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Exam 4

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Most of the exchange surfaces of multicellular animals are lined with

A) connective tissue.

B) smooth muscle cells.

C) neural tissue.

D) epithelial tissue.

E) adipose tissue.
D) epithelial tissue.
A necropsy (postmortem analysis) of a marine sea star that died after it was mistakenly placed in fresh water would likely show that it died because

A) it was stressed and needed more time to acclimate to the new conditions.

B) it was so hyperosmotic to the fresh water that it could not osmoregulate.

C) the sea star's kidneys could not handle the change in ionic content presented by the fresh water.

D) its contractile vacuoles ruptured.

E) its cells dehydrated and lost the ability to metabolize.
B) it was so hyperosmotic to the fresh water that it could not osmoregulate.
Organisms categorized as osmoconformers are most likely

A) found in freshwater lakes and streams.

B) marine.

C) amphibious.

D) found in arid terrestrial environments.

E) found in terrestrial environments with adequate moisture.
B) marine.
The body fluids of an osmoconformer would be ________ with its ________ environment.

A) hyperosmotic; freshwater

B) isotonic; freshwater

C) hyperosmotic; saltwater

D) isoosmotic; saltwater

E) hypoosmotic; saltwater
D) isoosmotic; saltwater
Compared to the seawater around them, most marine invertebrates are

A) hyperosmotic.

B) hypoosmotic.

C) isoosmotic.

D) hyperosmotic and isoosmotic.

E) hypoosmotic and isoosmotic.
C) isoosmotic.
The fluid with the highest osmolarity is

A) distilled water.

B) plasma in birds.

C) plasma in mammals.

D) seawater in a tidal pool.

E) estuarine water.
D) seawater in a tidal pool.
A human who has no access to fresh water but is forced to drink seawater instead

A) will thrive under such conditions, as long as he has lived at the ocean most of his life.

B) will excrete more water molecules than taken in, because of the high load of ion ingestion.

C) will develop structural changes in the kidneys to accommodate the salt overload.

D) will find that drinking saltwater satiates his thirst.

E) will risk becoming overhydrated within 12 hours.
B) will excrete more water molecules than taken in, because of the high load of ion ingestion.
Many marine and freshwater bony fish achieve osmoregulation via

A) loss of water through the gills.

B) gain of salt through the gills.

C) loss of water in the urine.

D) no drinking of water.

E) gain of water through food.
E) gain of water through food.
Unlike most bony fishes, sharks maintain body fluids that are isoosmotic to seawater, so they are considered by many to be osmoconformers. Nonetheless, these sharks osmoregulate at least partially by

A) using their gills and kidneys to rid themselves of sea salts.

B) monitoring dehydration at the cellular level with special gated aquaporins.

C) tolerating high urea concentrations that balance internal salt concentrations to seawater osmolarity.

D) synthesizing trimethylamine oxide, a chemical that binds and precipitates salts inside cells.

E) possessing a special adaptation that allows their cells to operate at an extraordinarily high salt concentration.
C) tolerating high urea concentrations that balance internal salt concentrations to seawater osmolarity.
The necropsy (postmortem analysis) of a freshwater fish that died after being placed accidentally in saltwater would likely show that

A) loss of water by osmosis from cells in vital organs resulted in cell death and organ failure.

B) high amounts of salt had diffused into the fish's cells, causing them to swell and lyse.

C) the kidneys were not able to keep up with the water removal necessary in this hyperosmotic environment, creating an irrevocable loss of homeostasis.

D) the gills became encrusted with salt, resulting in inadequate gas exchange and a resulting asphyxiation.

E) brain cells lysed as a result of increased osmotic pressure in this hyperosmotic environment, leading to death by loss of autonomic function.
A) loss of water by osmosis from cells in vital organs resulted in cell death and organ failure.
Urea is produced in the

A) liver from NH3 and CO2.

B) liver from glycogen.

C) kidneys from glucose.

D) kidneys from glycerol and fatty acids.

E) bladder from uric acid and H2O.
A) liver from NH3 and CO2.
Urea is

A) insoluble in water.

B) more toxic to human cells than ammonia.

C) the primary nitrogenous waste product of humans.

D) the primary nitrogenous waste product of most birds.

E) the primary nitrogenous waste product of most aquatic invertebrates.
C) the primary nitrogenous waste product of humans.
Which nitrogenous waste has the greatest number of nitrogen atoms?

A) ammonia

B) ammonium ions

C) urea

D) uric acid
D) uric acid
Ammonia is likely to be the primary nitrogenous waste in living conditions that include

A) lots of fresh water flowing across the gills of a fish.

B) lots of seawater, such as a bird living in a marine environment.

C) lots of seawater, such as the environment of a marine mammal (e.g., a polar bear).

D) a terrestrial environment, such as that supporting crickets.

E) a moist system of burrows, such as those of naked mole rats.
A) lots of fresh water flowing across the gills of a fish.
Among vertebrate animals, urea

A) is made in the kidneys and immediately excreted.

B) is added to the air in the lungs to be exhaled, along with carbon dioxide.

C) is made in the liver by combining two ammonia molecules with one carbon dioxide.

D) is made in the pancreas and added to the intestinal contents, along with bile salts, for excretion.

E) is rarely the nitrogenous waste of choice.
C) is made in the liver by combining two ammonia molecules with one carbon dioxide.
The nitrogenous waste that requires the most energy to produce is

A) ammonia.

B) ammonium.

C) urea.

D) uric acid.
D) uric acid.
Ammonia

A) is soluble in water.

B) can be stored in the body as a precipitate.

C) has low toxicity relative to urea.

D) is metabolically more expensive to synthesize than urea.

E) is the major nitrogenous waste excreted by insects.
A) is soluble in water.
The advantage of excreting nitrogenous wastes as urea rather than as ammonia is that

A) urea can be exchanged for Na+.

B) urea is less toxic than ammonia.

C) urea requires more water for excretion than ammonia.

D) urea does not affect the osmolar gradient.

E) less nitrogen is removed from the body.
B) urea is less toxic than ammonia.
The primary nitrogenous waste excreted by birds is

A) ammonia.

B) nitrate.

C) nitrite.

D) urea.

E) uric acid.
E) uric acid.
Which nitrogenous waste requires hardly any water for its excretion?

A) amino acids

B) urea

C) uric acid

D) ammonia

E) nitrogen gas
C) uric acid
In animals, nitrogenous wastes are produced mostly from the catabolism of

A) starch and cellulose.

B) triglycerides and steroids.

C) proteins and nucleic acids.

D) phospholipids and glycolipids.

E) fatty acids and glycerol.
C) proteins and nucleic acids.
Birds secrete uric acid as their nitrogenous waste because uric acid

A) is readily soluble in water.

B) is metabolically less expensive to synthesize than other excretory products.

C) requires little water for nitrogenous waste disposal, thus reducing body mass.

D) excretion allows birds to live in desert environments.
C) requires little water for nitrogenous waste disposal, thus reducing body mass.
Among the following choices, the most concentrated urine is excreted by

A) frogs.

B) kangaroo rats.

C) humans.

D) desert tortoises.

E) birds.
B) kangaroo rats.
Materials are returned to the blood from the filtrate by which of the following processes?

A) filtration

B) ultrafiltration

C) selective reabsorption

D) secretion

E) excretion
C) selective reabsorption
Excretory structures known as protonephridia are present in

A) flatworms.

B) earthworms.

C) insects.

D) vertebrates.

E) cnidarians.
A) flatworms.
Excretory organs known as Malpighian tubules are present in

A) earthworms.

B) flatworms.

C) insects.

D) jellyfish.

E) sea stars.
C) insects.
The osmoregulatory/excretory system of a freshwater flatworm is based on the operation of

A) protonephridia.

B) metanephridia.

C) Malpighian tubules.

D) nephrons.

E) ananephredia.
A) protonephridia.
The osmoregulatory process called secretion refers to the

A) formation of filtrate at an excretory structure.

B) reabsorption of nutrients from a filtrate.

C) selective elimination of excess ions and toxins from body fluids.

D) formation of an osmotic gradient along an excretory structure.

E) expulsion of urine from the body.
C) selective elimination of excess ions and toxins from body fluids.
The osmoregulatory/excretory system of an earthworm is based on the operation of

A) protonephridia.

B) metanephridia.

C) Malpighian tubules.

D) nephrons.

E) ananephredia.
B) metanephridia.
The osmoregulatory/excretory system of an insect is based on the operation of

A) protonephridia.

B) metanephridia.

C) Malpighian tubules.

D) nephrons.

E) ananephredia.
C) Malpighian tubules.
Which of the following pairs of organisms excrete nitrogenous wastes in the form of uric acid?

A) mice and birds

B) insects and birds

C) lions and horses

D) humans and frogs

E) fish and turtles
B) insects and birds
Choose a pair that correctly associates the mechanism for osmoregulation or nitrogen removal with the appropriate animal.

A) metanephridium—flatworm

B) Malpighian tubule—frog

C) kidney—insect

D) flame bulb—snake

E) exchange across the body surface—marine invertebrate
E) exchange across the body surface—marine invertebrate
An excretory system that is partly based on the filtration of fluid under high hydrostatic pressure is the

A) flame bulb system of flatworms.

B) protonephridia of rotifers.

C) metanephridia of earthworms.

D) Malpighian tubules of insects.

E) kidneys of vertebrates.
E) kidneys of vertebrates.
Freshwater flatworms form urine that is typically

A) of high solute concentration in order to conserve body fluids.

B) of very low volume in order to conserve body fluids.

C) of high solute concentration and very low volume in order to conserve body fluids.

D) of high solute concentration and high volume, similar to their normal fluid uptake.

E) of low solute concentration and high volume, similar to their normal fluid uptake.
E) of low solute concentration and high volume, similar to their normal fluid uptake.
The transfer of fluid from the glomerulus to Bowman's capsule

A) results from active transport.

B) transfers large molecules as easily as small ones.

C) is very selective as to which subprotein-sized molecules are transferred.

D) is mainly a consequence of blood pressure in the capillaries of the glomerulus.

E) usually includes the transfer of red blood cells into Bowman's capsule.
D) is mainly a consequence of blood pressure in the capillaries of the glomerulus.
Within a normally functioning kidney, blood can be found in

A) the vasa recta.

B) Bowman's capsule.

C) the loop of Henle.

D) the proximal tubule.

E) the collecting duct.
A) the vasa recta.
The filtrate in the renal pelvis enters directly from

A) the loop of Henle.

B) the collecting duct.

C) Bowman's capsule.

D) the proximal tubule.

E) the glomerulus.
B) the collecting duct.
Juxtamedullary nephrons can concentrate salt effectively in the renal medulla because of their long

A) loops of Henle.

B) distal convoluted tubules.

C) Bowman's capsules.

D) proximal convoluted tubules.

E) glomeruli.
A) loops of Henle.
The filtrate in the proximal convoluted tubule of the human does not normally include

A) ions.

B) glucose.

C) plasma proteins.

D) amino acids.

E) dissolved gasses.
C) plasma proteins.
The osmolarity of human urine

A) can be four times as great as the normal osmolarity of human plasma.

B) is always exactly equal to the plasma osmolarity.

C) is always less than the plasma osmolarity.

D) is always greater than the plasma osmolarity.

