that its body temperature and metabolic rate change with the ambient temperature. You conclude that it is an ectotherm.
D) You note that its environment has a high and stable temperature. Because its body temperature matches the environmental temperature, you conclude that it is an ectotherm.

Answer 47

C) You subject this reptile to various temperatures in the lab and find that its body temperature and metabolic rate change with the ambient temperature. Because its body temperature matches the environmental temperature, you conclude that it is an ectotherm

Question 48

A woman standing and watching the stars on a cool, calm night will lose most of her body heat by ________.
A) radiation
B) convection
C) conduction
D) evaporation

Answer 48

A) radiation

Question 49

There are advantages and disadvantages to adaptations. Animals that are endothermic are likely to be at the greatest disadvantage in ________.
A) very cold environments
B) very hot environments
C) environments with a constant food source
D) environments with variable and limited food sources

Answer 49

D) environments with variable and limited food sources

Question 50

Which principle of heat exchange is the most important explanation for why birds look larger in colder weather because they fluff their feathers?
A) Fluffing feathers results in less cooling by radiation because feathers emit less infrared radiation than other tissues do.
B) Fluffing decreases the amount of heat lost by conduction when the bird makes contact with cold objects in its environment.
C) Fluffing creates a pocket of air near the bird that acts as insulation.
D) Fluffing decreases the surface-area-to-volume ratio, thus decreasing the amount of heat lost to
the environment.

Answer 50

C) Fluffing creates a pocket of air near the bird that acts as insulation

Question 51

Snake behavior in Wisconsin changes throughout the year. For example, a snake is ________.
A) less active in winter because the food supply is decreased
B) less active in winter because it does not need to avoid predators
C) more active in summer because that is the period for mating
D) more active in summer because it can gain body heat by conduction

Answer 51

D) more active in summer because it can gain body heat by conduction

Question 52

Standard metabolic rate (SMR) and basal metabolic rate (BMR) are ________.
A) used differently: SMR is measured during exercise, whereas BMR is measured at rest
B) used to compare metabolic rates during feeding and other active conditions
C) both measured across a wide range of temperatures for a given species
D) both measured in animals in a resting and fasting state

Answer 52

D) both measured in animals in a resting and fasting state

Question 53

Independent of whether an organism is an endotherm or ectoderm, the least reliable indicator of an animal’s metabolic rate is the amount of ________.
A) food eaten in one day
B) heat generated in one day
C) oxygen used in mitochondria in one day
D) water consumed in one day

Answer 53

D) water consumed in one day

Question 54

Consider the energy budgets for a human, an elephant, a penguin, a mouse, and a snake. The ________ would have the highest total annual energy expenditure, and the ________ would have the highest energy expenditure per unit mass.
A) elephant; mouse
B) elephant; human
C) human; penguin
D) mouse; snake

Answer 54

A) elephant; mouse

Question 55

Which of the following animals most likely uses the largest percentage of its energy budget for homeostatic regulation?
A) a marine jelly (an invertebrate) living deep in the ocean
B) a snake in a tropical forest
C) a shark swimming in the open ocean
D) a bird living year-round in a desert

Answer 55

D) A bird living year-round in a desert

Question 56

A researcher is setting up an experiment to measure basal metabolic rate in prairie voles (Microtus ochrogaster—a small rodent). Which of the following would be the best set of conditions for the voles immediately before and during the measurement?
A) House the animals in a cage with plenty of food and water to avoid stress; conduct
measurements in a warmer room than the room where housed.
B) House the animals in a cage with plenty of food and water to avoid stress; conduct
measurements in a room the same temperature as the room where housed.
C) House the animals in a cage with no food for a few hours before measurement; conduct measurements in a colder room than the room where housed, and exercise the voles.
D) House the animals in a cage with no food for a few hours before measurement; conduct measurements in a room the same temperature as the room where housed.

Answer 56

D) House the animals in a cage with no food for a few hours before measurement; conduct measurements in a room the same temperature as the room where housed.

Question 57

Hummingbirds are small birds that require a regular food supply. When hummingbirds are faced with a situation that decreases their food supply, such as a storm, which of the following adaptations would be most useful for the bird to survive such an unpredictable and short-term absence of food resources?
A) shivering
B) torpor
C) hibernation
D) burrowing into soil

Answer 57

B) torpor

Question 58

Organisms maintain dynamic homeostasis through behavioral and physiological
mechanisms. Which of the following statements is an accurate explanation of a negative feedback mechanism used by animals to regulate body temperature?
A) Squirrels are able to cool themselves during warmer months by producing more brown fat, which contains abundant mitochondria and a rich blood supply.
B) Desert jackrabbits have unusually large ears that serve as solar heat collectors to enable them to maintain their body temperatures.
C) A ground squirrel’s hypothalamus detects changes in environmental temperatures and responds by activating or suppressing metabolic heat production.
D) A goldfish slows its movements when the water temperature is lower.

Answer 58

C) A ground squirrel’s hypothalamus detects changes in environmental temperatures and responds by activating or suppressing metabolic heat production

Question 59

The body tissue that consists largely of material located outside of cells is
A) epithelial tissue.
B) connective tissue.
C) muscle tissue.
D) nervous tissue.

Answer 59

B) connective tissue

Question 60

Which of the following would increase the rate of heat exchange between an animal and its environment?
A) feathers or fur
B) vasoconstriction
C) wind blowing across the body surface
D) countercurrent heat exchanger

Answer 60

C) wind blowing across the body surface

Question 61

Consider the energy budgets for a human, an elephant, a penguin, a mouse, and a snake. The ________ would have the highest total annual energy expenditure, and the ________ would have the highest energy expenditure per unit mass.
A) elephant; mouse
B) elephant; human
C) mouse; snake
D) penguin; mouse

Answer 61

A) elephant; mouse

Question 62

Compared with a smaller cell, a larger cell of the same shape has
A) less surface area.
B) less surface area per unit of volume.
C) the same surface-area-to-volume ratio.
D) a smaller cytoplasm-to-nucleus ratio.

Answer 62

B) less surface area per unit of volume

Question 63

An animal’s inputs of energy and materials would exceed its outputs
A) if the animal is an endotherm, which must always take in more energy because of its high metabolic rate.
B) if it is actively foraging for food.
C) if it is growing and increasing its mass.
D) never; due to homeostasis, these energy and material budgets always balance.

Answer 63

C) If it is growing and increasing its mass

Question 64

You are studying a large tropical reptile that has a high and relatively stable body temperature. How do you determine whether this animal is an endotherm or an ectotherm?
A) You know from its high and stable body temperature that it must be an endotherm.
B) You subject this reptile to various temperatures in the lab and find that its body temperature and metabolic rate change with the ambient temperature. You conclude that it is an ectotherm.
C) You note that its environment has a high and stable temperature. Because its body
temperature matches the environmental temperature, you conclude that it is an ectotherm.
D) You measure the metabolic rate of the reptile, and because it is higher than that of a related species that lives in temperate forests, you conclude that this reptile is an endotherm and its relative is an ectotherm.

Answer 64

B) You subject this reptile to various temperatures in the lab and find that its body temperature and metabolic rate change with the ambient temperature. You conclude that it is an ectotherm.

Question 65

Which of the following animals uses the largest percentage of its energy budget for
homeostatic regulation?
A) marine jelly (an invertebrate)
B) snake in a temperate forest
C) desert insect
D) desert bird

Answer 65

D) desert bird

Question 66

You are dissecting a fish in your biology laboratory section. Your teaching assistant points out a long oval structure and tells you it is an endocrine gland. Which of the following would you then know is a true statement about this structure?
A) It secretes a product that is released through a series of ducts.
B) The gland’s product will only interact with receptors on the cell membrane.
C) The gland’s product is lipid soluble.
D) The gland produces and secretes its product into the blood.

Answer 66

D) The gland produces and secretes its product into the blood

Question 67

In experiments where researchers suspect that a hormone may be responsible for a certain physiological effect, they may cut the neurons leading to the organ where the effect being studied occurs. What is the purpose of cutting these neurons?
A) to make sure that the effect is not occurring through actions in the nervous system
B) to make sure that the organ being affected cannot function unless the researchers stimulate it with an external electrical probe
C) to impair the normal functions of the organ so that the hormonal effect can be more easily studied
D) to numb the organ so that it can be probed without inducing pain in the lab animal

Answer 67

A) To make sure that the effect is not occurring through actions in the nervous system

Question 68

What is the only type of chemical signal that does not alter the physiology of the animal producing that signal?
A) neural
B) paracrine
C) neuroendocrine
D) pheromones

Answer 68

D) pheromones

Question 69

Testosterone is an example of a chemical signal that affects the very cells that synthesize it, the neighboring cells in the testis, along with distant cells outside the gonads. Thus, testosterone is an example of ________.
I) an autocrine signal
II) a paracrine signal
III) an endocrine signal
A) only I and II
B) only II and III
C) only I and III
D) I, II, and III

Answer 69

D) I, II, and III

Question 70

Prostaglandins are local regulators whose chemical structure is derived from ________.
A) oligosaccharides
B) fatty acids
C) steroids
D) amino acids

Answer 70

B) Fatty Acids

Question 71

Aspirin and ibuprofen both ________.
A) inhibit the synthesis of prostaglandins
B) inhibit the release of nitric oxide, a potent vasodilator
C) activate the paracrine signaling pathways that form blood clots
D) stimulate vasoconstriction in the kidneys

Answer 71

A) inhibit the synthesis of prostaglandins

Question 72

A cell with membrane-bound proteins that selectively bind a specific hormone is called that hormone’s ________.
A) secretory cell
B) endocrine cell
C) target cell
D) regulatory cell

Answer 72

C) target cell

Question 73

The steroid hormone aldosterone affects only a small number of cells in the body because ________.
A) only target cells are exposed to aldosterone
B) only target cells contain aldosterone receptors
C) aldosterone is unable to enter nontarget cells
D) nontarget cells destroy aldosterone before it can produce any effect

Answer 73

B) only target cells contain aldosterone receptors

Question 74

Different body cells can respond differently to the same polypeptide hormones because ________.
A) different target cells have different sets of genes
B) a target cell’s response is determined by the components of its signal transduction pathways
C) the circulatory system regulates responses to hormones by routing the hormones to specific targets
D) the hormone is chemically altered in different ways as it travels through the circulatory system

Answer 74

B) a target cell’s response is determined by the components of its signal transduction pathways

Question 75

Hormone X activates the cAMP second messenger system in its target cells. The greatest response by a target cell would come from ________.
A) applying a molecule of hormone X to the extracellular fluid surrounding the cell
B) injecting a molecule of hormone X into the cytoplasm of the cell
C) applying a molecule of cAMP to the extracellular fluid surrounding the cell
D) injecting a molecule of activated, cAMP-dependent protein kinase into the cytoplasm of the cell

