Honors Environmental Science
Lecture 2: Intro to Env. Sci.
What is Science?
QUESTION: Review
The term “environment” does NOT include:
a)
b)
c)
d)
Animals and plants
Oceans and rivers
Structures and urban centers
All of the above are included in this term
QUESTION: Review
The term “environment” does NOT include:
a)
b)
c)
d)
Animals and plants
Oceans and rivers
Structures and urban centers
All of the above are included in this term
The nature of science
• Science:
A systematic process for learning about the world and
testing our understanding of it
The accumulated body of knowledge arising from the
dynamic process of observation, testing, and
discovery
A way of learning about the world that tries to
eliminate sources of error when determining the
truth
The nature of science
• Civilization depends on science and technology
– Science tries to understand the world and steer a safe
course
– Vital for growth and development of new knowledge
and technologies
The nature of science
• Science is essential to sort fact from fiction:
– Attempts to eliminates subjective human elements
– Develop solutions to the problems we face
– It must be accessible and understandable to the
public
Applications of science
Policy decisions and
management practices
Restoration of forest ecosystems
altered by human suppression of fire
Developing technology
Vaccines can prevent infection and
disease
QUESTION: Review
Which of the following is correct about the term
“environmental science”?
a)
b)
c)
d)
It is a social movement to protect the environment.
It studies how the natural world works.
It usually does not include human activities.
It is a declining science.
Scientists ask and answer questions:
• It is an incremental approach to the truth
• Scientists do not simply accept conventional
wisdom
– They judge ideas by the strength of their evidence
• Scientists must be willing to change their ideas and
accepted notions in the presence of new, valid, and
contradictory data or experimental results
• Not knowing and being wrong are keystones of
science!!!
Science asks and answers questions
• Observational (descriptive) science:
– Information is gathered (observed) about organisms, systems,
processes, etc.
 Cannot be manipulated by experiments
 Phenomena are observed and measured
 Used in astronomy, paleontology, taxonomy, genomics,
epidemiology
• Hypothesis-driven science:
– Targeted research- Asks a particular question and predicts an
answer
 Experiments test hypotheses using the scientific method
 Results of experiment shape the course of the research
The scientific method: a traditional approach
• It tests ideas
– Scientists in different fields
approach problems
differently
• Assumptions:
– The universe works according
to unchanging natural laws
– Events arise from causes, and
cause other events
– We use senses and reason to
understand natural processes
The scientific process is part of a larger process
• Quality control
mechanisms guards
against faulty research
– Includes
peer review
Publication
competition for
funding
redaction of false
or dishonest work
The Scientific Method
• A scientist makes an observation and asks questions of
some phenomenon
• Hypothesis: a statement that tries to explain the question
– A starting point for more investigation
• The hypothesis generates predictions: specific statements
that can be directly tested
• The test results either support or reject the hypothesis
Experiments test the validity of a hypothesis
• Variable: ______________________________
Independent variable: ______________________
Dependent variable: _______________________
• Controlled experiment: __________________
– Except the ____________ whose effect is being tested
• Control: _______________________________
• Quantitative data: ______________________
• Qualitative data: ________________________
Experiments test the validity of a hypothesis
• Variable: a condition that can change or be
manipulated
Independent variable: ______________________
Dependent variable: ________________________
• Dependent variable: ____________________
• Controlled experiment: __________________
– Except the ____________ whose effect is being tested
• Control: _______________________________
• Quantitative data: ______________________
• Qualitative data: ________________________
Experiments test the validity of a hypothesis
• Variable: a condition that can change or be
manipulated
Independent variable: variable that is manipulated
Dependent variable: ________________________
• Controlled experiment: __________________
– Except the ____________ whose effect is being tested
• Control: _______________________________
• Quantitative data: ______________________
• Qualitative data: ________________________
Experiments test the validity of a hypothesis
• Variable: a condition that can change or be
manipulated
Independent variable: variable that is manipulated
Dependent variable: depends on the independent
variable
• Controlled experiment: __________________
– Except the ____________ whose effect is being tested
• Control: _______________________________