E) is determined primarily by the concentration of glucose.
A) can be four times as great as the normal osmolarity of human plasma.
A primary reason that the kidneys have one of the highest metabolic rates of all body organs is that

A) they store the body's excess fats.

B) they have membranes of varying permeability to water.

C) they operate an extensive set of active-transport ion pumps.

D) they are the body's only means of shedding excess nutrients.

E) they have an abundance of myogenic smooth muscle.
C) they operate an extensive set of active-transport ion pumps.
Low selectivity of solute movement is a characteristic of

A) salt pumping to control osmolarity.

B) H+ pumping to control pH.

C) reabsorption mechanisms along the proximal tubule.

D) filtration from the glomerular capillaries.

E) secretion along the distal tubule.
D) filtration from the glomerular capillaries.
If ATP production in a human kidney was suddenly halted, urine production would

A) come to a complete halt.

B) decrease, and the urine would be
hypoosmotic compared to plasma.

C) increase, and the urine would be isoosmotic compared to plasma.

D) increase, and the urine would be hyperosmotic compared to plasma.

E) decrease, and the urine would be isoosmotic compared to plasma.
C) increase, and the urine would be isoosmotic compared to plasma.
Compared to wetland mammals, water conservation in mammals of arid regions is enhanced by having more

A) juxtamedullary nephrons.

B) Bowman's capsules.

C) ureters.

D) podocytes.

E) urinary bladders.
A) juxtamedullary nephrons.
Processing of filtrate in the proximal and distal tubules

A) achieves the sorting of plasma proteins according to size.

B) achieves the conversion of toxic ammonia to less toxic urea.

C) maintains homeostasis of pH in body fluids.

D) regulates the speed of blood flow through the nephrons.

E) reabsorbs urea to maintain osmotic balance.
C) maintains homeostasis of pH in body fluids.
In humans, the transport epithelial cells in the ascending loop of Henle

A) are the largest epithelial cells in the body.

B) are not in contact with interstitial fluid.

C) have plasma membranes of low permeability to water.

D) have 50% of their cell mass made of smooth endoplasmic reticulum.

E) are not affected by high levels of nitrogenous wastes.
C) have plasma membranes of low permeability to water.
The typical osmolarity of human blood is

A) 30 mosm/L.

B) 100 mosm/L.

C) 200 mosm/L.

D) 300 mosm/L.

E) 500 mosm/L.
D) 300 mosm/L.
When stimulated by aldosterone, the reabsorption of Na+ is increased along

A) the loop of Henle.

B) the glomerulus.

C) Bowman's capsule.

D) the proximal tubule.

E) the distal tubule.
E) the distal tubule.
Increased ADH secretion is likely after

A) drinking lots of pure water.

B) sweating-induced dehydration increases plasma osmolarity.

C) ingestion of ethanol (drinking alcoholic drinks).

D) eating a small sugary snack.

E) blood pressure is abnormally high.
B) sweating-induced dehydration increases plasma osmolarity.
After blood flow is artificially reduced at one kidney, you would expect that kidney to secrete more of the hormone known as

A) erythropoietin.

B) angiotensinogen.

C) renin.

D) antidiuretic hormone.

E) atrial natriuretic peptide.
C) renin.
After drinking alcoholic beverages, increased urine excretion is the result of

A) increased aldosterone production.

B) increased blood pressure.

C) inhibited secretion of antidiuretic hormone (ADH).

D) increased reabsorption of water in the proximal tubule.

E) the osmoregulator cells of the brain increasing their activity.
C) inhibited secretion of antidiuretic hormone (ADH).
Osmoregulatory adjustment via the renin-angiotensin-aldosterone system can be triggered by

A) sleeping for one hour.

B) severe sweating on a hot day.

C) eating a bag of potato chips.

D) eating a pizza with olives and pepperoni.

E) drinking several glasses of water.
B) severe sweating on a hot day.
Antidiuretic hormone (ADH) functions at the cellular level by

A) stimulating the reabsorption of glucose through channel proteins.

B) triggering the synthesis of an enzyme that makes the phospholipid bilayer more permeable to water.

C) causing membranes to include more phospholipids that have unsaturated fatty acids.

D) causing an increase in the number of aquaporin molecules of collecting duct cells.

E) decreasing the speed at which filtrate flows through the nephron, leading to increased reabsorption of water.
D) causing an increase in the number of aquaporin molecules of collecting duct cells.
ADH and RAAS work together in maintaining osmoregulatory homeostasis through which of the following ways?

A) ADH regulates the osmolarity of the blood and RAAS regulates the volume of the blood.

B) ADH regulates the osmolarity of the blood by altering renal reabsorption of water, and RAAS maintains the osmolarity of the blood by stimulating Na+ and water reabsorption.

C) ADH and RAAS work antagonistically; ADH stimulates water reabsorption during dehydration and RAAS causes increased excretion of water when it is in excess in body fluids.

D) both stimulate the adrenal gland to secrete aldosterone, which increases both blood volume and pressure via receptors in the urinary bladder.

E) by combining at the receptor sites of proximal tubule cells, where reabsorption of essential nutrients takes place.
B) ADH regulates the osmolarity of the blood by altering renal reabsorption of water, and RAAS
maintains the osmolarity of the blood by stimulating Na+ and water reabsorption.
If a person loses a large amount of water in a short period of time, he or she may die from dehydration. ADH can help reduce water loss through its interaction with its target cells in the

A) anterior pituitary.

B) posterior pituitary.

C) adrenal gland.

D) bladder.

E) kidney.
E) kidney.
The body tissue that consists largely of material located outside of cells is

A) epithelial tissue.

B) connective tissue.

C) skeletal muscle.

D) smooth muscle.

E) nervous tissue.
B) connective tissue.
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) countercurrent heat exchanger

E) blubber or fat layer
C) wind blowing across the body surface
Which process in the nephron is least selective?

A) filtration

B) reabsorption

C) active transport

D) secretion

E) salt pumping by the loop of Henle
A) filtration
Homeostasis typically relies on negative feedback because positive feedback

A) requires a response but not a stimulus.

B) drives processes to completion rather than to a balance point.

C) acts within, but not beyond, a normal range.

D) can decrease but not increase a variable.

E) involves one location rather than several across the body.
B) drives processes to completion rather than to a balance point.
Which of the following is an accurate statement about thermoregulation?

A) Endotherms are regulators and ectotherms are conformers.

B) Endotherms maintain a constant body temperature and ectotherms do not.

C) Endotherms are warm-blooded and ectotherms are cold-blooded.

D) Endotherms and ectotherms differ in their primary source of heat for thermoregulation.

E) Endothermy has a lower energy cost than ectothermy.
D) Endotherms and ectotherms differ in their primary source of heat for thermoregulation.
Natural selection should favor the highest proportion of juxtamedullary nephrons in which of the following species?

A) a river otter

B) a mouse species living in a tropical rain forest

C) a mouse species living in a temperate broadleaf forest

D) a mouse species living in a desert

E) a beaver
D) a mouse species living in a desert
African lungfish, which are often found in small stagnant pools of fresh water, produce urea as a nitrogenous waste. What is the advantage of this adaptation?

A) Urea takes less energy to synthesize than ammonia.

B) Small stagnant pools do not provide enough water to dilute the toxic ammonia.

C) The highly toxic urea makes the pool uninhabitable to potential competitors.

D) Urea forms an insoluble precipitate.

E) Urea makes lungfish tissue hypoosmotic to the pool.
B) Small stagnant pools do not provide enough water to dilute the toxic ammonia.
Trees are rare in the savanna biome because of

A) insufficient annual precipitation.

B) acidic soils.

C) extreme winter temperatures.

D) large variations in seasonal rainfall.

E) permafrost.
C) extreme winter temperatures.
Which of the following statements best describes the effect of climate on biome distribution?

A) Average annual temperature and precipitation are sufficient to predict which biome will be found in an area.

B) Seasonal fluctuation of temperature is not a limiting factor in biome distribution if areas have the same annual temperature and precipitation means.

C) Not only is the average climate important in determining biome distribution, but so is the pattern of climatic variation.

D) Temperate forests and grasslands are different biomes because they receive a different quality and quantity of sunlight, even though they have essentially the same annual temperature and precipitation.

E) Correlation of climate with biome distribution is sufficient to determine the cause of biome patterns.
C) Not only is the average climate important in determining biome distribution, but so is the pattern of climatic variation.
In the ecological development of terrestrial biomes, which factor is most dependent on all the others?

A) the species of colonizing animals

B) prevailing temperature

C) prevailing rainfall

D) mineral nutrient availability

E) soil structure
A) the species of colonizing animals
The growing season would generally be shortest in which of the following biomes?

A) savanna

B) temperate broadleaf forest

C) temperate grassland

D) tropical rain forest

E) northern coniferous forest
E) northern coniferous forest
Trees are not usually found in the tundra biome because of

A) insufficient annual precipitation.

B) acidic soils.

C) extreme winter temperatures.

D) overbrowsing by musk ox and caribou.

E) permafrost.
E) permafrost.
Which of the following levels of ecological organization is arranged in the correct sequence from most to least inclusive?

A) community, ecosystem, individual, population

B) ecosystem, community, population, individual

C) population, ecosystem, individual, community

D) individual, population, community, ecosystem

E) individual, community, population, ecosystem
B) ecosystem, community, population, individual
Which of the following choices includes all of the others in creating global terrestrial climates?

A) differential heating of Earth's surface

B) ocean currents

C) global wind patterns

D) evaporation of water from ocean surfaces

E) Earth's rotation on its axis
A) differential heating of Earth's surface
Why is the climate drier on the leeward side of mountain ranges that are subjected to prevailing winds?

A) Deserts create dry conditions on the leeward side of mountain ranges.

B) The sun illuminates the leeward side of mountain ranges at a more direct angle, converting to heat energy, which evaporates most of the water present.

C) Pushed by the prevailing winds on the windward side, air is forced to rise, cool, condense, and drop its precipitation, leaving drier air to descend the leeward side.

D) Air masses pushed by the prevailing winds are stopped by mountain ranges and the moisture is used up in the stagnant air masses on the leeward side.

E) More organisms live on the sheltered, leeward side of mountain ranges where their utilization of water lowers the amount available when compared to the windward side.
C) Pushed by the prevailing winds on the windward side, air is forced to rise, cool, condense, and drop its precipitation, leaving drier air to descend the leeward side.
What would be the effect on climate in the temperate latitudes if Earth were to slow its rate of rotation from a 24-hour period of rotation to a 48-hour period of rotation?

A) Seasons would be longer and more distinct (colder winters and warmer summers).

B) There often would be a smaller range between daytime high and nighttime low temperatures.

C) Large-scale weather events such as tornadoes and hurricanes would no longer be a part of regional climates.

D) Winter seasons in both the northern and southern hemispheres would have more abundant and frequent precipitation events.

E) There often would be a larger range between daytime high and nighttime low temperatures.
E) There often would be a larger range between daytime high and nighttime low temperatures.
Palm trees and subtropical plants are commonplace in Land's End, England, whose latitude is the equivalent of Labrador in coastal Canada, where the local flora is subarctic. Which statement best explains why this apparent anomaly exists between North America and Europe?

A) Labrador does not get enough rainfall to support the subtropical flora found in Land's End.