Answer 75

A) applying a molecule of hormone X to the extracellular fluid surrounding the cell

Question 76

When a steroid hormone and a polypeptide hormone exert similar effects on a population of target cells, then _________.
A) the steroid and polypeptide hormones must use the same biochemical mechanisms
B) the steroid and polypeptide hormones must bind to the same receptor protein
C) the steroid hormones affect the synthesis of effector proteins, whereas polypeptide hormones
activate effector proteins already present in the cell
D) the steroid hormones affect the activity of certain proteins within the cell, whereas polypeptide hormones directly affect the processing of mRNA

Answer 76

C) the steroid hormones affect the synthesis of effector proteins, whereas polypeptide hormones activate effector proteins already present in the cell

Question 77

Growth factors are local regulators that ________.
A) are modified fatty acids that stimulate bone and cartilage growth
B) are found on the surface of cancer cells and stimulate abnormal cell division
C) bind to cell-surface receptors and stimulate growth and development of target cells
D) convey messages between nerve cells

Answer 77

C) bind to cell-surface receptors and stimulate growth and development of target cells

Question 78

Steroid and polypeptide hormones typically have in common ________.
A) the building blocks from which they are synthesized
B) their solubility in cell membranes
C) their requirement for travel through the bloodstream
D) their reliance on signal transduction in the cell

Answer 78

C) their requirement for travel through the bloodstream

Question 79

A cluster of tumor cells that produces and secretes growth factors to induce surrounding cells to grow and divide is showing which type of cell-to-cell signaling?
A) autocrine
B) paracrine
C) endocrine
D) neuroendocrine

Answer 79

B) paracrine

Question 80

If a portion of the pancreas is surgically removed from a rat and the rat subsequently loses its appetite, one explanation is that the removed portion contains cells that secrete a chemical signal that somehow stimulates appetite. Given this scenario, what type of chemical signaling is occurring?
A) autocrine
B) paracrine
C) endocrine
D) neuroendocrine

Answer 80

C) endocrine

Question 81

If a biochemist discovers a new molecule, which of the following pieces of data would allow her to draw the conclusion that the molecule is a steroid hormone?
I) The molecule is lipid soluble.
II) The molecule is derived from a series of steps beginning with cholesterol.
III) The molecule acts at a target tissue some distance from where it is produced.
IV)The molecule uses a transport protein when in an aqueous solution such as blood.
A) only I and III
B) only II and IV
C) only I, III, and IV
D) I, II, III, and IV

Answer 81

D) I, II, III, and IV

Question 82

Which of the following are similar in structure to cholesterol?
I) estradiol
II) insulin
III) glucocorticoids
IV)testosterone
V) antidiuretic hormone
A) I and II
B) I, II, and III
C) I, III, and IV
D) II and V

Answer 82

C) I, III, and IV

Question 83

Polypeptides can have which of the following types of effects?
I) autocrine
II) paracrine
III) endocrine
A) only I and III
B) only II and III
C) only I and II
D) I, II, and III

Answer 83

D) I, II, and III

Question 84

Which of the following are properties of steroid hormones?
I) Steroid hormones are lipid soluble and easily cross the phospholipid bilayer.
II) Steroid hormones usually exert their effects on target cells through membrane receptor proteins.
III) Steroid hormones act on cells close to where they were produced.
IV)Steroid hormones regulate gene transcription by binding to intracellular receptor proteins.
A) I and IV
B) I and II
C) II and III
D) I, II, III, and IV

Answer 84

A) I and IV

Question 85

Tadpoles must undergo a major metamorphosis to become frogs. This change includes reabsorption of the tail, growth of limbs, calcification of the skeleton, increase in rhodopsin in
the eye, development of lungs, change in hemoglobin structure, and reformation of the gut from the long gut of an herbivore to the short gut of a carnivore. Amazingly, all of these changes are induced by thyroxine. What is the most likely explanation for such a wide array of effects of
thyroxine?
A) There are many different forms of thyroxine, each specific to a different tissue.
B) Different tissues have thyroxine receptors that activate different signal transduction pathways.
C) Some tissues have membrane receptors for thyroxine, while other tissues have thyroxine receptors within the nucleus.
D) Different releasing hormones release thyroxine to different tissues.

Answer 85

B. Different tissues have thyroxine receptors that activate different signal transduction pathways

Question 86

What happens in a cell when adenylyl cyclase is activated?
A) cAMP is created
B) cAMP is destroyed
C) G proteins bind to cAMP
D) steroid hormones pass through the lipid bilayer

Answer 86

A) cAMP is created

Question 87

Nitric oxide and epinephrine ________.
A) both regulate blood flow
B) both function as steroid hormones
C) bind the same receptors
D) both cause a reduction in the blood levels of glucose

Answer 87

A) both regulate blood flow

Question 88

Insect hormones and their receptors ________.
A) act independently of each other
B) are a focus in pest control research
C) utilize cell-surface receptors only
D) are active independently of environmental cues

Answer 88

B) are a focus in pest control research

Question 89

During mammalian labor and delivery, the contraction of uterine muscles is enhanced by oxytocin. This is an example of _______.
A) a negative feedback system
B) a hormone that acts in an antagonistic way with another hormone
C) a hormone that is involved in a positive feedback loop
D) signal transduction immediately changing gene expression in its target cells

Answer 89

C) a hormone that is involved in a positive feedback loop

Question 90

Which of the following has both endocrine and exocrine activity?
A) the pituitary gland
B) parathyroid glands
C) salivary glands
D) the pancreas

Answer 90

D) the pancreas

Question 91

Analysis of a blood sample from a fasting individual who had not eaten for 24 hours would be expected to reveal high levels of ________.
A) insulin
B) glucagon
C) gastrin
D) glucose

Answer 91

B) glucagon

Question 92

The steroid hormone that coordinates molting in arthropods is ________.
A) ecdysteroid
B) glucagon
C) thyroxine
D) growth hormone

Answer 92

A) ecdysteroid

Question 93

Which of the following statements are correct?
I) Hormones often regulate homeostasis through antagonistic functions.
II) Hormones of the same chemical class usually have the same function.
III) Hormones are secreted by specialized cells usually located in exocrine glands.
IV) Hormones are often regulated through feedback loops.
A) only II and III
B) only I and III
C) only III and IV
D) only I and IV

Answer 93

D) only I and IV

Question 94

An example of antagonistic hormones controlling homeostasis is ________.
A) thyroxine and parathyroid hormone in calcium balance
B) insulin and glucagon in glucose metabolism
C) progestins and estrogens in sexual differentiation
D) epinephrine and norepinephrine in fight-or-flight responses

Answer 94

B) insulin and glucagon in glucose metabolism

Question 95

The relationship between the insect hormones ecdysteroid and prothoracicotrophic hormone (PTTH) is an example of ________.
A) an interaction of the endocrine and nervous systems
B) competitive inhibition of a hormone receptor
C) how polypeptide-derived hormones have more widespread effects than steroid hormones
D) homeostasis maintained by antagonistic hormones

Answer 95

A) an interaction of the endocrine and nervous systems

Question 96

Injury localized to the hypothalamus would most likely disrupt ________.
A) short-term memory
B) coordination during locomotion
C) executive functions, such as decision making
D) regulation of water balance

Answer 96

D) regulation of water balance

Question 96

Hormones secreted by the posterior pituitary gland are made in the ________.
A) cerebellum
B) thalamus
C) hypothalamus
D) anterior pituitary gland

Answer 96

C) hypothalamus

Question 97

Which of the following is an example of a simple endocrine pathway?
A) control of metabolism by thyroid hormones
B) release of secretin by cells of the duodenum in response to acid
C) release of antidiuretic hormone from the posterior pituitary gland to regulate water balance
D) regulation of growth by the production of growth hormone

Answer 97

B) release of secretin by cells of the duodenum in response to acid

Question 98

Portal blood vessels connect two capillary beds found in the ________.
A) hypothalamus and thalamus
B) anterior pituitary and posterior pituitary
C) hypothalamus and anterior pituitary
D) posterior pituitary and thyroid gland

Answer 98

C) hypothalamus and anterior pituitary

Question 99

If a person loses a large amount of water in a short period of time, he or she may die from dehydration. Antidiuretic hormone (ADH) can help reduce water loss through its interaction with its target cells in the ________.
A) anterior pituitary
B) posterior pituitary
C) bladder
D) kidney

Answer 99

D) kidney

Question 100

A product of the anterior pituitary gland that causes color changes in its target cells is ________.
A) follicle-stimulating hormone (FSH)
B) luteinizing hormone (LH)
C) thyroid-stimulating hormone (TSH)
D) melanocyte-stimulating hormone (MSH)

Answer 100

D) melanocyte-stimulating hormone (MSH)

Question 101

In a lactating mammal, the two hormones that promote milk synthesis and milk release, respectively, are ________.
A) prolactin and calcitonin
B) prolactin and oxytocin
C) follicle-stimulating hormone and luteinizing hormone
D) luteinizing hormone and oxytocin

Answer 101

B) prolactin and oxytocin

Question 102

Oxytocin and antidiuretic hormone (ADH) are synthesized in the ________ but released from the ________.
A) hypothalamus; posterior pituitary
B) adenohypophysis; posterior pituitary
C) posterior pituitary; anterior pituitary
D) hypothalamus; anterior pituitary

Answer 102

A) hypothalamus; posterior pituitary

Question 103

What would be a likely outcome of a person not consuming enough iodine in their diet?
A) high body temperature
B) high levels of circulating blood glucose
C) reduced cellular metabolism
D) stronger muscle contractions

Answer 103

C) reduced cellular metabolism

Question 104

Which of the following is the most likely explanation for hypothyroidism in a patient whose
iodine level is normal?
A) greater production of T3 than of T4
B) hyposecretion of thyroid-stimulating hormone (TSH)
C) hypersecretion of thyrotropin-releasing hormone (TRH)
D) a decrease in the thyroid secretion of calcitonin

Answer 104

B) hyposecretion of thyroid-stimulating hormone (TSH)

Question 105

When a person drinks alcohol, the rate of urination increases. Which of the following best accounts for the increase in urination above normal rates?
A) Alcohol stimulates the release of thyroid hormones.
B) Alcohol inhibits the release of ADH.
C) Alcohol inhibits the actions of calcitonin.
D) Alcohol stimulates the release of oxytocin which causes more water secretion.

