Download Populations Student Notes 5 2 - THCS-Biology

Name: _____________________________________
Period: ___________
Populations: Limits to Growth
Limiting Factors
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The primary productivity of an ecosystem can be reduced when there is
_______________________________________________________.
Ecologists call such substances _________________________.
A limiting nutrient is an example of a more general ecological concept: a
limiting factor.
In the context of populations, a ___________________ is a factor that causes
population growth to decrease.
Density-Dependent Factors
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A limiting factor that depends on population size is called a_________
__________________________________.
Density-dependent limiting factors include:
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_______________________
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_______________________
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_______________________
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_______________________
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Density-dependent factors exist only when the _______________ __
_______________________________. These factors exist most strongly
when a population is large and dense.
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They do not affect _______________________________ as greatly.
Competition
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When populations become crowded, __________________________
_______________________________________________________________.
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_______________________ among members of the same species is a
density-dependent limiting factor.
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Competition can also occur between members of _______________.
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This type of competition can lead to _____________________________.
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Over time, the species may _____________________________ ___ ____
________________________________________________.
Predation
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Populations in nature are often ________________________________.
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The regulation of a population by predation takes place within a
__________________________________, one of the best-known mechanisms
of population control.
Parasitism and Disease
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_____________________ can limit the growth of a population.
A parasite ______________________________________________________
_______________________________.
Density-Independent Factors
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___________________________________________ affect all populations in
similar ways, regardless of the population size.
Examples of density-independent limiting factors include:
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________________________
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________________________
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________________________
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Example: Deer foraging for food in deep snow during
the winter.
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