When the temperature of the outside air exceeds their internal body temperature, jackrabbits living in hot, arid lands will
A) constrict the blood vessels in their large ears to reduce transfer of external heat to the blood in their ears.
B) increase motor movements to find a sunny area to maximize heat transfer into their bodies.
C) begin involuntary shivering of their skeletal muscles in order to generate more metabolic heat.
D) increase pigmentation in their ears, darkening them to maximize their capacity to take up heat.
E) dilate the blood vessels in their large ears to transfer more body heat to the environment.
constrict the blood vessels in their large ears to reduce transfer of external heat to the blood in their ears
If thermoregulation is considered to be a secondary function of the large ears of jackrabbits, then the primary function of the ears is
A) to protect against pathogens by having a thick, waxy surface on the ears.
B) to detect predators by using the large size and flexible positioning of the external ears to channel sound waves into the ear canal.
C) to alter the rate of gas exchange, based on the adjustable radius of the ears' blood vessels.
D) to optimize nutrient intake through the thin, permeable surfaces on the ears.
E) to protect offspring from bright sunlight by the positioning of the ears to cast the maximum shadows.
to detect predators by using the large size and flexible positioning of the external ears to channel sound waves into the ear canal.
Which choice best describes a reasonable mechanism for animal structures becoming better suited over evolutionary time to specific functions?
A) Animals that eat the most food become the most abundant.
B) Animals with inventions that curtail reproduction will become more abundant.
C) Animals with parents that continually improve their offspring's structures will become more abundant.
D) Animals with mutations that give rise to effective structures will become more abundant.
E) Animals that restrict their food intake will become less abundant.
Animals with mutations that give rise to effective structures will become more abundant.
Penguins, seals, and tuna have body forms that permit rapid swimming, because
A) all of their bodies have been compressed since birth by intensive underwater pressures.
B) all share a common ancestor at some point in the past.
C) this is the only shape that will allow them to maintain a constant body temperature in water.
D) flying, pregnancy, and gill-breathing all require similar adaptations in form.
E) the shape is a convergent evolutionary solution to the need to reduce drag while swimming
the shape is a convergent evolutionary solution to the need to reduce drag while swimming.
The absorptive epithelia in the gut are considered "polarized" because
A) the structures on the apical surface are different than those on the basal surface.
B) thick and thin filaments are present.
C) they pump wastes into the lumen while pumping nutrients toward the blood.
D) the colors seen on the top and bottom of the cells are different.
E) they must fire action potentials to absorb most nutrients.
the structures on the apical surface are different than those on the basal surface.
Most of the exchange surfaces of multicellular animals are lined with
A) smooth muscle cells.
B) epithelial tissue.
C) neural tissue.
D) connective tissue.
E) adipose tissue.
An example of a connective tissue is the
B) cuboidal epithelium.
D) smooth muscles.
Stratified cuboidal epithelium is composed of
A) several layers of boxlike cells.
B) a hierarchical arrangement of flat cells.
C) an irregularly arranged layer of pillarlike cells.
D) a tight layer of square cells attached to a basement membrane.
E) a layer of ciliated, mucus-secreting cells.
several layers of boxlike cells.
Coordinating body functions via chemical signals is accomplished by
A) the excretory system.
B) the immune and lymphatic systems.
C) the integumentary system.
D) the endocrine system.
E) the respiratory system.
the endocrine system.
Connective tissues typically have
A) a supporting material such as chondroitin sulfate.
B) many densely packed cells with direct connections between the membranes of adjacent cells.
C) relatively few cells and a large amount of extracellular matrix.
D) the ability to shorten upon stimulation.
E) the ability to transmit electrochemical impulses.
relatively few cells and a large amount of extracellular matrix.
If you gently twist your earlobe, it does not remain distorted because it contains
A) loose connective tissue.
B) reticular fibers.
C) adipose tissue.
D) elastic fibers.
E) collagenous fibers.
The nourishment, insulation, and support for neurons is the result of activity by the
A) adipose tissue.
B) endocrine system.
C) intercalated disks.
D) glial cells.
E) smooth muscles.
A) interstitial fluids.
B) chondroitin sulfate.
C) calcium phosphate for bone.
D) proteins for connective fibers.
proteins for connective fibers.
Blood is best classified as connective tissue because
A) it is contained in vessels that "connect" different parts of an organism's body.
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.
E) its cells are separated from each other by an extracellular matrix.
its cells are separated from each other by an extracellular matrix.
Most types of communication between cells utilize
A) the exchange of cytosol between the cells.
B) a direct electrical connection between the cells.
C) the movement of the cells.
D) the release of chemical signals by the cell sending the message.
E) the exchange of DNA between the cells.
the release of chemical signals by the cell sending the message.
With its abundance of collagenous fibers, cartilage is an example of
A) adipose tissue.
B) nervous tissue.
C) connective tissue.
D) epithelial tissue.
E) reproductive tissue.
Imagine that you are a biologist who is attempting to get an accurate measure of an animal's basal metabolic rate. The best time to measure the metabolic rate is when the animal
A) is resting and has just completed its first meal of the day.
B) is resting and has not eaten its first meal of the day.
C) has just completed 30 minutes of vigorous exercise.
D) has recently eaten a sugar-free meal.
E) has not consumed any water for at least 48 hours.
is resting and has not eaten its first meal of the day
A moth preparing for flight on a cold morning warms its flight muscles via
A) evaporative cooling.
