Chapter 40 Bio 102

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 ground squirrel's hypothalamus detects changes in environmental temperatures and responds by activating or suppressing metabolic heat production.

Select the correct statement describing feedback control in animals.

An animal may be a regulator for one environmental variable but a conformer for another.

The use of brown fat to generate metabolic heat is mostly limited to small mammals. What is the basis of this adaptation?

Because of their large surface area to volume ratio, heat loss across the body surface is higher in small animals.

Which statement about endotherms and ectotherms is correct?

Ectotherms are more abundant and diverse than endotherms.

How do endotherms and ectotherms differ?

Endotherms and ectotherms differ in the means by which they regulate their body temperature.

Which principle of heat exchange is the most important explanation for why birds look larger in colder weather because they fluff their feathers?

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

A researcher is setting up an experiment to measure basal metabolic rate in prairie voles (Microtus ochrogastera small rodent). Which of the following would be the best set of conditions for the voles immediately before and during the measurement?

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.

Which organ system is responsible for protection against injury, infection, and dehydration?

Integumentary system

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?

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

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?

Round the clay up into a sphere.

Which of the following is a true statement about body size and physiology?

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.

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?

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

What would be an advantage for an animal that conforms to a changing environmental condition, such as temperature?

The animal would spend less energy regulating its internal temperature.

Which of the following is a correct statement about an organism and its environment?

The interstitial fluid is the exchange medium between body cells and the circulatory system in vertebrate animals.

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?

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

Tunas, sharks, penguins, and dolphins all have a basic fusiform shape, tapered at both ends. What explains this similarity in shape?

The similarity is due to convergent evolution, because all these animals share similar environmental challenges.

Which of the following primarily involves heat transfer by convection?

You roll down the car window to allow the cool breeze to blow through

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?

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.

Which of the following animals most likely uses the largest percentage of its energy budget for homeostatic regulation?

a bird living year round in a desert

In a physiological system operating with positive feedback, _____.

a change in a variable will amplify rather than reverse the change

Which of the following animals uses the largest percentage of its energy budget for homeostatic regulation?

a desert bird

Bone consists of ________.

a mixture of hardened collagen and minerals.

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 single layer of flattened cells

Interstitial fluid is ________.

a site of exchange between blood and body cells

These changes made in the cells of the gills during the lifetime of an individual salmon are an example of which of the following?

acclimatization

In many animals, fat is stored in specialized cells in the ________.

adipose tissue

Evolutionary adaptations that help some animals directly exchange matter between the cells of their body and the environment include ________.

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

Most land-dwelling invertebrates and all of the amphibians ________.

are ectothermic organisms with variable body temperatures

What is the name of the epithelial cell surface that faces the outside of an organ?

basal

Standard metabolic rate (SMR) and basal metabolic rate (BMR) are _____.

both measured in animals in a resting and fasting state

Most types of communication between cells utilize _____.

chemical or electrical signals

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 ________.

circadian rhythm

What type of homeostatic mechanism is this species using to regulate its internal salt levels?

conformation

The body tissue that consists largely of material located outside of cells is

connective tissue.

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.

elephant; mouse

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.

elephant; mouse

Much of the coordination of vertebrate body functions via chemical signals is accomplished by the _____.

endocrine system

Bats and hummingbirds are examples of _____.

endotherms that are also poikilotherms

Negative feedback is a method of homeostatic control that _____.

ensures that conditions in an organism do not vary too much above or below their set points

There are advantages and disadvantages to adaptations. Animals that are endothermic are likely to be at the greatest disadvantage in _____.

environments with variable and limited food sources

Most of the exchange surfaces of multicellular animals are lined with _____.

epithelial tissue

What are the four categories of tissue?

epithelial, connective, muscle, nervous

Elephants can often be observed cooling off by spraying water over their bodies with their trunks. What type of heat exchange is occurring?

evaporation

The panting responses observed in overheated birds and mammals dissipate excess heat by ________.

evaporation

Choose the list that correctly ranks metabolic rates per gram of body mass, from lowest to highest.

fish, dog, mouse

The body's automatic tendency to maintain a constant and optimal internal environment is termed as ________.

homeostasis

The temperature-regulating center of vertebrate animals is located in the _____.

hypothalamus

An animal's inputs of energy and materials would exceed its outputs

if it is growing and increasing its mass.

All types of muscle tissue have _____.

interactions between actin and myosin

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 _____.

invests little energy in temperature regulation

Blood is best classified as connective tissue because _____.

its cells are separated from each other by an extracellular matrix

Compared with a smaller cell, a larger cell of the same shape has

less surface area per unit of volume.

Homeostasis is the _____.

maintenance of a relatively constant and optimal internal environment

Snake behavior in Wisconsin changes throughout the year. For example, a snake is _____.

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

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 ________.

more branching or folds

All animals, whether large or small, have _____.

most of their cells in contact with an aqueous medium

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 _____.

negative feedback

The metabolic breakdown of specialized brown fat deposits in certain animals is substantially increased during ________.

nonshivering thermogenesis

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?

positive feedback

A woman standing and watching the stars on a cool, calm night will lose most of her body heat by _____.

radiation

To prepare flight muscles for use on a cool morning, hawkmoths _____.

rapidly contract and relax these muscles to generate metabolic warmth

A countercurrent heat exchanger enables an animal to _____.

reduce the loss of body heat to the environment

Connective tissues typically have _____.

relatively few cells and a large amount of extracellular matrix

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 _____.

sea star living deep in the ocean

Food moves along the digestive tract as the result of contractions by _____.

smooth muscle

Muscle cells are organized to perform specific types of contractions within a tissue. Which of the following is a characteristic of smooth muscle?

spindle-shaped cells with a single nucleus

Cardiac muscle cells are both _____.

striated and interconnected by intercalated disks

The metabolic rate of an animal is most accurately determined by ________.

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

An example of a properly functioning homeostatic control system is seen when ________.

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

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?

the presence of a growth hormone receptor on the responding tissue

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

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

Metabolic rate is _____.

the total amount of energy an animal uses in a unit of time

An emergent property belongs to

the whole of something but not its parts.

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?

torpor

Both the endocrine and nervous systems transmit information around an animal's body. Which of the following is a characteristic of nervous system signals?

travel quickly, allowing rapid transmission of signals

Independent of whether an organism is an endotherm or ectoderm, the least reliable indicator of an animal's metabolic rate is the amount of ________.

water consumed in one day

Which of the following would increase the rate of heat exchange between an animal and its environment?

wind blowing across the body surface