Answer 105

B) Alcohol inhibits the release of ADH

Question 106

Removing which of the following glands would have the most wide-reaching effect on bodily functions of an adult human?
A) adrenal glands
B) pituitary gland
C) thyroid gland
D) ovaries (in female) or testes (in male)

Answer 106

B) pituitary gland

Question 107

Glucocorticoids do which of the following?
A) promote the immune response
B) promote the release of fatty acids
C) increase blood glucose levels
D) increase insulin production

Answer 107

C) increase blood glucose levels

Question 108

Fight-or-flight reactions include activation of the ________.
A) parathyroid glands, leading to increased metabolic rate
B) anterior pituitary gland, leading to cessation of gonadal function
C) adrenal medulla, leading to increased secretion of epinephrine
D) pancreas, leading to a reduction in the blood sugar concentration

Answer 108

C) adrenal medulla, leading to increased secretion of epinephrine

Question 109

The amino acid tyrosine is a starting substrate for the synthesis of ________.
A) epinephrine
B) steroid hormones
C) parathyroid hormone
D) acetylcholine

Answer 109

A) epinephrine

Question 110

If the adrenal cortex were surgically removed, an increase in the plasma levels of ________ would likely be observed.
A) glucocorticoid hormones
B) epinephrine
C) adrenocorticotropic hormone (ACTH)
D) acetylcholine

Answer 110

C) adrenocorticotropic hormone (ACTH)

Question 111

During a stressful interval, ________.
A) thyroid-stimulating hormone (TSH) stimulates the adrenal cortex and medulla to secrete acetylcholine
B) increased acid in the duodenum stimulates the S cells to release secretin
C) adrenocorticotropic hormone (ACTH) stimulates the adrenal cortex, and neurons of the sympathetic nervous system stimulate the adrenal medulla
D) the calcium levels in the blood are increased due to actions of two antagonistic hormones, epinephrine and norepinephrine

Answer 111

C. adrenocorticotropic hormone (ACTH) stimulates the adrenal cortex, and neurons of the sympathetic nervous system stimulate the adrenal medulla

Question 112

In response to stress, the adrenal gland promotes the synthesis of glucose from noncarbohydrate substrates via the action of the steroid hormone ________.
A) estradiol
B) cortisol
C) thyroxine
D) adrenocorticotropic hormone (ACTH)

Answer 112

B) cortisol

Question 113

Melatonin is secreted by the ________.
A) hypothalamus during the day
B) pineal gland during the night
C) autonomic nervous system during the winter
D) posterior pituitary gland during the day

Answer 113

B) pineal gland during the night

Question 114

Diethylstilbestrol (DES) is called an “endocrine disrupting chemical” because it interferes with the endocrine secretions of the ________.
A) thyroid gland
B) adrenal medulla
C) ovaries
D) hypothalamus

Answer 114

C) Ovaries

Question 115

Following a stressful stimulus, the fight-or-flight response will cause ________.
A) glucose to be stored in liver cells
B) epinephrine to be released from the anterior pituitary
C) an increase release of thyroid hormones
D) the breakdown of glycogen into glucose

Answer 115

D) the breakdown of glycogen into glucose

Question 116

Osteoporosis is a condition in which the density of bones is decreased so much that the
individual is at a higher risk of fractures. The more calcium in the bones, the better the bone
density. Which of the following would produce the greatest increase in bone calcium levels?
A) calcitonin injection
B) calcitonin receptor blocker
C) parathyroid hormone injection
D) glucagon receptor blocker

Answer 116

A) calcitonin injection

Question 117

Predict the effects of a drug that increases adrenocorticotropic hormone (ACTH) synthesis.
A) increase in glucocorticoid production
B) increase in release of corticotropin-releasing hormone (CRH)
C) decrease in cortisol release
D) decrease in release of corticotropin-releasing hormone (CRH)

Answer 117

A) increase in glucocorticoid production

Question 118

People experiencing chronic stress may be more likely to become sick because ________.
A) too much thyroid hormone is being produced
B) elevated epinephrine concentrations deplete all of the available glucose in the body
C) high circulating glucocorticoid can suppress the immune response
D) their blood glucose is not being regulated appropriately

Answer 118

C) high circulating glucocorticoid can suppress the immune response

Question 119

Correct and appropriate signal transduction processes are generally under strong selective pressure and are determined by the properties of the molecules involved, the concentrations of signal and receptor molecules, and the binding affinities between signal and receptor. Therefore, a hormone action is very specific in a species at any one point in time. However, there are examples of very diverse functions of a specific hormone between groups of organisms. For example, thyroxin, which is produced in all vertebrates and many invertebrates, can trigger
growth, differentiation, metamorphosis, maturation, reproduction, behavior, temperature tolerance, osmoregulation, or seasonal adaptation depending on the organism in which it is produced. What is the most logical explanation for such different responses triggered by thyroxin in organisms?
A) The concentration of thyroxin varies in different organisms. Invertebrate organisms do not have as much thyroxin as vertebrate organisms.
B) Thyroxin and its receptor molecules have a different binding affinity in different organisms.
C) Receptor molecules for thyroxin are located on different tissues in different organisms.
D) The function of thyroxine in a particular tissue is determined by the genes that are transcribed by the activated thyroxine receptor.

Answer 119

D) the function of thyroxine in a particular tissue is determined by the genes that are transcribed

Question 120

The body’s reaction to parathyroid hormone (PTH), raising plasma levels of calcium, can be opposed by ________.
A) thyroxine
B) epinephrine
C) growth hormone
D) calcitonin

Answer 120

D) calcitonin

Question 121

Rapid changes to skin color in many vertebrates is under the control of ________.
A) melanocyte-stimulating hormone
B) adrenocorticotropic hormone
C) thyroxine
D) melatonin

Answer 121

A) melanocyte-stimulating hormone

Question 122

The detector of light during de-etiolation (greening) of a tomato plant is (are) ________.
A) carotenoids
B) xanthophylls
C) phytochrome
D) auxin

Answer 122

C) phytochrome

Question 123

Plant hormones ________.
A) in plant cells naturally exist in very large amounts
B) change their shape in response to stimulus
C) are unable to move from one cell to another
D) affect only cells with the appropriate receptor

Answer 123

D) affect only cells with the appropriate receptor

Question 124

Which of the following mechanisms is the correct sequence of events that takes place during the plant responses to internal and external signals?
A) transduction, reception, and response
B) reception and transduction
C) reception, transduction, and response
D) reception and response

Answer 124

C) reception, transduction, and response

Question 125

Which of the following mechanisms is in the correct sequence of steps (I-IV as listed below)
that takes place during the formation of de-etiolation (greening) response proteins in plants?
I. Detection of light signal
II. Activation of phytochrome
III. Activation of specific protein kinase1
IV.Formation of de-etiolation response protein
A) I, III, II, and IV
B) I, II, III, and IV
C) II, I, III, and IV
D) III, I, II, and IV

Answer 125

B) I, II, III, and IV

Question 126

Which of the following can function in signal transduction in plants?
I. calcium ions
II. nonrandom mutations
III. receptor proteins
IV. autochrome
V. secondary messengers
A) only I, III, and IV
B) only I, II, and V
C) only I, III, and V
D) only II, III, and V

Answer 126

C) Only I, III, and V

Question 127

Plant hormones produce their effects by ________.
I. altering the expression of genes
II. modifying the permeability of the plasma membrane
III. modifying the structure of the nuclear envelope membrane
A) only I
B) only II
C) only III
D) only I and II

Answer 127

D) only I and II

Question 128

Plant hormonal regulation differs from animal hormonal regulation in that ________.
A) there are no dedicated hormone-producing organs in plants as there are in animals
B) all production of hormones is local in plants with little long-distance transport
C) only animal hormone concentrations are developmentally regulated
D) only animal hormones may have either external or internal receptors

Answer 128

A) there are no dedicated hormone-producing organs in plants as there are in animals

Question 129

Auxins in plants are known to affect which of the following processes?
I. gravitropism of shoots
II. maintenance of seed dormancy
III. phototropism of shoots
IV. inhibition of lateral buds
V. apical dominance
A) only I and II
B) only I, III, and V
C) only I, III, IV, and V
D) only II, III, IV, and V

Answer 129

B) only I, III, and V

Question 130

Experiments on the positive phototropic response of plants indicate that ________.
A) light destroys auxin
B) auxin moves down the plant apoplastically
C) auxin is synthesized in the area where the stem bends
D) auxin can move to the shady side of the stem

Answer 130

D) auxin can move to the shady side of the stem

Question 131

What are the primary sites of auxin (IAA) production in plants?
A) shoot apical meristem and young leaves
B) roots
C) seeds
D) ripening fruits

Answer 131

A) shoot apical meristem and young leaves

Question 132

What are the primary sites of ethylene production in high concentrations in plants?
A) shoot apical meristem and young leaves
B) roots
C) seeds
D) ripening fruits

Answer 132

D) Ripening fruits

Question 133

Which one of the following hormones regulates cell division in plants?
A) auxin (IAA)
B) ethylene
C) gibberellins
D) cytokinins

Answer 133

D) cytokinins

Question 134

Which one of the following hormones stimulates stem elongation and pollen tube growth?
A) auxin (IAA)
B) ethylene
C) gibberellins
D) cytokinins

Answer 134

C) gibberellins

Question 135

Generally, each hormone has multiple functions in plants depending on ________.
I. site of action
II. its concentration
III. developmental stage
IV. age
A) I, II, III, and IV
B) I, II, and III
C) I and II
D) II

Answer 135

B) I, II, and III

Question 136

Apical dominance in plants is under the control of ________.
A) sugar
B) various plant hormones
C) cell division
D) sugar and various plant hormones

Answer 136

D) sugar and various plant hormones

Question 137

Arrange the following steps that occur during drought tolerance in plants in a correct sequence.
I. hormone ABA accumulation in the leaves
II. causes stomata to close
III. reduction in transpiration
IV. preventing further water loss
A) I, II, III, and IV
B) I, III, II, and IV
C) II, I, III, and IV
D) III, I, II, and IV

Answer 137

A) I, II, III, and IV

Question 138

Which of the following statements best summarizes the acid growth hypothesis in an actively growing shoot?
A) Auxin stimulates proton pumps in the plasma membrane and tonoplast.
B) Auxin-activated proton pumps lower the pH of the cell wall, which breaks bonds and makes the walls more flexible.
C) Auxins and gibberellins together act as a lubricant to help stretch cellulose microfibrils.
D) Auxins activate aquaporins that increase turgor pressure in the cells

Answer 138

B) Auxin-activated proton pumps lower the pH of the cell wall, which breaks bonds and makes the walls more flexible

Question 139

Which of the following conclusions is supported by the research of both Peter Boysen-Jensen and Charles and Francis Darwin on shoot responses to light?
A) When shoots are exposed to light, a chemical substance migrates toward the light.
B) A chemical substance involved in shoot bending is produced in shoot tips.
C) Once shoot tips have been cut, normal growth cannot be induced.
D) Light stimulates the synthesis of a plant hormone that responds to light.

