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Population Ecology Population Ecology Predator Prey Population

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Population Ecology Population Ecology Predator Prey Population Powered By Docstoc
					Population
  Ecology
Predator-Prey
   Population
    Dynamics

          Let’s look at the
 relationship between fox
   and rabbit populations.
  Fox-Rabbit
 Populations
    As the fox (predator)
population increases, the
  rabbit (prey) population
               decreases.
 Fox-Rabbit
Populations
Fewer rabbits leads to
         fewer foxes.
  Fox-Rabbit
 Populations
But, fewer foxes leads to
an increase in the rabbit
 population, starting the
     cycle all over again.
 Lynx-Hare
Populations
   Another example
  can be seen in the
         relationship
   between lynx and
   hare populations.
Wolf-Moose
Populations
       Look for the
        relationship
   between the wolf
        and moose
       populations.
Predator-Prey
  Relationship
      Regardless of the
     species, predator-
   prey populations are
         always linked.
   So What?

The number of organisms
 in any population cannot
         increase forever.
Human Population History
   Human
Population
   History
       Human
    Population
Since 1000 AD
         Human
      Population
        Increase
         by Year
<1 billion for 100,000+ years
1 billion              ~1850
2 billion              ~1930
3 billion              ~1960
4 billion              ~1975
5 billion              ~1989
6 billion              ~2000
6.7 billion             today
10 billion             ~2050
Human Population Since 1750
  Millions of People




                       Year
Human Population Since 1950
  Millions of People




                       Year
Earth from Space at Night
Unsustainable
      Growth

       The number of
     organisms in any
    population cannot
     increase forever.
But Humans
 Don’t Have
 Predators!

 True. We’re on top of
       the food chain.
  So what’s our “prey”?
What Humans
  Depend On
   What do we depend
        on to survive?


     What could cause
      our population to
              decline?
    Human
Impacts on
Ecosystems
    And … since our
         population is
       increasing at a
    breakneck pace,
  what impacts do we
 have on ecosystems
   around the world?

				
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