• Chapter 53 Population Ecology Study Guide Answers

1) Population ecologists are primarily interested in A) studying interactions among populations of organisms that inhabit the same area. B) understanding how biotic and abiotic factors influence the density, distribution, size, and age structure of populations. C) how humans affect the size of wild populations of organisms. D) how populations evolve as natural selection acts on heritable variations among individuals and changes in gene frequency. E) the overall vitality of a population of organisms. 8) 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) multiplying the number of moss plants counted in 10 quadrats of 1m² each by 100 to determine the density per kilometer².

E) counting the number of zebras from airplane census observations. 9) Which of the following assumptions have to be made regarding the capture-recapture estimate of population size? Marked and unmarked individuals have the same probability of being trapped. The marked individuals have thoroughly mixed with the population after being marked.

No individuals have entered or left the population by immigration or emigration, and no individuals have been added by birth or eliminated by death during the course of the estimate. A) I only B) II only C) I and II only D) II and III only E) I, II, and III. 10) 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. 12) 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 x 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. 16) 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.

17) 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) More individuals emigrate from, as opposed to immigrate into, a population. C) Over 50% of the marked individuals need to be trapped during the recapture phase.

D) There is a 50:50 ratio of males to females in the population before and after trapping and recapture. E) Marked individuals have the same probability of being recaptured as unmarked individuals during the recapture phase. 24) Consider two forests: one is an undisturbed old-growth forest, while the other has recently been logged.

In which forest are species likely to experience exponential growth, and why? A) Old growth, because of stable conditions that 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. 31) Which of the following statements about the evolution of life histories is correct? A) Stable environments with limited resources favor r-selected populations. B) K-selected populations are most often found in environments where density-independent factors are important regulators of population size. C) Most populations have both r- and K-selected characteristics that vary under different environmental conditions. D) The reproductive efforts of r-selected populations are directed at producing just a few offspring with good competitive abilities.

E) K-selected populations rarely approach carrying capacity. 32) 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. 33) 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. 34) 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. 37) Which variables define the ecological life history of a species? 43) 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) Owl populations frequent the area more often because of increased hunting success. B) Females undergo hormonal changes that delay sexual maturation and many individuals suffer depressed immune systems and die due to the stress of overpopulation. C) Clumped dispersion of the population leads to increased spread of disease and parasites, resulting in a population crash.

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) Because the individuals are vulnerable they are more likely to die off if a drought or flood were to occur. 44) Why is territoriality an adaptive behavior for songbirds maintaining populations at or near their carrying capacity? A) Songbirds expend a tremendous amount of energy defending territories so that they spend less time feeding their young and fledgling mortality increases. B) Only the fittest males defend territories and they attract the fittest females so the best genes are conveyed to the next generation. C) Songbird males defend territories commensurate with the size from which they can derive adequate resources for themselves, their mate, and their chicks. D) Many individuals are killed in the agonistic behaviors that go along with territorial defense.

E) Adult songbirds make improvements to the territories they inhabit so that they can produce successfully fledged chicks. 46) An ecological footprint is a construct that is useful A) for a person living in a developed nation to consider to make better choices when using global food and energy resources. B) for a person living in a developing country to see how much of the world's resources are left for him/her.

C) in converting human foods' meat biomass to plant biomass. D) in making predictions about the global carrying capacity of humans.

E) in determining which nations produce the least amount of carbon dioxide from the burning of fossil fuels. 55) Which statement best explains survivorship curve B?

Chapter 53 Population Ecology Study Guide Answers

A) It is likely a species that provides little postnatal care, but lots of care for offspring during midlife as indicated by increased survivorship. B) This curve is likely of a species that produces lots of offspring, only a few of which are expected to survive. C) It is likely a species where no individuals in the cohort die when they are at 60—70% relative age. D) There was a mass emigration of young to middle-aged individuals in this cohort.

E) Survivorship can only decrease; therefore, this curve could not happen in nature. Please read the paragraph below and review Figure 53.2 to answer the following question. Researchers in the Netherlands studied the effects of parental care given in European kestrels over five years. The researchers transferred chicks among nests to produce reduced broods (three or four chicks), normal broods (five or six chicks), and enlarged broods (seven or eight chicks).

