Ch 40 Questions
Rooted plants are found only in the _____ zone of a lake. A. Littoral B. Thermocline C. Limnetic D. Pelagic E. None of choices is correct
A. Littoral (Rooted and floating aquatic plants flourish in the littoral zone, the shallow, well-lit waters close to shore)
A certain species of seal breeds and rears its young on rocky beaches. Competition for breeding sites is fierce, and males that so not secure a site will not reproduce. This behavior is an example of which mechanism of density-dependent population regulation? A. Territoriality B. Predation C. Toxic wastes D. Competition of resources E. Intrinsic factors
A. Territoriality (The inability of a male to secure a breeding territory will limit his ability to mate)
When the per capita birth rate equals the per capita death rate, _____. A. The size of a population remains constant B. Density dependent limiting factors do not affect the population C. A population grows rapidly D. A population goes through up and downs cycle E. A population is in danger of extinction
A. The size of a population remains constant (Excluding the possible effects of migration, when the per capita birth rate and per capita death rate are equal, the population size will remain constant)
In an equilibrium population (at its carrying capacity), thousands of eggs and hundreds of tadpoles are produced by a single pair of frogs. On average, about how many offspring per pair will live to reproduce the next year? A. 0 B. 2 C. 10 to 20 D. 100 E. more than 100
B. 2 (Ecologists define "carrying capacity" as the maximum population size that a particular environment can support. A single pair of frogs would not be expected to replace itself, certainly it is at equilibrium and thus nor changing)
Which is most likely a density-dependent growth regulator of animal populations? A. Hurricanes B. A decrease in a clutch size C. Fires D. Droughts E. All of the choices are correct
B. A decrease in a clutch size (A density-dependent factor intensifies as the population increases in size)
Organisms that live in a homogeneous abiotic environment and cooperate to avoid being eaten would likely show a(n) ___ pattern of dispersion. A. Uniform B. Clumped C. Even D. Continuous E. Random
B. Clumped (This pattern results from an uneven distribution of resources or from certain social behavior)
What would most likely be an example of density-independent factor limited population growth? A. Food availability B. Daily temperature extremes C. Parasites D. Diseases E. Accumulation of toxic wastes
B. Daily temperature extremes (Density-independent factors such as daily temperatures are unrelated to population size)
Life tables typically follow the fate of a cohort, a __________. A. Group of individuals who migrated to the same area at the same time B. Group of individuals who are the same age C. Group of individuals who died from the same disease D. Group of individuals who reproduced at the same age E. Group of individuals who live in the same community
B. Group of individuals who are the same age (Life tables are age-specific summaries of the survival pattern of a population)
Assuming that r has a positive value in the formula dN/dt=rmaxN(K-N)lK, the factor rN tends to cause the population to ____. A. Decrease in size B. Grow increasingly rapidly C. Grow at a slower rate than the (K-N/K) factor D. Remain stable at the carrying capacity E. None of the above
B. Grow increasingly rapidly (The difference between birth rates and death rates is represented by r. N is the population size. Therefore, rN is the population growth rate)
A population will always grow exponentially _____. A. If it is limited only by density-dependent factors B. If there are no limiting factors C. Until it reaches carrying capacity D. If it is a population with an equilibrium life history E. None of the above
B. If there are no limiting factors (Limiting factors determine the maximum number of individuals that can be supported by a given environment. In the absence of such factors, a population will reproduce at its maximum rate)
A variety of opossum that lives on an island with no predators lives much longer than its relatives on the mainland, even when both are kept safely in a zoo. The island variant's genes have been selected for slow aging, whereas the mainland variant's genes have been selected for quick reproduction. The island opossum exhibits _____ selection, and the mainland opossum exhibits _____ selection. A. random... clumped B. K... r C. nutrient... territory D. r... K E. clumped ... uniform
B. K... r (K-selection is most likely at work in the island population because many of the opossums live for a long time, making resource competition more of an issue. The mainland opossums do not approach their carrying capacity because of predation, so r-selection is most likely occurring in that population)
A newly mated queen ant founds a nest in an unoccupied patch of suitable habitat. Assuming that no disasters strike the nest, which of the following types of equations is likely to best describe the population growth of the new colony? A. Circular B. Logistic C. Exponential D. Linear E. None of the above
B. Logistic (The logistic model of population growth assumes there is a maximum population size that the environment can support and that population growth slows as the population approaches carrying capacity)
No population can grow indefinitely. The ultimate size of any population is limited by _____. A. Its death rate B. The carrying capacity of its environment C. Reproductive isolation D. It's r E. Its birth rate
B. The carrying capacity of its environment (Ecologists define "carrying capacity" as the maximum population size that a particular environment can support)
Bodies of water tend to moderate climate because __________. A. Water is always cooler than nearby landmasses B. The high specific heat of water C. The water has a high heat of vaporization D. The hydrogen bonding on water causes it to be cohesive E. All of the above
B. The high specific heat of water (prevents it from changing temperature rapidly. Because there are such large bodies of water on Earth that do not change temperature as quickly as air or land, water moderates climate.
