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Chapter 1
Studying the State of Our Earth
Pfiesteria Cell
Environmental Science.. Controversial
and Related to Humans!
Neuse River Fish Killer
• 1991 in North Carolina 1 billion fish died.
• Pfiesterisa, a free living aquatic organism
identified as the cause.
• Emits a toxin.
• 24 different life stages…usually harmless.
• Large influxes of nutrients to blame.
• Not proven until 16yrs later!
Our World and How We Influence It
Environment: the sum of all the conditions
surrounding us that influence life.
Environmental Science: field that looks at
interactions among human systems and those
found in nature.
System: any set of interacting components that
influence one another.
The study of environmental science uses
knowledge from many disciplines.
Humans Alter Natural Systems
• Environmental Scientist study ecosystems
including both the biotic and abiotic factors.
Abiotic: Non-living.
Biotic: Living.
• Humans manipulate the environment more than
any other species (2.5 myo).
• We have had the biggest impact the last 10,00020,000 yrs.
Los Angeles in 1880 with less than 6000 people.
Los Angeles in 2009 with 3.8 million people.
Monitoring Natural Systems
Environmental Indicators: Used to describe the
health and quality of natural systems. Help us
analyze the health of the planet .
Examples: human population, ecological footprint,
extinction rate, water quality, habitat loss, etc.
Sustainability: Living on Earth in a way that allows
us to use its resources without depriving future
generations of those resources.
5 Global Scale Environmental
Indicators
1. Biodiversity
a. Genetic Diversity
b. Species Diversity
c. Ecosystem Diversity
• 2 million species identified.
Speciation: making a new species(1-3 new/yr).
Background Extinction Rate: average rate in which
a species goes extinct (1 species per million/yr).
• Scientists estimate that more than 10,000
species are currently going extinct each year.
• Human intervention has saved some species.
Species Diversity
American Bison
Peregrine Falcon
Snow Leopard
West Indian Manatee
2. Food Production
• Ability to grow food and nourish the human
population.
• Has increased since the 1950s due to genetic
engineering, fertilization, and expanded
irrigation.
• Worldwide production of grain per person,
also called per capita has leveled off.
• Grain production is not keeping up with
population growth.
Try This: calculate the approximate percent
change in world grain production per person
between 1950 and 2000.
3. Average Global Surface Temps and
Carbon Dioxide Concentrations
• The greenhouse gas (CO2) helps to maintain a
constant temp on Earth.
• Over the last 2 centuries the concentration of
CO2 has increased.
• Increase is anthropogenic- derived from human
activities.
4. Human Population
• Currently 7.2 billion and growing.
• Places demands on the natural environment.
• Over 1 million additional people every five
days!
Kolkata, India
5. Resource Depletion
• Resources are becoming depleted.
• Extracting resources negatively effect the
environment.
• Non-renewable resources include coal, oil,
and uranium (finite).
• Al and Cu are finite but can be recycled.
• Consumption is directly related to
development.
• 20% of the global pop lives in developed
nations but uses most of the worlds
resources.
Humans Need Sustainable Practices
• Easter Island- lets learn from it!!
In order to live sustainably :
1. Environmental systems must not be
damaged beyond control.
2. Renewable resources must not be depleted
faster than they can regenerate.
3. Nonrenewable resources must be used
sparingly.
Ecological Footprint
Ecological footprint is a measure of how much
that a person consumes, expressed in area of
land. The total amount of land required to
support a person’s lifestyle.
Science as a Process
Scientific Method (controlled & natural
experiments)
1.
2.
3.
4.
5.
Observations and Questions
Forming Hypothesis
Collecting Data
Interpreting Results
Disseminate Findings
a. Theory: repeatedly tested and accepted.
b. Natural Law: no known exceptions,
withstood rigorous testing.
Natural Experiment: Mount St. Helens preeruption forest area.
The same location post-eruption in 1982.
The same location in 2009 showing forest
re-growth.
Environmental Science and Unique
Challenges
• Lack of Baseline Data: no “control planet”.
• Subjectivity: Our choices involve personal
opinions and value judgments.
• Interactions: Results of one system may not work
for another.
• Human Well Being: When basic needs are not
being met, natural environment is less of a
concern.