CHAPTER 1 INTRODUCTION TO
ENVIRONMENTAL SCIENCE AND THE
NATURE OF SCIENCE
COLLEGE ENVIRONMENTAL SCIENCE
MRS. CIRILLO
OUR ISLAND, EARTH
• The Earth may seem enormous to us
• But Earth and its systems are finite and limited
• We can change Earth and damage its systems
• Environment: all the living and nonliving things
around us
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Continents, oceans, clouds, ice caps
Animals, plants, forests, farms, etc.
Structures, urban centers, living spaces
Social relationships and institutions
PEOPLE EXIST WITHIN THE
ENVIRONMENT
• Humans depend on a healthy, functioning planet
• The fundamental insights of environmental science:
• We are part of the natural world, but we can also change it
• Our interactions with its other parts matter a great deal
• We depend completely on the environment for survival
• Increased health, longer lives, wealth, mobility, leisure
• But natural systems have been degraded by pollution,
soil erosion, species extinction, etc.
• Environmental changes threaten our long-term well-being and
survival
ENVIRONMENTAL SCIENCE EXPLORES
OUR INTERACTIONS WITH THE
WORLD
• Environmental science is the study of:
• How the natural world works
• How the environment affects humans and vice versa
• We need to understand our interactions with the
environment
• To creatively solve environmental problems
• Global conditions are rapidly changing
• We are also rapidly gaining knowledge
• We still have the opportunity to solve problems
WE RELY ON NATURAL RESOURCES
• Natural resources: substances and energy sources
we need for survival
• Renewable natural resources: replenished over
short periods
• Perpetually renewed: sunlight, wind, wave energy
• Renewed over short periods and can be depleted:
timber, water, soil
• Nonrenewable natural resources: unavailable after
depletion
• Oil, coal, minerals
WE RELY ON ECOSYSTEM
SERVICES
• Natural resources are “goods” produced by nature
• Earth’s natural resources provide “services” to us
• Ecosystem services: arise from the normal functioning of
natural services and allow us to survive
• Purify air and water, cycle nutrients, regulate climate
• Pollinate plants, receive and recycle wastes
• We degrade ecosystem services by depleting
resources, destroying habitat, generating pollution
• Increased human affluence and population have intensified
degradation
HUMAN POPULATION GROWTH
AMPLIFIES IMPACTS
• There are now over 7 billion humans
• Agricultural revolution: 10,000 years ago
• Growing crops and livestock led to sedentary lives
• Stable food supplies increased survival and children
• Industrial revolution: mid 1700s
• Urbanized society powered
fossil fuels
coal)
• Sanitation and medicines
• Pesticides, fertilizers
by
(oil, gas,
THE NATURE OF SCIENCE
• Science: a systematic process for learning about the
world and testing our understanding of it
• The body of knowledge arising from the dynamic process of
questioning, observation, testing, discovery
• Knowledge gained from science can solve society’s
needs
• Develop technology
• Inform policy and management decisions
• Scientists are motivated to:
• Develop useful applications
• Understand how the world works
APPLICATIONS OF SCIENCE
Engineering and technology
Energy-efficient electric car
Policy and management
Prescribed burning restores
healthy forests
SCIENCE TESTS IDEAS BY EXAMINING
EVIDENCE
• Science asks and answers questions
• Scientists do not simply accept conventional wisdom
• They judge ideas by the strength of their evidence
• Observational (descriptive) science: information is
gathered about organisms, systems, processes, etc.
• Cannot be manipulated by experiments
• Phenomena are observed and measured
• Used in astronomy, paleontology, taxonomy, genomics
• Hypothesis-driven science: targeted, structured
research
• Experiments test hypotheses using the scientific method
THE SCIENTIFIC METHOD: A
TRADITIONAL APPROACH
• It tests ideas with observations
• A scientist makes an
observation and asks
questions about some
phenomenon
• Hypothesis: a statement that
tries to answer the question
• The hypothesis generates
predictions: specific statements
that can be directly tested
THE SCIENTIFIC METHOD TESTS
HYPOTHESES
• Experiment: tests the validity
of a prediction or hypothesis
• Variables: conditions that
can change or be
manipulated
• The data (information) are
analyzed and interpreted
• By statistical tests
• The experiment either
supports or rejects the
hypothesis
EXPERIMENTS MANIPULATE
VARIABLES
• Independent variable: can be 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: an unmanipulated point of comparison
• Treatment: a manipulated point of comparison
• Quantitative data: information expressed by numbers
• Qualitative Data: information that describes something
HYPOTHESES ARE TESTED IN
DIFFERENT WAYS
• Manipulative experiments: reveal causal relationships
• The independent variable is manipulated
• Yields the strongest evidence
• Long-term, large-scale processes can’t be manipulated
• Natural tests: search for correlations among variables
• Compare how dependent variables are expressed in
different contexts
• Weaker evidence, but shows real-world complexity
• Results are not neat-and-clean, or black-and-white
• Addresses immense-scale questions (i.e., ecosystems)
THE SCIENTIFIC PROCESS: PART OF
THE SCIENTIFIC COMMUNITY
• Peer review: other
scientists judge the work
• Conferences: scientists
interact with others
• Grants and funding:
from private or
government sources
• Intense competition
• Repeatability: others
try to reproduce
the results
THEORIES AND PARADIGM SHIFTS
• Theory: a well-tested and widely accepted explanation
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Extensively validated by great amounts of research
Consolidates widely supported, related hypotheses
It is not “just a theory” (speculation)
Example: Darwin’s theory of evolution by natural selection
• With more data, scientific interpretations can change
• Paradigm shift: a new dominant view replaces the old
• Example: Earth, not the sun, is the center of the universe
• Example: plate tectonics move continents