Download Humans and Population Ecology

Humans and
Population Ecology
Demography: the field
of collecting, compiling,
and presenting
information about human
populations
Demographers believe that by 2100 our J-curve of
exponential growth could level off to more of an “S” shape.
Demographers have difficulty categorizing the human
population:
We have characteristics of weedy
species that move from place to place
quickly and that grow exponentially.
BUT we also have characteristics
of species that have long life
spans, higher parental care and
fewer offspring (elephants).
We act both as local populations, with
population characteristics such as family
size and life expectancy……
And as part of a larger global whole.
How have humans managed to become such a dominant part
of Earth?
1. Neolithic Revolution: Evolution from hunter-gathers to
practicing agriculture!
Agriculture allows
permanent settlements
and the specialization of
labor (more incentive and
potential for technology)
2. Industrial Revolution: the use of fossil fuels! First coal,
then oil and gas.
This energy was used by humans to do work that we would
never have been able to do: move large objects/quantities,
produce more food, etc.
3. Medical Revolution: Vaccinations, water and sewage
treatment, improvements in healthcare!
Better sanitation, medicine, and nutrition brought
reductions in mortality – while birth rates remained high!
4. Green Revolution: Again agriculture!
Development of pesticides, increase in irrigation and
fertilizer use/technology = industrialized agriculture!
So do Humans have a Carrying Capacity??
Review - Carrying capacity: the max. population of a given
species that an ecosystem can support without being
degraded or destroyed in the long run.
Some argue we will never have a carrying capacity, that we
will continue our ingenuity and grow – even into space!
Others disagree and say that we will hit a carrying
capacity – even though we have removed limited factors
(seasonal hunting, energy requirements) – our newest
factor is pollution!
In 2004, scientists identified a number of limiting factors
for humans:
- Water availability
- Energy
- Forest products
- Non-renewable resources
- Available land for food production
These scientists concluded that our carrying capacity
would be 7.7 billion. (We are currently at 7.3 billion)
Population and Consumption
The World Bank divides the countries of the world into
three main economic categories:
1. High-income, highly developed, industrialized (USA,
Canada, Japan, Korea, Western Europe etc.)
2. Middle-income, moderately developed (Latin America,
North and South Africa, China, Eastern Europe, etc.)
3. Low-income, developing countries (India, Southern Asia,
Eastern, Western, Central Africa)
Population Growth in Rich and Poor Nations
Sweden: growth rate of 0.1% = adding less than 1 million to
the world population in a year
Indonesia and Burkina Faso: growth rate of 1.5% = adding
75 million in a year
More than 98% of world population growth is occurring in
the developing countries!
This issue is taken seriously! The UN held a conference in
1994 to discuss the links between poverty, population
growth and development.
There, they agreed that:
1. Women’s rights to health care, education, and
employment were foundational to achieving slower
population growth
2. Development must be linked to a reduction in poverty
3. The existing poverty in the developing countries was an
affront to human dignity that should not be tolerated
4. Both poverty and development were a threat to the
health of the environment and that only sustainable
development would prevent a future of unprecedented
biological and human impoverishment