The Immune System, Homeostasis and Ecology

1.

1 point

Which of the following could be a density-independent factor limiting human population growth?

social pressure for birth control

plagues

pollution

earthquakes

famines

2.

1 point

Which of the following statements about human population in industrialized countries is incorrect?

Average family size is relatively small.

The survivorship curve is Type I.

The population has undergone the demographic transition.

Age distribution is relatively uniform.

Life history is r-selected.

3.

1 point

A key part of the humoral immune response is

the attack of cytotoxic T cells on infected host cells.

the attack of phagocytes on living pathogens.

the initiation of programmed cell death in infected host cells.

perforation of infected host cells by perforin.

the production of antibodies by plasma cells.

4.

1 point

After drinking alcoholic beverages, increased urine excretion is the result of

increased reabsorption of water in the proximal tubule.

inhibited secretion of antidiuretic hormone (ADH).

increased aldosterone production.

the osmoregulator cells of the brain increasing their activity.

increased blood pressure.

5.

1 point

In the nitrogen cycle, the bacteria that replenish the atmosphere with N2 are

denitrifying bacteria.

nitrogen-fixing bacteria.

Rhizobium bacteria.

methanogenic protozoans.

nitrifying bacteria.

6.

1 point

Which of the following terms encompasses all of the others?

herbivores

primary consumers

heterotrophs

carnivores

secondary consumers

7.

1 point

Osmoconforming sharks take in water, as needed,

via active transport of water across the cells on their gills.

by migrating to freshwater rivers to drink fresh water.

via osmosis, as their body cells are slightly hyperosmotic to seawater.

by selective transport of water molecules across the wall of the gut.

by water diffusion from seawater, which is hyperosmotic to the fluids in their cells.

8.

1 point

Approximately how many kg of carnivore biomass can be supported by a field plot containing 1,000 kg of plant material?

10,000

1,000

10

1

100

9.

1 point

?A population's carrying capacity

can be accurately calculated using the logistic growth model.

may change as environmental conditions change.

can never be exceeded.

increases as the per capita growth rate (r) decreases.

generally remains constant over time.

10.

1 point

Why do populations grow more slowly as they approach their carrying capacity?

Individuals voluntarily stop mating so that overcrowding does not occur.

Density-independent factors lead to fewer births and increased mortality.

Density-dependent factors lead to fewer births and increased mortality.

Hormonal changes promote higher death rates in crowded populations.

The incoming energy decreases in populations experiencing a high rate of increase.

11.

1 point

A patient complaining of watery, itchy eyes and sneezing after being given a flower bouquet as a birthday gift should first be treated with

sterile pollen.

complement.

antihistamines.

monoclonal antibodies.

a vaccine.

12.

1 point

Excretory organs known as nephridia are present in

earthworms.

flatworms.

jellyfish.

insects.

sea stars.

13.

1 point

An advantage of a complete digestive system over a gastrovascular cavity is that the complete system

allows specialized functions in specialized regions.

facilitates intracellular digestion.

allows extensive branching.

excludes the need for extracellular digestion.

allows digestive enzymes to be more specific.

14.

1 point

Positive feedback differs from negative feedback in that

positive feedback benefits the organism, whereas negative feedback is detrimental.

the positive feedback's effector responses are in the same direction as the initiating stimulus rather than opposite to it.

positive feedback systems have control centers that are lacking in negative feedback systems.

positive feedback systems have only effectors, whereas negative feedback systems have only receptors.

the effector's response increases some parameter (such as body temperature), whereas in negative feedback it can only decrease the parameter.

15.

1 point

The cell-mediated immunity that destroys virally infected cells involves

macrophages.

cytotoxic T cells.

natural killer cells.

helper T cells.

B cells.

16.

1 point

How does phosphorus normally enter ecosystems?

rock weathering

photosynthesis

vulcanism

cellular respiration

atmospheric phosphorous gas

17.

1 point

The MHC is important in a T cell's ability to

recognize differences among types of cancer.

identify specific bacterial pathogens.

distinguish self from nonself.

identify specific viruses.

recognize specific parasitic pathogens.

18.