Answer 139

B) A chemical substance involved in shoot bending is produced in shoot tips

Question 140

An eccentric millionaire botanist has offered a $25,000 scholarship to anyone who can successfully get a plant to grow through a vertical maze in complete darkness. The maze is not in a box; the maze is simply drawn on the wall, and the contestants must get their plant to grow in a pattern that matches the path through the maze. You need the money and feel confident that you can accomplish this task. Which of the following techniques will help you succeed?
A) Apply auxin directly to the shoot tip on the side to which you want the tip to bend.
B) Apply auxin directly to the part of the stem just below the tip opposite from the direction you want the stem to bend.
C) Inject compounds that block auxin receptors into the part of the stem opposite from the direction you want the stem to bend.
D) Plant the roots in two different pots, and apply auxin to the root bucket that is on the same side as the direction you want the plant to bend.

Answer 140

B) Apply auxin directly to the part of the stem just below the tip opposite from the direction you want the stem to bend

Question 141

You have a small tree in your yard that is the height that you want it, but does not have as many branches as you want. How can you prune it to trigger it to increase the number of branches?
A) Cut off the leaves at the ends of several branches.
B) Cut off the tips of the main shoots.
C) Cut off lower branches.
D) Cut off the leaves at the base of most of the branches.

Answer 141

B) Cut off the tips of the main shoots

Question 142

As cytokinins are primarily produced in roots, what route would they travel to influence lateral shoot formation in a recently topped tree?
A) symplastic
B) tracheids/vessels
C) phloem
D) apoplastic

Answer 142

D) apoplastic

Question 143

Who might be interested in using cytokinins?
A) grocers, to spray on fruit to enhance ripening in the store
B) consumers, to spray on fruit before eating to enhance taste
C) florists, to dip stems in to keep leaves green longer
D) farmers, to spray on fruit after picking to stall ripening

Answer 143

B) consumers to spray on fruit before eating to enhance taste

Question 144

If a farmer wanted more loosely packed clusters of grapes, he would most likely spray the immature bunches with ________.
A) auxin
B) gibberellins
C) cytokinins
D) abscisic acid

Answer 144

B) gibberelins

Question 145

________ prevents seeds from germinating until conditions are favorable for the growth of the plant.
A) Ethylene
B) Zeaxanthin
C) Gibberellin
D) Abscisic acid

Answer 145

D) Abscisic acid

Question 146

A population of plants experiences several years of severe drought. Much of the population dies due to lack of water, but a few individuals survive. You set out to discover the physiological basis for their adaptation to such an extreme environmental change. You hypothesize that the survivors have the ability to synthesize higher levels of ________ than their siblings do.
A) auxin
B) gibberellin
C) cytokinin
D) abscisic acid

Answer 146

D) abscisic acid

Question 147

If you were shipping green bananas to a supermarket thousands of miles away, which of the following chemicals would you want to eliminate from the plants’ environment?
A) carbon dioxide
B) cytokinins
C) ethylene
D) auxin

Answer 147

C) ethylene

Question 148

In the fall, the leaves of some trees change color. This happens because chlorophyll breaks down and the accessory pigments become visible. What hormone is responsible for this?
A) phototropin
B) abscisic acid
C) cytokinin
D) ethylene

Answer 148

D) ethylene

Question 149

Which type of mutant would be most likely to produce a bushier phenotype?
A) auxin overproducer
B) strigolactone overproducer
C) cytokinin underproducer
D) strigolactone underproducer

Answer 149

D) strigolactone underproducer

Question 150

Vines in tropical rain forests must grow toward large trees before being able to grow toward the sun. To reach a large tree, the most useful kind of growth movement for a tropical vine presumably would be ________.
A) negative thigmotropism
B) negative phototropism
C) negative gravitropism
D) the opposite of circadian rhythms

Answer 150

B) negative phototropism

Question 151

Upon exposure to blue light, plants not only begin to grow toward the light, but move their chloroplasts to the sunny side of each cell. The adaptive advantage of moving chloroplasts to the sunny side of each cell ________.
A) maximizes light absorption by the chloroplasts for photosynthesis
B) increases production of phototropic hormones
C) maximizes heat absorption by the chloroplasts for cellular respiration
D) increases adenosine triphosphate (ATP) production during the light-independent reactions

Answer 151

A) maximizes light absorption by the chloroplasts for photosynthesis

Question 152

Mammalian eyes sense light because the photoreceptor cells have molecules called opsins, which change structure when exposed to light. Which of the following plant molecules would be analogous to mammalian opsins in their light-sensing ability?
A) auxin and phytochrome
B) auxin and Pfr
C) Pfr and phytochrome
D) cytokinins and phototropins

Answer 152

C) Pfr and phytochrome

Question 153

Seed packets give a recommended planting depth for the enclosed seeds. The most likely reason some seeds are to be covered with only 1/4 inch of soil is that the ________.
A) seedlings do not have an etiolation response
B) seeds require light to germinate
C) seeds require a higher temperature to germinate
D) seeds are very sensitive to waterlogging

Answer 153

B) seeds require light to germinate

Question 154

Suppose a plant had a photosynthetic pigment that absorbed far-red wavelengths of light. In which of the following environments could that plant thrive?
A) on the surface of a lake
B) on the forest floor, beneath a canopy of taller plants
C) on the ocean floor, in very deep waters
D) on mountaintops, closer to the Sun

Answer 154

B) on the forest floor, beneath a canopy of taller plants

Question 155

The biological clock controlling circadian rhythms must ultimately ________.
A) depend on environmental cues
B) affect gene transcription
C) stabilize on a 24-hour cycle
D) speed up or slow down with increasing or decreasing temperature

Answer 155

B) affect gene transcription

Question 156

Which of the colors of visible light induces curvature in coleoptile most effectively?
A) red
B) blue
C) violet
D) orange

Answer 156

B) blue

Question 157

Phytochrome plays a critical role in seed germination. Which of the colors maximizes the seed germination?
A) red
B) blue
C) violet
D) orange

Answer 157

A) red

Question 158

Many plants flower in response to day-length cues. Which of the following statements best summarizes this phenomenon?
A) As a rule, short-day plants flower in the summer.
B) As a rule, long-day plants flower in the spring or fall.
C) Long-day plants flower in response to long days, not short nights.
D) Flowering in short-day and long-day plants is controlled by phytochrome.

Answer 158

D) Flowering in short-day and long-day plants is controlled by phytochrome

Question 159

Plants often use changes in day length (photoperiod) to trigger events such as dormancy and flowering. It is logical that plants have evolved this mechanism because photoperiod changes ________.
A) are more predictable than air temperature changes
B) predict moisture availability
C) are modified by soil temperature changes
D) can reset the biological clock

Answer 159

A) are more predictable than air temperature changes

Question 160

A gardener in Canada wants to surprise his mother on her birthday and make her favorite hibiscus bush flower in May instead of at the end of June. The bush is growing in the greenhouse. Which of the following might make the hibiscus bush flower early?
A) grafting leaves of a hibiscus that was exposed to long nights
B) grafting leaves of a hibiscus that was exposed to short nights
C) exposing flower buds of the hibiscus bush to long nights
D) exposing flower buds of the hibiscus bush to short nights

Answer 160

B) grafting leaves of a hibiscus that was exposed to short nights

Question 161

Which of the following environmental factors can be sensed by plants?
I) gravity
II) pathogens
III) wind
IV)light
A) only I and III
B) only I, II, and IV
C) only II, III, and IV
D) I, II, III, and IV

Answer 161

D) I, II, III, and IV

Question 162

Shoots that grow vertically toward the sun can be characterized as ________.
A) positive for phototropism and negative for gravitropism
B) neutral for phototropism and positive for gravitropism
C) negative for phototropism and positive for gravitropism
D) positive for phototropism and neutral for gravitropism

Answer 162

A) positive for phototropism and negative for gravitropism

Question 163

The rapid leaf movements resulting from a response to touch (thigmotropism) primarily involve ________.
A) potassium channels
B) nervous tissue
C) aquaporins
D) stress proteins

Answer 163

A) potassium channels

Question 164

In extremely cold regions, woody species may survive freezing temperatures by ________.
A) emptying water from the vacuoles to prevent freezing
B) decreasing the numbers of phospholipids in cell membranes
C) decreasing the fluidity of all cellular membranes
D) increasing cytoplasmic levels of specific solute concentrations, such as sugars

Answer 164

D) increasing cytoplasmic levels of specific solute concentrations, such as sugars

Question 165

Most scientists agree that global warming is underway; thus, it is important to know how plants respond to heat stress. Which of the following would be a useful line of inquiry to try and improve plant response and survival to heat stress?
A) the production of heat-stable carbohydrates
B) increased production of heat-shock proteins
C) the opening of stomata to increase evaporational heat loss
D) protoplast fusion experiments with xerophytic plants

Answer 165

B) increased production of heat-shock proteins

Question 166

When an arborist prunes a limb off a valuable tree, he or she may paint the cut surface. The primary purpose of the paint is to ________.
A) minimize water loss by evaporation from the cut surface
B) improve the appearance of the cut surface
C) stimulate growth of the cork cambium to “heal” the wound
D) block entry of pathogens through the wound

Answer 166

D) block entry of pathogens through the wound

Question 167

You are out working in your garden, and you notice that one of your favorite flowering plants has black, dead spots on the leaves. You immediately suspect that the plant has been invaded by a pathogen and has initiated a(n) ________.
A) avirulence response
B) hypersensitive response
C) resistance response
D) virulence response

Answer 167

B) hypersensitive response

Question 168

Generalized defense responses in organs distant from the infection site are called ________.
A) hyperactive responses
B) systemic acquired resistance
C) pleiotropy
D) hyperplasia

Answer 168

B) systemic acquired resistance

Question 169

A particular species of virus carries a gene for salicylate hydroxylase, an enzyme that breaks down salicylic acid. Will this virus be more or less virulent to plants than other viruses?
A) more virulent
B) less virulent
C) same virulent
D) faster virulent

Answer 169

A) more virulent

Question 170

Which event during the evolution of land plants favored the synthesis of secondary compounds?
A) the greenhouse effect throughout the Devonian period
B) the reverse-greenhouse effect during the Carboniferous period
C) the association of the roots of land plants and fungi
D) the rise of herbivory

Answer 170

D) the rise of herbivory

Question 171

For a plant to initiate chemical responses to herbivory, before it is directly affected by herbivores, ________.
A) a plant must have already flowered at least once
B) volatile “signal” compounds must be perceived
C) gene-for-gene intraspecific recognition must occur
D) phytoalexins must be released

Answer 171

B) volatile “signal” compounds must be perceived

Question 172

You may have observed plants rotate towards a light source, thereby increasing the plant’s ability to intercept light energy and increase photosynthesis. You, however, are given the task of preventing grass seedlings from rotating toward the light. Using your knowledge of phototropism, which of the following experimental procedures would you use to complete your task?
A) Cover the growing tip of the grass seedling with black paper.
B) Supply the seedlings with very dim light (red light does not induce a bend).
C) Cover the portion of the seedling below the tip with a black shield.
D) Supply the seedling with nutrient-rich fertilizer solution.

