Bio 104 Exam 2

Which is the correct sequence of bodily responses to increased temperature? 1. Thermostat in hypothalamus activates cooling mechanisms. 2. Body temperature decreases. 3. Body temperature increases. 4. Sweat glands secrete sweat, and blood vessels in skin dilate.

3, 1, 4, 2

Flowers differ in how much sunlight they absorb. Why might this matter to a hummingbird seeking nectar on a cool morning?

A hummingbird has a high metabolic rate since it is so small. Through absorbing sunlight, the flowers nectar will be warmer which means the hummingbird is saved the metabolic expense of warming the nectar to the body temperature

If a mouse and a small lizard of the same mass (both at rest) were placed in experimental chambers under identical environmental conditions, which animal would consume oxygen at a higher rate? Explain.

The mouse would consume oxygen at a higher rate because it is an endotherm compared to the ectothermic lizard

Which animal must eat a larger proportion of its weight in food each day: a house cat or an African lion caged in a zoo? Explain

a house cat; smaller animals have a higher metabolic rate and a greater demand for food

The standard metabolic rate (SMR) of an American alligator is less than 1/20th the energy used by a comparably sized adult human. One conclusion that can be drawn from this statement is that _____. a.) ectothermy has a higher energetic requirement than endothermy b.) changes in the environmental temperature have no effect on metabolic rate c.) standard metabolic rate must be measured under a comfortable temperature range d.) ectothermy has a lower energetic requirement than endothermy

ask professor

In mammals, brown fat in the neck and shoulder area is specialized for rapid heat production. Which of the following is a correct statement about brown fat? a.) It represents about 95% of total body weight in human infants. b.) Extra mitochondria in brown fat produce its characteristic color. c.) Brown fat has recently been detected in hibernating mammals. d.) Individuals in warm environments have increased amounts of brown fat.

b.) Extra mitochondria in brown fat produce its characteristic color.

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 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

b.) You subject this reptile to various temperature and metabolic rate change with the ambient temperature. You conclude that it is an ectotherm

Acclimatization differs from adaptation in that _____. a.) adaptation is a temporary change during an animal's lifetime b.) acclimatization is when internal conditions are brought into alignment with external variables such as altitude changes c.) acclimatization only refers to changes in kidney function d.) acclimatization always alters homeostasis

b.) acclimatization is when internal conditions are brought into alignment with external variables such as altitude changes

The redness of the skin of a sunburned person is the result of vasodilation of the small arteries in the skin. The skin remains red when the sunburned person is not visibly sweating. At times when a sunburned person is not sweating, heat is being transferred from the person into the air mostly by which of the following? (Hint: Heat transfer is more effective by this means when the person is running or is in a strong breeze.) a.) radiation b.) convection c.) conduction d.) evaporation e.) absorption

b.) convection

The river otter is a regulator rather than a conformer with regard to the environmental variable temperature because _____. a.) it allows its internal condition to vary in accordance with external changes b.) it uses internal mechanisms to control internal change in the face of external fluctuation c.) it uses internal mechanisms to control internal change in the face of internal fluctuation d.) Its internal solute concentrations may be kept constant but internal temperature may change in response to fluctuations in the ocean's temperature

b.) it uses internal mechanisms to control internal change in the face of external fluctuation

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

b.) less surface area per unit of volume

Men who overuse synthetic testosterone (as in anabolic steroids) may experience testicular atrophy, reduced sperm count, and low levels of circulating FSH. The physiological explanation for these observations is _____. a.) that synthetic testosterone is not as effective as natural testosterone b.) negative feedback c.) positive feedback d.) that such men have inadequate numbers of FSH receptors e.) that such men have inadequate numbers of testosterone receptors

b.) negative feedback

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 in mass d.) never; due to homeostasis, these energy and material budgets always balance

c.) if it is growing and increasing in mass

Which of the following statements regarding the nervous system's transmission of signals is false? a.) Information is conveyed by the particular pathway the signal takes. b.) Communication usually involves more than one type of signal. c.) The effects can be long lasting. d.) Transmission is extremely fast for directing rapid responses to the environment. e.) Impulses can act on neurons, muscle cells, and cells or glands that produce secretions.

c.) the effects can be long lasting.

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.) counter current heat exchanger

c.) wind blowing across the body surface

What mode of heat exchange is involved in "wind chill", when moving air feels colder than still air at the same temperature?

convection; moving air contributes to heat loss from the skin surface

For our bodies and those of most other animals, increasing the number of cells decreases the ratio of outer surface area to total volume. What features of even the largest of animal bodies allow all cells access to oxygen, nutrients, and other resources? a.)Specialized structures that may be extensively branched or folded enable exchange with the environment. b.) In organisms with body plans that are more complex than hydra or tapeworm, harmless bloodborne microorganisms provide exchange surfaces for nutrient and gas transfer to body cells. c.) Internal body fluids, such as interstitial fluid, link surfaces for nutrient and gas exchange to body cells. d.) a and c e.) a and b

d.) a and c

Which of the following animals uses the largest percentage of its energy budget for homeostatic regulation? a.) marine jelly b.) snake in a temperate forest c.) desert insect d.) desert bird

d.) desert bird

Consider the energy budget 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.

elephant; mouse