Reviewing the “Tragedy of the Commons”
Practice Questions…
1. Along with population growth, which of the following is a major root of
the environmental problems caused by humans?
[A] our exploitation & consumption of resources
[B] our renewable energy initiatives
[C] our reforestation projects
[D] our sustainable development practices
2. One example of the tragedy of the commons can occur when several
farmers share the same pasture for feeding sheep. The root cause of this
tragedy is that
[A] people are bad
[B] sheep reproduce too quickly
[C] the market cannot support too many farmers
[D] the farmers believe that if I don’t use it then someone else will.
[E] The cost of the sheep is lessened by bulk purchase power
Introduction to APES
Studying the State of Our Earth
Friday, July 31st, 2015
Textbook pages 2-11
Interactions between systems
Environmental
how
Science
nature works.
how the environment effects us.
how we effect the environment.
how we can live more sustainably
without degrading our life-support
system.
Examples of systems
 Environment
 External
conditions that affect living
organisms
 Ecosystem
 Has
both biotic (living) and abiotic
(non-living) components
 Ecology
 Study
of relationships between living
organisms and their environment
(relationships between the biotic and the
abiotic)
• Humans alter natural
systems more than any
other species.
• Environmental scientists
monitor natural systems
for signs of stress by
looking at environmental
indicators.
Environmental Indicators

Environmental indicators describe the health/quality
of a system ( and the “ecosystem services” it
provides)
Table 1.2 from textbook:
Indicator
Biological diversity
Food production
“Five key global environmental indicators”
Recent Trend
Large number of extinctions, extinction rate
increasing
Per capita production possibly leveling off
CO2 concentrations and temperatures increasing
Average global
surface temperature
and CO2
concentrations
Human population
Still increasing, but growth rate slowing
Resource depletion
Many resources being depleted at rapid rates. But
human ingenuity frequently develops “new”
resources, and efficiency of resource use is
increasing in many cases
Outlook for future
Overall impact on
environmental quality
Extinctions will continue
Negative
Unclear
May affect the number of
people Earth can support
Probably will continue to
increase, at least short
term
Effects are uncertain and
varied, but probably
detrimental
Population leveling off.
Resource consumption rates
are also a factor
Unknown
Negative
Increased use of most
resources has negative
effects
Linear Growth
 Quantity
120
100
80
increases by a
constant amount per unit of
time
 1,2,3,4,5, … or 2, 4, 6, 8
 When plotted on a graph, growth yields
a fairly straight line
 sloping upward (positive growth)
 Sloping downward (negative “growth” or
decreasing amounts)
60
40
20
0
1960
1980
2000
2020
Exponential Growth
 Growth
yields a Jshaped curve
 Describes the human
population problem
that disturbs the
environment today
Population Growth
3000
2500
2000
1500
1000
500
0
1970 1980 1990 2000 2010 2020
Fun Fact: Expected to see the population boom to 8.1 billion – 9.6
billion in 2050, then stabilize between 6.8 - 10.5 billion by 2100.
“Rule of 70”
 How
long does it take to double?
Resource
use
Population size
Money in a savings account
 Rule
70
of 70
divided by the percentage growth
rate = doubling time in years
70 / 7% means it takes ten years to
double
Sustainable Development
Assumes
the right to use the earth’s
resources and earth capital to meet needs
It is our obligation to create sustainability
Environmentally sustainable societies
meets basic needs of its people in a just
and equitable manner without degrading
the natural capital that supplies these
resources.
Resources: a supply
of something
Renewable
Non-Renewable
Potentially
Renewable
Direct solar
energy
Fossil fuels
Fresh air
Winds, tides,
flowing water
Metallic minerals (iron,
copper, aluminum)
Fresh water
Nonmetallic minerals (clay,
sand, phosphates)
Fertile soil
Plants and
animals
(biodiversity)
Biodiversity
 Genetic

Variety in a genetic makeup among individuals within a
single species
 Species

Diversity
Diversity
Variety among the species or distinct types of living
organisms found in different habitats of the planet
 Ecological

Diversity
Variety of forests, deserts, grasslands, streams, lakes,
oceans, wetlands, and other communities
Environmental Degradation
Common Property Resources
Tragedy
of the Commons
Resources owned by none,
but available to all users
free of charge
May convert potentially
renewable resources into
nonrenewable resources
Practice Questions…
3. What is genetic diversity?
[A] The distinction between species
[B] The variety of environments
[C] The genetic makeup of individuals
[D] The different genes from mating
[E] Hybrid species mating
4. What is used in order to calculate the doubling of a
resource, population, money, etc.?
(A) Rule of 2
(C) Rule of 20
(B) Rule of 40
(D) Rule of 70
(E) Rule of 90
5. Which of the following events has increased the impact of
humans on the environment?
I. Advances in technology
II. Use of tools for hunting
III. Reduced human population growth
[A] I only
[B] I and II only
[D] II and III only
[E] I, II, and III
[C] I and III only
6. Which statement regarding a global environmental indicator
is not correct?
[A] Concentrations in atmospheric carbon dioxide have been rising
quite steadily since the Industrial Revolution.
[B] World grain production has increased fairly steadily since
1950, but worldwide production of grain per capita has decreased
dramatically over the same period.
[C] For the past 130 years, average global surface temperatures
have shown an overall increase that seems likely to continue.
[D] World population is expected to be between 8.1 billion and
9.6 billion by 2050.
[E] Some natural resources are available in finite amounts and are
consumed during a one-time use, whereas other finite resources
can be used multiple times through recycling.