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Semester Review


Environmental Science Semester Review – PowerPoint PPT presentation

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Title: Semester Review

Environmental Science
  • Semester Review

  • Define environmental science and compare
    environmental science with ecology and
  • 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

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
  • To creatively solve environmental problems

NYC Today and 400 yrs ago
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
  • Environmental studies programs

Environmental science
  • Can help us avoid mistakes made by past
  • 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?
Environmental Science is not Environmentalism
  • Environmental science
  • Pursues knowledge about the environment and our
    interactions with it
  • Scientists try to remain objective and free from
  • Environmentalism
  • A social movement
  • Tries to protect the natural world from
    human-caused changes

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

Ecology is the Foundation of Environmental Science
  • Ecology the study of how living organisms
    interact with each other and their non-living

Fields of Study that Contribute to Environmental
  • Biology the study of living organisms
  • Chemistry the study chemicals and their
  • Physics the study of matter and energy
  • Earth Science the study of earths nonliving
  • Social Sciences the study of human populations

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
  • Oil, coal, minerals

Natural Resources
  • Renewable resources like sunlight cannot be
  • 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
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!
  • Humans have surpassed the Earths capacity to
    support us

We are using renewable resources 30 faster than
they are being replenished
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
  • 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

Ecological Footprints are not Equal
  • Not everyone benefits equally from rising
  • The ecological footprints of countries vary
  • The U.S. footprint is much greater than the
    worlds average
  • In the U.S. the richest 1
  • Have 25 of all income

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?

Sustainability and the Future of our World
  • Sustainability we must live within our planets
  • 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 Earths total wealth of
  • We are withdrawing it faster that its being
  • We must live off Earths natural interest
    (replenishable resources), not its natural capital

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

Humanitys challenge is to develop solutions that
further our quality of life while protecting and
restoring the environment.
Will we develop in a sustainable way?
This is the single most important question we
  • 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

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
  • 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

Science Asks and Answers Questions
  • It is an incremental approach to the truth
  • Scientists do not simply accept conventional
  • They judge ideas by the strength of their
  • Observational (descriptive) science information
    is gathered about organisms, systems, processes,
  • Cannot be manipulated by experiments
  • Phenomena are observed and measured
  • Used in astronomy, paleontology, taxonomy,
  • Hypothesis-driven science targeted research
  • Experiments test hypotheses using the scientific

The Scientific Method A Traditional Approach
  • Science tests ideas
  • Scientists in different fields approach problems
  • 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

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
Applications of Science
  • Technology is another application of science.
  • Energy-efficient methanol-powered fuel cell car
    from DaimlerChrysler

Figure 1.8b
Scientific Method Assumptions
  • Fixed natural laws govern how the universe works
  • All events arise from causes, and cause other
  • We can use our senses and reason to detect and
    describe natures laws

Scientific Method
  • A step-by-step method for testing ideas with
  • 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
Scientific Process
  • Peer review, publication, and debate are parts of
    the larger scientific process.

Figure 1.11
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

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

Hypotheses are Tested in Different Ways
  • Natural tests
  • Results are not neat and clean
  • Show real-world complexity
  • Answers arent black and white
  • Manipulative experiments
  • Yield the strongest evidence
  • Reveals causal relationships
  • Lots of things cant be manipulated

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

  • 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
  • May have led to the disappearance of many large
    mammal species such as ground sloths, giant
    bison, mastodons, cave bears, and saber-tooth

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

Industrial Revolution
  • There was a shift to fossil fuels as an energy
  • 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.

Thomas Malthus and human population
  • Thomas Malthus
  • 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.

Human Population Levels Throughout History
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

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