Biology Exam #3 Chapter 53 – Flashcards
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Population
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organisms living in the same place at the same time
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3 important characteristics of populations
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Range Spacing Size
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Geographic ranges
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Change over time
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Demography
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Study of populations
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2 ways to approach studies of population changes over time
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Entire population (increasing? decreasing?) Component of population (birth and death rate at certain age)
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Factors that my influence population growth
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Sex ratio Generation times Life span
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Survivorship
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certain age for population to survive to
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Natural populations
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Cannot grow at an exponential rate
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Attributes to the logistic curve
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Mathematical simplicity Apparent reality
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Population density
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number of individuals per unit area
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Patterns of dispersion
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Clumped Uniform Random
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When do the populations increase?
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Births and immigration
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When do the populations decrease?
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deaths and emigration
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What summarizes specific tends in demography?
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Life tables, survivor ship, curves and reproductive tables
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exponential growth equation
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dN/dt = r(max)N
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Carrying capactiy
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the maximum population size the environment can support
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Logistic growth equation
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dN/dt = r(max)N(K-N)/K
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Life history
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evolutionary outcomes reflected in organisms
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Semelparous
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reproduce once and die
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Iteroparous
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reproduce repeatedly
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K-selection
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density-dependent selection
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r-selection
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density-independent selection
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density-dependent
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death rates raise and birth rates fall
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density-independent
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birth and death rates do not vary
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What are some limiting factors for density-dependence?
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competition, increased predation, disease, stress, toxic substances
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Metapopulation
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group of populations linked by immigration and emigration
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Ecological footprint
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aggregate land and water area needed to produce all the resources a person or group of people consume and to absorb all their wastes
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Population ecologists follow the fate of same-age cohorts to A) determine a population's carrying capacity B) determine the birth rate and death rate of each group in a population C) determine if a population is regulated by density-dependent processes D) determine the factors that regulate the size of a population E) determine if a population's growth is cyclic
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B) determine the birth rate and death rate of each group in a population
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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
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A) may change as environmental conditions change
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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
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C) multiple biotic and abiotic factors contribute to the cycling of the hare and lynx populations
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Based on current growth rate, Earth's human population in 2012 will be closest to A) 2 million B) 3 billion C) 4 billion D) 7 billion E) 10 billion
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D) 7 billion
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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
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E) the ecological footprint of the United States is large because per capita resource use is high
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The observation that members of a population are uniformly distributed suggests that A) the size of the area occupied by the population is increasing B) resources are distributed unevenly C) the members of the population are competing for access to a resource D) the members of the population are neither attracted to nor repelled by one another E) the density of the population is low
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C) the members of the population are competing for access to a resource
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According to the logistic growth equation dN/dt = r(max)N (K - N)/K A) the number of individuals added per unit time is greatest when N is close to zero B) the per capita growth rate (r) increases as N approaches K C) population growth is zero when N equals K D) the population grows exponentially when K is small E) the birth rate (b) approaches zero as N approaches K
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C) population growth is zero when N equals K
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Which pair of terms most accurately describes life history traits for a stable population of wolves? A) semelparous; r-selected B) semelparous; K-selected C) iteroparous; r-selected D) iteroparous; K-selected E) iteroparous; N-selected
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D) iteroparous; K-selected
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During exponential growth, a population always A) grows by thousands of indivduals B) grows at its maximum per capita rate C) quickly reaches its carrying capacity D) cycles through time E) loses some individuals to emigration
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B) grows at its maximum per capita rate
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Which of the following statements about human population in industrialized countries is incorrect? A) life history is r-selected B) average family size is relatively small C) the population has undergone the demographic transition D) the survivorship curve is Type 1 E) age distribution is relatively uniform
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A) life history is r-selected