C) nonshivering thermogenesis.
D) shivering thermogenesis.
Catabolism of specialized brown fat depots in certain animals is substantially increased during
C) nonshivering thermogenesis.
D) evaporative cooling.
E) shivering thermogenesis.
Panting by an overheated dog achieves cooling by
B) shivering thermogenesis.
D) nonshivering thermogenesis.
Hibernation and estivation during seasons of environmental stress are both examples of
B) evaporative cooling.
C) shivering thermogenesis.
E) nonshivering thermogenesis.
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) water consumed in one day.
B) carbon dioxide produced in one day.
C) food eaten in one day.
D) oxygen used in mitochondria in one day.
E) heat generated in one day.
water consumed in one day.
Standard metabolic rate (SMR) and basal metabolic rate (BMR) are
A) both standard measurements of fat metabolism in mammals.
B) used to compare metabolic rate between hibernating and nonhibernating states.
C) both measured in animals in a resting and fasting state.
D) used differently: SMR is measured during exercise, whereas BMR is measured at rest.
E) both measured across a wide range of temperatures for a given species.
both measured in animals in a resting and fasting state
Seasonal changes in snake activity are due to the fact that the snake
A) is more active in summer because that is the period for mating.
B) is more active in summer because it can gain body heat by conduction.
C) is less active in winter because the food supply is decreased.
D) is more active in summer as a result of being disturbed by other animals.
E) is less active in winter because it does not need to avoid predators.
is more active in summer because it can gain body heat by conduction.
A female Burmese python incubating her eggs can warm them using
B) nonshivering thermogenesis.
D) shivering thermogenesis.
E) evaporative cooling.
The temperature-regulating center of vertebrate animals is located in the
B) thyroid gland.
C) subcutaneous layer of the skin.
D) medulla oblongata.
Most land-dwelling invertebrates and all of the amphibians
A) have a net loss of heat across a moist body surface, even in direct sun.
B) are endotherms but become thermoconformers only when they are in water.
C) become more active when environmental temperatures drop below 15°C.
D) are ectothermic organisms with variable body temperatures.
E) alter their metabolic rates to maintain a constant body temperature of 37°C.
are ectothermic organisms with variable body temperatures
An example of an organism that has only behavioral controls over its body temperature is the
A) house sparrow.
B) bluefin tuna.
C) green frog.
D) gray wolf.
The panting responses that are observed in overheated birds and mammals dissipates excess heat by
E) countercurrent exchange
The thermoregulatory response of an overheated dog in a very hot environment is impaired if the response causes
A) body temperature to increase to match the environmental temperature.
B) blood vessels near the skin to vasoconstrict.
C) metabolic heat production to decrease.
D) evaporative heat loss to increase.
E) a behavioral response that takes the dog to a cooler location.
body temperature to increase to match the environmental temperature.
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, a marine invertebrate.
B) bluefin tuna, a predatory fish.
C) terrestrial lizard.
D) honeybee in a hive.
sea star, a marine invertebrate.
Humans can lose, but cannot gain, heat through the process of
In a survivably cold environment, an ectotherm is more likely to survive an extended period of food deprivation than would an equally sized endotherm because the ectotherm
A) invests little energy in temperature regulation.
B) has greater insulation on its body surface.
C) maintains a higher basal metabolic rate.
D) metabolizes its stored energy more readily than can the endotherm.
E) expends more energy per kg of body mass than does the endotherm.
invests little energy in temperature regulation.
To prepare flight muscles for use on a cool morning, hawkmoths
A) reduce the metabolic rate of the muscles to rest them before flight.
B) decrease their standard metabolic rate.
C) walk to shaded areas to avoid direct sunlight.
D) rapidly contract and relax these muscles to generate metabolic warmth.
E) relax the muscles completely until after they launch themselves into the air.
rapidly contract and relax these muscles to generate metabolic warmth
Positive feedback differs from negative feedback in that
A) positive feedback systems have control centers that are lacking in negative feedback systems.
B) positive feedback systems have only effectors, whereas negative feedback systems have only receptors.
C) positive feedback benefits the organism, whereas negative feedback is detrimental.
D) the positive feedback's effector responses are in the same direction as the initiating stimulus rather than opposite to it.
E) the effector's response increases some parameter (such as body temperature), whereas in negative feedback it can only decrease the parameter.
the positive feedback's effector responses are in the same direction as the initiating stimulus rather than opposite to it.
An example of effectors' roles in homeostatic responses is observable when
A) an increase in body temperature results from involuntary shivering.
B) the rising sun causes an increase in body temperature in a stationary animal.
C) an increase in body temperature results from exercise.
D) an increase in body temperature results from fever.
E) a decrease in body temperature results from shock.
an increase in body temperature results from involuntary shivering
An example of a properly functioning homeostatic control system is seen when
A) a blood cell shrinks when placed in a solution of salt and water.
B) the blood pressure increases in response to an increase in blood volume.
C) the kidneys excrete salt into the urine when dietary salt levels rise.
D) the core body temperature of a runner rises gradually from 37°C to 45°C.
E)the level of glucose in the blood is abnormally high whether or not a meal has been eaten.
the kidneys excrete salt into the urine when dietary salt levels rise
The body's automatic tendency to maintain a constant and optimal internal environment is termed
A) balanced equilibrium.
D) physiological chance.
E) static equilibrium.
Muscles are joined to bones by
A) spindle fibers.
B) Haversian systems.
C) loose connective tissue.