Mastering Biology: Chapter 53 Population Dynamics Tutorials

25 July 2022
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question
You are doing a mark-recapture experiment to determine the population size of the MendAliens living on an island in my back yard. Initially, you catch and mark 130 MendAliens, which you then release. Next, you capture 90 MendAliens, of which 20 are marked. What is your estimate of the population size of MendAliens living on the island in my back yard?
answer
585
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Mark-Recapture Method
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A sampling technique used to estimate wildlife populations. [(Number Marked) x (Total Caught Second Time)]/(Number of marked recaptures)
question
Assume there are 200 MendAliens living on an island in my back yard. If my island has an area of 20 hectares, what is the population density of MendAliens in terms of MendAliens per hectare?
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10 MendAliens per hectare
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Population Density
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Population density = size of population/ area of land
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The mark-recapture method would be best for sampling a population of _____.
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sharks
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The mark-recapture method works best for
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active species whose individuals tend to be highly mobile.
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3 types of survival ship curves
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1. Species with many young, but few survive to adulthood 2. Species with few young and a large percent survive to adulthood 3. Intermediate species with a mortality rate constant over its lifespan.
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Which of these species typically has a mortality rate that remains fairly constant over an individual's life span?
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Robins
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Oyster populations are primarily, if not exclusively, composed of _____.
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Adults
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Which of these organisms has a survivorship curve similar to that of oysters?
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Grasses
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Which of these organisms has a survivorship curve similar to that of humans?
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Elephants
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What is represented on the x-axis of this graph?
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Individuals' life spans as a percentage of the maximum life span for the species
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Why is a percentage scale used for the x-axis rather than actual ages?
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This scale allows you to compare species with widely varying life spans on the same graph.
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For a species with a Type II curve, less than ____% of individuals survive for 50% of the maximum life span.
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10
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At 50% of maximum life span, how does survivorship for a Type I curve compare to survivorship for a Type III curve?
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Survivorship for a Type I curve is nearly 1,000 times as great as survivorship for a Type III curve.
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For species with a Type III curve, most individuals reach the maximum life span.
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Not supported
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According to this graph, species that exhibit a Type III curve typically produce large numbers of offspring
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Cannot be determined from this graph
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In species that exhibit a Type II survivorship curve, individuals are no more likely to die at one stage of the life cycle than another.
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Supported
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What is shown on the x-axis?
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percentage of the maximum life span of a species
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Look closely at the scale on the y-axis. What number would be represented by the point midway between the tick mark labeled 10 and the tick mark labeled 100?
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approximately 32
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In a population of 1,000 elephants, how many individuals would survive for 50% of the species' maximum life span?
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about 100
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According to the graph, which modern animal has a relatively constant mortality rate throughout its life span?
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starling
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At 50% of maximum life span, how does the survivorship of Albertosaurus compare to the survivorship of the crocodile?
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The survivorship of Albertosaurus is about 100 times greater than that of the crocodile.
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Is the following statement supported or not supported by the data shown in the graph? The maximum life span of Albertosaurus was about 100 years.
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cannot be determined from this graph
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Is the following statement supported or not supported by the data shown in the graph? The mortality rate of Albertosaurus dinosaurs aged between 25% and 50% of their maximum life span was far greater than the mortality rate of dinosaurs that reached 75% of their maximum life span.
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not supported
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K (carrying capacity) increases
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a main competitor for food is eliminated, increasing food availability an abandoned building creates more nesting areas
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K (carrying capacity) decreases
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a parking lot is built, shrinking the habitat wetlands are drained, decreasing the amount of available water a species with the same food requirements is introduced
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no effect on K (carrying capacity)
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offspring live longer
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Rank the population sizes (N) from fastest to slowest growth. If two population sizes have the same growth, overlap them.
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N=1250 N=1500 N=1000 N= 750 N= 500 N= 250
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Use the data below to make a graph showing the logistic growth of a hypothetical population. Choose one row of data in the table to plot on each axis (shown here as x and y).
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Plot generation on x axis Plot Population Size (N) on y axis Should result in an s-shaped curve
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The figure below shows the logistic growth of a hypothetical population of animals. Drag the labels to their appropriate locations on the graph.
