1. Environmental Science
Semester Review

2. Objectives
Define environmental science and compare environmental science with ecology and environmentalism.
List five major fields of study that contribute to environmental science.
Distinguish between a renewable resource and a non-renewable resource.
Explain the concept of sustainability and why it is a goal in environmental science.
Explain the concept of an Ecological Footprint

3. Environmental Science
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
NYC Today and 400 yrs ago

4. The Nature of Environmental Science
Environment  impacts  Humans
Its applied goal: solving environmental problems
Solutions are applications of science
An interdisciplinary field
Natural sciences: examines the natural world
Environmental science programs
Social sciences: examines values and human behavior
Environmental studies programs

5. Environmental science
Can help us avoid mistakes made by past civilizations
Human survival depends on how we interact with our environment.
Our impacts are now global.
Many great civilizations have fallen after depleting their resources.
The lesson of Easter Island: people annihilated their culture by destroying their environment. Can we act more wisely to conserve our resources?

6. Environmental Science is not Environmentalism
Pursues knowledge about the environment and our interactions with it
Scientists try to remain objective and free from bias
Environmentalism
A social movement
Tries to protect the natural world from human-caused changes

7. Goals of Environment Science
To understand and solve environmental problems
Ecosystem functions
Air Pollution
Water Pollution
Toxic Chemicals
Climate Change
Resource usage

8. Ecology is the Foundation of Environmental Science
Ecology: the study of how living organisms interact with each other and their non-living environment

9. Fields of Study that Contribute to Environmental Science
Biology: the study of living organisms
Chemistry: the study chemicals and their interactions
Physics: the study of matter and energy
Earth Science: the study of earth’s nonliving systems
Social Sciences: the study of human populations

10. We Rely on Natural Resources
Natural resources = substances and energy sources needed for survival
Renewable natural resources: can be replenished
Perpetually renewed: sunlight, wind, wave energy
Renew themselves over short periods: timber, water, soil
These can be destroyed
Nonrenewable natural resources: unavailable after depletion
Oil, coal, minerals

11. Natural Resources
Renewable resources like sunlight cannot be depleted.
Nonrenewable resources like oil CAN be depleted.
Resources like timber and clean water are renewable only if we do not overuse them.
Figure 1.1

12. Our “Ecological Footprint”
Affluence increases consumption
Ecological footprint: the environmental impact of a person or population
The area of biologically productive land + water
To supply raw resources and dispose/recycle waste
People in rich nations have much larger ecological footprints
If everyone consumed the amount of resources the U.S. does, we would need 4.5 Earths!

13. Overshoot
Humans have surpassed the Earth’s capacity to support us
We are using renewable resources 30% faster than they are being replenished

14. Population & Consumption
Population growth amplifies all human impacts
The growth rate has slowed, but we still add more than 200,000 people to the planet each day
Resource consumption has risen faster than population
Life has become more pleasant
Rising consumption also amplifies our demands on the environment
The 20 wealthiest nations have 55 times the income of the 20 poorest nations
Three times the gap that existed 40 years ago

15. Ecological Footprints are not Equal
Not everyone benefits equally from rising affluence
The ecological footprints of countries vary greatly
The U.S. footprint is much greater than the world’s average
In the U.S. the richest 1%
Have 25% of all income

16. Sustainability is the Goal!
Condition in which human needs are met without harming future generations.
We are not living sustainably today.
What needs to change?

17. Sustainability and the Future of our World
Sustainability: we must live within our planet’s means
So the Earth and its resources can sustain us and all life for the future
Sustainability involves conserving resources
Developing long-term solutions
Keeping fully functioning ecosystems
Natural capital: Earth’s total wealth of resources
We are withdrawing it faster that it’s being replenished
We must live off Earth’s natural interest (replenishable resources), not its natural capital

18. Sustainable Solutions
Sustainable development
using resources to satisfy current needs without compromising future availability of resources
Sustainability involves
Renewable energy sources
Soil conservation, high-efficiency irrigation, organic agriculture
Pollution reduction
Habitat and species protection
Recycling
Fighting global climate change
Humanity’s challenge is to develop solutions that further our quality of life while protecting and restoring the environment.