Answer 172

A) Cover the growing tip of the grass seedling with black paper.

Question 173

A plant scientist was hired by a greenhouse operator to devise a way to force iris plants to bloom in the short days of winter. Iris normally blooms as a long-day (short-night) plant. Which
of the following has the best chance of creating iris blooms in winter?
A) Artificially increase the period of darkness in the greenhouse.
B) Increase the temperature to more closely follow summer temperatures.
C) Alternate four hours of darkness with four hours of light repeatedly over each 24-hour period.
D) Interrupt the long winter nights with a brief period of light.

Answer 173

D) interrupt the long winter nights with a brief period of light.

Question 174

An individual plant was discovered that could not grow towards light. After some research, it was determined that the reason was a defective gene that did not allow for the level of cell elongation necessary for a phototropic response. This mutation greatly reduces the fitness of the individual plant. Which reason best describes the reason for the loss of fitness?
A) The plant was too short to attract insects for pollination.
B) The plant could not adjust to directional light, which reduced photosynthetic activity and
therefore energy available for reproduction.
C) Because the plant grew much taller and straighter, resources that could be used for reproduction were used for growth.
D) The loss of a phototropic response meant that the plant’s seeds could not germinate, so reproduction would be unsuccessful.

Answer 174

B) The plant could not adjust to directional light, which reduced photosynthetic activity and therefore energy available for reproduction

Question 175

Suppose researchers marked 800 turtles and later were able to trap a total of 300 individuals in that population, of which 150 were marked. What is the estimate for total population size?
A) 200
B) 1,050
C) 1,600
D) 2,100

Answer 175

C) 1600

Question 176

Which of the following assumptions must be made regarding the mark-recapture estimate of population size?
I) Marked and unmarked individuals have the same probability of being trapped.
II) The marked individuals have thoroughly mixed with the population after being marked.
III) No individuals have entered or left the population by immigration or emigration, and no individuals have been added by birth or eliminated by death during the course of the estimate.
A) I only
B) II only
C) I and II only
D) I, II, and III

Answer 176

D) I, II, and III

Question 177

Which of the following is the most important assumption for the mark-recapture method to estimate the size of wildlife populations?
A) More individuals emigrate from, as opposed to immigrate into, a population.
B) Over 50% of the marked individuals were trapped during the recapture phase.
C) There is a 50:50 ratio of males to females in the population before and after trapping and recapture.
D) Marked individuals have the same probability of being recaptured as unmarked individuals during the recapture phase.

Answer 177

D) Marked individuals have the same probability of being recaptured as unmarked individuals during the recapture phase

Question 178

To measure the population of lake trout in a 250-hectare lake, 400 individual trout were netted and marked with a fin clip, then returned to the lake. The next week, the lake was netted again, and out of the 200 lake trout that were caught, 50 had fin clips. Using the mark-recapture estimate, the lake trout population size could be closest to which of the following?
A) 200
B) 400
C) 1,600
D) 80,000

Answer 178

C) 1600

Question 179

Long-term studies of Belding’s ground squirrels show that immigrants move nearly 2 kilometers from where they are born and become 1%-8% of the males and 0.7%-6% of the females in other populations. On an evolutionary scale, why is this significant?
A) These immigrants make up for the deaths of individuals, keeping the other populations’ size stable.
B) These immigrants provide a source of genetic diversity for the other populations.
C) Those individuals that emigrate to these new populations are looking for less crowded conditions with more resources.
D) Gradually, the populations of ground squirrels will move from a clumped to a uniform population pattern of dispersion.

Answer 179

B) These immigrants provide a source of genetic diversity for the other populations

Question 180

An ecologist recorded 12 white-tailed deer, Odocoileus virginianus, per square kilometer (km²) in one woodlot and 20 km² in another woodlot. What was the ecologist comparing?
A) density
B) dispersion
C) carrying capacity
D) range

Answer 180

A) density

Question 180

Uniform spacing patterns in plants such as the creosote bush are most often associated with ________.
A) patterns of high humidity
B) the random distribution of seeds
C) competitive interaction between individuals of the same population
D) the concentration of nutrients within the population’s range

Answer 180

C) competitive interaction between individuals of the same population

Question 181

Which of the following groups would be most likely to exhibit uniform dispersion?
A) red squirrels, who actively defend territories
B) cattails, which grow primarily at edges of lakes and streams
C) dwarf mistletoes, which parasitize particular species of forest tree
D) lake trout, which seek out cold, deep water high in dissolved oxygen

Answer 181

A) red squirrels, who actively defend territories

Question 182

Which of the following examples would most accurately measure the dispersion of a population being studied?
A) counting the number of times a one-kilometer transect is intersected by tracks of red squirrels after a snowfall
B) measuring the distance between several burrows within a large prairie dog colony in a grassland
C) measuring the average distance between individuals and their nearest neighbor, and then analyzing the variation and comparing those measurements at larger scales
D) counting the number of zebras from airplane census observations

Answer 182

C) measuring the average distance between individuals and their nearest neighbor, and then analyzing the variation and comparing those measurements at larger scales

Question 183

Which of the following scenarios would provide the most accurate data on population density?
A) Count the number of nests of a particular species of songbird and multiply this by a factor that extrapolates these data to actual animals.
B) Count the number of pine trees in several randomly selected 10-meter-square plots and extrapolate this number to the fraction of the study area these plots represent.
C) Use the mark-recapture method to estimate the size of the population.
D) Calculate the difference between all of the immigrants and emigrants to see if the population is growing or shrinking.

Answer 183

B) Count the number of pine trees in several randomly selected 10-meter-square plots and extrapolate this number to the fraction of the study area these plots represent

Question 184

Which of the following is the best natural example of a uniform pattern of dispersion?
A) bees collecting pollen in a wildflower meadow
B) moss spores floating in the wind to new locations of a forest
C) territorial songbirds in a mature forest during mating season
D) mushrooms growing on the floor of an old growth forest

Answer 184

D) mushrooms growing on the floor of an old growth forest

Question 185

In July 2008, the United States had a population of approximately 302,000,000 people. How many Americans were there in July 2009, if the estimated 2008 growth rate was 0.88%?
A) 567,760,000
B) 304,657,600
C) 304,000,000
D) 2,657,600

Answer 185

B) 304,657,600

Question 186

In 2008, the population of New Zealand was approximately 4,275,000 people. If the birth rate was 14 births for every 1,000 people, approximately how many births occurred in New Zealand in 2008?
A) 6,000
B) 42,275
C) 59,850
D) 140,000

Answer 186

C) 59,850

Question 187

A population of ground squirrels has an annual per capita birth rate of 0.06 and an annual per capita death rate of 0.02. Using these birth and death rates, calculate an estimate of the total number of individuals added to (or lost from) a population of 1,000 individuals in one year.
A) 120 individuals added
B) 40 individuals added
C) 20 individuals added
D) 400 individuals added

Answer 187

B) 40 individuals added

Question 188

Starting from a single individual, what is the size of a population of bacteria at the end of a 2-hour time period if they reproduce by binary fission every 20 minutes? (Assume unlimited resources and no mortality.)
A) 16
B) 32
C) 64
D) 128

Answer 188

C) 64

Question 189

During exponential growth, a population always ________.
A) grows at its maximum per capita rate
B) quickly reaches its carrying capacity
C) adds more new individuals when the population is small than when it is large
D) loses some individuals to emigration

Answer 189

A) grows at its maximum per capita rate

Question 190

Consider two old-growth forests: One is undisturbed while the other is being logged. In which region are species likely to experience exponential growth, and why?
A) old growth, because of stable conditions that would favor exponential growth of all species in the forest
B) old growth, because each of the species is well established and can produce many offspring
C) logged, because the disturbed forest affords more resources for increased specific populations to grow
D) logged, because the various populations are stimulated to a higher reproductive potential

Answer 190

C) logged, because the disturbed forest affords more resources for increased specific populations to grow.

Question 191

Imagine that you are managing a large game ranch. You know from historical accounts that a species of deer used to live there, but they have been extirpated. After doing some research to determine what might be an appropriately sized founding population, you reintroduce them. You then watch the population increase for several generations, and graph the number of individuals
(vertical axis) against the number of generations (horizontal axis). With no natural predators impacting the population, the graph will likely appear as ________.
A) a diagonal line, getting higher with each generation
B) an “S” that ends with a vertical line
C) an upside-down “U”
D) a “J,” increasing with each generation

Answer 191

D) a “J,” increasing with each generation

Question 192

Which statements about K are correct?
I) K varies among populations.
II) K varies in space.
III) K varies in time.
IV)K is constant for any given species.
A) only I and III
B) only II and IV
C) only I, II, and III
D) only II, III, and IV

Answer 192

C) only I, II, and III

Question 193

As N approaches K for a certain population, which of the following outcomes is predicted by the logistic equation?
A) The population growth rate will not change.
B) The population growth rate will approach zero.
C) The population size will increase exponentially.
D) The carrying capacity of the environment will increase.

Answer 193

B) The population growth rate will approach zero

Question 194

Which of the following causes populations to shift most quickly from an exponential to a logistic population growth?
A) favorable climatic conditions
B) removal of predators
C) decreased death rate
D) competition for resources

Answer 194

D) competition for resources

Question 195

According to the logistic growth equation, _______
A) the number of individuals added per unit time is greatest when N is close to zero
B) the per capita growth rate (r) increases as N approaches K
C) population growth is zero when N equals K
D) the population grows exponentially when K is small

Answer 195

C) population growth is zero when N equals K

Question 196

What is the primary limiting factor that determines why no female animal can produce a very large number of very large eggs?
A) Time is limited.
B) There are energy constraints.
C) Temperature constraints will prevent females from carrying too many eggs.
D) There will be an increase in predation pressure if the females carry too many large eggs.

Answer 196

B) There are energy constraints

Question 197

You observe two breeding female fish of the same species. One female lays 100 eggs and the other female lays 1,000 eggs. Which one of the following outcomes is most likely, given the
limits of fitness trade-offs?
A) The female laying 1,000 eggs breeds more often than the female laying 100 eggs.
B) The female laying 100 eggs lives longer than the female laying 1,000 eggs.
C) The eggs from the female laying 1,000 eggs have larger yolks than the yolks of the eggs from the female laying 100 eggs.
D) The female laying 100 eggs is larger than the female laying 1,000 eggs.