B) Regions such as Labrador are actually colder than England because colder arctic air is pulled down to eastern North America and not to England.

C) Rainfall fluctuates greatly in England; rainfall is consistently high in Labrador.

D) Labrador is too windy to support tall plants, such as palm trees.

E) Labrador receives sunlight of lower duration and intensity than does Land's End.
B) Regions such as Labrador are actually colder than England because colder arctic air is pulled down to eastern North America and not to England.
In mountainous areas of western North America, north-facing slopes would be expected to

A) receive more sunlight than similar southern exposures.

B) be warmer and drier than comparable southern-exposed slopes.

C) consistently be steeper than southern exposures.

D) support biological communities similar to those found at lower elevations on similar south- facing slopes.

E) support biological communities similar to those found at higher elevations on similar south- facing slopes.
E) support biological communities similar to those found at higher elevations on similar south- facing slopes.
Deserts typically occur in a band around 30 degrees north and south latitude because

A) descending air masses originating from the tropics tend to be dry.

B) trade winds have little moisture.

C) moisture-laden air is heavier than dry air and is not carried to these latitudes.

D) ascending air from these regions tends to be moist, removing available water and creating a desert.

E) these locations get the most intense solar radiation of any location on Earth.
A) descending air masses originating from the tropics tend to be dry.
Which of the following events might you predict to occur if the tilt of Earth's axis relative to its plane of orbit was increased to 33 1/2 degrees?

A) Summers and winters in the United States would likely become warmer and colder, respectively.

B) Winters and summers in Australia would likely become less distinct seasons.

C) Seasonal variation at the equator might decrease.

D) Both northern and southern hemispheres would experience summer and winter at the same time.

E) Both poles would experience massive ice melts.
A) Summers and winters in the United States would likely become warmer and colder, respectively.
Imagine some cosmic catastrophe jolts Earth so that its axis is perpendicular to the orbital plane between Earth and the sun. The most obvious effect of this change would be

A) the elimination of tides.

B) an increase in the length of night.

C) an increase in the length of a year.

D) a decrease in temperature at the equator.

E) the elimination of seasonal variation.
E) the elimination of seasonal variation.
The main reason polar regions are cooler than the equator is that

A) there is more ice at the poles.

B) sunlight strikes the poles at a lower angle.

C) the poles are farther from the sun.

D) the polar atmosphere is thinner and contains fewer greenhouse gases.

E) the poles are permanently tilted away from the sun.
B) sunlight strikes the poles at a lower angle.
Which of the following environmental features might influence microclimates?

A) forest canopy

B) freshly plowed field

C) log on the forest floor

D) large boulder

E) All of the options are correct.
E) All of the options are correct.
Generalized global air circulation and precipitation patterns are caused by

A) rising, warm, moist air masses that cool and release precipitation as they rise and then, at high altitude, cool and sink back to the surface as dry air masses after moving north or south of the tropics.

B) air masses that are dried and heated over continental areas that rise, cool aloft, and descend over oceanic areas followed by a return flow of moist air from ocean to land, delivering high amounts of precipitation to coastal areas.

C) polar, cool, moist high-pressure air masses from the poles that move along the surface, releasing precipitation along the way to the equator where they are heated and dried.

D) the revolution of Earth around the sun.

E) mountain ranges that deflect air masses containing variable amounts of moisture.
A) rising, warm, moist air masses that cool and release precipitation as they rise and then, at high altitude, cool and sink back to the surface as dry air masses after moving north or south of the tropics.
Air masses formed over the Pacific Ocean are moved by prevailing westerlies where they encounter extensive north-south mountain ranges, such as the Sierra Nevadas and the Cascades. Which statement best describes the outcome of this encounter between a landform and an air mass?

A) The cool, moist Pacific air heats up as it rises, releasing its precipitation as it passes the tops of the mountains, and this warm, now dry air cools as it descends on the leeward side of the range.

B) The warm, moist Pacific air rises and cools, releasing precipitation as it moves up the windward side of the range, and this cool, now dry air mass heats up as it descends on the leeward side of the range.

C) The cool, dry Pacific air heats up and picks up moisture from evaporation of the snowcapped peaks of the mountain range, releasing this moisture as precipitation when the air cools while descending on the leeward side of the range.

D) These air masses are blocked by the mountain ranges, producing high annual amounts of precipitation on the windward sides of these mountain ranges.

E) These air masses remain essentially unchanged in moisture content and temperature as they pass over these mountain ranges.
B) The warm, moist Pacific air rises and cools, releasing precipitation as it moves up the windward side of the range, and this cool, now dry air mass heats up as it descends on the leeward side of the range.
Coral reefs can be found on the southeast coast of the United States but not at similar latitudes on the southwest coast. Differences in which of the following most likely account for this?

A) sunlight intensity

B) precipitation

C) day length

D) ocean currents

E) salinity
D) ocean currents
What is the limiting factor for the growth of trees in the tundra?

A) low precipitation

B) lack of sunlight

C) insufficient minerals in bedrock

D) pH of soils

E) permafrost
E) permafrost
In which of the following terrestrial biome pairs are both dependent upon periodic burning?

A) tundra and coniferous forest

B) chaparral and savanna

C) desert and savanna

D) tropical forest and temperate broadleaf forest

E) grassland and tundra
B) chaparral and savanna
Fire suppression by humans

A) will always result in an increase in species diversity in a given biome.

B) can change the species composition within biological communities.

C) will result ultimately in sustainable production of increased amounts of forest products for human use.

D) is necessary for the protection of threatened and endangered forest species.

E) is a management goal of conservation biologists to maintain the healthy condition of forest communities.
B) can change the species composition within biological communities.
Which of the following statements best describes the interaction between fire and ecosystems?

A) The likelihood of a wildfire occurring in a given ecosystem is highly predictable over the short term.

B) Many kinds of plants and plant communities have adapted to frequent fires.

C) The suppression of forest fires by man has prevented certain communities, such as grasslands, from reaching their climax stage.

D) Chaparral communities have evolved to the extent that they rarely burn.

E) Fire is unnatural in ecosystems and should be prevented.
B) Many kinds of plants and plant communities have adapted to frequent fires.
Imagine that a deep temperate zone lake did not "turn over" during the spring and fall seasons. Based on the physical and biological properties of limnetic ecosystems, what would be the difference from normal seasonal turnover?

A) The lake would be uniformly cold during the winter and summer.

B) The lake would fail to freeze over in winter.

C) An algal bloom would result every spring.

D) The lake would suffer a nutrient depletion in its surface layers.

E) The pH of the lake would become increasingly alkaline.
D) The lake would suffer a nutrient depletion in its surface layers.
Which marine zone has the lowest rates of primary productivity (photosynthesis)?

A) pelagic

B) abyssal

C) neritic

D) continental shelf

E) intertidal
B) abyssal
If a meteor impact or volcanic eruption injected a lot of dust into the atmosphere and reduced the sunlight reaching Earth's surface by 70% for one year, which of the following marine communities most likely would be least affected?

A) deep-sea vent

B) coral reef

C) intertidal

D) pelagic

E) estuary
A) deep-sea vent
Which statement describes how climate might change if Earth was 75% land and 25% water?

A) Terrestrial ecosystems would likely experience more precipitation.

B) Earth's daytime temperatures would be higher and nighttime temperatures lower.

C) Summers would be longer and winters shorter at midlatitude locations.

D) Earth would experience an unprecedented global warming.

E) More terrestrial microclimates would be created because of daily fluctuations in climate.
B) Earth's daytime temperatures would be higher and nighttime temperatures lower.
Which of the following examples of an ecological effect leading to an evolutionary effect is most correct?

A) When seeds are not plentiful, trees produce more seeds.

B) A few organisms of a larger population survive a drought and then these survivors emigrate to less arid environments.

C) A few individuals with denser fur survive the coldest days of an ice age, and the reproducing survivors of the ice age all have dense fur.

D) Fish that swim the fastest in running water catch the most prey and more easily escape predation.

E) The insects that spend the most time exposed to sunlight have the most mutations.
C) A few individuals with denser fur survive the coldest days of an ice age, and the reproducing survivors of the ice age all have dense fur.
Which of the following are important biotic factors that can affect the structure and organization of biological communities?

A) precipitation, wind

B) nutrient availability, soil pH

C) predation, competition

D) temperature, water

E) light intensity, seasonality
C) predation, competition
A certain species of pine tree survives only in scattered locations at elevations above 2,800 m in the western United States. To understand why this tree grows only in these specific places, an ecologist should

A) conclude that lower elevations are limiting to the survival of this species.

B) study the anatomy and physiology of this species.

C) investigate the various biotic and abiotic factors that are unique to high altitude.

D) analyze the soils found in the vicinity of these trees, looking for unique chemicals that may support their growth.

E) collect data on temperature, wind, and precipitation at several of these locations for a year.
C) investigate the various biotic and abiotic factors that are unique to high altitude.
Studying species transplants is a way that ecologists

A) determine the abundance of a species in a specified area.

B) determine the distribution of a species in a specified area.

C) develop mathematical models for distribution and abundance of organisms.

D) determine if dispersal is a key factor in limiting distribution of organisms.

E) consolidate a landscape region into a single ecosystem.
D) determine if dispersal is a key factor in limiting distribution of organisms.
A population is correctly defined as having which of the following characteristics?
I. inhabiting the same general area
II. belonging to the same species
III. possessing a constant and uniform density and dispersion

A) I only

B) III only

C) I and II only

D) II and III only

E) I, II, and III
C) I and II only
An ecologist recorded 12 white-tailed deer, Odocoileus virginianus, per square mile in one woodlot and 20 per square mile in another woodlot. What was the ecologist comparing?

A) density

B) dispersion

C) carrying capacity

D) cohorts

E) range
A) density
Uniform spacing patterns in plants such as the creosote bush are most often associated with

A) chance.

B) patterns of high humidity.

C) the random distribution of seeds.

D) competitive interaction between individuals of the same population.

E) the concentration of nutrients within the population's range.
D) competitive interaction between individuals of the same population.
Which of the following groups would be most likely to exhibit uniform dispersion?

A) red squirrels, who actively defend territories

B) cattails, which grow primarily at edges of lakes and streams

C) dwarf mistletoes, which parasitize particular species of forest trees

D) moths, in a city at night

E) lake trout, which seek out cold, deep water high in dissolved oxygen
A) red squirrels, who actively defend territories
To construct a reproductive table for a sexual species, one needs to

A) assess sperm viability for the males in the population.

B) keep track of all of the offspring of a cohort.

C) keep track of the females in a cohort.

D) keep track of all of the offspring of the females in a cohort.

E) analyze the ratio of deaths to births in a cohort.
C) keep track of the females in a cohort.
Which of the following examples would most accurately measure the density of the population being studied?

A) counting the number of prairie dog burrows per hectare

B) counting the number of times a 1-kilometer transect is intersected by tracks of red squirrels after a snowfall

C) counting the number of coyote droppings per hectare

D) counting the number of moss plants in 1-m2 quadrats

E) counting the number of zebras from airplane census observations.
D) counting the number of moss plants in 1-m2 quadrats
Long-term studies of Belding's ground squirrels show that immigrants move nearly 2 km from where they are born and become 1-8% of the males and 0.7-6% of the females in other populations. On an evolutionary scale, why is this significant?