When people speak of the "rain shadow" of the California Coast Range, they are referring to the A. The forested condition on the eastern flank of the range compared with the western flank B. The scarcity of rain on the eastern flank and adjacent lowlands compared with the western flank C. The dark- colored chaparral vegetation that grows on the eastern flank D. The shadow cast by mist and clouds that hover above the crest of the range E. None of the above
B. The scarcity of rain on the eastern flank and adjacent lowlands compared with the western flank (on the leeward side of a mountain, cooler dry air descends, absorbing moisture and producing a rain shadow, an area of low precipitation).
Which choice below describes a feature of grassland that explains why its remnants are concentrated in arid regions of North American and central Asia? A. Woody shrubs and trees have taken over in areas that receive more precipitation B. The soil is fertile and most grassland has been converted to farmland C. Large grazers, such as bison and wild horses, have depletes grassland D. Grassland is often consumed by fire E. Grassland has been found to be a good source of minerals and oil
B. The soil is fertile and most grassland has been converted to farmland (The grassland in drier areas is less desirable for agricultural use)
What are three basic issues that life histories entail? A. When reproduction begins, level of parental, and how many offspring are produced during each reproductive episode B. When reproduction begins, how often the organism breeds, and how many offspring are produced during each reproductive episode C. Whether or not reproduction is a conscious decision, level of parenteral care, and how many offspring are produced during each reproductive cycle D. When reproduction begins, how often the organism breeds, an how many offspring from each reproductive episode survive to also reproduce E. Whether or not reproduction is a conscious decision, how often the organism breeds, and how many offspring are produced during each reproductive episode
B. When reproduction begins, how often the organism breeds, and how many offspring are produced during each reproductive episode (The various possibilities associated with these basic issues are integrated into the life history patterns observes in nature)
A wildlife biologist is trying to predict what will happen to a bear population if bear hunting is banned. He had the equations all worked out but then realized that he has grossly underestimated the amount of food available to the bears. To make his prediction more accurate he should ____ the value of ____ in his equation. (Consider food to be a factor that limited the size of the bear population.) A. decrease... N B. increase... K C. increase... N D. decrease... r E. decrease... K
B. increase... K (Because food is a factor that limes the size of particular bear population, the increased food availability would increase carrying capacity)
When needed resources are unevenly distributed, organisms often show a(n) _____ dispersion pattern. A. Density-dependent B. Uniform C. Clumped D. Random E. Exponential
C. Clumped (Individuals will be found primarily in proximity to resources)
Pine trees in a forest tend to shade and kill pine seedlings that sprout nearby. This causes the pine trees to _____. A. Increase exponentially B. Exceed their carrying capacity C. Grow in a uniform pattern D. Grow in a clumped pattern E. Grow in a random pattern
C. Grow in a uniform pattern (The area shaded by each tree will determine pine tree distribution)