1 point

Which of the following best describes resource partitioning?

competitive exclusion that results in the success of the superior species

a climax community that is reached when no new niches are available

slight variations in niche that allow similar species to coexist

two species that can coevolve to share identical niches

differential resource utilization that results in a decrease in community species diversity

19.

1 point

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.

human; penguin

penguin; mouse

mouse; snake

elephant; mouse

elephant; human

20.

1 point

The receptors on T cells and B cells bind to

double-stranded RNA.

antigens.

antibodies.

natural killer cells.

immunoglobulins.

21.

1 point

Which of the following statements is not true?

A pathogen makes more than one antigen.

A lymphocyte has receptors for multiple different antigens.

Class I MHCs are found on all nucleated cells.

A liver cell makes one class of MHC molecule.

An antibody has more than one antigen-binding site.

22.

1 point

Which of the following causes populations to shift most quickly from an exponential to a logistic population growth?

competition for resources

favorable climatic conditions

increased birth rate

removal of predators

decreased death rate

23.

1 point

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. Which of the following best describes the interactions between dwarf mistletoes and trees?

parasitism

commensalism

facilitation

competition

mutualism

24.

1 point

Bacteria entering the body through a small cut in the skin

stimulate apoptosis of nearby body cells.

inactivate the erythrocytes.

stimulate release of interferons.

activate a group of proteins called complement.

stimulate natural killer cell activity.

25.

1 point

Which statement is true with regard to human population growth?

It is at a zero reproduction rate.

Its rate of growth is increasing.

There is no scientific prediction that can be made about human population growth.

Its rate of increase continues to grow at an exponential rate.

Its rate of growth is slowing.

26.

1 point

Urea is

insoluble in water.

the primary nitrogenous waste product of humans.

the primary nitrogenous waste product of most birds.

the primary nitrogenous waste product of most aquatic invertebrates.

more toxic to human cells than ammonia.

27.

1 point

The large surface area in the gut directly facilitates

elimination.

absorption.

filtration

secretion.

temperature regulation.

28.

1 point

The function of antibodies is to

mark pathogenic cells for destruction.

inject toxins into living pathogens.

act as Toll-like receptors.

secrete cytokines that attract macrophages to infection sites.

release perforins to disrupt infected cells.

29.

1 point

A cell type that interacts with both the humoral and cell-mediated immune pathways is a

natural killer cell.

cytotoxic T cell.

CD8 cell.

helper T cell.

plasma cell.

30.

1 point

In terms of community ecology, why are pathogens more virulent now than ever before?

Sequencing of genes in pathogenic organisms is particularly difficult.

Medicines for treating pathogenic disease are in short supply.

Human activities are transporting pathogens globally at an unprecedented rate.

Host organisms have become more susceptible because of weakened immune systems.

More new pathogens have recently evolved.

31.

1 point

Which of the following is characteristic of K-selected populations?

small offspring

many offspring per reproductive episode

a high intrinsic rate of increase

early parental reproduction

offspring with good chances of survival

32.

1 point

An example of effectors' roles in homeostatic responses is observable when

an increase in body temperature results from involuntary shivering.

the rising sun causes an increase in body temperature in a stationary animal.

an increase in body temperature results from exercise.

an increase in body temperature results from fever.

a decrease in body temperature results from shock.

33.

1 point

As N approaches K for a certain population, which of the following is predicted by the logistic equation?

The growth rate will not change.

The population will increase exponentially.

The carrying capacity of the environment will increase.

The growth rate will approach zero.

The population will show an Allee effect.

34.

1 point

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. Calculate an estimate of the number of individuals added to (or lost from) a population of 1,000 individuals in one year.

400 individuals added

20 individuals added

120 individuals added

20 individuals lost

40 individuals added

35.

1 point

In animals, nitrogenous wastes are produced mostly from the catabolism of

triglycerides and steroids.

phospholipids and glycolipids.

starch and cellulose.

proteins and nucleic acids.

fatty acids and glycerol.

36.

1 point

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

metabolizes its stored energy more readily than can the endotherm.

expends more energy per kg of body mass than does the endotherm.

invests little energy in temperature regulation.

has greater insulation on its body surface.

maintains a higher basal metabolic rate.

37.

1 point

An inflammation-causing signal released by mast cells at the site of an infection is

mucus

lymphatic fluid.

sodium ions.

an interferon.

histamine.