C O L L E G E E N V I R O N M E N T A L S C I E N C EM R S . C I R I L L O

CHAPTER 1 INTRODUCTION TO ENVIRONMENTAL SCIENCE AND THE

NATURE OF SCIENCE

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• 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

by fossil fuels (oil, gas, coal)

• Sanitation and medicines• Pesticides, fertilizers

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

Prescribed burning restores healthy forests

Engineering and technology

Energy-efficient electric car

Policy and management

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• 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