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a. K b. N c. time d. r-selection predominates e. K-selection predominates
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Which processes increase a population's size?
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Births and immigration
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True or false? Factors that determine the per capita rate of increase of a population include the age of breeding and the number of offspring produced each year.
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True
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Which factor does not affect a habitat's carrying capacity?
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Genetic variation in the population
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Which equation represents the logistic growth rate of a population?
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ΔN/Δt=rmaxN[(K−N)/K]
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Which of the following statements about density-independent growth is true?
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Density-independent growth is also known as exponential growth.
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Under which of the following conditions would a population most likely experience exponential growth?
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Young populations with few individuals
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Which of the following statements about a population experiencing logistic growth is true?
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If N is greater than K, the population will shrink.
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What does the right y-axis represent?
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resources, with quantity decreasing from bottom to top
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What does the orange graph line represent?
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logistic growth
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Which of the following statements are true of logistic growth? Select all that apply.
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As the population approaches carrying capacity, it grows more slowly. When the population reaches carrying capacity, it stops growing.
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Which of the following statements are true of a population at carrying capacity? Select all that apply.
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The birth rate equals the death rate. The population growth rate equals zero. The rate at which resources are used is equal to the rate at which they are supplied.
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As a population approaches carrying capacity, environmental resistance __________.
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increases
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Which of the following factors does not contribute to environmental resistance?
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birth rate
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Which graph best represents the growth of the beetle population in the sack of corn meal?
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Graph C
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Which of the three graphs shown in Part G best represents the growth of these yeast population?
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Graph A
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Which of the three graphs shown in Part G best represents the growth of this coyote population?
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Graph B
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Drag the labels onto the table to identify the characteristics of each type of population growth. Labels can be used once, more than once, or not at all.
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a. exponential growth b. logistic growth c. abundant resources d. limited resources e. faster as population size increases f. slows as population size increases g. no limit to population size h. carrying capacity i. Isabela Island Geckos j. Daphne Major Geckos
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Drag a label under each graph to indicate whether it shows density-dependent population regulation or density-independent population regulation. Labels may be used once, more than once, or not at all.
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a. density-dependent birth rate b. density-dependent death rate c. density- dependent birth rate d. density- independent death rate
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The population of Greece is expected to _______.
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decline
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Assuming the current trend continues, in 30 years Greece will have more children than reproductive-age individuals.
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False
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Assuming the current trend continues, in 30 years Greece will have more children than elderly members of the population.
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False
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Assuming the current trend continues, in 30 years Greece will have more reproductive-age individuals than children.
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False
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Assuming the current trend continues, in 30 years Greece will have more elderly than reproductive-age individuals.
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True
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Greece had more females than males in 2000. Which of the following is the most likely explanation for this?
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Males generally have a shorter lifespan than females
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The population of Colombia is currently _______.
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expanding
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Assuming the current trend continues, in 30 years Colombia will have more children than reproductive-age individuals.
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True
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Assuming the current trend continues, in 30 years Colombia will have more children than elderly members of the population.
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True
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Assuming the current trend continues, in 30 years Colombia will have more reproductive-age individuals than children.
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False
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Assuming the current trend continues, in 30 years Colombia will have more elderly than reproductive-age individuals.
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False
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Which of these was the first of the major events that stimulated an increase in the size of the human population?
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The advent of agriculture
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Which of these was the second of the major events that stimulated an increase in the size of the human population?
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The Industrial Revolution
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Which of these was the third of the major events that stimulated an increase in the size of the human population?
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The discovery of vaccines and the discovery of antibodies
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Which factors have permitted the human population to continue increasing despite using nonrenewable resources at an unsustainable rate?
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expansion of high-density urban areas improvements in medical care
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Ignoring migration, the age structure of a human population likely to increase in size will have what shape?
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Pyramid
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Ignoring migration, the age structure of a human population likely to decrease in size will have what shape?
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Inverted pyramid
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Ignoring migration, the age structure diagram of a human population likely to maintain a relatively stable size will have what shape?
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a rectangle tapering toward the top
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What are population dynamics?
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Changes in populations through time.
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Which of the following statements about age pyramids is true?
