populations do these two things inevitably
1. impact population they interact with
2. alter the abiotic factors around them
for most species eco-foot print is
human population reached 1 million
around 1830
# of people born a year
3 options for future of human population
1. continues to grow exponentially then crashes
2. human population levels off
3. human growth rate slows down
human population metabolic energy
food; demanding more food; as wealth increases food demand increases
human population non-metabolic energy
manufacturing energy; increase in technology equals an increase in energy consumption
human population effect on 2nd hallmark
rise in population and rise in wealth equals rise in waste
human population effect on 3rd hallmark
humans control herbivores/how our population is controlled
human population effect on 4/5th hallmark
populations have simplified things and decreased biodiversity/ecosystem’s resilience
2 things to consider when thinking about how we can’t maintain exponential population growth
1. human ingenuity
2. healthy stewardship ethics
human population growth equation
I humans= (Khu * Phu)*A*T
description of human pop equation
influence= (envir. impact*population)*Affluence*Technology
Environ. knowledge*Stewardship ethic
3 predictions for human pop. growth by 2200
1. 14 billion by 2200
2. drop to 2 billion by 2200
3. plateau at 10 billion (most accepted)
why disparity in growth rates in the world?
modern stability
birthrate=death rate
demographic transition phase I
primitive stability; rising birthrate rising deathrate; slow growth
demographic transition phase II
epidemiologic; falling death rate; rapid growth
demographic transition phase III
fertility; falling birthrate; rapid growth
demographic transition phase IV
modern stability; low birth/death rates; slow growth
much larger _____ after D.T.
as populations increase there are
less resources per person
environment resources equation
ER= 1/p
Environment Resources equation and humans
doesn’t apply; we modify our environment to capture more resources
after progressing through DT resources are
greater per capita
characteriistics of phase IV in D.T.
highest standard of living
longest lives
healthiest employment
lowest total fertility rates
lowest misery
demographic transition is
automatic unintended consequence of industrialization
countries in stage IV
US UK Netherlands Japan Sweden Germany
reasons countries stay in phase I for >40 years
rapid population growth
shrinking economies
high unemployment
high poverty
short life expectancy
traditional model to push to get countries to IV
economic development will push them through
increase in money and development = phase IV
how is traditional model to get countries to phase IV put into action
world bank loans to developing countries for industry
projects: factories, electrification, industrial agriculture
how did traditional models for the push to Phase IV work out?
failed; debt increased faster than economy grew
consequences of rapid population growth on humans
shrinking potential per capita resource base
societal pressure to contribute to political instability (??)
consequences of rapid population growth on the environment
increasing demands on the limited natural resources and ecosystem services
increase pressure on natural ecosystems
environmental degradation
poverty population trap
argues that rapid population growth undermines economic growht
developed nations skipped poverty population trap, how?
the epidemiologic transition was slow
alternative method for addressing how to push phase ! countries to phase IV?
focus on family size; lower family size= progress to Phase IV
4 methods for the alternative model (push to phase IV)
reduce infant mortality
old age security
education system
where does money go in the alternative model?
poorest of poor
how to reduce infant mortality
aid health care system
reduce # of replacement kids
how to provide old-security
reduce family care givers
social security system
must have political stability
how to provide education system
mandatory elementary education
improved literacy
delayed economic productivity for family
rise in literacy rate correlates to
drop in fertility
what about contraceptives
contraceptives have strongest correlation
increase contraceptive use= reduced fertility rate
poverty cycle
poverty–>environmental degradation—->high fertility—>repeat
% of earth covered in water
% of earth’s water that’s fresh
% of fresh water available
4 main processes of the hydrologic cycle
gravitational flow
3 loops of hydrologic cycle
surface run-off
ground water
2 functions of hydrolic cycle
replenishes water supplies
removes impurities
fresh water supplies are under pressure from
pollution and consumption
3 benefits of good water management
1. decrease water bourne illness
2. development of undesirable land
3. industrial and domestic applications
modern irrigation/agriculture cause ___% growth of world’s food
effect of industrialization
shift away from agriculture towards industry
agriculture accounts for __% of grain
agriculture accounts for __% of meat
agriculture accounts for __% of dairy
top 3 consuming nations
americans eat ___ times as much beef
1st law of ecology
everything is related to everything
a large amount of environmental problems are due to
the direct/indirect impact on the water cycle
4 environmental issues for water cycle that are caused by humans
1. changes to the surface of the earth
2. withdrawal of water supplies
3. atmospheric pollution
4. climate change
changes to earth’s surface
removal of vegetation which leads to increase run off
changes to earth surface leads to
less filtration through groundwater
less evaporation
less ground water recharge
water withdrawal % freshwater
water withdrawal % ground freshwater
water withdrawal % surface saline
water withdrawal % ground saline
consumptive water use is
no longer available
__% of water is used for consumption
__ gallons of consumptive use in US per day
this accounts for 81% use of freshwater in US
this accounts for 81% use of freshwater in US
nonconsumptive water use is
still available
non consumptive water use includes
domestic use
power production
atmospheric pollution
air-bourne particles become nuclei water condenses around them
increased aerosols leads to increased cloud cover cooling potentially reducing evaporation and precipitation
atmospheric pollution
air-bourne particles become nuclei water condenses around them
increased aerosols leads to increased cloud cover cooling potentially reducing evaporation and precipitation
global climate change
changes water cycle
rise in greenhouse gases
surface water is
more readily available
66% of domestic use
salt water usually provides a
minority of demand except in arid and industrialized nations
recharge rate of ground water
is slower than surface water
why do rainforests soil suck
ecosystems increase til resources are in shortage
biological population
group of interbreeding individuals in an area
biotic potential
they are capable of growing when given an opportunity
environmental resistance factors
factors that cut back populations and keep them from growing
natural enemies
adverse weather
carrying capacity
maximum population an environment can support
if too many herbivores plants are eaten faster than they can grow which leads to
over grazing and degradation
3rd hallmark of sustainability
for sustainability, the size of the herbivore population is controlled so that overgrazing doesn’t occur
multiple species at each trophic level
maximizes energy flow and nutrient recycling
with multiple prey populations
predators can switch to the most common prey
with multiple predators
prey populations always experience predation pressure
competition ___ growth rates of all competitors
competition ___ growth rates of all competitors
complexity promotes
ecosystems tend towards
an equilibrium
ecosystem disturbances cause
redistribution of nutrients
organisms to be removed
types of mechanical disturbances
mowing grass
tree falling
biotic disturbances
exotic speicies become pests (rabbits in austrailia)
PA’s leading industry
recreation for PA
3rd largest state park system
threats to biodiversity
human overpopulation
invasive speicies
examples of invasive species
zebra mussels
gypsy moth
purple loosestrife
5th hallmark
for sustainability ecosystems depend on biodiversity