How Populations Grow Section 5-1

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How Populations GrowSection 5-1

• e. Explain how the amount of life any environment
  can support is limited by the available matter
  and energy and by the ability of ecosystems to
  recycle the residue of dead organic materials.
• i. Explain the concept of carrying capacity
• j. Describe the growth of populations, including
  exponential and logistic growth .

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What do ALL tables and graphs need?

• Title
• Labeled axes
• Evenly spaced intervals on axes
• On which axis do you plot the independent
  variable?

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Inquiry Activity How Do Populations Grow?

• Textbook p.118 (20 minutes)
• Math Hint

Year of Rabbits of Couples of Offspring
1 2 1 6
2 6
3
4
5
When setting up your graph, pay attention to the
fact that you will have to extrapolate data
through 20 years (so leave that room!)
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The Sea Otters and the Giant Kelp

• http//www.youtube.com/watch?vv_aSl3iL7rM
• Kelp forest? sea urchins ? sea otters
• What is this relationship called?
• What do the arrows indicate?
• A century-old tale of population growth and
  decline (p.119)
• These population changes are studied in
  population biology.

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Characteristics of Populations

• Three important characteristics
• Geographic distribution (where? range?)
• Population density the number of individuals per
  unit area (grass blades vs. pine trees)
• Growth rate (how fast?)

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Population Growth

• Three factors that affect population size
• of births
• of deaths
• of individuals that enter or leave the
  population
• What is migration?
• Immigration the movement of individuals into an
  area
• Emigration the movement of individuals out of an
  area (individuals exiting an area)

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Two Types of Growth Patterns

• Exponential growth
• Occurs under ideal conditions ample food and
  space, protection from predators and disease
• Individuals reproduce at a constant rate
• Graph is a J-shaped curve
• Logistic growth
• Population growth slows as resources become less
  available
• Produces an S-shaped graph

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Carrying Capacity

• Definition the maximum number of individuals
  that a given environment can support

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The Sea Otters and the Giant Kelp

• What type of growth would you expect to have seen
  
• in the sea urchins when the otters were hunted?
• in the sea urchins as the kelp disappeared?
• in the kelp when the sea otters were protected?
• in the sea otters when they were first protected?
• Where on a population graph would you expect the
  populations of sea otters, sea urchins, and giant
  kelp to be found now?

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Assignment

• Analyzing Data Population Trends (p.123)