Answer 197

B) The female laying 100 eggs lives longer than the female laying 1000 eggs

Question 198

Which pair of terms most accurately describes life history traits for a stable population of wolves?
A) semelparous; r-selected
B) semelparous; K-selected
C) iteroparous; r-selected
D) iteroparous; K-selected

Answer 198

D) iteroparous; K-selected

Question 199

Natural selection involves energetic trade-offs between ________.
A) choosing how many offspring to produce over the course of a lifetime and how long to live
B) producing large numbers of gametes when employing internal fertilization versus fewer numbers of gametes when employing external fertilization
C) increasing the number of individuals produced during each reproductive episode and a corresponding decrease in parental care
D) high survival rates of offspring and the cost of parental care

Answer 199

D) high survival rates of offspring and the cost of parental care

Question 200

Which of the following traits is characteristic of K-selected populations?
A) offspring with good chances of survival
B) many offspring per reproductive episode
C) small offspring
D) a high intrinsic rate of increase

Answer 200

A) offspring with good chances of survival

Question 201

In which of the following situations would you expect to find the largest number of r-selected individuals?
A) a recently abandoned agricultural field in Colorado
B) a sand dune community south of Lake Michigan
C) an old-growth forest with large, mature trees
D) a coral reef community off the coast of Mexico

Answer 201

A) a recently abandoned agricultural field in Colorado

Question 202

A population of white-footed mice becomes severely overpopulated in a habitat that has been disturbed by human activity. Sometimes intrinsic factors cause the population to increase in mortality and cause lower reproduction rates to occur in reaction to the stress of overpopulation. Which of the following is an example of intrinsic population control?
A) Owl populations frequent the area more often because of increased hunting success.
B) Females undergo hormonal changes that delay sexual maturation, and many individuals suffer depressed immune systems and die due to the stress of overpopulation.
C) Clumped dispersion of the population leads to increased spread of disease and parasites, resulting in a population crash.
D) All of the resources (food and shelter) are used up by overpopulation, and much of the population dies of exposure and/or starvation.

Answer 202

B) Females undergo hormonal changes that delay sexual maturation, and many individuals suffer depressed immune systems and die due to the stress of overpopulation

Question 203

Which of the following statements regarding the future of populations in developing, less
industrialized countries are correct?
I) The reproductive rates are predicted to remain below replacement level.
II) Survivorship will increase.
III) Overall population size will increase dramatically.
IV)The fertility rate is predicted to remain high, especially in some regions.
A) only I and III
B) only II and IV
C) only II, III, and IV
D) only I, II, and III

Answer 203

C) only II, III, and IV

Question 204

Why does the U.S. population continue to grow even though the United States has essentially established a zero population growth (ZPG)?
A) emigration
B) immigration
C) baby boomer reproduction
D) the 2007-2009 economic recession

Answer 204

B) immigration

Question 205

A recent study of ecological footprints concluded that ________.
A) Earth’s carrying capacity would increase if per capita meat consumption increased
B) current demand by industrialized countries for resources is much smaller than the ecological footprint of those countries
C) it is not possible for technological improvements to increase Earth’s carrying capacity for humans
D) the ecological footprint of the United States is large because per capita resource use is high

Answer 205

D) the ecological footprint of the United States is large because per capita resource use is high

Question 206

Which of the following statements about human population in industrialized countries are correct?
I) Life history is r-selected.
II) The population has undergone the demographic transition.
III) The survivorship curve is Type III.
IV) Age distribution is relatively uniform.
A) only I and III
B) only II and IV
C) only I, II, and IV
D) only II, III, and IV

Answer 206

B) only II and IV

Question 207

Some birds follow moving swarms of army ants in the tropics. As the ants march along the forest floor hunting insects and small vertebrates, birds follow and pick off any insects or small
vertebrates that fly or jump out of the way of the ants. This situation is an example of what kind of species interaction between the birds and the ants?
A) consumption
B) commensalism
C) parasitism
D) mutualism

Answer 207

B) commensalism

Question 208

As you study two closely related predatory insect species, the two-spot and the three-spot avenger beetles, you notice that each species seeks prey at dawn in areas without the other species. However, where their ranges overlap, the two-spot avenger beetle hunts at night and the three-spot hunts in the morning. When you bring them into the laboratory and isolate the two different species, you discover that the offspring of both species are found to be nocturnal. You have discovered an example of ________.
A) mutualism
B) character displacement
C) Batesian mimicry
D) resource partitioning

Answer 208

D) resource partitioning

Question 209

The symbols +, -, and 0 are used to show the results of interactions between individuals and groups of individuals. The symbol + denotes a positive interaction, - denotes a negative interaction, and 0 denotes interactions in which individuals are not affected. The first symbol refers to the first organism mentioned. What interactions exist between a lion pride and African wild dogs, if the dogs are found to typically avoid areas with lions?
A) +/+
B) +/-
C) 0/0
D) -/-

Answer 209

B) +/-

Question 210

The symbols +, -, and 0 are used to show the results of interactions between individuals and groups of individuals. The symbol + denotes a positive interaction, - denotes a negative interaction, and 0 denotes interactions in which individuals are not affected. The first symbol refers to the first organism mentioned. Which fact is correct when describing species
interactions?
A) +/0 will always remain such.
B) A +/- interaction could shift to +/0 or +/+ over time, depending on other factors such as competition, population density, or environmental changes.
C) Species interactions occur in isolation and cannot affect the structure of ecological communities.
D) A -/- interaction benefits both of the species in the relationship.

Answer 210

B) A +/- interaction could shift to +/0 or +/+ over time, depending on other factors such as competition, population density, or environmental changes

Question 211

Which of the following statements is consistent with the principle of competitive exclusion?
A) The random distribution of one competing species will have a positive impact on the population growth of the other competing species.
B) If two species have the same fundamental niche, one will exclude the other competing species.
C) Even a slight reproductive advantage will eventually lead to the elimination of the less well adapted of two competing species.
D) Natural selection tends to increase competition between related species.

Answer 211

C) Even a slight reproductive advantage will eventually lead to the elimination of the less well-adapted of two competing species

Question 212

If two species are close competitors, and one species is experimentally removed from the community, the remaining species would be expected to ________.
A) change its fundamental niche
B) decline in abundance
C) become the target of specialized parasites
D) expand its realized niche

Answer 212

D) expand its realized niche

Question 213

Which of the following is an example of a commensalism?
A) fungi residing in plant roots, such as endomycorrhizae
B) bacteria fixing nitrogen on the roots of some plants
C) rancher ants that protect aphids in exchange for sugar-rich honeydew
D) cattle egrets eating insects stirred up by grazing bison

Answer 213

D) cattle egrets eating insects stirred up by grazing bison

Question 214

Resource partitioning would be most likely to occur between ________.
A) sympatric populations of species with similar ecological niches
B) sympatric populations of a flowering plant and its specialized insect pollinator
C) allopatric populations of the same animal species
D) allopatric populations of species with similar ecological niches

Answer 214

A) sympatric populations of species with similar ecological niches

Question 215

Character displacement differs from resource partitioning because character displacement ________.
A) is a fundamental difference in feeding behaviors of individuals
B) is directly linked to the evolution of genotypes that have allowed alternate resource use
C) is a difference in the niche within a habitat that is preferred to be used by a species
D) is not the result of competition

Answer 215

B) is directly linked to the evolution of genotypes that have allowed alternated resource use

Question 216

Which of the following is an example of Müllerian mimicry?
A) two species of unpalatable butterfly that have the same color pattern
B) a day-flying hawkmoth that looks like a wasp
C) a chameleon that changes its color to look like a dead leaf
D) one species of a non-venomous snake which rattles its tail to mimic a venomous rattlesnake

Answer 216

A) two species of unpalatable butterfly that have the same color pattern

Question 217

Which of the following is an example of Batesian mimicry?
A) a butterfly that resembles a leaf
B) a nonvenomous larva of a moth that moves like a venomous snake
C) a fawn with fur coloring that camouflages it in the forest environment
D) a snapping turtle that uses its tongue to mimic a worm, thus attracting fish

Answer 217

B) a nonvenomous larva of a moth that moves like a venomous snake

Question 218

Which of the following is an example of aposematic coloration?
A) a non-poisonous snake mimics the color of a poisonous one
B) the brightly colored patterns of monarch butterfly caterpillars
C) green color of a plant
D) a katydid whose wings look like a dead leaf

Answer 218

B) the brightly colored patterns of monarch butterfly caterpillars

Question 219

Dwarf mistletoes are flowering plants that grow on certain forest trees. They obtain nutrients and water from the vascular tissues of the trees. The trees derive no known benefits from the dwarf mistletoes, nor are they negatively affected by this interaction. Which of the following best describes the interactions between dwarf mistletoes and trees?
A) mutualism
B) commensalism
C) competition
D) facilitation

Answer 219

B) commensalism

Question 220

In some circumstances, grasses that initially lose tissues from being consumed by animals such as elk or cattle regrow more than they would have otherwise, and benefit from the moderate levels of grazing. Which of the following terms would best describe such a plant-herbivore interaction?
A) mutualism
B) commensalism
C) parasitism
D) predation

Answer 220

A) Predation (if severe grazing)
B) Commensalism (if moderate grazing)

Hence, B

Question 221

Which of the following measurements would be most helpful in understanding the structure of an ecological community?
I) determining how many species are present overall
II) determining which particular species are present
III) determining the kinds of interactions that occur among individuals of the same species
IV) determining the abundance of resources available for one species
A) only I and II
B) only II and IV
C) only I, II, and III
D) I, II, III, and IV

Answer 221

A) only I and II

Question 222

Which of the following studies would a community ecologist undertake to learn about competitive interactions?
I) selectivity of nest sites among cavity-nesting songbirds
II) the grass species preferred by grazing pronghorn antelope and bison
III)stomach analysis of brown trout and brook trout in streams where they coexist
A) only I and II
B) only I and III
C) only II and III
D) I, II, and III

Answer 222

D) I, II, and III

Question 223

How might an ecologist test whether a species is occupying all of its fundamental niche or only a portion of it?
A) Study the temperature range and humidity requirements of the species.
B) Observe if the species expands its range after the removal of a competitor.
C) Measure the change in reproductive success when the species is subjected to environmental stress.
D) Observe if the niche size changes after the introduction of a similar non-native species.

Answer 223

B) Observe if the species expands its range after the removal of a competitor

Question 224

The symbols +, -, and 0 are to be used to show the results of interactions between individuals and groups of individuals. The symbol + denotes a positive interaction, - denotes a negative interaction, and 0 denotes where individuals are not affected by interacting. The first symbol refers to the first organism mentioned. What interactions exist between cellulose-digesting organisms in the gut of a termite and the termite?
A) +/+
B) +/0
C) +/-
D) 0/0

Answer 224

A) +/+

Question 225

The symbols +, -, and 0 are to be used to show the results of interactions between individuals and groups of individuals. The symbol + denotes a positive interaction, - denotes a negative interaction, and 0 denotes where individuals are not affected by interacting. The first symbol
refers to the first organism mentioned. What interactions exist between mycorrhizae and evergreen tree roots?
A) +/+
B) +/0
C) +/-
D) 0/0

Answer 225

A) +/+

Question 226

Bouchard and Brooks studied the effect of insect flight on dispersal and speciation in rain forest insects. They sampled all of the insects in the study area and found that 60 insect species are flightless and 19 are able to fly. What can you conclude so far about this study? (P. Bouchard and D. R. Brooks. 2004. Effect of vagility potential on dispersal and speciation in rainforest insects. Journal of Evolutionary Biology 17:994-1006.)
A) Flightless insects have a greater dispersal potential from this study area.
B) Flightless insects are more numerous in the study area.
C) Flightless insects have a higher species richness in the study area.
D) Flightless insects are better suited for the tropics.

