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POPULATIONS

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POPULATIONS 1. S curve = Logistic growth Resource availability will cause the population to level off over time When we look at how populations grow, we can observe 2 ... – PowerPoint PPT presentation

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Title: POPULATIONS


1
POPULATIONS
2
1. S curve Logistic growth
When we look at how populations grow, we can
observe 2 types of growth curves 1. S shaped
curve- Logistic growth 2. J shaped
curve- Exponential growth
  • Resource availability will cause the population
    to level off over time

3
2. J curve Exponential growth J Shape
  • Happens during ideal conditions
  • Plenty of food, shelter etc.
  • Unlimited resources
  • No limiting factors
  • POPULATION EXPLOSION

4
  • Horizontal line where growth of the population
    has leveled off is the CARRYING CAPACITY
  • Carrying Capacity The number of individuals in
    a population that an environment can support over
    a long period of time
  • As growth continues, the environment's resources
    are shared by more and more individuals.
  • Eventually, some resources are in short supply
    and become a limiting factor
  • Determine an environments carry capacity
  • things that prevent a population from growing any
    larger

5
In the graph below, what factors would cause the
growth rate to decrease or level off?
6
Limiting Factor a factor that causes the growth
of a population to decrease.
  • 1. Density dependent (biotic)
  • Competition may use same food, or shelter.
  • Predation predatorprey curve (pop. control)
  • Parasitism and disease
  • 2. Density independent (abiotic)
  • Natural disasters
  • Human disturbances (construction)
  • Weather

7
How does the difference in water temperature
affect the growth rate of the three species of
fish depicted in the graph?
8
GROUP ACTVITY.QUESTION Has the Earth reached
its carrying capacity for Humans?
  • Based on what you have learned about carrying
    capacity, answer the
  • following questions.
  • Some scientists believe we have passes Earths
    Carrying capacity for humans. Some believe we may
    reach it when the human population reaches 12
    billion.
  • In your opinion, has the earth passed its
    carrying capacity? Justify your answer.
  • - Give 3 reasons to support each argument.
  • What would limit humans from increasing its
    population indefinitely?

9
EXPONENTIAL LOGISTIC GROWTH CURVES WKST
10
PREDATOR PREY CURVE
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