For what could a climograph be used? A. To compare geographic range and diversity of organisms in different biomes B. To compare the temperature and altitude of different biomes C. To compare the temperature and precipitation of different biomes D. To compare the latitude and precipitation of different biomes E. To compare average wind speeds and precipitation of different biomes
C. To compare the temperature and precipitation of different biomes (A climograph is a plot of the temperature and precipitation in a particular region)
Of these biomes, vertical stratification (layers of plants) is most pronounced in the _____. A. Savanna B. Grassland C. Tropical rain forest D. Tundra E. Desert
C. Tropical rain forest (Tropical rain forests have pronounced vertical stratification, which provides varied habitats and abundant rainfall both of which favor a great diversity of species)
An oak tree produces thousands of acorns, but very few grow into mature oak trees. The oak tree exhibits a _____ survivorship curve. A. Type I B. Type II C. Type III D. Type I or II E. Type I or III
C. Type III (This is the name given to the survivorship curve that displays high rates of juvenile mortality)
Temperature, precipitation, sunlight, and wind are the major components of ... A. Climate B. Ecosystems C. Biotic factors D. Dispersal E. Biomes
Climate.
Kingfish, Louisiana, had a population of 1,100 individuals. They had a birth rate of 12/100, a death rate of 8/100, and an emigration (individuals leaving the population) rate of 2/100. How many people were added to Kingfish's population in one year? A. 2 B. 6 C. 20 D. 22 E. 1,122
D. 22 (The birth rate of 12/100 should yield 132 new babies; the death rate of 8/100 should yield 88 deaths; the emigration rate of 2/100 indicated 22 people moved out. The net gain is 132 - 88 - 22 = 22)
Which population probably exhibits exponential growth? A. A population of deer in an area with few palatable food plants B. A redwood tree population in a forest C. A protozoan population grown in a sealed glass culture flask D. A fruit fly population that recently arrived on a lush mid-ocean is island previously inhabited only by plants E. A population of deer in an area with any hungry wolves
D. A fruit fly population that recently arrived on a lush mid-ocean is island previously inhabited only by plants (Growth of the fruit fly population is not limited by competition from other organisms)
A population that is growing logistically _____. A. Is always slowed by density-independent factors B. Grows fastest when density is lowest C. Has a high r D. Grows fastest at an intermediate population density E. Grows fastest as it approaches carrying capacity
D. Grows fastest at an intermediate population density (At very small population sizes the population growth rate will be low, but it will increase as the population increases, up to a point. At this point the population growth rate slows as carrying capacity is approached)
What biome is the largest terrestrial biome on Earth? A. Savanna B. Desert C. Tropical forest D. Northern coniferous forest E. Temperature broadleaf forest
D. Northern coniferous forest
In a famous case of species transplantation, starlings were introduced into North America from Europe in 1890 by an eccentric Shakespeare fan. Though the actual range of starlings was originally in the eastern hemisphere, it is clear that North American was part of its ____ range. A. Biotic B. Natural C. Ecological D. Potential E. Biogeographical
D. Potential (Starlings are very successful in North America, so North America has always been part of the starling's potential range. They needed some help to disperse to North America)
What biome is dominated by gymnosperm or conifer trees? A. Desert B. Broadleaf forest C. Tundra D. Taiga E. Tropical rain forest