Answer 226

C) Flightless insects have a higher species richness in the study area

Question 227

Approximately how many kilograms (kg) of carnivore (secondary consumer) biomass can be supported by a field plot containing 1000 kg of plant material?
A) 1000
B) 100
C) 10
D) 1

Answer 227

C) 10

Question 228

Elephants are not the most abundant species in African grasslands, yet they influence community structure. The grasslands contain scattered woody plants, but they are kept in check by the uprooting activities of the elephants. Take away the elephants, and the grasslands are converted to forests or to shrublands. The newly growing forests support fewer species than the previous grasslands. Which of the following statements describes why elephants are the keystone species in this scenario?
A) Elephants exhibit a disproportionate influence on the structure of the community relative to
their abundance.
B) Grazing animals depend upon the elephants to convert forests to grassland.
C) Elephants are the biggest herbivore in this community.
D) Elephants help other populations survive by keeping out many of the large African predators.

Answer 228

A) Elephants exhibit a disproportionate influence on the structure of the community relative to their abundance

Question 229

According to bottom-up and top-down control models of community organization, which of the following expressions would imply that an increase in the size of a carnivore (C) population would negatively impact its prey (P) population, but not vice versa? The arrows between species indicate a negative impact toward the population at the arrowhead.
A) P ← C
B) P → C
C) C ↔ P
D) P ← C → P

Answer 229

A) P ← C

Question 230

Which of the following statements is a likely explanation for why invasive species take over communities into which they have been introduced?
A) Invasive species are less efficient than native species in competing for the limited resources of the environment.
B) Invasive species are not held in check by the predators and agents of disease that have always been in place for native species.
C) Invasive species have a higher reproductive potential than native species.
D) Invasive species come from geographically isolated regions, so when they are introduced to regions where there is more competition, they thrive.

Answer 230

B) Invasive species are not held in check by the predators and agents of the disease that have always been in place for native species

Question 231

Imagine five forest communities, each with one hundred individuals distributed among four different tree species (W, X, Y, and Z). Which forest community would be most diverse?
A) 25W, 25X, 25Y, 25Z
B) 40W, 30X, 20Y, 10Z
C) 50W, 25X, 15Y, 10Z
D) 70W, 10X, 10Y, 10Z

Answer 231

A) 25W, 25X, 25Y, 25Z

Question 232

Keystone predators can maintain species diversity in a community if they ________.
A) competitively exclude other predators
B) prey on the community’s dominant species
C) allow immigration of other predators
D) prey only on the least abundant species in the community

Answer 232

B) prey on the community’s dominant species

Question 233

Food chains are sometimes short because ________.
A) only a single species of herbivore feeds on each plant species
B) local extinction of a species causes extinction of the other species in its food chain
C) most of the energy in a trophic level is lost as it passes to the next higher level
D) predator species tend to be less diverse and less abundant than prey species

Answer 233

C) most of the energy in a trophic level is lost as it passes to the next higher level

Question 234

Which of the following could qualify as a top-down control on a grassland community?
A) limitation of plant biomass by rainfall amount
B) influence of temperature on competition among plants
C) influence of soil nutrients on the abundance of grasses versus wildflowers
D) effect of grazing intensity by bison on plant species diversity

Answer 234

D) effect of grazing intensity by bison on plant species diversity

Question 235

Recall that Clements’s view of biological communities is that of a highly predictable and interrelated structure, while Gleason’s view of biological communities is that individual species
operate independently. If we set up many identical sterilized ponds in the same area and allowed them to be colonized, what result should we expect Gleason had a more accurate view of
communities than did Clement’s hypothesis?
A) Identical plankton communities will develop in all ponds.
B) Similar plankton communities will develop in all ponds.
C) Different plankton communities will develop in all ponds.
D) Limited plankton communities will develop in all ponds.

Answer 235

C) Different plankton communities will develop in all ponds

Question 236

According to the nonequilibrium model of community diversity, ________.
A) community structure remains stable in the absence of interspecific competition
B) communities are assemblages of closely linked species that are permanently changed by disturbance
C) interspecific interactions induce changes in community composition over time
D) communities are constantly changing after being influenced by disturbances

Answer 236

D) communities are constantly changing after being influenced by disturbances

Question 237

Why do moderate levels of disturbance result in an increase in community diversity?
A) Habitats are opened up for less competitive species.
B) Competitively dominant species infrequently exclude less competitive species after a moderate disturbance.
C) The resulting uniform habitat supports stability, which in turn supports diversity.
D) Less-competitive species evolve strategies to compete with dominant species.

Answer 237

A) Habitats are opened up for less competitive species

Question 238

Based on the intermediate disturbance hypothesis, a community’s species diversity is increased by ________.
A) frequent immigrations of new species
B) stable conditions with no disturbance
C) moderate levels of disturbance
D) intensive disturbance by humans

Answer 238

C) moderate levels of disturbance

Question 239

In a particular case of secondary succession, three species of wild grass all invaded a field. By the second season, a single species dominated the field and the other two species had a lower relative abundance. A possible factor contributing to the abundances of these species in this example of secondary succession is ________.
A) equilibrium
B) immigration
C) inhibition
D) parasitism

Answer 239

C) inhibition

Question 240

There are more species in tropical areas than in places more distant from the equator. This is probably a result of ________.
A) fewer predators and parasites
B) more dispersed annual solar radiation compared to the poles
C) more frequent ecological disturbances over a longer time span
D) a longer time frame without disturbances for evolution and speciation

Answer 240

D) a longer time frame without disturbances for evolution and speciation

Question 241

Which of the following is a widely supported explanation for the tendency of tropical communities to have greater species diversity than temperate or polar communities?
A) There are fewer parasites to negatively affect the health of tropical communities.
B) Tropical communities are low in altitude, whereas temperate and polar communities are high in altitude.
C) Tropical communities have higher sunlight and precipitation, and are generally older than temperate or polar communities.
D) More competitive dominant species have evolved in temperate and polar communities.

Answer 241

C) Tropical communities have higher sunlight and precipitation, and are generally older than temperate or polar communities

Question 242

Which of the following is a correct statement about MacArthur and Wilson’s island equilibrium model?
A) As the number of species on an island increases, the emigration rate decreases.
B) Competitive exclusion is less likely on an island that has large numbers of species.
C) Small islands receive few new immigrant species.
D) Islands closer to the mainland have higher extinction rates.

Answer 242

C) Small islands receive a few new immigrant species

Question 243

According to the island equilibrium model, species richness would be lowest on an island that is ________.
A) large and close to a mainland
B) large and remote
C) small and remote
D) small and close to a mainland

Answer 243

C) small and remote

Question 244

One plausible hypothesis to explain why species richness is higher in tropical than in temperate regions is that ________.
A) tropical communities are younger
B) tropical regions generally have more available water and higher levels of solar radiation
C) higher temperatures cause more rapid speciation
D) tropical regions have very high rates of immigration and very low rates of extinction

Answer 244

B) tropical regions generally have more available water and higher levels of solar radiation

Question 245

Zoonotic disease ________.
A) is caused by suborganismal pathogens such as viruses, viroids, and prions only
B) is caused by pathogens that are transferred from other animals to humans by direct contact or by means of a vector
C) can only be spread from animals to humans through direct contact
D) can only be transferred from animals to humans by means of an intermediate host

Answer 245

B) is caused by pathogens that are transferred from other animals to humans by direct contact or by means of a vector

Question 246

Why is a pathogen generally more virulent in a new habitat?
A) Intermediate host species are more motile and transport pathogens to new areas.
B) Pathogens evolve more efficient forms of reproduction in new environments.
C) Hosts in new environments have not had a chance to become resistant to the pathogen through natural selection.
D) New environments are almost always smaller in area so that transmission of pathogens is easily accomplished between hosts.

Answer 246

C) Hosts in new environments have not had a chance to become resistant to the pathogen through natural selection

Question 247

Which of the following best describes the consequences of white-band disease in Caribbean coral reefs?
A) Staghorn coral is decimated by the pathogen, and Elkhorn coral takes its place.
B) Key habitat for lobsters, snappers, and other reef fishes improves.
C) Algal species take the place of the dead coral, and the fish community is dominated by herbivores.
D) Algal species take over and the overall reef diversity increases due to increases in primary productivity.

Answer 247

C) Algal species take the place of the dead coral, and the fish community is dominated by herbivores

Question 248

Which of the following studies would shed light on the mechanism of spread of H5N1 virus from Asia to North America?
A) Perform cloacal or saliva smears of migrating waterfowl to monitor whether any infected birds show up in Alaska.
B) Test fecal samples for H5N1 in Asian waterfowl that live near domestic poultry farms in Asia.
C) Test for the presence of H5N1 in poultry used for human consumption worldwide.
D) Locate and destroy birds infected with H5N1 in Asian open-air poultry markets.

Answer 248

A) Perform cloacal or saliva smears of migrating waterfowl to monitor whether any infected birds show up in Alaska

Question 249

In terms of community ecology, why are pathogens often more virulent now than in the past?
A) More new pathogens have recently evolved.
B) Host organisms have become more susceptible because of weakened immune systems.
C) Human activities are transporting pathogens into new habitats (or communities) at an unprecedented rate.
D) Medicines for treating pathogenic disease are in short supply.

Answer 249

C) Human activities are transporting pathogens into new habitats (or communities) at an unprecedented rate

Question 250

The oak tree fungal pathogen, Phytophthora ramorum, has migrated 800 kilometers in 15 years. West Nile virus spread from New York State to 46 other states in 5 years. The difference
in the rate of spread is probably related to ________.
A) the lethality of each pathogen
B) the mobility of their hosts
C) the fact that viruses are very small
D) innate resistance

Answer 250

B) the mobility of their hosts

Question 251

Scientists interested in how populations interact within communities are attempting to determine the species diversity of an island under study. What kind of data would be most helpful to the scientists in determining diversity?
A) the number of different species on the island and the size of the population of each species
B) the number of species on the island that are consumers, producers, and decomposers
C) the relative biomass of each species on the island separated by trophic level
D) the number of trophic levels on the island and the niche of each species

Answer 251

A) the number of different species on the island that are consumer

Question 252

Red-cheeked salamanders are partially protected from predators because of cardiac glycosides they produce from glands on their back. When ingested, cardiac glycosides disrupt normal heart rhythms. A different salamander species, the imitator salamander, also has red
cheek patches, but does not produce cardiac glycosides. It does gain protection from predators that have learned to avoid red-cheeked salamanders. How does this relationship affect the population dynamics of both species?
A) Both species are negatively affected.
B) Both species are positively affected.
C) The red-cheeked salamander is positively affected; the imitator is negatively affected.
D) The red-cheeked salamander is not affected; the imitator is positively affected.

