Question 1

Which of the following is an example of negative feedback?

Accepted Answer

Negative feedback involves a response that counters or opposes the initial stimulus. In this case, when the body temperature exceeds the set-point of 37◦C, the brain signals for sweat to be released, which leads to evaporative cooling and a lowering of body temperature, thus counteracting the initial stimulus of high body temperature.

Question 2

Sweating allows a person to lose heat through which process?

Accepted Answer

Sweat is primarily composed of water, which absorbs heat from the body when it evaporates. This process is known as evaporation, and it allows the body to lose heat and cool down. Conduction and convection involve the transfer of heat through physical contact or motion of fluids, while radiation involves the emission of heat through energy waves. Acclimatization refers to the process by which the body adjusts to a new environment over time, including changes in temperature and humidity.

Question 3

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

Accepted Answer

The woman standing and watching the stars on a cool, calm night will lose most of her body heat by radiation. Radiation is the transfer of heat through the emission of electromagnetic waves, and it is the primary way in which heat is lost to the environment in the absence of a medium or contact with another object.

Question 4

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

Accepted Answer

Wind blowing across the body surface would increase the rate of heat exchange between an animal and its environment by increasing convective heat loss.

Question 5

The crucian carp (Carassius carassius)is a Northern European freshwater fish often inhabiting ponds that become hypoxic (have reduced oxygen levels)and even anoxic (have no oxygen)when the surface freezes during the winter.Surprisingly,when oxygen levels are normal,these fish lack the lamellae that provide a large surface area for gas exchange between water and blood: their gills are smooth.Yet when the level of oxygen in the water falls,the gill morphology undergoes a change: packing cells stop dividing and programmed cell death is induced,exposing gill lamellae that were buried in other tissue.With lamellae exposed,the gills have increased surface area for gas exchange.These changes in gill lamellar profile are reversible: investigators observed that the gills return to their normal structure within seven days after returning the fish to well-oxygenated water.(Jørund Sollid,Paula De Angelis,Kristian Gundersen,and Göran E.Nilsson.2003.Hypoxia induces adaptive and reversible gross morphological changes in crucian carp gills.Journal of Experimental Biology 206:3667-73.)
Gills serve multiple functions in fish in addition to gas exchange.Given the large surface area of gills with lamellae,what is the most likely explanation for why crucian carp cover protruding lamellae in their gills when levels of oxygen are normal?

Accepted Answer

Covering the lamellae when oxygen levels are normal likely helps prevent the loss of ions to the surrounding water, as the large surface area of exposed lamellae could lead to increased ion exchange and potential ion imbalance.

Question 6

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

Accepted Answer

An animal's inputs of energy and materials would exceed its outputs if it is growing and increasing its mass. This is because growth requires the accumulation of energy and materials to build new tissues, which means the animal must consume more than it expends or excretes.

Question 7

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.What is regulating the blood glucose level?

Accepted Answer

The regulation of blood glucose levels through the secretion of insulin and glucagon by the pancreas is an example of negative feedback. In negative feedback, the output of a system inhibits or reduces the stimulus of the system, in this case, the secretion of insulin reduces the blood glucose level, and the secretion of glucagon increases the blood glucose level, thus maintaining a stable blood glucose level.

Question 8

If you were to view a sample of animal tissue under a light microscope and notice an extensive extracellular matrix surrounding a tissue,which tissue type would you most suspect?

Accepted Answer

Connective tissue is known for having an extensive extracellular matrix, which is composed of various proteins and glycoproteins such as collagen and elastin. Epithelial tissue forms the lining of organs and does not typically have a significant amount of extracellular matrix. Nervous tissue forms the nervous system and is composed of neurons and supporting cells. Striated and smooth muscle tissues are both specialized for contraction and do not have extensive extracellular matrices. Therefore, the best choice is A) connective tissue.

Question 9

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?

Accepted Answer

The best way to determine whether this animal is an endotherm or ectotherm is to subject it to various temperatures and monitor its body temperature and metabolic rate. If its body temperature and metabolic rate change with the ambient temperature, then it is an ectotherm, as its metabolic processes are controlled by the environment rather than by internal physiological mechanisms.

Question 10

If an organism was discovered that had no epithelial tissues,it would require adaptations to maintain homeostasis in which of the following areas?

Accepted Answer

Epithelial tissues play a crucial role in protecting against water loss and in binding tissues and organs. Without them, the organism would need adaptations to prevent water loss and to hold tissues and organs in place.

Question 11

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?

Accepted Answer

The bacteria are using a conformation mechanism, where their internal environment changes to match the external environment, rather than regulating or maintaining a constant internal environment.

Question 12

Which of the following is indicative of connective tissue?

Accepted Answer

Connective tissue is characterized by having relatively few cells and a large amount of extracellular matrix, which provides support and structure to the tissue.

Question 13

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?

Accepted Answer

A sphere has the smallest surface area relative to its volume compared to any other three-dimensional shape. By rounding the clay up into a sphere, the surface area of the clay will decrease relative to its volume.

Question 14

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 freshwater,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 freshwater 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?

Accepted Answer

Acclimatization refers to the physiological adjustments made by an organism in response to changes in its environment, such as the changes in gill cells of salmon when moving between freshwater and saltwater.

Question 15

You are looking through a microscope at a slide of animal tissue and see a single layer of flat,closely packed cells that cover a surface.What tissue are you most likely looking at?

Accepted Answer

Epithelial tissue is characterized by closely packed cells that form a protective barrier or lining. This tissue can be found covering surfaces such as the skin, lining organs, and lining blood vessels. Adipose tissue is composed of fat cells, connective tissue consists of cells embedded in a matrix, muscle tissue is composed of muscle fibers, and nervous tissue is composed of neurons and supporting cells. None of these tissues are characterized by a single layer of flat, closely packed cells that cover a surface.

Question 16

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?

Accepted Answer

The mouse will cool down faster because it has a higher surface-area-to-volume ratio. This means that a higher percentage of its body is exposed to the environment, allowing for more efficient heat loss. The elephant's larger size and lower surface-area-to-volume ratio mean that it will cool down more slowly.

Question 17

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

Accepted Answer

Desert birds use the largest percentage of their energy budget for homeostatic regulation due to the extreme temperatures of their environment. They must expend significant energy to maintain their body temperature, especially in the face of high daytime temperatures and cold nights.

Question 18

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.

Accepted Answer

Elephant would have the highest total annual energy expenditure due to its large size and high metabolic rate. On the other hand, mouse would have the highest energy expenditure per unit mass due to its small size and high metabolic rate. Therefore, option A is the best choice.

Quiz 40: Basic Principles of Animal Form and Function