A) These immigrants make up for the deaths of individuals, keeping the other populations' size stable.

B) Young reproductive males tend to stay in their home population and are not driven out by other territorial males.

C) These immigrants provide a source of genetic diversity for the other populations.

D) Those individuals that emigrate to these new populations are looking for less crowded conditions with more resources.

E) Gradually, the populations of ground squirrels will move from a clumped to a uniform population pattern of dispersion.
C) These immigrants provide a source of genetic diversity for the other populations.
Which of the following sets of measurements would best describe a population's physical structure and vital statistics?

A) density, dispersion, and demographics

B) gene frequency over time and the ratio of reproductive to nonreproductive individuals

C) annual precipitation averages and mean annual temperatures

D) minimum and maximum amounts of precipitation and annual temperature extremes

E) ratio of predators and the number of immigrants and emigrants
A) density, dispersion, and demographics
Which of the following scenarios would provide the most legitimate data on population density?

A) Count the number of nests of a particular species of songbird and multiply this by a factor that extrapolates these data to actual animals.

B) Count the number of pine trees in several randomly selected 10-m by 10-m plots and extrapolate this number to the fraction of the study area these plots represent.

C) Use the mark-and-recapture method to estimate the size of the population.

D) Calculate the difference between all of the immigrants and emigrants to see if the population is growing or shrinking.

E) Add the number of births and subtract the individuals that die to see if the population's density is increasing or decreasing.
B) Count the number of pine trees in several randomly selected 10-m by 10-m plots and extrapolate this number to the fraction of the study area these plots represent.
Which of the following is the best natural example of uniform distribution?

A) bees collecting pollen in a wildflower meadow

B) snails in an intertidal zone at low tide

C) territorial songbirds in a mature forest during mating season

D) mushrooms growing on the floor of an old-growth forest

E) a cultivated cornfield in the Midwest
C) territorial songbirds in a mature forest during mating season
Which of the following choices would most likely promote random distribution?

A) territorial species

B) species that secrete chemicals to attract or inhibit other individuals

C) flocking and schooling behaviors

D) spacing during the breeding season

E) homogeneous chemical and physical factors in the environment
E) homogeneous chemical and physical factors in the environment
Which of the following best defines a cohort?

A) a group of individuals that inhabits a small isolated region within the range for the species

B) all of the individuals that are annually added to a population by birth and immigration

C) the reproductive males and females within the population

D) a group of the individuals from the same age group, from birth until they are all dead

E) the number of individuals that annually die or emigrate out of a population
D) a group of the individuals from the same age group, from birth until they are all dead
Why do some invertebrates, such as lobsters, show a "stair-step" survivorship curve?

A) Many invertebrates mate and produce offspring on multiyear cycles.

B) Within a species of invertebrates, younger individuals have a higher survivorship than older individuals.

C) Many invertebrates molt in order to grow, and they are vulnerable to predation during their "soft shell" stage.

D) Many invertebrate species have population cycles that go up and down according to the frequency of sunspots.

E) The number of fertilized eggs that mature to become females in many species of invertebrates is based on ambient temperature.
C) Many invertebrates molt in order to grow, and they are vulnerable to predation during their "soft shell" stage.
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.

A) 120 individuals added

B) 40 individuals added

C) 20 individuals added

D) 400 individuals added

E) 20 individuals lost
B) 40 individuals added
Starting from a single individual, what is the size of a population of bacteria that reproduce by binary fission every 20 minutes at the end of a 2-hour time period? (Assume unlimited resources and no mortality.)

A) 8

B) 16

C) 32

D) 64

E) 128
D) 64
Which of the following is the equation for zero population growth (ZPG)?

A) b = m or r = 0

B) dN/dt = rN

C) dN/dt = rmax N (K - N)/K

D) dN/dt = rmax N

E) dN/dt = 1.0N
A) b = m or r = 0
In July 2008, the United States had a population of approximately 302,000,000 people. How many Americans were there in July 2009, if the estimated 2008 growth rate was 0.88%?

A) 2,700,000

B) 5,500,000

C) 303,000,000

D) 304,700,000

E) 2,710,800,000
D) 304,700,000
In 2008, the population of New Zealand was approximately 4,275,000 people. If the birth rate was 14 births for every 1,000 people, approximately how many births occurred in New Zealand in 2008?

A) 6,000

B) 42,275

C) 60,000

D) 140,000

E) 600,000
C) 60,000
Consider two forests: one is an undisturbed old-growth forest, whereas the other has recently been logged. In which forest are species likely to experience exponential growth, and why?

A) Old growth, because the stable conditions would favor exponential growth of all species in the forest.

B) Old growth, because each of the species is well established and can produce many offspring.

C) Logged, because the disturbed forest affords more resources for increased specific populations to grow.

D) Logged, because the various populations are stimulated to a higher reproductive potential.

E) Exponential growth is equally probable in old-growth and logged forests.
C) Logged, because the disturbed forest affords more resources for increased specific populations to grow.
As N approaches K for a certain population, which of the following is predicted by the logistic equation?

A) The growth rate will not change.

B) The growth rate will approach zero.

C) The population will show an Allee effect.

D) The population will increase
exponentially.

E) The carrying capacity of the environment will increase.
B) The growth rate will approach zero.
In models of logistic population growth,

A) the population growth rate slows dramatically as N approaches K.

B) new individuals are added to the population most rapidly at the beginning of the population's growth.

C) new individuals are added to the population as N approaches K.

D) only density-dependent factors affect the rate of population growth.

E) carrying capacity is never reached.
A) the population growth rate slows dramatically as N approaches K.
Carrying capacity is

A) seldom reached by marine producers and consumers because of the vast resources of the ocean.

B) the maximum population size that a particular environment can support.

C) fixed for most species over most of their range most of the time.

D) determined by density and dispersion data.

E) the term used to describe the stress a population undergoes due to limited resources.
B) the maximum population size that a particular environment can support.
Which of the following causes populations to shift most quickly from an exponential to a logistic population growth?

A) increased birth rate

B) removal of predators

C) decreased death rate

D) competition for resources

E) favorable climatic conditions
D) competition for resources
Natural selection involves energetic trade-offs between

A) choosing how many offspring to produce over the course of a lifetime and how long to live.

B) producing large numbers of gametes when employing internal fertilization versus fewer numbers of gametes when employing external fertilization.

C) the emigration of individuals when they are no longer reproductively capable or committing suicide.

D) increasing the number of individuals produced during each reproductive episode with a corresponding decrease in parental care.

E) high survival rates of offspring and the cost of parental care.
E) high survival rates of offspring and the cost of parental care.
The three basic variables that make up the life history of an organism are

A) life expectancy, birth rate, and death rate.

B) number of reproductive females in the population, age structure of the population, and life expectancy.

C) age when reproduction begins, how often reproduction occurs, and how many offspring are produced per reproductive episode.

D) how often reproduction occurs, life expectancy of females in the population, and number of offspring per reproductive episode.

E) the number of reproductive females in the population, how often reproduction occurs, and death rate.
C) age when reproduction begins, how often reproduction occurs, and how many offspring are produced per reproductive episode.
Which of the following pairs of reproductive strategies is consistent with energetic trade-off and reproductive success?

A) Pioneer species of plants produce many very small, highly airborne seeds, whereas large elephants that are very good parents produce many offspring.

B) Female rabbits that suffer high predation rates may produce several litters per breeding season, and coconuts produce few fruits, but most survive when they encounter proper growing conditions.

C) Species that have to broadcast to distant habitats tend to produce seeds with heavy protective seed coats, and animals that are caring parents produce fewer offspring with lower infant mortality.

D) Free-living insects lay thousands of eggs and provide no parental care, whereas flowers take good care of their seeds until they are ready to germinate.

E) Some mammals will not reproduce when environmental resources are low so they can survive until conditions get better, and plants that produce many small seeds are likely found in stable environments.
B) Female rabbits that suffer high predation rates may produce several litters per breeding season, and coconuts produce few fruits, but most survive when they encounter proper growing conditions.
Pacific salmon and annual plants are excellent examples of

A) cohort disintegration.

B) dispersion.

C) the Allee effect.

D) iteroparous reproduction.

E) semelparous reproduction.
E) semelparous reproduction.
Which of the following is characteristic of K-selected populations?

A) offspring with good chances of survival

B) many offspring per reproductive episode

C) small offspring

D) a high intrinsic rate of increase

E) early parental reproduction
A) offspring with good chances of survival
Which variables define the ecological life history of a species?

A) the age at which reproduction begins, frequency of reproduction, and the number of offspring for each reproductive episode

B) the ratio of females to males, the length of the breeding season, and the number of offspring for each reproductive episode

C) the number of offspring produced over a lifetime by a breeding pair and the survivability of the offspring

D) timing breeding sessions with optimal environmental conditions and the number of offspring produced during each breeding session

E) the amount of parental care given after birth, the number of reproductive episodes per year, and the number of years females are capable of producing viable offspring
A) the age at which reproduction begins, frequency of reproduction, and the number of offspring for each reproductive episode
Which pattern of reproduction is correctly paired with a species?

A) iteroparity—Pacific salmon

B) iteroparity—elephant

C) semelparity—oak tree

D) semelparity—rabbit

E) semelparity—polar bear
B) iteroparity—elephant
In which of the following situations would you expect to find the largest number of K- selected individuals?

A) a recently abandoned agricultural field in Ohio

B) a shifting sand dune community of south Lake Michigan

C) an old-growth forest

D) South Florida after a hurricane

E) a newly emergent volcanic island
C) an old-growth forest
Which of the following is most likely to contribute to density-dependent regulation of populations?

A) the removal of toxic waste by decomposers

B) intraspecific competition for nutrients

C) earthquakes

D) floods

E) fires
B) intraspecific competition for nutrients
Why do populations grow more slowly as they approach their carrying capacity?

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

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

C) Hormonal changes promote higher death rates in crowded populations.

D) Individuals voluntarily stop mating so that overcrowding does not occur.

E) The incoming energy decreases in populations experiencing a high rate of increase.
A) Density-dependent factors lead to fewer births and increased mortality.
Which of the following could be a density-independent factor limiting human population growth?

A) social pressure for birth control

B) earthquakes

C) plagues

D) famines

E) pollution
B) earthquakes
Which of the following biomes is correctly paired with the description of its climate?

A) savanna-low temperature, precipitation uniform during the year

B) tundra-long summers, mild winters

C) temperate broadleaf forest-relatively short growing season, mild winters

D) temperate grasslands-relatively warm winters, most rainfall in summer

E) tropical forests-nearly constant day length and temperature
E) tropical forests-nearly constant day length and temperature
A population's carrying capacity

A) may change as environmental conditions change.

B) can be accurately calculated using the logistic growth model.

C) generally remains constant over time.

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

E) can never be exceeded.
A) may change as environmental conditions change.
When climbing a mountain, we can observe transitions in biological communities that are analogous to the changes

A) in biomes at different latitudes.

B) in different depths in the ocean.

C) in a community through different seasons.

D) in an ecosystem as it evolves over time.

E) across the United States from east to west.
A) in biomes at different latitudes.
If the direction of Earth's rotation reversed, the most predictable effect would be

A) no more night and day.

B) a big change in the length of the year.

C) winds blowing from west to east along the equator.