• Quantitative data: ______________________
• Qualitative data: ________________________
Experiments test the validity of a hypothesis
• Variable: a condition that can change or be
manipulated
Independent variable: variable that is manipulated
Dependent variable: depends on the independent
variable
• Controlled experiment: the effects of all variables
are controlled
– Except the ____________ whose effect is being tested
• Control: _______________________________
• Quantitative data: ______________________
• Qualitative data: ________________________
Experiments test the validity of a hypothesis
• Variable: a condition that can change or be
manipulated
Independent variable: variable that is manipulated
Dependent variable: depends on the independent
variable
• Controlled experiment: the effects of all variables
are controlled
– Except the independent variable whose effect is being
tested
• Control: _______________________________
• Quantitative data: ______________________
• Qualitative data: ________________________
Experiments test the validity of a hypothesis
• Variable: a condition that can change or be
manipulated
Independent variable: variable that is manipulated
Dependent variable: depends on the independent
variable
• Controlled experiment: the effects of all variables
are controlled
– Except the independent variable whose effect is being
tested
• Control: a non-manipulated point of comparison
• Quantitative data: ______________________
• Qualitative data: ________________________
Experiments test the validity of a hypothesis
• Variable: a condition that can change or be
manipulated
Independent variable: variable that is manipulated
Dependent variable: depends on the independent
variable
• Controlled experiment: the effects of all variables
are controlled
– Except the independent variable whose effect is being
tested
• Control: a non-manipulated point of comparison
• Quantitative data: uses numbers and measurements
• Qualitative data: ________________________
Experiments test the validity of a hypothesis
• Variable: a condition that can change or be
manipulated
Independent variable: variable that is manipulated
Dependent variable: depends on the independent
variable
• Controlled experiment: the effects of all variables
are controlled
– Except the independent variable whose effect is being
tested
• Control: a non-manipulated point of comparison
• Quantitative data: uses numbers and measurements
• Qualitative data: focuses on subjective, quality
related variables
QUESTION: Interpreting Graphs and Data
What happens if test
results can not reject a
hypothesis?
a) The scientist formulates
a new hypothesis.
b) It shows the test failed.
c) The hypothesis was
supported
d) The predictions may not
have been correct.
Hypotheses are tested in different ways
Manipulative experiments yield
the strongest evidence (why?)
• Can reveal causal relationships
• Lots of things can’t be
manipulated
Natural tests show real-world
complexity
• Results are not neat and clean
• Answers aren’t black and
white
Hypotheses are tested in different ways
•Experiments are better at
producing a strong body of
evidence to support
causation. Experimentation is
important to all fields of
science, though not always
possible (or ethical)
•Correlations are also
important for establishing
relationships between events.
Correlations relies on statistical
relationships to typically
establish attribution rather
than causation.
Hypotheses are tested in different ways
Bradford Hill Criteria for Causation:
 Strength of Association
Consistency of Findings (across studies)
Specificity- lack of other possibilities
Temporality- sequence of events (cause must precede
effect)
Biological gradient- more means greater effect
Plausibility- a plausible mechanism exists whereby
the cause can effect change (sometimes limited by
current knowledge
Coherence-between epidemiological and laboratory
findings
Experiment- occasionally available
Analogy- similar factors might have similar effects
QUESTION: Review
If you add various amounts of fertilizer to plants in a
laboratory, the fertilizer would be a ______
variable.
a)
b)
c)
d)
Correlative
Natural
Independent
Rare
QUESTION: Review
If you add various amounts of fertilizer to plants in a
laboratory, the fertilizer would be a ______
variable.
a)
b)
c)
d)
Correlative
Natural
Independent
Rare
Theories and paradigm shifts
• Theory: a well-tested and widely accepted explanation
– Consolidates widely-supported, related hypotheses
• Paradigm shift – a dramatic upheaval in thought
– It changes the dominant viewpoint
• Wicked problems: are complex, with no simple solution
– I.e. environmental problems
Theories and paradigm shifts
• Paradigm shift – changes in how one sees
information. New Paradigms emerge that are
different and better.
Examples:
Ptolemaic to Copernican
Cosmology
Spontaneous generation
to Biogenesis
Continental Drift to Plate
tectonics
Science and the Environment
• Environmental Science deals with many complex systems
to determine relationships and establish patterns
 Food production
 Pollution
 Biodiversity
 Energy
 Climate
 Solutions!