They then measured the percentage of male and female parent birds that survived the following winter. (Both males and females provide care for chicks.) Figure 53.2: Brood size manipulations in the kestrel: Effects on offspring and parent survival.

58) Which of the following is a conclusion that can be drawn from this graph? A) Female survivability is more negatively affected by larger brood size than is male survivability.

B) Male survivability decreased by 50% between reduced and enlarged brood treatments. C) Both males and females had increases in daily hunting with the enlarged brood size. D) There appears to be a negative correlation between brood enlargements and parental survival.

E) Chicks in reduced brood treatment received more food, weight gain, and reduced mortality. Refer to Figure 53.4 and then answer the following questions. Figure 53.4: Infant mortality and life expectancy at birth in developed and developing countries (data as of 2005). 65) What is a logical conclusion that can be drawn from the graphs above?

A) Developed countries have lower infant mortality rates and lower life expectancy than developing countries. B) Developed countries have higher infant mortality rates and lower life expectancy than developing countries. C) Developed countries have lower infant mortality rates and higher life expectancy than developing countries. D) Developed countries have higher infant mortality rates and higher life expectancy than developing countries. E) Developed countries have a life expectancy that is about 42 years more than life expectancy in developing countries.

Refer to Figure 53.4 and then answer the following questions. Figure 53.4: Infant mortality and life expectancy at birth in developed and developing countries (data as of 2005). 66) In terms of demographics, which country is likely to experience the greatest population growth problem over the next ten years? A) Mexico, because there are fewer pre-reproductive individuals in their population B) China, whose population is more than a billion, but whose expected fertility rate is 1.8 children C) Germany, where the growth rate of the population is 0.1% per year D) United States (2009 population 205,000,000, where 200,000 Americans are added to the population each day) E) Afghanistan, with a 3.85 annual growth rate.

68) Your friend comes to you with a problem. It seems his shrimp boats aren't catching nearly as much shrimp as they used to. He can't understand why because he used to catch all the shrimp he could handle. Each year he added a new boat, and for a long time each boat caught tons of shrimp. As he added more boats, there came a time when each boat caught somewhat fewer shrimp, and now, each boat is catching a lot less shrimp. Which of the following topics might help your friend understand the source of his problem? A) density-dependent population regulation and intrinsic characteristics of population growth B) exponential growth curves and unlimited environmental resources C) density-independent population regulation and chance occurrence D) pollution effects of a natural environment and learned shrimp behavior E) a K-selected population switching to an r-selected population.

69) Imagine that you are managing a large game ranch. You know from historical accounts that a species of deer used to live there, but they have been extirpated.

You decide to reintroduce them. After doing some research to determine what might be an appropriately sized founding population, you do so. You then watch the population increase for several generations, and graph the number of individuals (vertical axis) against the number of generations (horizontal axis). Solutions manual wald general relativity pdf.

The graph will likely appear as A) a diagonal line, getting higher with each generation. B) an 'S,' increasing with each generation. C) an upside-down 'U.' D) a 'J,' increasing with each generation. E) an 'S' that ends with a vertical line.

72) Scientific study of the population cycles of the snowshoe hare and its predator, the lynx, has revealed that A) the prey population is controlled by predators alone. B) hares and lynx are so mutually dependent that each species cannot survive without the other.

C) multiple biotic and abiotic factors contribute to the cycling of the hare and lynx populations. D) both hare and lynx populations are regulated mainly by abiotic factors. E) the hare population is r-selected and the lynx population is K-selected. 74) A recent study of ecological footprints concluded that A) Earth's carrying capacity for humans is about 10 billion.

B) Earth's carrying capacity would increase if per capita meat consumption increased. C) current demand by industrialized countries for resources is much smaller than the ecological footprint of those countries. D) it is not possible for technological improvements to increase Earth's carrying capacity for humans.

E) the ecological footprint of the United States is large because per capita resource use is high.