D) a loss of seasonal variation at high latitudes.

E) the elimination of ocean currents.
C) winds blowing from west to east along the equator.
Which of the following statements is consistent with the principle of competitive exclusion?

A) Bird species generally do not compete for nesting sites.

B) The random distribution of one competing species will have a positive impact on the population growth of the other competing species.

C) Two species with the same fundamental niche will exclude other competing species.

D) Even a slight reproductive advantage will eventually lead to the elimination of the less well adapted of two competing species.

E) Natural selection tends to increase competition between related species.
D) Even a slight reproductive advantage will eventually lead to the elimination of the less well adapted of two competing species.
According to the competitive exclusion principle, two species cannot continue to occupy the same

A) habitat.

B) niche.

C) territory.

D) range.

E) biome.
B) niche.
Which of the following best describes resource partitioning?

A) competitive exclusion that results in the success of the superior species

B) slight variations in a species' niche that allow similar species to coexist

C) two species that can coevolve to share identical niches

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

E) a climax community that is reached when no new niches are available
B) slight variations in a species' niche that allow similar species to coexist
As you study two closely related predatory insect species, the two-spot and the three-spot avenger beetles, you notice that each species seeks prey at dawn in areas without the other species. However, where their ranges overlap, the two-spot avenger beetle hunts at night and the three-spot hunts in the morning. When you bring them into the laboratory and isolate the two different species, you discover that the offspring of both species are found to be nocturnal. You have discovered an example of

A) mutualism.

B) character displacement.

C) Batesian mimicry.

D) facultative commensalism.

E) resource partitioning.
E) resource partitioning.
Resource partitioning would be most likely to occur between

A) sympatric populations of a predator and its prey.

B) sympatric populations of species with similar ecological niches.

C) sympatric populations of a flowering plant and its specialized insect pollinator.

D) allopatric populations of the same animal species.

E) allopatric populations of species with similar ecological niches.
B) sympatric populations of species with similar ecological niches.
Which of the following is an example of cryptic coloration?

A) bands on a coral snake

B) brown or gray color of tree bark

C) markings of a viceroy butterfly's
wings

D) colors of an insect-pollinated flower's petals

E) a "walking stick" insect that resembles a twig
E) a "walking stick" insect that resembles a twig
Which of the following is an example of Müllerian mimicry?

A) two species of unpalatable butterfly that have the same color pattern

B) a day-flying hawkmoth that looks like a wasp

C) a chameleon that changes its color to look like a dead leaf

D) two species of rattlesnakes that both rattle their tails

E) two species of moths with wing spots that look like an owl's eyes
A) two species of unpalatable butterfly that have the same color pattern
Which of the following is an example of Batesian mimicry?

A) an insect that resembles a twig

B) a butterfly that resembles a leaf

C) a nonvenomous snake that looks like a venomous snake

D) a fawn with fur coloring that camouflages it in the forest environment

E) a snapping turtle that uses its tongue to mimic a worm, thus attracting fish
C) a nonvenomous snake that looks like a venomous snake
Which of the following is an example of aposematic coloration?

A) the brightly colored patterns of poison dart frogs

B) eye color in humans

C) green color of a plant

D) colors of an insect-pollinated flower

E) a katydid whose wings look like a dead leaf
A) the brightly colored patterns of poison dart frogs
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?

A) mutualism

B) parasitism

C) commensalism

D) facilitation

E) competition
B) parasitism
Evidence shows that some grasses benefit from being grazed. Which of the following terms would best describe this plant-herbivore interaction?

A) mutualism

B) commensalism

C) parasitism

D) competition

E) predation
A) mutualism
Which of the following would be most significant in understanding the structure of an ecological community?

A) determining how many species are present overall

B) determining which particular species are present

C) determining the kinds of interactions that occur among organisms of different species

D) determining the relative abundance of species

E) all of the above
E) all of the above
Which of the following studies would a community ecologist undertake to learn about competitive interactions?

A) selectivity of nest sites among cavity-nesting songbirds

B) the grass species preferred by grazing pronghorn antelope and bison

C) nitrate and phosphate uptake by various hardwood forest tree species

D) stomach analysis of brown trout and brook trout in streams where they coexist

E) all of the above
E) all of the above
White-breasted nuthatches and Downy woodpeckers both eat insects that hide in the furrows of bark in hardwood trees. The Downy woodpecker searches for insects by hunting from the bottom of the tree trunk toward the top, whereas the white-breasted nuthatch searches from the top of the trunk down. These hunting behaviors best illustrate which of the following ecological concepts?

A) competitive exclusion

B) resource partitioning

C) character displacement

D) keystone species

E) bottom-up and top-down hypotheses
B) resource partitioning
Which statement best describes the evolutionary significance of mutualism?

A) Mutualism offers more biodiversity to a community.

B) Individuals partaking in a mutualistic relationship are more resistant to parasites.

C) Interaction increases the survival and reproductive rates of mutualistic species.

D) Mutualistic interaction lessens competition in communities where it is present.

E) Mutualistic relationships allow organisms to synthesize and use energy more efficiently.
C) Interaction increases the survival and reproductive rates of mutualistic species.
How might an ecologist test whether a species is occupying all of its fundamental niche or only a portion of it?

A) Study the temperature range and humidity requirements of the species.

B) Observe if the niche size changes after the addition of nutritional resources to the habitat.

C) Observe if the niche size changes after the introduction of a similar non-native species.

D) Measure the change in reproductive success when the species is subjected to environmental stress.

E) Observe if the species expands its range after the removal of a competitor.
E) Observe if the species expands its range after the removal of a competitor.
Which of the following terms is used by ecologists to describe the community interaction where one organism makes the environment more suitable for another organism?

A) parasitism

B) mutualism

C) inhibition

D) facilitation

E) commensalism
D) facilitation
How did Eugene Odum describe an ecological niche?

A) the "address" of an organism

B) an entity that is synonymous with an organism's specific trophic level

C) an organism's "profession" in the community

D) the organism's role in recycling nutrients in its habitat

E) the interactions of the organism with other members of the community
C) an organism's "profession" in the community
In a tide pool, 15 species of invertebrates were reduced to 8 after one species was removed. The species removed was likely a(n)

A) pathogen.

B) keystone species.

C) herbivore.

D) resource partitioner.

E) mutualistic organism.
B) keystone species.
Elephants are not the most dominant species in African grasslands, yet they influence community structure. The grasslands contain scattered woody plants, but they are kept in check by the uprooting activities of the elephants. Take away the elephants, and the grasslands convert to forests or to shrublands. The newly growing forests support fewer species than the previous grasslands. Which of the following describes why elephants are the keystone species in this scenario?

A) Elephants exhibit a disproportionate influence on the structure of the community relative to their abundance.

B) Grazing animals depend upon the elephants to convert forests to grassland.

C) Elephants prevent drought in African grasslands.

D) Elephants are the biggest herbivore in this community.

E) Elephants help other populations survive by keeping out many of the large African predators.
A) Elephants exhibit a disproportionate influence on the structure of the community relative to their abundance.
According to bottom-up and top-down control models of community organization, which of the following expressions would imply that an increase in the size of a carnivore (C) population would negatively impact on its prey (P) population, but not vice versa?

A) P ← C

B) P → C

C) C ↔ P

D) P ← C → P

E) C ← P →
A) P ← C
Which of the following is a likely explanation for why invasive species take over communities into which they have been introduced?

A) Invasive species are less efficient than native species in competing for the limited resources of the environment.

B) Invasive species are not held in check by the predators and agents of disease that have always been in place for native species.

C) Humans carefully select which species will outcompete nuisance native species.

D) Invasive species have a higher reproductive potential than native species.

E) Invasive species come from geographically isolated regions, so when they are introduced to regions where there is more competition, they thrive.
B) Invasive species are not held in check by the predators and agents of disease that have always been in place for native species.
Biomanipulation can best be described as

A) removing many of the organisms at the next higher trophic level so that the struggling trophic level below can recover.

B) a means of reversing the effects of pollution by applying antidote chemicals that have a neutralizing effect on the community.

C) an example of how one would use the bottom-up model for community restoration.

D) adjusting the numbers of each of the trophic levels back to the numbers that they were before human disturbance.

E) monitoring and adjusting the nutrient and energy flow through a community with new technologies.
A) removing many of the organisms at the next higher trophic level so that the struggling trophic level below can recover.
Imagine five forest communities, each with 100 individuals distributed among four different tree species (W, X, Y, and Z). Which forest community would be most diverse?

A) 25W, 25X, 25Y, 25Z

B) 40W, 30X, 20Y, 10Z

C) 50W, 25X, 15Y, 10Z

D) 70W, 10X, 10Y, 10Z

E) 100W, 0X, 0Y, 0Z
A) 25W, 25X, 25Y, 25Z
Why are food chains relatively short?

A) Top-level feeders tend to be more numerous than lower-trophic-level species.

B) Top-level feeders tend to be small but are capable of conserving more energy.

C) Longer chains are less stable and energy transfer between trophic levels is inefficient.

D) There are only so many organisms that are adapted to feed on other types of organisms.

E) Food chain length is ultimately determined by the photosynthetic efficiency of producers.
C) Longer chains are less stable and energy transfer between trophic levels is inefficient.
According to the nonequilibrium model,

A) communities will remain in a climax state if there are no human disturbances.

B) community structure remains stable in the absence of interspecific competition.

C) communities are assemblages of closely linked species that are irreparably changed by disturbance.

D) interspecific interactions induce changes in community composition over time.

E) communities are constantly changing after being influenced by disturbances.
E) communities are constantly changing after being influenced by disturbances.
In a particular case of secondary succession, three species of wild grass all invaded a field. By the second season, a single species dominated the field. A possible factor in this secondary succession was

A) equilibrium.

B) facilitation.

C) immigration.

D) inhibition.

E) parasitism.
D) inhibition.
The 1988 Yellowstone National Park lodgepole pine forest fires were likely the result of

A) overgrazing by elk.

B) infrequent rain episodes.

C) years of fire suppression by humans.

D) unextinguished campfires.

E) geysers.
C) years of fire suppression by humans.
Why do moderate levels of disturbance result in an increase in community diversity?

A) Habitats are opened up for less competitive species.

B) Competitively dominant species infrequently exclude less competitive species after a moderate disturbance.

C) The environmental conditions become optimal.

D) The resulting uniform habitat supports stability, which in turn supports diversity.

E) Less-competitive species evolve strategies to compete with dominant species.
A) Habitats are opened up for less competitive species.
Species richness increases

A) as we increase in altitude in equatorial mountains.

B) as we travel southward from the North Pole to the equator.

C) on islands as distance from the mainland increases.

D) as depth increases in aquatic communities.

E) as community size decreases.
B) as we travel southward from the North Pole to the equator.
There are more species in tropical areas than in places more distant from the equator. This is probably a result of

A) fewer predators.

B) more intense annual solar radiation.

C) more frequent ecological disturbances.

D) fewer agents of disease.

E) fewer predators, more intense annual solar radiation, more frequent ecological disturbances, and fewer agents of disease.
B) more intense annual solar radiation.
Why do tropical communities tend to have greater species diversity than temperate or polar communities?

A) They are less likely to be affected by human disturbance.

B) There are fewer parasites to negatively affect the health of tropical communities.