D. Taiga (A northern coniferous forest, or taiga, supports cone-bearing trees, such as pine, spruce, fir and hemlock.
Which describes the distribution of survivorship or mortality for a population that has a Type II survivorship curve? A. Little death occurs until late in life B. Survivorship is greatest in young individuals C. Most of the mortality occurs among young individuals D. The chance of death is roughly constant over all ages E. Survivorship is greatest in individuals that are intermediate in age
D. The chance of death is roughly constant over all ages (The curve is intermediate between Type I and Type II survivorship curves)
Which choice is an example of expression of population density? A. 255 dogfish sharks B. The total dry mass of trout in a lake C. The total number of sturgeon per cubic meter in San Fransisco Bay and Tomales Bay D. The number of Paramecium caudate in a 250-mL solution in a glass flask E. 100 sea stars, barnacles and mussels per 25 m^2 of a tide pool
D. The number of Paramecium caudate in a 250-mL solution in a glass flask (Population density is the number of individual species per unit area or volume)
A climograph shows the mean temperature and precipitation values that support different biomes. What information is missing that would help predict what biome should be found in a particular range? A. Day length B. Microclimate C. Dominant plant species D. The pattern of climatic variation, including seasonal differences E. Latitude and longitude
D. The pattern of climatic variation, including seasonal differences (A climograph shows mean annual temperature and precipitation. Different biomes will occur in areas where the rainfall i evenly distributed throughout the year, for instance, as opposed to concentrated in a wet season.)
To calculate the human population density of your community, you would need to know the number of people living there and _____. A. The dispersion pattern of the population B. The carrying capacity C. Whether the population growth is logistical or exponential D. The size of the area in which they live E. The birth rate of the population
D. The size of the area in which they live (Density is the number of individuals of a population per unit area or volume)
Wet and dry seasons in tropical deciduous forests are ultimately caused by _____. A. Proximity to bodies of water B. Microclimates C. Changes in day length D. The tile of the Earth E. Upwelling of cold ocean water
D. The tilt of the Earth (causes seasonality. When different parts of the Earth are receiving greater or lesser amounts of solar radiation, the belts of wet and dry air on either side of the equator move north or south, causing wet or dry seasons in the tropics).
In which biome would you expect decomposers to work most rapidly and efficiently? A. Taiga B. Desert C. Savanna D. Tropical rain forest E. Tundra
D. Tropical rain forest (Tropical rain forest temperatures accommodate rapid rates of decomposition and thus quickly recycle nutrients from dead organisms back to living organisms)
Herring gulls fiercely defend the areas around their nests in cliff-top breeding colonies. Within the colony, they would show a _____ dispersion pattern. A. Clumped B. Density-independent C. Dense D. Uniform E. Random
D. Uniform (Territorial behavior often results in a uniform distribution)
Why do populations grow more slowly as they approach their carrying capacity?
Density-dependent factors lead to fewer births and increased mortality.
Kingfish, Louisiana, had a population of 1,100 individuals. They had a birth rate of 12/100, a death rate of 8/100, and an emigration (individuals leaving the population) rate of 2/100. What was the per capita rate of increase, including emigration, for this year in Kingfish? A. 22 B. 4 C. 2 D. 0.22 E. 0.02
E. 0.02 (The per capita rate of increase would be per capita birth rate minus per capita death rate minus per capita emigration rate or 0.12 - 0.08 - 0.02 = 0.02)
A particular environmental change causes the deaths of 25 individuals in a herd of 100 wild horses, and it kills 50 individuals in a herd of 200 horses. In this case, the growth of a wild horse population is most likely limited by _____. (Assume that the two herds are found in territories of equal size.) A. Food supply B. A density-dependent factor C. The presence of another species that uses the same food resources D. A predator E. A density-independent factor
E. A density-independent factor (A density-independent factor affects the same percentage of the population regardless of population density)
Chimpanzees have a relatively low birth rate. They care for their young, and most chimps live a long life. The chimp survivorship curve would look like _____. A. A horizontal line B. A line that drops steeply at first, then flattens out C. A line that slopes gradually upward D. A line that slopes gradually downward E. A relatively flat line that drops steeply at the end
E. A relatively flat line that drops steeply at the end (There is significant probability of survival through adulthood, with the probability of death increasing significantly in old age)
