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Exponential growth “J curve” Population Growth Patterns Type of Growth?
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Population Growth Patterns Some populations of organisms reach a plateau in their growth. This is called their carrying capacity. These populations are said to be growing with logistical growth. “S curve” carrying capacity
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Carrying capacity – The number of organisms that can be supported by a particular ecosystem *within natural resource limits- without destroying it. *Limiting Factors…
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Population Growth Patterns 1.What is the carrying capacity of the population on the right? 2.About how many days did it take for the population to reach carrying capacity? 3.Which of the following is probably NOT a reason the population reached and maintained a plateau? a. limits in food supply b. competition with other species c. competition for space d. a major storm Logistical vs. Exponential
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Population Growth Patterns What is the carrying capacity of the population on the right? around 135 individuals About how many days did it take for the population to reach carrying capacity? about 80 days Which of the following is probably NOT a reason the population reached and maintained a plateau? a. limits in food supply b. competition with other species c. competition for space d. a major storm would probably not cause a population to maintain its size Logistical vs. Exponential
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N = Population SIze dN = Change in Population Size dt = Change in Time; generation r = 1.0 = BR – DR (2-1 in this case) 1,500 = ? *N small compared to K- Max rate of Increase *N large/K limiting, Rate of increase is small (K-N/K is close to zero)
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N = Population SIze dN = Change in Population Size dt = Change in Time; generation r = 1.0 = BR – DR (2-1 in this case) 1,500 = ? *N small compared to K- Max rate of Increase *N large/K limiting, Rate of increase is small (K-N/K is close to zero)
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Birth rate/Death rate United States 14.1/8.7 Australia 12.7/7.3 Iraq 34.2/6.0 Japan 10.0/8.5 Italy 8.9/10.1 Russia 9.7/13.9 Other Factors? Migration: Emigration,Immigration Why?….for people… Life Expectancy,Health Care,Sanitation Economics,Quality of Life,Education
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Density Dependent Factors: related to the density of the population. (disease, predation, competition) Density Independent Factors: Not related to population size (killing frost, severe blizzard, hurricane, etc)
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Three Patterns of Population Growth Causes?
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http://www.census.gov/population/international/data/ http://www.census.gov/population/international/data/ International Data International Data China Single Birth PolicyWhen Instituted?
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In 1990?
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HW 52-9 Handout: Review of characteristics, curves
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P/S: Compare how matter and energy operate in ecosystems? (Are they recycled)? HW Ch54-2 Matter and Energy in an Ecosystem
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Text p1167
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Shows the energy available at each trophic level. The size of the blocks represents the proportion of energy Measured in Joules or Calories
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Illustration of the number of organisms at each level
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Usually 5 max Number of energy steps from the sun Tropho = nourishment
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Definitions: ? HW Ch 53-10 P/S: Humans: keystone or dominant species? Dominant: Most abundant species in a community Keystone: Species that has greater influence on community structure than you would predict based on #’s. Maintains species diversity (predation) Grey Wolf Fig Tree ?
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Persistence: Characteristics of certain chemicals that are extremely stable and may take many years to be broken down into simpler forms by a natural process. Biological Accumulation: Buildup of a persistent toxic substance such as pesticides, in an organisms body. Biological Magnification:The increase in concentration of a persistent toxin in the tissues of organisms at higher trophic levels. HW54-7
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