Biosphere and Population Ecology

Question 1

Two plant species live in the same biome but on different continents. Although the two species are not at all closely related, they may appear quite similar as a result of

a) allopatric speciation
b) convergent evolution
c) introgression
d) parallel evolution
e) gene flow

Answer 1

b) convergent evolution

Question 2

The main reason polar regions are cooler than the equator is that

a) the polar atmosphere is thinner and contains fewer greenhouse gases
b) the poles are farther from the sun
c) the poles are permanently tilted away from the sun
d) sunlight strikes the poles at a lower angle
e) there is more ice at the poles

Answer 2

b) sunlight strikes the poles at a lower angle

Question 3

Which of the following abiotic factors has the greatest influence on the metabolic rates of plants and animals?

a) temperature
b) wind
c) disturbances
d) water
e) rocks and soil

Answer 3

a) temperature

Question 4

Which of the following can be said about light in aquatic environments?

a) water selectively reflects and absorbs certain wavelengths of light
b) photosynthetic organisms that live in deep water probably use red light
c) Most photosynthetic organisms avoid the surface where the light is too intense
d) longer wavelengths penetrate to greater depths
e) Light penetration seldom limits the distribution of photosynthetic species

Answer 4

a) water selectively reflects and absorbs certain wavelengths of light

Question 5

Air masses formed over the Pacific Ocean are moved by prevailing westerlies where they encounter extensive north-south mountain ranges, such as the Sierra Nevada 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) These air masses remain essentially unchanged in moisture content and temperature as they pass over these mountain ranges.

c) 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.

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) 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.

Answer 5

c) 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.

Question 6

A population of white-footed mice becomes severely overpopulated in a habitat that has been disturbed by human activity. Sometimes intrinsic factors cause the population to increase in mortality and lower reproduction rates to occur in reaction to the stress of overpopulation. Which of the following is an example of intrinsic population control?

a) Clumped dispersion of the population leads to increased spread of disease and parasites, resulting in a population crash.

b) Because the individuals are vulnerable, they are more likely to die off if a drought or flood were to occur.

c) Females undergo hormonal changes that delay sexual maturation and many individuals suffer depressed immune systems and die due to the stress of overpopulation.

d) All of the resources (food and shelter) are used up by overpopulation and much of the population dies of exposure and/or starvation.

e) Owl populations frequent the area more often because of increased hunting success.

Answer 6

c) Females undergo hormonal changes that delay sexual maturation and many individuals suffer depressed immune systems and die due to the stress of overpopulation.

Question 7

Which of the following is the most important assumption for the capture-recapture method to estimate the size of wildlife populations?

a) All females in the population have the same litter size

b) There is a 50:50 ratio of males to females in the population before and after trapping and recapture

c) Marked individuals have the same probability of being recaptured as unmarked individuals during the recapture phase

d) Over 50% of the marked individuals need to be trapped during the recapture phase

e) More individuals emigrate from, as opposed to immigrate into, a population.

Answer 7

c) Marked individuals have the same probability of being recaptured as unmarked individuals during the recapture phase

Question 8

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) floods
d) fires
e) earthquakes

Answer 8

b) intraspecific competition of nutrients

Question 9

Which of the following groups would be most likely to exhibit uniform dispersion?

a) red squirrels, who actively defend territories
b) lake trout, which seek out cold, deep water high in dissolved oxygen
c) dwarf mistletoes, which parasitize particular species of forest tree
d) moths, in a city at night
e) cattails, which grow primarily at edges of lakes and streams

Answer 9

a) red squirrels, who actively defend territories

Question 10

Which of the following is the best example of uniform distribution?

a) snails in an intertidal zone at low tide
b) a cultivated cornfield in the Midwest
c) mushrooms growing on the floor of an old growth forest
d) bees collecting pollen in a wildflower meadow
e) territorial songbirds in a mature forest during mating season

Answer 10

e) territorial songbirds in a mature forest during mating season

Question 11

Iodine is added to table salt to help prevent deficiencies of an essential mineral needed for the proper function of the

a) thyroid glands
b) adrenal glands
c) the exocrine pancreas
d) parathyroid glands
e) the endocrine pancreas

Answer 11

a) thyroid glands

Question 12

All hormones’

a) elicit the same biological response from all of their target cells
b) are produced by endocrine glands
c) are carried to target cells in the blood
d) are lipid-soluble molecules
e) are protein molecules

Answer 12

c) are carried to target cells in the blood

Question 13

A reproductive difference between sea urchins and humans is

a) the sea urchin egg completes meiosis prior to fertilization, but meiosis in humans is completed after fertilization.

b) sea urchin eggs and sperm are of equal size, but human eggs are much bigger than human sperm.

c) sea urchins, but not humans, have a need to block polyspermy because only in sea urchins can there be more than one source of sperm to fertilize the eggs.

d) sea urchin eggs are produced by meiosis, but human eggs are produced by mitosis.

e) sea urchin zygotes get their mitochondria from the sperm but human zygotes get their mitochondria from the egg.