C) Tropical communities are low in altitude, whereas temperate and polar communities are high in altitude.

D) Tropical communities are generally older than temperate and polar communities.

E) More competitive dominant species have evolved in temperate and polar communities.
D) Tropical communities are generally older than temperate and polar communities.
Which of the following is a correct statement about the McArthur/Wilson Island Equilibrium Model?

A) The more species that inhabit an island, the lower the extinction rate.

B) As the number of species on an island increases, the emigration rate decreases.

C) Competitive exclusion is less likely on an island that has large numbers of species.

D) Small islands receive few new immigrant species.

E) Islands closer to the mainland have higher extinction rates.
D) Small islands receive few new immigrant species.
Which of the following best describes the consequences of white-band disease in Caribbean coral reefs?

A) Staghorn coral has been decimated by the pathogen, and Elkhorn coral has taken its place.

B) Key habitat for lobsters, snappers, and other reef fishes has improved.

C) Algal species take the place of the dead coral, and the fish community is dominated by herbivores.

D) Algal species take over and the overall reef diversity increases due to increases in primary productivity.

E) Other coral species take the place of the affected Staghorn and Elkhorn species.
C) Algal species take the place of the dead coral, and the fish community is dominated by herbivores.
Zoonotic disease

A) is caused by suborganismal pathogens such as viruses, viroids, and prions only.

B) is caused by pathogens that are transferred from other animals to humans by direct contact or by means of a vector.

C) can only be spread from animals to humans through direct contact.

D) can only be transferred from animals to humans by means of an intermediate host.

E) is too specific to study at the community level, and studies of zoonotic pathogens are relegated to organismal biology.
B) is caused by pathogens that are transferred from other animals to humans by direct contact or by means of a vector.
Which of the following studies would shed light on the mechanism of spread of H5N1 from Asia?

A) Perform cloacal or saliva smears of migrating waterfowl to monitor whether any infected birds show up in Alaska.

B) Test fecal samples for H5N1 in Asian waterfowl that live near domestic poultry farms in Asia.

C) Test for the presence of H5N1 in poultry used for human consumption worldwide.

D) Locate and destroy birds infected with H5N1 in Asian open-air poultry markets.

E) Keep domestic and wild fowl from interacting with each other to minimize the probability that wild fowl could get infected and migrate out of Asia.
A) Perform cloacal or saliva smears of migrating waterfowl to monitor whether any infected birds show up in Alaska.
Why is a pathogen generally more virulent in a new habitat?

A) More pathogens tend to immigrate into newer habitats.

B) Intermediate host species are more motile and transport pathogens to new areas.

C) Pathogens evolve more efficient forms of reproduction in new environments.

D) Hosts in new environments have not had a chance to become resistant to the pathogen through natural selection.

E) New environments are almost always smaller in area, so that transmission of pathogens is easily accomplished between hosts.
D) Hosts in new environments have not had a chance to become resistant to the pathogen through natural selection.
In terms of community ecology, why are pathogens often more virulent now than before?

A) More new pathogens have recently evolved.

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

C) Human activities are transporting pathogens into new habitats (or communities) at an unprecedented rate.

D) Medicines for treating pathogenic disease are in short supply.

E) Sequencing of genes in pathogenic organisms is particularly difficult.
C) Human activities are transporting pathogens into new habitats (or communities) at an unprecedented rate.
The oak tree pathogen Phytophthora ramorum has migrated 800 km in 15 years. West Nile virus spread from New York State to 46 other states in 5 years. The difference in the rate of spread is probably related to

A) the lethality of each pathogen.

B) the mobility of their hosts.

C) the fact that viruses are very small.

D) innate resistance.

E) dormancy viability.
B) the mobility of their hosts.
The feeding relationships among the species in a community determine the community's

A) secondary succession.

B) ecological niche.

C) species richness.

D) species-area curve.

E) trophic structure.
E) trophic structure.
Based on the intermediate disturbance hypothesis, a community's species diversity is increased by

A) frequent massive disturbance.

B) stable conditions with no disturbance.

C) moderate levels of disturbance.

D) human intervention to eliminate disturbance.

E) intensive disturbance by humans.
C) moderate levels of disturbance.
Which of the following could qualify as a top-down control on a grassland community?

A) limitation of plant biomass by rainfall amount

B) influence of temperature on competition among plants

C) influence of soil nutrients on the abundance of grasses versus wildflowers

D) effect of grazing intensity by bison on plant species diversity

E) effect of humidity on plant growth rates
D) effect of grazing intensity by bison on plant species diversity
How do the Taylor Glacier bacteria produce their energy?

A) photosynthesis

B) heterotrophism

C) chemoautotrophism

D) thermophobism

E) photoautotrophism
C) chemoautotrophism
In ecosystems, why is the term cycling used to describe material transfer, whereas the term flow is used for energy exchange?

A) Materials are repeatedly used, but energy flows through and out of ecosystems.

B) Both material and energy are recycled and are then transferred to other ecosystems as in a flow.

C) Materials are cycled into ecosystems from other ecosystems, but energy constantly flows within the ecosystem.

D) Both material and energy flow in a never-ending stream within an ecosystem.

E) None of the choices is correct.
A) Materials are repeatedly used, but energy flows through and out of ecosystems.
Which statement most accurately describes how matter and energy are used in ecosystems?

A) Matter flows through ecosystems; energy cycles within ecosystems.

B) Energy flows through ecosystems; matter cycles within and through ecosystems.

C) Energy can be converted into matter; matter cannot be converted into energy.

D) Matter can be converted into energy; energy cannot be converted into matter.

E) Matter is used in ecosystems; energy is not.
B) Energy flows through ecosystems; matter cycles within and through ecosystems.
The law of conservation of matter states that matter cannot be created, yet matter is sometimes gained or lost to an ecosystem. What is the reason for this seeming contradiction?

A) Chemoautotrophic organisms can convert matter to energy.

B) Ecosystems are open systems; therefore, matter can be moved in/out of an ecosystem from/to another ecosystem.

C) Photosynthetic organisms convert sugars to more complex organic molecules.

D) Detrivores convert matter to energy.

E) Heterotrophs convert heat to energy.
B) Ecosystems are open systems; therefore, matter can be moved in/out of an ecosystem from/to another ecosystem.
Photosynthetic organisms are unique to most ecosystems because they

A) synthesize organic compounds they obtain from decaying heterotrophs.

B) synthesize inorganic compounds from organic compounds.

C) use light energy to synthesize organic compounds from inorganic compounds.

D) use chemical energy to synthesize organic compounds.

E) convert light energy into matter.
C) use light energy to synthesize organic compounds from inorganic compounds.
A cow's herbivorous diet indicates that it is a(n)

A) primary consumer.

B) secondary consumer.

C) decomposer.

D) autotroph.

E) producer.
A) primary consumer.
To recycle nutrients, an ecosystem must have, at a minimum,

A) producers.

B) producers and decomposers.

C) producers, primary consumers, and decomposers.

D) producers, primary consumers, secondary consumers, and
decomposers.

E) producers, primary consumers, secondary consumers, top carnivores, and decomposers.
B) producers and decomposers.
Which of the following terms encompasses all of the others?

A) heterotrophs

B) herbivores

C) carnivores

D) primary consumers

E) secondary consumers
A) heterotrophs
Which of the following is an example of an ecosystem?

A) all of the brook trout in a 500-square-hectare river drainage system

B) the plants, animals, and decomposers that inhabit an alpine meadow

C) a pond and all of the plant and animal species that live in it

D) the intricate interactions of the various plant and animal species on a savanna during a drought

E) all of the organisms and their physical environment in a tropical rain forest
E) all of the organisms and their physical environment in a tropical rain forest
If the sun were to suddenly stop providing energy to Earth, most ecosystems would vanish. Which of the following ecosystems would likely survive the longest after this hypothetical disaster?

A) tropical rain forest

B) tundra

C) deep-sea vent community

D) grassland

E) desert
C) deep-sea vent community
Which of the following is true of detritivores?

A) They recycle chemical elements directly back to primary consumers.

B) They synthesize organic molecules that are used by primary producers.

C) They convert organic materials from all trophic levels to inorganic compounds usable by primary producers.

D) They secrete enzymes that convert the organic molecules of detritus into CO2 and H2O.

E) Some species are autotrophic, whereas others are heterotrophic.
C) They convert organic materials from all trophic levels to inorganic compounds usable by primary producers.
The major role of detritivores in ecosystems is to

A) provide a nutritional resource for heterotrophs.

B) recycle chemical nutrients to a form capable of being used by autotrophs.

C) prevent the buildup of the organic remains of organisms, feces, and so on.

D) return energy lost to the ecosystem by other organisms.
B) recycle chemical nutrients to a form capable of being used by autotrophs.
The major role of detrivores in ecosystems is to

A) provide a nutritional resource for heterotrophs.

B) recycle chemical nutrients to a form capable of being used by autotrophs.

C) prevent the buildup of the inorganic remains of organisms, feces, and so on.

D) return energy lost to the ecosystem by other organisms.
B) recycle chemical nutrients to a form capable of being used by autotrophs.
In a typical grassland community, which of the following is the primary consumer?

A) hawk

B) snake

C) shrew

D) grasshopper

E) grass
D) grasshopper
Which of the following statements is true?

A) An ecosystem's trophic structure determines the rate at which energy cycles within the system.

B) At any point in time, it is impossible for consumers to outnumber producers in an ecosystem.

C) Chemoautotrophic prokaryotes near deep-sea vents are primary producers.

D) There has been a well-documented increase in atmospheric nitrogen over the past several decades.

E) The reservoir of ecosystem phosphorous is the atmosphere.
C) Chemoautotrophic prokaryotes near deep-sea vents are primary producers.
Approximately 1% of the solar radiation that strikes a plant is converted into the chemical bond energy of sugars. Why is this amount so low?

A) Approximately 99% of the solar radiation is converted to heat energy.

B) Only 1% of the wavelengths of visible light is absorbed by photosynthetic pigments.

C) Most solar energy strikes water and land surfaces.

D) Approximately 99% of the solar radiation is reflected.

E) Only the green wavelengths are absorbed by plants for photosynthesis.
B) Only 1% of the wavelengths of visible light is absorbed by photosynthetic pigments.
What percentage of solar radiation striking a plant is converted into chemical energy?

A) 1%

B) 10%

C) 25%

D) 50%

E) 100%
A) 1%
Subtraction of which of the following will convert gross primary productivity into net primary productivity?

A) the energy contained in the standing crop

B) the energy used by heterotrophs in respiration

C) the energy used by autotrophs in respiration

D) the energy fixed by photosynthesis

E) all solar energy
C) the energy used by autotrophs in respiration
Which of these ecosystems accounts for the largest amount of Earth's net primary productivity?

A) tundra

B) savanna

C) salt marsh

D) open ocean

E) tropical rain forest
D) open ocean
Which of these ecosystems has the highest net primary productivity per square meter annually?

A) savanna

B) open ocean

C) boreal forest

D) tropical rain forest

E) temperate forest
D) tropical rain forest
Which of the following is a true statement regarding mineral nutrients in soils and their implication for primary productivity?

A) Globally, phosphorous availability is most limiting to primary productivity.

B) Adding a nonlimiting nutrient will stimulate primary productivity.

