Science, Matter, Energy, and Ecosystems

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Science, Matter, Energy, and Ecosystems

• Chapter 2

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2-1 What Is Science?

• Concept 2-1 Scientists collect data and develop
  theories, models, and laws about how nature
  works.

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Science Is a Search for Order in Nature (1)

• Identify a problem
• Find out what is known about the problem
• Ask a question to be investigated
• Gather data
• Hypothesize
• Make testable predictions
• Keep testing and making observations
• Accept or reject the hypothesis

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Science Is a Search for Order in Nature (2)

• Important features of the scientific process
• Curiosity
• Skepticism
• Peer review
• Reproducibility
• Openness to new ideas

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Scientific Theories and Laws Are the Most
Important Results of Science

• Scientific theory
• Widely tested
• Supported by extensive evidence
• Accepted by most scientists in a particular area
• Scientific law, law of nature

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The Results of Science Can Be Tentative,
Reliable, or Unreliable

• Tentative science, frontier science
• Reliable science
• Unreliable science

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Science Focus The Scientific Consensus over
Global Warming

• How much has the earths atmosphere warmed during
  the last 50 years?
• How much of this warming is due to human
  activity?
• How much is the atmosphere likely to warm in the
  future?
• Will this affect climate?
• 1988 Intergovernmental Panel on Climate Change
  (IPCC)

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Environmental Science Has Some Limitations

• Particular hypotheses, theories, or laws have a
  high probability of being true while not being
  absolute
• Bias can be minimized by scientists
• Statistical methods may be used to estimate very
  large or very small numbers
• Environmental phenomena involve interacting
  variables and complex interactions
• Scientific process is limited to the natural
  world

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2-2 What Is Matter and How Can Matter Change?

• Concept 2-2A Matter consists of elements and
  compounds, which are in turn made up of atoms,
  ions, or molecules.
• Concept 2-2B When matter undergoes a physical or
  chemical change, no atoms are created or
  destroyed (the law of conservation of matter).

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Matter Consists of Elements and Compounds

• Matter
• Has mass and takes up space
• Elements
• Unique properties
• Cannot be broken down chemically into other
  substances
• Compounds
• Two or more different elements bonded together in
  fixed proportions

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Atoms Are Building Blocks of Matter

• Atomic theory
• Subatomic particles
• Protons (p) with positive charge and neutrons (0)
  with no charge in nucleus
• Negatively charged electrons (e) orbit the
  nucleus
• Mass number
• Protons plus neutrons
• Isotopes

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Ions and Molecules Are Two Other Building Blocks
of Matter (1)

• Ions
• Gain or lose electrons
• Form ionic compounds
• pH
• Measure of acidity
• H and OH-

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Ions and Molecules Are Two Other Building Blocks
of Matter (2)

• Molecule
• Two or more atoms of the same or different
  elements held together by chemical bonds
• Chemical formula

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Organic Compounds Are the Chemicals of Life

• Inorganic compounds
• Organic compounds
• Hydrocarbons and chlorinated hydrocarbons
• Simple carbohydrates
• Macromolecules complex organic molecules
• Complex carbohydrates
• Proteins
• Nucleic acids
• Lipids

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Matter Comes to Life through Genes, Chromosomes,
and Cells

• Cells fundamental units of life
• Genes sequences of nucleotides within the DNA
• Chromosomes composed of many genes

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Some Forms of Matter Are More Useful than Others

• High-quality matter
• Low-quality matter

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We Cannot Create or Destroy Matter (1)

• Law of conservation of matter
• Matter consumption
• Matter is converted from one form to another

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We Cannot Create or Destroy Matter (2)

• Physical change
• Chemical change, chemical reaction

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2-3 What is Energy and How Can It Be Changed?

• Concept 2-3A When energy is converted from one
  form to another in a physical or chemical change,
  no energy is created or destroyed (first law of
  thermodynamics).
• Concept 2-3B Whenever energy is changed from one
  form to another, we end up with lower- quality or
  less usable energy than we started with (second
  law of thermodynamics).

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Energy Comes in Many Forms

• Kinetic energy
• Heat
• Transferred by radiation, conduction, or
  convection
• Electromagnetic radiation
• Potential energy
• Stored energy
• Can be changed into kinetic energy

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Some Types of Energy Are More Useful Than Others

• High-quality energy
• Low-quality energy

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Energy Changes Are Governed by Two Scientific Laws

• First Law of Thermodynamics
• Energy input always equals energy output
• Second Law of Thermodynamics
• Energy always goes from a more useful to a less
  useful form when it changes from one form to
  another
• Energy efficiency or productivity

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2-4 What Keeps Us and Other Organisms Alive?

• Concept 2-4 Life is sustained by the flow of
  energy from the sun through the biosphere, the
  cycling of nutrients within the biosphere, and
  gravity.

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Ecology Is the Study Connections in Nature

• Ecology
• Levels of organization
• Population
• Genetic diversity
• Community
• Ecosystem
• Biosphere

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Species

• Species
• 1.75 Million species identified
• Insects make up most of the known species
• Perhaps 1014 million species not yet identified

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Science Focus Have You Thanked the Insects
Today?