We face challenges in agriculture
• Technology expanded food production
– Leading to increased population and consumption
• Agriculture is one of humanity’s greatest
achievements, but it can come at an enormous
environmental cost
– Nearly half of the land surface is used for agriculture
– Chemical fertilizers and pesticides pollute and change
natural systems
– Erosion, climate change and poor management destroy
millions of acres each year
Humans have changed the Earth’s
landscape
Agriculture, urban sprawl, and other land uses have
substantially affected most of the landscape of all nations
We face challenges in pollution
• Waste products and artificial chemicals
– Are used in farms, industries, and households
– Contaminate land, water and air
– Kill millions of people
• Humans are affecting the Earth’s climate
–
–
–
–
Melting glaciers
Rising sea levels
Impacted wildlife, forests, health and crops
Changed rainfall and increased storms
Since the Industrial Revolution, atmospheric carbon dioxide concentrations have
risen by 39%, to the highest level in 800,000 years
We face challenges in biodiversity
• Biodiversity: the
cumulative number and
diversity of living things
• Human actions have driven
many species extinct
– Biodiversity is declining
dramatically
– We are setting in motion a
mass extinction event
Biodiversity loss may be our biggest
problem; once a species is extinct, it is
gone forever
The Millennium Ecosystem
Assessment
• The most comprehensive scientific assessment
of the condition of the world’s ecological
systems
• In 2005, 2000 of the world’s leading scientists
from 100 nations reported :
–
–
–
–
Humans have drastically altered ecosystems
These changes have contributed to human wellbeing and economic development, but at a cost
Environmental degradation could get much worse
Degradation can be reversed, but it requires work
Our energy choices will affect our
future
• The lives we live today are due to fossil fuels
–
–
–
–
Machines
Chemicals
Transportation
Products
• Fossil fuels are a one-time bonanza
– Supplies will certainly decline
We have used up ½ of the world’s oil supplies; how
will we handle this imminent fossil fuel shortage?
Sustainable solutions abound
We must develop solutions that protect both our
quality of life and the environment
•
•
•
•
•
•
Renewable energy and efficiency
Organic agriculture
Legislation and technology to reduce pollution
Protect species and their habitat
Recycling, decreasing waste
Decrease greenhouse gas emissions
Are things getting better or worse?
• Many people think environmental conditions are
better
– Cornucopians: human ingenuity will solve any problem
• Some think things are much worse
– Cassandras: predict doom and disaster
• How can you decide who is correct?
– Are the impacts limited to humans, or are other organisms
or systems involved?
– Are the proponents thinking in the long or short term?
– Are they considering all costs and benefits?
Sustainable development
• Involves environmental protection, economic
well-being and social equity
• It does not threaten economic and social needs
– Humans cannot exist without an intact, functioning
ecosystem
• Sustainable development:
– The use of resources to satisfy current needs
– Without compromising future availability of resources
Sustainable development
• The poor suffer the most from environmental
degradation
• Development: purposeful changes to improve the
quality of life
• Sustainable development: resources satisfy current
needs
–
–
–
–
Without compromising future availability of resources
It is not ever increasing economic gain
It values and prioritizes environmental protection
Human-made capital cannot substitute for natural capital
Will we develop in a sustainable way?
• The triple bottom line:
sustainable solutions that
meet
– Environmental protection
– Economic goals
– Social equity
• Humans must apply
knowledge from the sciences
to
– Limit environmental impacts
– Maintain functioning
environmental systems
We must make an ethical commitment to current and future generations
Conclusion
• Environmental science helps us understand our
relationship with the environment
– It informs our attempts to solve and prevent problems
• Identifying a problem is the first step in solving it
• Solving environmental problems can move us
towards health, longevity, peace and prosperity
– Environmental science can help us find balanced
solutions to environmental challenges
QUESTION: Weighing the Issues
Do you think it is ethical for the United States to
have the largest ecological footprint in the
world?
a) Yes, because we find the most new technologies
and resources.
b) Yes, because the footprint of the United States is
not really that large.
c) Definitely not; people in the United States need to
reduce their footprint.
d) It does not matter; it’s not that important.