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MB 3.1: Life in a community MB 4.1: Population Dynamics
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What was a Limiting Factor? What are the two types of limiting factors? A factor that restrains the growth of a population 2 Types: Density Dependent Density Independent Populations cannot grow indefinitely because the resources they depend upon become scarce and wastes accumulate.
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Journal: What are some things that you think may be limiting factors???
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Limiting Factors Density-Independent Factors -Reduce the population size by the same proportion, regardless of the population’s size. Ex. weather, flood, fires
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Limiting Factors Density-Dependent Factors -Reduce the population size and are triggered by increasing population density. Ex. Shortage of food, nesting sites, resource limitations, Disease
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The graph below is an example of a _______________.
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What is the limiting factor for plant growth that is studied in this tolerance curve?
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Succession Primary Succession: occurs following an opening of uninhabited, barren habitat without plants and topsoil.
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Secondary Succession: occurs on preexisting soil after the environment has been disrupted
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Population A population is a group of organisms that belong to the same species and live in a particular place at the same time. Ex. all the bass living in a pond during a certain period of time.
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Properties of Populations 1.Population Size- the number of individuals it contains COUNTRYPOPULATION SIZE PERCENTAGE World6,671,226,000100% China1,323,324,00019.84% India1,131,729,00016.96% United States303,885,0004.56% Iceland316,2520.005%
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Properties of Populations 2. Population Density- measures how crowded a population is. It is expressed as the number of individuals per unit of area or volume Ex. U.S. states with greatest population density New Jersey and lowest population density Alaska.
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Properties of Populations 3. Dispersion- the spatial distribution of individuals within a population. Ex. random, clumped, even
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Exponential Growth When a population increases rapidly, only after a few generations and the larger the population gets, the faster it grows. Exponential population growth forms a characteristic J- shaped curve Ex. Bacteria and flies
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Limiting Factor A factor that restrains the growth of a population Journal: What are some examples of limiting factors?
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Limiting Factor A factor that restrains the growth of a population In reality populations cannot grow indefinitely because the resources they depend upon become scarce and wastes accumulate.
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Limiting Factors 1. Density-Independent Factors -Reduce the population size by the same proportion, regardless of the population’s size. Ex. weather, flood, fires
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Limiting Factors 2. Density-Dependent Factors -Reduce the population size and are triggered by increasing population density. Ex. Shortage of food, nesting sites, resource limitations, Disease
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Logistic Model of Pop. Growth The logistic model builds on the exponential model but accounts for the influence of limiting factors.
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Logistic Model of Pop. Growth Carrying Capacity- the number of individuals the environment can support over a long period of time. A graph of logistic growth is S- shaped
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Competition Occurs when fundamental niches overlap Species use the same limited resources. – Competitive Exclusion
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Resource Partitioning
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Begin Succession Activity
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