Answer 252

D) The red-cheeked salamander is not affected; the imitator is positively affected

Question 253

If the sun were to suddenly stop providing energy to Earth, most ecosystems would eventually vanish. Which of the following ecosystems would likely survive the longest after this hypothetical disaster?
A) pelagic ocean
B) tundra
C) deep benthic ocean
D) a desert spring

Answer 253

C) deep benthic ocean

Question 254

Which of the following terms encompasses all of the others?
A) heterotrophs
B) herbivores
C) carnivores
D) primary consumers

Answer 254

A) heterotrophs

Question 255

To recycle nutrients, an ecosystem must have, at a minimum, ________.
A) producers
B) producers and decomposers
C) producers, primary consumers, and decomposers
D) producers, primary consumers, secondary consumers, and decomposers

Answer 255

B) producers and decomposers

Question 256

Which of the following organisms is correctly paired with its trophic level?
A) cyanobacterium—primary consumer
B) grasshopper—secondary consumer
C) phytoplankton—primary producer
D) fungus—primary consumer

Answer 256

C) phytoplankton—primary producer

Question 257

Which of the following has the greatest effect on the rate of chemical cycling within an ecosystem?
A) the ecosystem’s rate of primary production
B) the secondary production efficiency of the ecosystem’s consumers
C) the rate of decomposition in the ecosystem
D) the trophic efficiency of the ecosystem

Answer 257

C) the rate of decomposition in the ecosystem

Question 258

Matter may be gained by, or lost from, ecosystems. How does this occur?
A) Chemoautotrophic organisms can convert matter to energy.
B) Matter can move from one ecosystem to another.
C) Photosynthetic organisms convert solar energy to sugars.
D) Heterotrophs convert heat to energy.

Answer 258

B) Matter can move from one ecosystem to another

Question 259

Why is terrestrial productivity higher in equatorial climates?
A) Productivity increases with temperature.
B) Productivity increases with water availability.
C) Productivity increases with available sunlight.
D) The answer is most likely a combination of the other responses.

Answer 259

D) The answer is most likely a combination of the other responses

Question 260

During a year, plants never use 100% of the incoming solar radiation for photosynthesis. What is a reasonable explanation for this?
A) Plants cannot photosynthesize as well in warm temperatures as in cold temperatures.
B) Plants do not intercept all incoming light, as some light will strike water, bare soil, or rock.
C) The pigments that drive photosynthesis absorb all of the wavelengths of light that are available; however, some of the light is subsequently reflected.
D) At least 75% of all incoming light is reflected, absorbed, or scattered back by clouds in the atmosphere.

Answer 260

B) Plants do not intercept all incoming light, as some light will strike water, bare soil, or rock

Question 261

You own 300 acres of patchy temperate forest mixed with grassy meadows. Which one of the following actions would increase the net primary productivity of the area the most?
A) adding fertilizer to the entire area
B) introducing 100 rabbits into the area
C) planting 500 new trees
D) relocating all of the deer found in the area

Answer 261

C) planting 500 new trees

Question 262

Suppose you are studying the nitrogen cycling between vegetation, sediments, and water in a pond ecosystem over the course of a month. While you are collecting data, a flock of 100 Canada
geese lands and spends the night during a fall migration. What could you do to eliminate error in your study as a result of this event?
A) Find out how much nitrogen is consumed in plant material by a Canada goose over about a 12-hour period, multiply this number by 100, and add that amount to the total nitrogen in the ecosystem.
B) Find out how much nitrogen is eliminated by a Canada goose over about a 12-hour period, multiply this number by 100, and subtract that amount from the total nitrogen in the ecosystem.
C) Find out how much nitrogen is consumed from vegetation and eliminated by a Canada goose over about a 12-hour period and multiply this number by 100; enter this +/- value into the nitrogen budget of the ecosystem.
D) Put a net over the pond so that no more migrating flocks can land on the pond and alter the nitrogen balance of the pond.

Answer 262

C) Find out how much nitrogen is consumed from vegetation and eliminated by a Canada goose over about a 12-hour period and multiply this number by 100; enter this +/- value into the nitrogen budget of the system

Question 263

Many of the organisms in the ocean are nutrient-limited. If you wanted to investigate this phenomenon, one reasonable approach would be to ________.
A) observe Antarctic Ocean productivity from year to year to see if it changes
B) experimentally enrich some areas of the ocean and compare their productivity to that of untreated areas
C) compare nutrient concentrations between the photic zone and the benthic zone in various marine locations
D) contrast nutrient uptake by autotrophs in marine locations that are different temperatures

Answer 263

B) experimentally enrich some areas of the ocean and compare their productivity to that of untreated areas

Question 264

If you applied a fungicide to a cornfield, what would you expect to happen to the rate of decomposition and net ecosystem production (NEP)?
A) Both decomposition rate and NEP would decrease.
B) Both decomposition rate and NEP would increase.
C) Decomposition rate would increase and NEP would decrease.
D) Decomposition rate would decrease and NEP would increase.

Answer 264

D) Decomposition rate would decrease and NEP would increase

Question 265

Which of the following is an accurate statement regarding mineral nutrients in soils and their implication for primary productivity?
A) Globally, phosphorous availability is most limiting to primary productivity.
B) Adding a nonlimiting nutrient will stimulate primary productivity.
C) Phosphorous is sometimes unavailable to producers due to leaching.
D) Alkaline soils are more productive than acidic soils.

Answer 265

C) Phosphorus is sometimes unavailable to producers due to leaching

Question 266

What advantage would there be for an ecosystem ecologist to measure net ecosystem production (NEP) instead of net primary production (NPP)?
A) NPP cannot be expressed in energy/unit of area/unit of time.
B) NEP can be expressed in terms of carbon fixed by photosynthesis for an entire ecosystem, minus respiration by producers, allowing the measurement of net CO2 flux.
C) NEP represents the amount of energy from light converted to chemical energy, minus the energy used by all organisms for cellular respiration, which could indicate whether or not carbon
is being stored.
D) NPP shows the rate at which the standing crop is utilized by consumers.

Answer 266

C) NEP represents the amount of energy from light converted to chemical energy, minus the energy cell used by all organisms for cellular respiration, which could indicate whether or not carbon is being stored

Question 267

How is net ecosystem production (NEP) typically estimated in ecosystems?
A) by detecting the amount of heat energy released by the ecosystem
B) by measuring gas exchange from vegetation as well as estimates of respiration by all other
organisms
C) by measuring the rate of decomposition by detritivores
D) by calculating the annual total of incoming solar radiation per unit of area

Answer 267

B) by measuring gas exchange from vegetation as well as estimates of respiration by all other organisms

Question 268

Which of the following ecosystems would likely have the largest net primary productivity
per hectare and why?
A) open ocean, because of the total biomass of photosynthetic autotrophs
B) grassland, because of rapid growth, the small standing crop biomass that results from
consumption by herbivores, and rapid decomposition
C) tundra, because of the incredibly rapid period of growth during the summer season
D) deep ocean, due to the high activity of chemoautotrophs at deep sea vents

Answer 268

B) grassland, because of rapid growth, the small standing crop biomass that results from consumption by herbivores, and rapid decomposition

Question 269

Why is it that satellites, using wavelength reflectance technology, detect variable levels of
productivity across Earth’s oceans, rather than an increase toward the equator?
A) Temperatures at the equator often exceed those which are optimal for primary production.
B) Light at the equator is too constant and direct.
C) NPP in Earth’s open oceans could differ due to variability in depth, the presence of coral
reefs, or by ocean currents.
D) Satellites detect differences by measuring the amount of water vapor emitted by transpiring
producers, and this is a variable measurement in the oceans.

Answer 269

C) NPP in Earth’s open oceans could differ due to variability in depth, the presence of coral reefs, or by ocean currents

Question 270

Which one of the following correctly ranks these organisms in order from lowest to highest
percent in production efficiency?
A) mammals, fish, insects
B) insects, fish, mammals
C) fish, insects, mammals
D) mammals, insects, fish

Answer 270

A) mammals, fish, insects

Question 271

Owls eat rats, mice, shrews, and small birds. Assume that, over a period of time, an owl
consumes 5,000 J of animal material. The owl loses 2,300 J in feces and owl pellets and uses
2,500 J for cellular respiration. What is the production efficiency of this owl?
A) 8%
B) 7.4%
C) 2%
D) 40%

Answer 271

B) 7.4%

Question 272

How does inefficient transfer of energy among trophic levels result in the typically high endangerment status of many top-level predators?
A) Top-level predators are destined to have small populations that are sparsely distributed.
B) Predators have relatively large population sizes.
C) Predators are more disease-prone than animals at lower trophic levels.
D) Top-level predators are more likely to be stricken with parasites.

Answer 272

A) Top-level predators are destined to have small populations that are sparsely distributed

Question 273

Why does a vegetarian leave a smaller ecological footprint than an omnivore?
A) Fewer animals are slaughtered for human consumption.
B) There is an excess of plant biomass in all terrestrial ecosystems.
C) Vegetarians need to ingest less chemical energy than omnivores.
D) Eating meat is an inefficient way of acquiring photosynthetic productivity.

Answer 273

D) Eating meat is an inefficient way of acquiring photosynthetic productivity

Question 274

For most terrestrial ecosystems, pyramids composed of species abundances, biomass, and
energy are similar in that they have a broad base and a narrow top. The primary reason for this
pattern is that ________.
A) secondary consumers and top carnivores require less energy than producers
B) at each step, energy is lost from the system
C) biomagnification of toxic materials limits the secondary consumers and top carnivores
D) top carnivores and secondary consumers have a more general diet than primary producers

Answer 274

B) at each step, energy is lost form the system

Question 275

Which of the following is primarily responsible for limiting the number of trophic levels in most ecosystems?
A) Many primary and higher-order consumers are opportunistic feeders.
B) Decomposers compete with higher-order consumers for nutrients and energy.
C) Nutrient cycling rates tend to be limited by decomposition.
D) Energy transfer between trophic levels is usually less than 20 percent efficient.

Answer 275

D) Energy transfer between trophic levels is usually less than 20 percent efficient

Question 276

Which trophic level is most vulnerable to extinction?
A) producer level
B) primary consumer level
C) secondary consumer level
D) tertiary consumer level

Answer 276

D) tertiary consumer level