19. Will we develop in a sustainable way?
This is the single most important question we face.

20. Objectives Understand the Nature of Science
Understand how scientific inquiry and technological design, including mathematical analysis, can be used to pose questions, seek answers, and develop solutions.
Describe and Apply the Scientific Process
Describe how humanity altered the environmental
Hunter-gatherers
Agricultural revolution
Industrial revolution

21. 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
Civilization depends on science and technology
Science tries to understand the world and steer a safe course
Science is essential to sort fact from fiction
Develop solutions to the problems we face
It must be accessible and understandable to the public

22. Science Asks and Answers 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
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 research
Experiments test hypotheses using the scientific method

23. The Scientific Method: A Traditional Approach
Science 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

24. Applications of Science
Policy decisions and management practices are applications of science.
Prescribed burning, used to restore forest ecosystems altered by human suppression of fire.
Figure 1.8a

25. Applications of Science
Technology is another application of science.
Energy-efficient methanol-powered fuel cell car from DaimlerChrysler
Figure 1.8b

26. Scientific Method: Assumptions
Fixed natural laws govern how the universe works
All events arise from causes, and cause other events
We can use our senses and reason to detect and describe nature’s laws

27. Scientific Method
A step-by-step method for testing ideas with observations.
Scientists use educated guesses called hypotheses to generate predictions
hypotheses are tested experimentally.
Results may reject or support a hypothesis.
Results never prove a hypothesis, but only lend support to it by failing to reject it.
Figure 1.9

28. Scientific Process
Peer review, publication, and debate are parts of the larger scientific process.
Figure 1.11

29. Hypothesis, Theory, and Paradigm
Hypothesis = an educated guess, to be tested
Theory = a well-tested and widely accepted explanation, validated by much previous research
Paradigm = a dominant view. May shift if new results show old results or assumptions to be wrong

30. Experiments Test the Validity of a Hypothesis
Variable: a condition that can change
Independent variable: is manipulated
Dependent variable: is measured and 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 un-manipulated point of comparison
Quantitative data: uses numbers
Qualitative data: does not use numbers

31. Hypotheses are Tested in Different Ways
Manipulative experiments
Yield the strongest evidence
Reveals causal relationships
Lots of things can’t be manipulated
Natural tests
Results are not neat and clean
Show real-world complexity
Answers aren’t black and white

32. Human Impact Over Earth’s History
Wherever humans have hunted, grown food, or settled we have changed the environment.
How have those changes impacted the environment over human history?

33. Hunter-Gatherers Most of human history
Obtained food by moving around collecting plants and hunting wild animals.
Affected the environment:
Set fires to drive game during hunting
Spread plant species as they moved from place to place
May have led to the disappearance of many large mammal species such as ground sloths, giant bison, mastodons, cave bears, and saber-tooth cats

34. Agricultural Revolution
Plants and animals were domesticated and population grew
10,000 years ago
Life got easier
Settlements began forming
Impact on environment grew
Habitat destroyed
Artificial selection of domesticated crops
Farmland replaced forest
Agricultural Revolution

35. Industrial Revolution
There was a shift to fossil fuels as an energy source
Mid-1700s
Life got easier
Advances in technology
Healthcare and sanitation improved
People lived longer
People moved to cities away from farms
Increased environmental impact.

36. Thomas Malthus and human population
Population growth must be
controlled, or it will outstrip food
production.
Starvation, war, disease
Neo-Malthusians
Population growth has disastrous effects.
Paul and Anne Ehrlich, The Population Bomb (1968)
Agricultural advances have only postponed crises.

37. Human Population Levels Throughout History

38. Loss of Biodiversity
Biodiversity: the number and variety of species that live in an area
Why is loss of biodiversity a bad thing?
Higher biodiversity = healthier ecosystem
Organisms are considered a natural resource

39. 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