Answer 13

a) sea urchin egg completes meiosis prior to fertilization, but meiosis in humans is completed after fertilization

Question 14

The outer-to-inner sequence of tissue layers in a post-gastrulation vertebrate embryo is

a) endoderm → mesoderm → ectoderm.
b) mesoderm → endoderm → ectoderm.
c) ectoderm → mesoderm → endoderm.
d) ectoderm → endoderm → mesoderm.
e) endoderm → ectoderm → mesoderm.

Answer 14

c) ectoderm → mesoderm → endoderm

Question 15

Acidity in human urine is an example of

a) antibody activation.
b) innate immunity.
c) adaptive immunity.
d) cell-mediated immune responses.
e) acquired immunity.

Answer 15

b) innate immunity

Question 16

A key part of the humoral immune response is

a) the production of antibodies by plasma cells
b) the attack of phagocytes on living pathogens
c) the attack of cytotoxic T cells on infected host cells
d) perforation of infected host cells by perforin
e) the initiation of programmed cell death in infected host cells

Answer 16

a) the production of antibodies by plasma cells

Question 17

Many marine and freshwater bony fish achieve osmoregulation via

a) gain of salt through the gills
b) no drinking of water
c) loss of water through the gills
d) loss of water in the urine
e) gain of water through food

Answer 17

e) gain of water through food

Question 18

The fluid with the highest osmolarity is

a) plasma in mammals
b) sea water in a tidal pool
c) estuarine water
d) distilled water
e) plasma in birds

Answer 18

b) sea water in a tidal pool

Question 19

Damage to the sinoatrial node in humans

a) is a major contributor to heart attacks.
b) would block conductance between the bundle branches and the Purkinje fibers.
c) would have a negative effect on peripheral resistance.
d) would disrupt the rate and timing of cardiac muscle contractions.
e) would have a direct effect on blood pressure monitors in the aorta.

Answer 19

d) would disrupt the rate and timing of cardiac muscle contractions

Question 20

Which of the following is the correct sequence of blood flow in reptiles and mammals?

a) left ventricle → aorta → lungs → systemic circulation
b) right ventricle → pulmonary vein → pulmocutaneous circulation
c) pulmonary vein → left atrium → left ventricle → pulmonary circuit
d) vena cava → right atrium → right ventricle → pulmonary circuit
e) right atrium → pulmonary artery → left atrium → ventricle

Answer 20

d) vena cava → right atrium → right ventricle → pulmonary circuit

Question 21

A certain species of pine tree survives only in scattered locations at elevations above 2800 m in the western United States. To understand why this tree grows only in these specific places, an ecologist should

a) investigate the various biotic and abiotic factors that are unique to high altitude.
b) study the anatomy and physiology of this species.
c) analyze the soils found in the vicinity of these trees, looking for unique chemicals that may support their growth.
d) conclude that lower elevations are limiting to the survival of this species.
e) collect data on temperature, wind, and precipitation at several of these locations for a year.

Answer 21

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

Question 22

What is the limiting factor for the growth of trees in the tundra?

a) cold temperatures
b) insufficient minerals in bedrock
c) pH of soils
d) low precipitation
e) permafrost

Answer 22

e) permafrost

Question 23

If you are interested in observing a relatively simple community structure in a clear water lake, you would do well to choose diving into

a) an oligotrophic lake.
b) a lake with consistently warm temperatures.
c) a relatively shallow lake.
d) a nutrient-rich lake.
e) a eutrophic lake.

Answer 23

a) an oligotrophic lake

Question 24

Which of the following statements best describes the interaction between fire and ecosystems?

a) Chaparral communities have evolved to the extent that they rarely burn.
b) The suppression of forest fires by man has prevented certain communities, such as grasslands, from reaching their climax stage.
c) The likelihood of a wildfire occurring in a given ecosystem is highly predictable over the short term.
d) Many kinds of plants and plant communities have adapted to frequent fires.
e) Fire is unnatural in ecosystems and should be prevented.

Answer 24

d) many kinds of plants and plant communities have adapted to frequent fires

Question 25

Which of the following is responsible for the differences in summer and winter temperature stratification of deep temperate zone lakes?

a) Winter ice sinks in the summer.
b) Stratification always follows the fall and spring turnovers.
c) Water is densest at 4°C.
d) Stratification is caused by a thermocline.
e) Oxygen is most abundant in deeper waters.

Answer 25

c) water is densest at 4°C.