C) Adding more of a limiting nutrient will increase primary productivity, indefinitely.

D) Phosphorous is sometimes unavailable to producers due to leaching.

E) Alkaline soils are more productive than acidic soils.
D) Phosphorous is sometimes unavailable to producers due to leaching.
The total biomass of photosynthetic autotrophs present in an ecosystem is known as

A) gross primary productivity.

B) standing crop.

C) net primary productivity.

D) secondary productivity.

E) trophic efficiency.
B) standing crop.
How is it that the open ocean produces the highest net primary productivity of Earth's ecosystems, yet net primary productivity per square meter is relatively low?

A) Oceans contain greater concentrations of nutrients compared to other ecosystems.

B) Oceans receive a lesser amount of solar energy per unit area.

C) Oceans have the largest area of all the ecosystems on Earth.

D) Ocean ecosystems have less species diversity.

E) Oceanic producers are generally much smaller than oceanic consumers.
C) Oceans have the largest area of all the ecosystems on Earth.
Why is net primary production (NPP) a more useful measurement to an ecosystem ecologist than gross primary production (GPP)?

A) NPP can be expressed in energy/unit of area/unit of time.

B) NPP can be expressed in terms of carbon fixed by photosynthesis for an entire ecosystem.

C) NPP represents the stored chemical energy that will be available to consumers in the ecosystem.

D) NPP is the same as the standing crop.

E) NPP shows the rate at which the standing crop is utilized by consumers.
C) NPP represents the stored chemical energy that will be available to consumers in the ecosystem.
How is net ecosystem production (NEP) typically estimated in ecosystems?

A) the ratio of producers to consumers

B) the amount of heat energy released by the ecosystem

C) the net flux of CO2 or O2 in or out of an ecosystem

D) the rate of decomposition by detritivores

E) the annual total of incoming solar radiation per unit of area
C) the net flux of CO2 or O2 in or out of an ecosystem
Aquatic primary productivity is most limited by which of the following?

A) light and nutrient availability

B) predation by primary consumers

C) increased pressure with depth

D) pollution

E) temperature
A) light and nutrient availability
Aquatic ecosystems are most likely to be limited by which of the following nutrients?

A) nitrogen

B) carbon

C) potassium

D) iron

E) zinc
A) nitrogen
What is the primary limiting factor for aquatic productivity?

A) pressure

B) lack of nutrients

C) light availability

D) herbivores

E) competition
B) lack of nutrients
Which of the following ecosystems would likely have a larger net primary productivity/hectare, and why?

A) open ocean because of the total biomass of photosynthetic autotrophs

B) a temperate grassland because of the small standing crop biomass that results from consumption by herbivores and rapid decomposition

C) tropical rain forest because of the high species diversity

D) cave due to the lack of photosynthetic autotrophs

E) tundra because of the incredibly rapid period of growth during the summer season
C) tropical rain forest because of the high species diversity
How is it that satellites can detect differences in primary productivity on Earth?

A) Photosynthetic organisms absorb more visible light in the 350-750 wavelengths.

B) Satellite instruments can detect reflectance patterns of the photosynthetic organisms of different ecosystems.

C) Sensitive satellite instruments can measure the amount of NADPH produced in the summative light reactions of different ecosystems.

D) Satellites detect differences by comparing the wavelengths of light captured and reflected by photoautotrophs to the amount of light reaching different ecosystems.

E) Satellites detect differences by measuring the amount of water vapor emitted by transpiring producers.
D) Satellites detect differences by comparing the wavelengths of light captured and reflected by photoautotrophs to the amount of light reaching different ecosystems.
Which of the following lists of organisms is ranked in correct order from lowest to highest percent in production efficiency?

A) mammals, fish, insects

B) insects, fish, mammals

C) fish, insects, mammals

D) insects, mammals, fish

E) mammals, insects, fish
A) mammals, fish, insects
A 3-hectare lake in the American Midwest suddenly has succumbed to an algal bloom. What is the likely cause of eutrophication in freshwater ecosystems, such as this one?

A) increased solar radiation

B) introduction of non-native tertiary consumer fish

C) nutrient-rich runoff

D) accidental introduction of a prolific culture of algae

E) iron dust blowing into the lake
C) nutrient-rich runoff
Approximately how many kg of carnivore biomass can be supported by a field plot containing 1,000 kg of plant material?

A) 10,000

B) 1,000

C) 100

D) 10

E) 1
D) 10
The amount of chemical energy in a consumer's food that is converted to its own new biomass during a given time period is known as which of the following?

A) biomass

B) standing crop

C) biomagnification

D) primary production

E) secondary production
E) secondary production
What is secondary production?

A) energy converted by secondary consumers from primary consumers

B) solar energy that is converted to chemical energy by photosynthesis

C) food that is converted to new biomass by consumers

D) energy that is not used by consumers for growth and reproduction

E) growth that takes place during the second year of life in consumers
C) food that is converted to new biomass by consumers
How does inefficient transfer of energy among trophic levels result in the typically high endangerment status of many top-level predators?

A) Top-level predators are destined to have small populations that are sparsely distributed.

B) Predators have relatively large population sizes.

C) Predators are more disease-prone than animals at lower trophic levels.

D) Predators have short life spans and short reproductive periods.

E) Top-level predators are more likely to be stricken with parasites.
A) Top-level predators are destined to have small populations that are sparsely distributed.
Trophic efficiency is

A) the ratio of net secondary production to assimilation of primary production.

B) the percentage of production transferred from one trophic level to the next.

C) a measure of how nutrients are cycled from one trophic level to the next.

D) usually greater than production efficiencies.

E) about 90% in most ecosystems.
B) the percentage of production transferred from one trophic level to the next.
Owls eat rats, mice, shrews, and small birds. Assume that, over a period of time, an owl consumes 5,000 J of animal material. The owl loses 2,300 J in feces and owl pellets and uses 2,600 J for cellular respiration. What is the production efficiency of this owl?

A) 0.02%

B) 1%

C) 4%

D) 10%

E) 40%
C) 4%
Why does a vegetarian leave a smaller ecological footprint than an omnivore?

A) Fewer animals are slaughtered for human consumption.

B) There is an excess of plant biomass in all terrestrial ecosystems.

C) Vegetarians need to ingest less chemical energy than omnivores.

D) Vegetarians require less protein than do omnivores.

E) Eating meat is an inefficient way of acquiring photosynthetic productivity.
E) Eating meat is an inefficient way of acquiring photosynthetic productivity.
For most terrestrial ecosystems, pyramids composed of species abundances, biomass, and energy are similar in that they have a broad base and a narrow top. The primary reason for this pattern is that

A) secondary consumers and top carnivores require less energy than producers.

B) at each step, energy is lost from the system because of the second law of thermodynamics.

C) as matter passes through ecosystems, some of it is lost to the environment.

D) biomagnification of toxic materials limits the secondary consumers and
top carnivores.

E) top carnivores and secondary consumers have a more general diet than primary producers.
B) at each step, energy is lost from the system because of the second law of thermodynamics.
Which of the following is primarily responsible for limiting the number of trophic levels in most ecosystems?

A) Many primary and higher-order consumers are opportunistic feeders.

B) Decomposers compete with higher-order consumers for nutrients and energy.

C) Nutrient cycles involve both abiotic and biotic components of ecosystems.

D) Nutrient cycling rates tend to be limited by decomposition.

E) Energy transfer between trophic levels is almost always less than 20% efficient.
E) Energy transfer between trophic levels is almost always less than 20% efficient.
Which trophic level is most vulnerable to extinction?

A) producer level

B) primary consumer level

C) secondary consumer level

D) tertiary consumer level

E) decomposer level
D) tertiary consumer level
Which statement best describes what ultimately happens to the chemical energy that is not converted to new biomass in the process of energy transfer between trophic levels in an ecosystem?

A) It is undigested and winds up in the feces and is not passed on to higher trophic levels.

B) It is used by organisms to maintain their life processes through the reactions of cellular respiration.

C) Heat produced by cellular respiration is used by heterotrophs to thermoregulate.

D) It is eliminated as feces or is dissipated into space as heat in accordance with the second law of thermodynamics.

E) It is recycled by decomposers to a form that is once again usable by primary producers.
D) It is eliminated as feces or is dissipated into space as heat in accordance with the second law of thermodynamics.
Consider the food chain grass → grasshopper → mouse → snake → hawk. How much of the chemical energy fixed by photosynthesis of the grass (100%) is available to the hawk?

A) 0.01%

B) 0.1%

C) 1%

D) 10%

E) 60%
A) 0.01%
If the flow of energy in an arctic ecosystem goes through a simple food chain, perhaps involving humans, starting from phytoplankton to zooplankton to fish to seals to polar bears, then which of the following could be true?

A) Polar bears can provide more food for humans than seals can.

B) The total biomass of the fish is lower than that of the seals.

C) Seal meat probably contains the highest concentrations of fat-soluble toxins.

D) Seal populations are larger than fish populations.

E) The fish can potentially provide more food for humans than the seal meat can.
E) The fish can potentially provide more food for humans than the seal meat can.
Nitrogen is available to plants mostly in the form of

A) N2 in the atmosphere.

B) nitrite ions in the soil.

C) uric acid from animal excretions.

D) nucleic acids from decomposing plants and animals.

E) nitrate and ammonium ions in the soil.
E) nitrate and ammonium ions in the soil.
Which of the following locations is the main reservoir for nitrogen in Earth's nitrogen cycle?

A) atmosphere

B) sedimentary bedrock

C) fossilized plant and animal remains (coal, oil, and natural gas)

D) plant and animal biomass

E) soil
A) atmosphere
Which of the following locations is the reservoir for carbon in the carbon cycle?

A) atmosphere

B) sediments and sedimentary rocks

C) fossilized plant and animal remains (coal, oil, and natural gas)

D) plant and animal biomass

E) all of the above
E) all of the above
In the nitrogen cycle, the bacteria that replenish the atmosphere with N2 are

A) Rhizobium bacteria.

B) nitrifying bacteria.

C) denitrifying bacteria.

D) methanogenic protozoans.

E) nitrogen-fixing bacteria.
C) denitrifying bacteria.
How does phosphorus normally enter ecosystems?

A) cellular respiration

B) photosynthesis

C) rock weathering

D) vulcanism

E) atmospheric phosphorous gas
C) rock weathering
Which of the following statements is correct about biogeochemical cycling?

A) The phosphorus cycle involves the recycling of atmospheric phosphorus.

B) The phosphorus cycle involves the weathering of rocks.

C) The carbon cycle is a localized cycle that primarily involves the burning of fossil fuels.

D) The carbon cycle has maintained a constant atmospheric concentration of CO2 for the past million years.

E) The nitrogen cycle involves movement of diatomic nitrogen between the biotic and abiotic components of the ecosystem.
B) The phosphorus cycle involves the weathering of rocks.
Why do logged tropical rain forest soils typically have nutrient-poor soils?

A) Tropical bedrock contains little phosphorous.

B) Logging results in soil temperatures that are lethal to nitrogen-fixing bacteria.

C) Most of the nutrients in the ecosystem are removed in the harvested timber.

D) The cation exchange capacity of the soil is reversed as a result of logging.