A demographer may study _____. A. Immigration rates in Melbourne, Australia B. Birth rates in a small town in Iowa C. Emigration rates in a forest that has been cleared partially for farming D. Offspring mortality rates of humpback whales E. All of the choices are correct
E. All of the choices are correct (Demography is the study of vital statistics of populations and how they change over time)
A population that grows rapidly at first and then levels off at carrying capacity can be modeled _____ . A. As an introduced species B. As dN/dt = b-d C. As relatively unaffected by limiting factors D. as dN/dt = rN E. By a logistic equation
E. By a logistic equation (The logistic equation, dN/dt=rmaxN(K-N)lK describes such a curve)
The logistic growth model differs from the exponential growth model in that it ____. A. Implies that a population's growth rate will be highest when population is small B. is J-shaped and exponential growth model is S-shaped C. Never shows the effects of population-limiting factors D. Implies that population size stabilized at K when the birth rate is zero E. Expresses the effects of population-limiting factors on exponential growth
E. Expresses the effects of population-limiting factors on exponential growth (In the logistic model, the term (K-N)lK represents the effects of population-limiting factors that depress the exponential growth tendency, rN, to a greater degree as population size approaches the carrying capacity)
An ecologist might conduct research to answer which of the following questions? A. How does caffeine affect the transmission of nerve impulses in humans? B. How do genes specify protein construction? C. How are different species of fish related (in an evolutionary sense) to each other? D. How does the uneven heating of Earth's surface cause the movement of air and water masses? E. How do tapeworms adapt to life in the human intestine?
E. How do tapeworms adapt to life in the human intestine?
After nutrient enrichment from sewage contamination, a lake often becomes inhospitable to fish. Why? A. Nutrient input to Lake poisons the organisms that fish eat B. nutrient input to a Lake poisons the fish C. Nutrient input causes the death of algae and cyanobacteria and thus the ultimate sources of organic compounds in the Lake ecosystem. Eventually this reduces the availability of food for fish within the Lake leading to their death D. Nutrient input to a lake causes the explosive growth of algal and cyanobacterial populations. This reduces the penetration of light into the Lake, the water temperature falls, and eventually the fish population dies E. Nutrient input to a Lake causes the explosive growth of algal and cyanobacterial populations. Decompensation of dead algae and cyanobacteria by bacteria results in the depletion of oxygen in the water, which leads to the death of fish
E. Nutrient input to a Lake causes the explosive growth of algal and cyanobacterial populations. Decompensation of dead algae and cyanobacteria by bacteria results in the depletion of oxygen in the water, which leads to the death of fish (A lack of oxygen is the ultimate cause of fish death in an example such as this. The lake may become essentially anaerobic)
Permafrost is characteristic of the _____. A. Desert B. Tropical forest C. Taiga D. Temperate forest E. Tundra.
E. Tundra. (Permafrost -permanent frozen subsoil-, bitterly cold temperatures, and high winds are responsible for the absence of trees and plants in the arctic tundra.
What is one application of the metapopulation concept?
It provides a framework for species conservation when those species live in a network or habitat fragments and reserves
What is an assumption of the logistic model of population growth?
Populations adjust instantaneously to growth.
As N approaches K for a certain population, which of the following is predicted by the logistic equation?
The population growth rate will approach zero
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?
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.
Which of the following best defines a cohort?
a group of individuals from the same age group, from birth until they are all dead
In which of the following situations would you expect to find the largest number of K-selected individuals?
an old-growth forest
Fire suppression by humans
can change the species composition within biological communities
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?
density
Which of the following levels of ecological organization is arranged in the correct sequence from most to least inclusive?
ecosystem, community, population, individual
Which of the following would most likely promote random distribution?
homogeneous chemical and physical factors in the environment
Which of the following is an expected characteristic of K-selected populations?
offspring with good chances of survival
Which of the following groups would be most likely to exhibit uniform dispersion?
red squirrels, animals that actively defend territories
Which of the following is a physical factor that can limit the geographic distribution of species?
soil structure
In mountainous areas of western North America, north-facing slopes would be expected to
support biological communities similar to those found at higher elevations on similar south-facing slopes.