Docstoc

Overpopulation Theory _Malthus_

Document Sample
Overpopulation Theory _Malthus_ Powered By Docstoc
					Population Theories
• Break up into groups of 4 FAST!!
• You will need discussion to fill in parts of
  this chart today.
• On the back of your chart copy down the
  Family Sizes activity.
      Family Sizes - Activity
# children you would like.

Avg. # children the class
would like.
# children your parents
had.
Avg. # children your
parents had.
# children your
grandparents had.
Avg. # children your
grandparents had.
      Family Sizes - Activity
• After reviewing the numbers what trends in
  family sizes do you notice?




• What factors might contribute to these
  trends?
   The Demographic Transition Model




This model describes the phenomenon of a country’s
high birth rates and death rates changing over time to
low birth and death rates.
       Demographic Transition Model

PHASE ONE: Pre-transition
  Birth rates and death rates are high. The natural increase
  gap is small - population grows slowly.
       Demographic Transition Model
PHASE TWO: Early Transition
 Death rate declines and birth rate remains high. The
  natural increase gap becomes larger – population
  explosion.
       Demographic Transition Model
PHASE THREE: Late Transition
 Birth rate begins to decline and the death rate remains
  low. The natural increase gap narrows – population
  explosion slows.
                                          Brazil
       Demographic Transition Model
PHASE FOUR: Post-Transition
  Birth rate and death rate tend to be low and steady. The
  natural increase gap is small – slow population growth.


                Scotland
       Demographic Transition Model
PHASE FIVE: ???
   Birth rates drop lower than death rates. The natural
  increase becomes negative – the population shrinks!
Overpopulation
    Theories
  Overpopulation
               Theories
• Malthusian theory:

  – Spoke and wrote about the dangers of
    population growth in 1798.
  – Stated that if human population grows
    faster than food supply the result is
    widespread famine, disease, and war.
  – He called these “population checks.”
• William Catton:

  – Introduced the idea of
    carrying capacity (that
    the earth can only
    sustain a certain
    population per species)
  – Believed that we are
    exceeding this capacity
    and using up the world’s
    fixed non-renewable
    resources.
• William Catton:

  – Exceeding carrying
    capacity produces a
    “phantom carrying
    capacity”, at which
    point economic and
    ecological systems
    must collapse.
• D.J. Bogue:

  – Described the theory of
    demographic
    regulation.
  – States that over time a
    population naturally
    limits its own
    population, and will
    only grow in response
    to the Earth’s ability to
    support it.
• Cornocopian:

  – Belief that humans will find
    technological innovations that will
    produce an increase in the Earth’s
    carrying capacity. (Industrial
    revolution).

				
DOCUMENT INFO
Shared By:
Categories:
Tags:
Stats:
views:46
posted:4/25/2011
language:English
pages:22