• Pollinators
• Eat other insects
• Loosen and renew soil
• Reproduce rapidly
• Very resistant to extinction

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The Earths Life-Support System Has Four Major
Components

• Atmosphere
• Troposphere
• Stratosphere
• Hydrosphere
• Geosphere
• Biosphere

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Life Exists on Land and in Water

• Biomes
• Aquatic life zones
• Freshwater life zones
• Lakes and streams
• Marine life zones
• Coral reefs
• Estuaries
• Deep ocean

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Three Factors Sustain Life on Earth

• One-way flow of high-quality energy beginning
  with the sun
• Cycling of matter or nutrients
• Gravity

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What Happens to Solar Energy Reaching the Earth?

• UV, visible, and IR energy
• Radiation
• Absorbed by ozone
• Absorbed by the earth
• Reflected by the earth
• Radiated by the atmosphere as heat
• Natural greenhouse effect

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2-5 What Are the Major Components of an
Ecosystem?

• Concept 2-5 Ecosystems contain living (biotic)
  and nonliving (abiotic) components, including
  producers, which produce the nutrients they need
  consumers, which get their nutrients by consuming
  other organisms and detrivores, which recycle
  nutrients back to producers.

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Ecosystems Have Living and Nonliving Components

• Abiotic
• Water
• Air
• Nutrients
• Rocks
• Heat
• Solar energy
• Biotic
• Living and once living

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Several Abiotic Factors Can Limit Population
Growth

• Limiting factor principle
• Too much or too little of any abiotic factor can
  limit or prevent growth of a population, even if
  all other factors are at or near the optimal
  range of tolerance

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Producers and Consumers Are the Living Components
of Ecosystems (1)

• Producers, autotrophs
• Photosynthesis
• Chemosynthesis
• Consumers, heterotrophs
• Primary
• Secondary
• Third and higher level
• Decomposers

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Producers and Consumers Are the Living Components
of Ecosystems (2)

• Detritivores
• Aerobic respiration
• Anaerobic respiration, fermentation

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Energy Flow and Nutrient Cycling Sustain
Ecosystems and the Biosphere

• One-way energy flow
• Nutrient cycling of key materials

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Science Focus Many of the Worlds Most
Important Species Are Invisible to Us

• Microorganisms
• Bacteria
• Protozoa
• Fungi

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2-6 What Happens to Energy in an Ecosystem?

• Concept 2-6 As energy flows through ecosystems
  in food chains and webs, the amount of chemical
  energy available to organisms at each succeeding
  feeding level decreases.

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Energy Flows Through Ecosystems in Food Chains
and Food Webs

• Food chain
• Food web

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Usable Energy Decreases with Each Link in a Food
Chain or Web

• Biomass
• Ecological efficiency
• Pyramid of energy flow

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Some Ecosystems Produce Plant Matter Faster Than
Others Do

• Gross primary productivity (GPP)
• Net primary productivity (NPP)
• Ecosystems and life zones differ in their NPP

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2-7 What Happens to Matter in an Ecosystem?

• Concept 2-7 Matter, in the form of nutrients,
  cycles within and among ecosystems and in the
  biosphere, and human activities are altering
  these chemical cycles.

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Nutrients Cycle in the Biosphere

• Biogeochemical cycles, nutrient cycles
• Hydrologic
• Carbon
• Nitrogen
• Phosphorus
• Sulfur
• Connect past, present , and future forms of life

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Water Cycles through the Biosphere

• Natural renewal of water quality three major
  processes
• Evaporation
• Precipitation
• Transpiration
• Alteration of the hydrologic cycle by humans
• Withdrawal of large amounts of freshwater at
  rates faster than nature can replace it
• Clearing vegetation
• Increased flooding when wetlands are drained

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Carbon Cycle Depends on Photosynthesis and
Respiration

• Link between photosynthesis in producers and
  respiration in producers, consumers, and
  decomposers
• Additional CO2 added to the atmosphere
• Tree clearing
• Burning of fossil fuels

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Nitrogen Cycles through the Biosphere Bacteria
in Action (1)

• Nitrogen fixed
• Lightning
• Nitrogen-fixing bacteria
• Nitrification
• Denitrification

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Nitrogen Cycles through the Biosphere Bacteria
in Action (2)

• Human intervention in the nitrogen cycle
• Additional NO and N2O
• Destruction of forest, grasslands, and wetlands
• Add excess nitrates to bodies of water
• Remove nitrogen from topsoil

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Phosphorus Cycles through the Biosphere

• Cycles through water, the earths crust, and
  living organisms
• May be limiting factor for plant growth
• Impact of human activities
• Clearing forests
• Removing large amounts of phosphate from the
  earth to make fertilizers

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The Earths Rocks Are Recycled Very Slowly (1)

• Rock cycle
• Slowest of the earths cyclic processes

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The Earths Rocks Are Recycled Very Slowly (2)

• Three broad classes of rocks, based on formation
• 1. Igneous
• Granite
• Lava rock
• 2. Sedimentary
• Sandstone
• shale

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The Earths Rocks Are Recycled Very Slowly (3)

• Metamorphic
• Anthracite
• Slate
• Marble