Resources and Population Size - Middle School Life Science
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What is carrying capacity (K) for a population in a habitat?
What is carrying capacity (K) for a population in a habitat?
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The maximum population size the available resources can support. Resources set the upper limit for sustainable population size.
The maximum population size the available resources can support. Resources set the upper limit for sustainable population size.
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What is the most direct effect of decreased water availability on a population size?
What is the most direct effect of decreased water availability on a population size?
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Population size tends to decrease. Water scarcity causes dehydration, reducing survival and reproduction.
Population size tends to decrease. Water scarcity causes dehydration, reducing survival and reproduction.
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Choose the word that completes the statement: If resources increase, carrying capacity usually ______.
Choose the word that completes the statement: If resources increase, carrying capacity usually ______.
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Increases. More resources allow the environment to support larger populations.
Increases. More resources allow the environment to support larger populations.
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Which observation best supports that disease spread is density-dependent: outbreaks at high density or equal outbreaks at all densities?
Which observation best supports that disease spread is density-dependent: outbreaks at high density or equal outbreaks at all densities?
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Outbreaks at high density. Disease spreads more easily when individuals are crowded together.
Outbreaks at high density. Disease spreads more easily when individuals are crowded together.
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Which option is density-independent: competition, predation, or hurricane?
Which option is density-independent: competition, predation, or hurricane?
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Hurricane. Natural disasters affect all individuals equally, regardless of crowding.
Hurricane. Natural disasters affect all individuals equally, regardless of crowding.
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Identify the most likely population response after a drought reduces plant biomass for herbivores.
Identify the most likely population response after a drought reduces plant biomass for herbivores.
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Herbivore population size decreases. Less plant food means fewer herbivores can survive.
Herbivore population size decreases. Less plant food means fewer herbivores can survive.
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Identify the best evidence that water is limiting a population: crowded nests, dry streams, or low predation rates.
Identify the best evidence that water is limiting a population: crowded nests, dry streams, or low predation rates.
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Dry streams. Lack of water sources directly limits population survival.
Dry streams. Lack of water sources directly limits population survival.
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Which option is density-dependent: disease, drought, or wildfire?
Which option is density-dependent: disease, drought, or wildfire?
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Disease. Spreads faster in crowded populations, making it density-dependent.
Disease. Spreads faster in crowded populations, making it density-dependent.
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Which change most directly suggests the population exceeded K: increased births, increased emigration, or increased resources?
Which change most directly suggests the population exceeded K: increased births, increased emigration, or increased resources?
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Increased emigration. Animals leave when resources can't support the population.
Increased emigration. Animals leave when resources can't support the population.
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What is the cause-and-effect relationship between competition and population size as density rises?
What is the cause-and-effect relationship between competition and population size as density rises?
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More competition reduces growth, so population size levels off or drops. Limited resources intensify competition, reducing individual fitness.
More competition reduces growth, so population size levels off or drops. Limited resources intensify competition, reducing individual fitness.
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What is the cause-and-effect relationship between predation and prey population size?
What is the cause-and-effect relationship between predation and prey population size?
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More predation lowers prey survival, decreasing prey population size. Predators remove individuals, directly reducing prey numbers.
More predation lowers prey survival, decreasing prey population size. Predators remove individuals, directly reducing prey numbers.
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Identify the best evidence that food is limiting a deer population: stable numbers, many fawns, or many deer are underweight.
Identify the best evidence that food is limiting a deer population: stable numbers, many fawns, or many deer are underweight.
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Many deer are underweight. Low body weight indicates insufficient food resources.
Many deer are underweight. Low body weight indicates insufficient food resources.
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What is the most direct effect of reduced shelter or nesting sites on a population?
What is the most direct effect of reduced shelter or nesting sites on a population?
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Lower survival and reproduction, so population size decreases. Without adequate shelter, organisms face higher mortality.
Lower survival and reproduction, so population size decreases. Without adequate shelter, organisms face higher mortality.
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Identify the limiting resource if plants are plentiful but nest sites are scarce for birds.
Identify the limiting resource if plants are plentiful but nest sites are scarce for birds.
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Nesting sites (shelter). The scarcest resource limits population despite abundant food.
Nesting sites (shelter). The scarcest resource limits population despite abundant food.
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What is the most direct effect of increased food availability on a population size?
What is the most direct effect of increased food availability on a population size?
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Population size tends to increase. More food supports higher birth rates and survival.
Population size tends to increase. More food supports higher birth rates and survival.
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Which type of population growth occurs as resources become limited near K?
Which type of population growth occurs as resources become limited near K?
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Logistic growth. Growth slows as competition for scarce resources intensifies near K.
Logistic growth. Growth slows as competition for scarce resources intensifies near K.
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Which type of population growth occurs when resources are unlimited?
Which type of population growth occurs when resources are unlimited?
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Exponential growth. Without resource limits, populations grow rapidly without constraint.
Exponential growth. Without resource limits, populations grow rapidly without constraint.
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Identify the limiting resource: plants decline after drought, and herbivore numbers drop soon after.
Identify the limiting resource: plants decline after drought, and herbivore numbers drop soon after.
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Food (plant biomass). Herbivores depend on plants; drought reduces plant food supply.
Food (plant biomass). Herbivores depend on plants; drought reduces plant food supply.
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What is the expected population effect when a new water source is added to a habitat?
What is the expected population effect when a new water source is added to a habitat?
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Population size tends to increase until a new limiting factor appears. Removing one limit allows growth until another limit is reached.
Population size tends to increase until a new limiting factor appears. Removing one limit allows growth until another limit is reached.
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What is the most direct evidence that a population exceeded carrying capacity?
What is the most direct evidence that a population exceeded carrying capacity?
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Resource shortages followed by increased deaths and population decline. Overpopulation depletes resources, causing die-offs.
Resource shortages followed by increased deaths and population decline. Overpopulation depletes resources, causing die-offs.
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What is one density-independent factor that can reduce population size regardless of density?
What is one density-independent factor that can reduce population size regardless of density?
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Drought, flood, wildfire, or extreme temperature. Natural disasters affect populations regardless of size.
Drought, flood, wildfire, or extreme temperature. Natural disasters affect populations regardless of size.
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What is one density-dependent factor that directly involves resources?
What is one density-dependent factor that directly involves resources?
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Competition for limited food, water, or space. More individuals means less resources per organism.
Competition for limited food, water, or space. More individuals means less resources per organism.
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Which type of limiting factor does not depend on population density: density-dependent or density-independent?
Which type of limiting factor does not depend on population density: density-dependent or density-independent?
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Density-independent. Affects all individuals equally regardless of crowding (e.g., weather).
Density-independent. Affects all individuals equally regardless of crowding (e.g., weather).
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Which type of limiting factor depends on population density: density-dependent or density-independent?
Which type of limiting factor depends on population density: density-dependent or density-independent?
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Density-dependent. Effects intensify as population density increases (e.g., competition).
Density-dependent. Effects intensify as population density increases (e.g., competition).
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Which term describes an organism’s need for food, water, and space: resource or habitat?
Which term describes an organism’s need for food, water, and space: resource or habitat?
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Resource. Resources are materials organisms need; habitat is where they live.
Resource. Resources are materials organisms need; habitat is where they live.
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