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Predictions of a population's future take into account such factors as increasing survivorship and fecundity levels that remain the same.
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True or false? The growth rate of a certain population increases very quickly for a time and then levels off to zero. The most likely reason that the growth rate leveled off to zero is that the population reached the carrying capacity of that environment.
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True
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The average age of childbearing in country A is 26, whereas the average age in country B is 30. In each country, the average number of offspring per woman is 3. Which of the following statements about the population growth rate in each country must be true?
answer
It is not possible to compare the population growth rates of countries A and B.
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In 1970, the average age of childbearing was 28, and the average number of offspring per woman was 3 in a certain country. In 1980, the average age of childbearing was still 28, but the average number of offspring per woman was 2 in that country. If the death rate in the country remained constant during those years, how did the population growth rate change from 1970 to 1980?
answer
The population growth rate decreased.
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What is represented by the distance between two vertical white gridlines on this graph?
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A time span of 50 years
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What is represented by the vertical blue bars on this graph?
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The number of people added to the population annually in each decade
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According to this graph, the world population doubled between _______.
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1930 and 1975
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Which decade had, or is projected to have, the highest annual population increase?
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1980-1990
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During the 20th century, the human population increased from less than 2 billion to more than 6 billion.
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Supported
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Total population size is projected to increase through the middle of the 21st century.
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Supported
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The rate of human population growth is increasing.
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Not supported
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From 1500 to 2010, the human population approximately followed the exponential growth model.
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Supported
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What do the bars on this graph represent?
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The numbers of males and females in each age group
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Approximately how many 15-19-year-old males were there in China in 2010?
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56 million
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After rapid population growth from 1966 to 1975, the Chinese government instituted policies aimed at reducing population growth. The effects can be seen in most age-groups born since then. However, the population representing children born in 1986-1990 is larger than any other age-group. What data in the age structure diagram provide the best explanation for this exception?
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This exception can be explained by population momentum from the 1966-1970 age-group.
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Like the United States, China experienced a "baby boom" after World War II ended in 1945.
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Not supported
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In 1985, China's rate of population increase was nearly 15 per 1,000. Based on the portion of the population in their prereproductive years, China's population will continue to grow at a high rate of increase through the 21st century.
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Not supported
question
Look at the age-structure pyramids. The numbers between the bars (in the middle of the graphs) serve as the y-axis. What do these numbers represent?
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the age classes, in 5-year ranges
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What do the bars on the graphs represent?
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the number of males and females in each age group
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In 2010, how many 25- to 29-year-old women lived in Niger?
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about 0.5 million
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The colors of the bars on the graphs indicate the life stage of the people in that age class. What does it mean if a bar is colored blue?
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The people in that age class are of reproductive age.
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The 2010 age-structure pyramid for Niger indicates that the population of Niger ________.
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was increasing
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In Canada in 2010, which age classes contained the largest number of people?
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adults between 45 and 54
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In Canada in 2010, people between the ages of 45 and 54 made up the largest percentage of the population. What factor is most likely to have caused this bulge in the age pyramid?
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a surge in the birth rate after World War II ended in 1945
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Assuming that current trends continue, predict how the age structure of Canada in 2030 will likely differ from that in 2010.
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The proportion of the population made up of older adults (65+) will increase.
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Based on a comparison of the age-structure pyramids, which of the following would likely be a higher priority in Canada than in Niger?
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providing long-term care for the elderly
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What does the left y-axis of the graph represent?
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birth rate or death rate
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What does the green graph line represent?
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total number of individuals in the population
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Which stage in the graph shows the greatest overall decline in death rate?
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Stage 2
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What factor would contribute to a sharp decline in death rate, such as the one shown in Stage 2?
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improved sanitation
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Which stage represents the fertility transition--a period of declining fertility rates related to economic and social change?
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Stage 3
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In which stage or stages is the size of the population relatively stable?
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Stage 1 and 4
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Is the following statement supported or not supported by the data shown in the graph? The population grows most rapidly when the birth rate is significantly greater than the death rate.
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Supported
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Is the following statement supported or not supported by the data shown in the graph? In the future the birth rate and death rate will be balanced, so the total population will remain relatively constant.
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Cannot be determined from the graph