E) Nutrients evaporate easily into the atmosphere in the post-logged forest.
C) Most of the nutrients in the ecosystem are removed in the harvested timber.
Which of the following ecological locations has the greatest species diversity?

A) tundra

B) deciduous forests

C) tropical rain forest

D) grasslands

E) islands
C) tropical rain forest
Invasive species are introduced by humans to new geographic locations and

A) are successful in colonizing a novel area.

B) spread because they encounter none of their natural predators.

C) All of the choices are correct.

D) can outcompete and displace native
species for biotic and abiotic resources.

E) are usually considered pests by ecologists.
C) All of the choices are correct.
Which of the following terms includes all of the others?

A) species diversity

B) biodiversity

C) genetic diversity

D) ecosystem diversity

E) species richness
B) biodiversity
What term did E. O. Wilson coin for our innate appreciation of wild environments and living organisms?

A) bioremediation

B) bioethics

C) biophilia

D) biophobia

E) landscape ecology
C) biophilia
We should care about loss in biodiversity in the populations of other species because of

A) biophilia.

B) potential loss of medicines and other products yet undiscovered from threatened species.

C) potential loss of genes, some of which may code for proteins useful to humans.

D) the risk to global ecological stability.

E) All of the options are correct.
E) All of the options are correct.
The most serious consequence of a decrease in global biodiversity would be the

A) increase in global warming and thinning of the ozone layer.

B) potential loss of ecosystem services on which people depend.

C) increase in the abundance and diversity of edge-adapted species.

D) loss of sources of genetic diversity to preserve endangered species.

E) loss of species for use as crops.
B) potential loss of ecosystem services on which people depend.
What is the biological significance of genetic diversity between populations?

A) Genes for adaptive traits to local conditions make microevolution possible.

B) The population that is most fit would survive by competitive exclusion.

C) Genetic diversity allows for species stability by preventing speciation.

D) Isolated populations become more fit.

E) Diseases and parasites are not spread between separated populations.
A) Genes for adaptive traits to local conditions make microevolution possible.
Introduced species can have deleterious effects on biological communities by

A) preying on native species.

B) competing with native species for food or light.

C) displacing native species.

D) competing with native species for space or breeding/nesting habitat.

E) All of the options are correct.
E) All of the options are correct.
Review the formula for effective population size. Imagine a population of 1,000 small rodents. Of these, 300 are breeding females, 300 are breeding males, and 400 are nonbreeding juveniles. What is the effective population size?

A) 1,000

B) 1,200

C) 600

D) 400

E) 300
C) 600
If the sex ratio in a population is significantly different from 50:50, then which of the following will always be true?

A) The population will enter the extinction vortex.

B) The genetic variation in the population will increase over time.

C) The genetic variation in the population will decrease over time.

D) The effective population size will be greater than the actual population size.

E) The effective population size will be less than the actual population size.
E) The effective population size will be less than the actual population size.
Which of the following life history traits can potentially influence effective population size (Ne)?

A) maturation age

B) genetic relatedness among individuals in a population

C) population size

D) gene flow between geographically separated populations

E) All of the options are correct.
E) All of the options are correct.
The word triage originated during World War I and was first used by French doctors in prioritizing patients based on the severity of their wounds, because there were more wounded soldiers in need of urgent care than there were resources to treat them. Conservation biologists have to make similar determinations with degraded ecosystems. Which of the following is the most important consideration when it comes to managing for maintenance of biodiversity?

A) identifying large, high-profile vertebrates first, because steps to saving them would be most recognized by the public

B) determining which species is most important for conserving biodiversity as a whole

C) replanting suitable habitat for fauna

D) assessing the economic costs and the gains for society

E) maintaining optimum size of all populations in the ecosystem
B) determining which species is most important for conserving biodiversity as a whole
The primary difference between the small-population approach (S-PA) and the declining- population approach (D-PA) to biodiversity recovery is

A) S-PA is interested in bolstering the genetic diversity of a threatened population rather than the environmental factors that caused the population's decline.

B) S-PA kicks in for conservation biologists when population numbers fall below 500.

C) D-PA would likely involve bringing together individuals from scattered small populations to interbreed in order to promote genetic diversity.

D) S-PA would investigate and eliminate all of the human impacts on the habitat of the species being studied for recovery.

E) D-PA would use recently collected population data to calculate an extinction vortex.
A) S-PA is interested in bolstering the genetic diversity of a threatened population rather than the environmental factors that caused the population's decline.
The long-term problem with red-cockaded woodpecker habitat intervention in the southeastern United States is

A) the only habitat that can support their recovery is large tracts of mature oak forest.

B) the mature pine forests in which they live cannot ever be subjected to forest fire.

C) all of the appropriate red-cockaded woodpecker habitat has already been logged or converted to agricultural land.

D) the social organization of the red-cockaded woodpecker precludes the dispersal of reproductive individuals.

E) what habitat remains for the red-cockaded woodpecker does not contain trees suitable for nest-cavity construction.
D) the social organization of the red-cockaded woodpecker precludes the dispersal of reproductive individuals.
Managing southeastern forests specifically for the red-cockaded woodpecker

A) required the growth of a dense understory of trees and shrubs.

B) contributed to greater abundance and diversity of other forest bird species.

C) caused other species of songbird to decline.

D) involved strict fire-suppression measures.

E) involved the creation of fragmented forest habitat.
B) contributed to greater abundance and diversity of other forest bird species.
Which of the following is true about the current research regarding forest fragmentation?

A) Fragmented forests support a greater biodiversity because they result in the combination of forest-edge species and forest-interior species.

B) Fragmented forests support a lesser biodiversity because the forested-adapted species leave, and only the edge and open-field species can occupy fragmented forests.

C) Fragmented forests are the goal of conservation biologists who design wildlife preserves.

D) Harvesting timber that results in forest fragmentation results in less soil erosion.

E) The disturbance of timber extraction causes the species diversity to increase because of the new habitats created.
B) Fragmented forests support a lesser biodiversity because the forested-adapted species leave, and only the edge and open-field species can occupy fragmented forests.
Brown-headed cowbirds utilize fragmented forests effectively by

A) feeding on the fruits of shrubs that tend to grow at the forest/open-field interface.

B) parasitizing the nests of forest birds, and feeding on open-field insects.

C) roosting in forest trees, and nesting in grassy fields.

D) outcompeting other songbird species in fragmented communities.

E) using forest cover to escape from predators in their normal grassland habitat.
B) parasitizing the nests of forest birds, and feeding on open-field insects.
Which of the following is consistent with forest fragmentation research?

A) Productivity is the same in both fragmented forests and forest interiors.

B) Edge communities consistently have low species diversity.

C) Forest-interior species show declines in small patch communities.

D) New-edge species that migrate in do not seem to compete with forest species and often increase biodiversity in fragmented forests.

E) Species diversity is always lower in fragmented forests when compared to forest interiors in the same region.
C) Forest-interior species show declines in small patch communities.
Biodiversity hot spots are not necessarily the best choice for nature preserves because

A) hot spots are situated in remote areas not accessible to wildlife viewers.

B) their ecological importance makes land purchase very expensive.

C) a hot spot for one group of organisms may not be a hot spot for another group.

D) hot spots are designated by the abiotic factors present, not the biotic factors.

E) designated hot spots change on a daily basis.
C) a hot spot for one group of organisms may not be a hot spot for another group.
The success with which plants extend their range northward following glacial retreat is best determined by

A) whether there is simultaneous migration of herbivores.

B) their tolerance to shade.

C) their seed dispersal rate.

D) their size.

E) their growth rate.
C) their seed dispersal rate.
As the climate changes because of global warming, species' ranges of plants in the Northern Hemisphere may move northward, using effective reproductive adaptations to disperse their seeds. The trees that are most likely to avoid extinction in such an environment are those that

A) have seeds that are easily dispersed by wind or animals.

B) have thin seed coats.

C) produce well-provisioned seeds.

D) have seeds that become viable only
after a forest fire.

E) disperse many seeds in close proximity to the parent tree.
A) have seeds that are easily dispersed by wind or animals.
Which of the following investigations would shed the most light on the future distribution of organisms in temperate regions that are faced with climate change?

A) Remove, to the mineral soil, all of the organisms from an experimental plot and monitor the colonization of the area over time in terms of both species diversity and abundance.

B) Look at the climatic changes that occurred since the last ice age and how species redistributed as glaciers melted, then make predictions on future distribution in species based on past trends.

C) Compare and contrast the flora and fauna of warm/cold/dry/wet climates to shed light on how they evolved to be suited to their present-day environment.

D) Quantify the impact of humankind's activities on present-day populations of threatened and endangered species to assess the rate of extirpation and extinction.

E) There is no scientific investigation that can help make predictions on the future distribution of organisms.
B) Look at the climatic changes that occurred since the last ice age and how species redistributed as glaciers melted, then make predictions on future distribution in species based on past trends.
What is a critical load?

A) the amount of nutrient augmentation necessary to bring a depleted habitat back to its former level

B) the level of a given toxin in an ecosystem that is lethal to 50% of the species present

C) the maximum abundance level of a particular species, beyond which additional numbers will degrade a habitat

D) the amount of added nutrient that can be absorbed by plants without damaging ecosystem integrity

E) the number of predators an ecosystem can support that effectively culls prey populations to healthy levels
D) the amount of added nutrient that can be absorbed by plants without damaging ecosystem integrity
The use of DDT as an insecticide in the United States has been outlawed since 1971, yet is still a problem for certain top-level carnivores in the United States. Which of the following choices best explains this apparent incongruity?

A) DDT is still used for mosquito control in tropical countries, and certain migratory predators can be affected by a seasonal biomagnification.

B) DDT is persistent in the environment, and all of the pre-1971 DDT is still available in toxic form to poison top-level carnivores.

C) Pre-1971 DDT has been deposited in certain habitats, particularly wetlands and estuaries, so predators in these ecosystems are vulnerable to biomagnifications of DDT.

D) Whereas most DDT-susceptible species have become resistant to persistent DDT, others are still vulnerable.

E) All of the options are correct.
A) DDT is still used for mosquito control in tropical countries, and certain migratory predators can be affected by a seasonal biomagnification.
Agricultural lands frequently require nutrient augmentation because

A) nitrogen-fixing bacteria are not as plentiful in agricultural soils because of the use of pesticides.

B) the nutrients that become the biomass of plants are not cycled back to the soil on lands where they are harvested.

C) land that is available for agriculture tends to be nutrient-poor.

D) grains raised for feeding livestock must be fortified, and thus require additional nutrients.

E) cultivation of agricultural land inhibits the decomposition of organic matter.
B) the nutrients that become the biomass of plants are not cycled back to the soil on lands where they are harvested.
What causes extremely high levels of toxic chemicals in fish-eating birds?

A) depletion of ozone layer

B) acid precipitation

C) biological magnification

D) greenhouse effect

E) eutrophication
C) biological magnification
What is caused by excessive nutrient runoff into aquatic ecosystems?

A) depletion of ozone layer

B) acid precipitation

C) biological magnification

D) greenhouse effect

E) eutrophication
E) eutrophication
Which of the following refers to the reflecting and absorption of infrared radiation by atmospheric methane, carbon dioxide, and water?

A) depletion of ozone layer

B) acid precipitation

C) biological magnification

D) greenhouse effect

E) eutrophication
D) greenhouse effect
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