Question 26

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) cohorts
b) carrying capacity
c) range
d) density
e) dispersion

Answer 26

d) density

Question 27

The human population

a) is no longer growing exponentially but still increasing rapidly.
b) and its carrying capacity can be estimated using age structure pyramids.
c) worldwide has reached its demographic transition.
d) is still growing exponentially, but is increasing slowly.
e) can keep increasing because technology will enable continuous growth.

Answer 27

a) is no longer growing exponentially but still increasing rapidly.

Question 28

Carrying capacity is

a) seldom reached by marine producers and consumers because of the vast resources of the ocean.
b) the term used to describe the stress a population undergoes due to limited resources.
c) determined by density and dispersion data.
d) fixed for most species over most of their range most of the time.
e) the maximum population size that a particular environment can support.

Answer 28

e) the maximum population size that a particular environment can support

Question 29

Elephants and sea turtles are both long-living vertebrates. What type of survivorship curve would you expect to see for these two species, respectively?

a) Type 1 and Type111
b) Type 1 and Type1
c) Type 11 and Type11
d) Type 111 and Type111
e) Type 1 and Type11

Answer 29

a) type 1 and type 111

Question 30

Which of the following pairs of reproductive strategies is consistent with energetic trade-off and reproductive success?

a) 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.
b) 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.
c) 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.
d) Pioneer species of plants produce many very small, highly airborne seeds, whereas large elephants that are very good parents produce many offspring.
e) 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.

Answer 30

c) 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.

Question 31

The endocrine glands include the

a) salivary glands
b) sweat glands
b) gallbladder
c) parathyroid glands
e) sebaceous glands

Answer 31

c) parathyroid

Question 32

During a stressful interval

a) the alpha cells of islets secrete insulin and simultaneously the beta cells of the islets secrete glucagon.
b) the posterior pituitary gland secretes more growth hormones.
c) TSH stimulates the adrenal cortex and medulla to secrete acetylcholine.
d) the calcium levels in the blood are increased due to actions of two antagonistic hormones, epinephrine and norepinephrine.
e) ACTH stimulates the adrenal cortex, and neurons of the sympathetic nervous system stimulate the adrenal medulla.

Answer 32

e) ACTH stimulates the adrenal cortex, and neurons of the sympathetic nervous system stimulate the adrenal medulla

Question 33

Generally speaking, deserts are located in places where air masses are usually

a) tropical
b) expanding
c) rising
d) descending
e) humid

Answer 33

d) descending

Question 34

“How do seed-eating animals affect the distribution and abundance of the trees?” This question

a) would be difficult to answer because a long-term experiment would be required.
b) is one that a present-day ecologist would be likely to ask.
c) would be difficult to answer because a large experimental area would be required.
d) would require an elaborate experimental design to answer.
e) All options are correct.

Answer 34

e) all options are correct

Question 35

Which of the following examples of an ecological effect leading to an evolutionary effect is most correct?

a) Fish that swim the fastest in running water catch the most prey and more easily escape predation.
b) A few organisms of a larger population survive a drought and then these survivors emigrate to less arid environments.
c) The insects that spend the most time exposed to sunlight have the most mutations.
d) When seeds are not plentiful, trees produce more seeds.
e) A few individuals with denser fur survive the coldest days of an ice age, and the reproducing survivors of the ice age all have long fur.

Answer 35

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

Question 36

Trees are not usually found in the tundra biome because of

a) extreme winter temperatures.
b) acidic soils.
c) permafrost.
d) insufficient annual precipitation.
e) overbrowsing by musk ox and caribou.

Answer 36

c) permafrost

Question 37

Why is the climate drier on the leeward side of mountain ranges that are subjected to prevailing winds?

a) 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.
b) Pushed by the prevailing winds on the windward side, air is forced to rise, cool, condense, and drop its precipitation, leaving only dry air to descend the leeward side.
c) 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.
d) Deserts usually are found on the leeward side of mountain ranges.
e) 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.

Answer 37

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

Question 38

Exponential growth of a population is represented by dN/dt =

Answer 38

rN

Question 39

In which of the following situations would you expect to find the largest number of K-selected individuals?

a) the flora and fauna of a coral reef in the Caribbean
b) a recently abandoned agricultural field in Ohio
c) South Florida after a hurricane
d) a newly emergent volcanic island
e) the sand dune communities of south Lake Michigan

Answer 39

a) the flora and fauna of a coral reef in the Caribbean

Question 40

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

a) removal of predators
b) increased birth rate
c) competition for resources
d) favourable climatic conditions
e) decreased death rate

Answer 40

c) competition for resources

Question 41

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

a) pollution
b) plagues
c) famines
d) social pressure for birth control
e) earthquakes

Answer 41

e) earthquakes