CHAPTER
3
Earth’s Environmental Systems
The Gulf of Mexico’s
Dead Zone
• Nutrient-rich runoff causes plankton blooms and
hypoxia—low oxygen levels—in the Gulf of Mexico.
• Hypoxia kills or displaces marine organisms, causing a
decline in the fisheries and the fishing industry.
• U.S. government and farmers debate the need to cut
down on fertilizer use.
Talk About It Do you think the distance between the source of
the nitrogen and phosphorus and the dead zones themselves
makes it difficult to manage this problem? Why or why not?
Lesson 3.1 Matter and the Environment
Water’s abundance is a primary reason there is life
on Earth.
Lesson 3.1 Matter and the Environment
Atoms and Elements
• Atoms are the basic unit
of matter.
• Nucleus: Contains
protons and neutrons
• Electrons: Move around
the nucleus
• An element is a
substance that cannot
be broken down into
other substances.
Did You Know? There are 92 elements
that occur naturally, and scientists have
created about 20 others in labs.
What are the basic units of
matter?
A. Elements
B. Atoms
C. Electrons
D. Neutrons
E. Protons
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Lesson 3.1 Matter and the Environment
Bonding
• Atoms combine by bonding:
• Covalent bonds: Electrons
are shared.
• Ionic bonds: Electrons are
transferred.
• Molecule: Two or more atoms
joined by covalent bonds
• Compound: Substance
composed of atoms of two or
more different elements
Covalent bonding
Ionic bonding
When electrons are transferred
what type of bond is it?
A. Covalent
B. Ionic
C. Molecule
D. Compound
E. Atomic
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Lesson 3.1 Matter and the Environment
Organic and Inorganic Compounds
• Organic compounds:
Consist of covalently bonded
carbon atoms and often
include other elements,
especially hydrogen
• Hydrocarbons: Organic
compounds, such as
petroleum and wood smoke,
that contain only hydrogen
and carbon
• Inorganic compounds: Lack
carbon-to-carbon bonds
Organic compounds include natural gas,
petroleum, coal, and gasoline.
Which of the following is NOT an
organic compound
A. Petroleum
B. Natural gas
C. Coal
D. Gasoline
E. Ammonia
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Lesson 3.1 Matter and the Environment
Solutions
• A mixture is a combination of elements, molecules, or
compounds that are not bonded chemically.
• Solutions are mixtures in which all ingredients are equally
distributed.
• Mixtures can be solids, liquids, or gases.
Blood, sea water, plant sap, and metal
alloys, such as brass, are all solutions.
Lesson 3.1 Matter and the Environment
Macromolecules
• Large organic compounds that are essential to life
• Proteins: Serve many functions in organisms; include C, H,
O, N, S; may help with production of tissues, store energy,
act as hormones, or serve as enzymes
• Nucleic Acids: Direct protein production; include
DNA (carries hereditary info and is responsible for passing
on traits) and RNA (copies DNA to make protein)
• Carbohydrates: Provide energy and structure;
include sugars, starch, and cellulose (C, H, O)
• Lipids: Not soluble in water; many functions;
include fats, waxes, and hormones; not a polymer
Which of the following is NOT a
macromolecule
A. Proteins
B. Nucleic Acid
C. Carbohydrates
D. Atoms
E. Lipids
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Lesson 3.1 Matter and the Environment
Water
• Water is required by all living
things for survival.
• Polar molecule: shared
electrons are not evenly
distributed
• Oxygen end is more negative
• Hydrogen bond: an oxygen
atom of a water molecule is
weakly attracted to one or two
hydrogen atoms of another
Lesson 3.1 Matter and the Environment
Water
• Hydrogen bonding gives water many unique properties:
• Cohesion
• Water sticks to itself
• Allows the transport of materials, like nutrients and waste, in plants and
animals
• Resistance to temperature change
• Water can absorb a large amount of energy with only small changes in
its temperature
• Helps stabilize aquatic ecosystems and climates in which they exist
• Ice density
• Water molecules in ice are farther apart than in liquid water
• Less dense when frozen
• Universal solvent: Ability to dissolve many other molecules
Which property of water allows it
to stick to itself?
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A. Ice density
B. Universal Solvent
C. Cohesion
D. Resistance to
temperature
E. Buoyancy
Lesson 3.1 Matter and the Environment
Acids, Bases, and pH
• The separation of water
molecules into ions causes
solutions to be acidic, basic,
or neutral.
• The pH scale measures how
acidic or basic a solution is.
• pH of 7—Neutral: Equal
concentrations of H+ and OH-
• pH below 7—Acidic: Relatively
high concentration of H+
• pH above 7—Basic: Relatively
high concentration of OH-
Lesson 3.2 Systems in Environmental Science
Positive feedback loops can help
erosion turn a fertile field to desert in
just a few years.
Dust storm, Stratford
Texas, 1930s
Lesson 3.2 Systems in Environmental Science
Interacting Systems
• Inputs into Earth’s interconnected systems include energy,
information, and matter.
• Feedback loops - regulate systems – circular process that
describes how an event is both a cause and an effect in the
same system
Negative feedback loop
• Negative feedback
loops: Result in
stabilization
of a system
• Positive feedback
loops: Result in a
system moving
to an extreme
Did You Know? Predator-prey cycles are negative feedback
loops. If prey populations rise, predator populations can rise in
response, causing prey populations to fall. Then predator
populations may decline, allowing prey populations to rise
again, and so on.
Which of following results in the
stabilization of a system?
A. Positive feedback
loop
B. Feedback Loop
C. Neutral Feedback
Loop
D. Negative
Feedback Loop
E. Feedback system
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Identify and explain if it is a
negative or positive feedback loop
• You get a rash from poison ivy. You know you
shouldn't scratch it, but it itches. So you scratch. But
scratching makes it itch more, and can even make the
rash spread to areas that didn't itch before. The more
you scratch, the more it itches.
Identify and explain if it is a
negative or positive feedback loop
• The thermostat attached to an air conditioner helps
maintain a constant temperature in your house. During
the summer, the sun heats the house and the
temperature goes up. When the temperature goes up,
the thermostat turns on the air conditioner, causing the
house to cool down. When the house is cool again, the
thermostat turns the air conditioner off.
Identify and explain if it is a
negative or positive feedback loop
• In the picture below, blood pressure has increased.
Receptors in the carotid arteries detect the change in
blood pressure and send a message to the brain. The
brain will cause the heart to beat slower and thus
decrease the blood pressure.
Identify and explain if it is a
negative or positive feedback loop
My mom had a blood clot at the age of 40. Once a
vessel is damaged, platelets start to cling to the injured
site and release chemicals that attract more platelets.
The platelets continue to pile up and release
chemicals until a clot is formed.
Identify and explain if it is a
negative or positive feedback loop
• Regulation of blood sugar in humans - When blood
sugar rises, insulin sends a signal to the liver, muscles
and other cells to store the excess glucose. Some is
stored as body fat and other is stored as glycogen in
the liver and muscles.
Identify and explain if it is a
negative or positive feedback loop
• Carbon dioxide is considered a "greenhouse gas"
since it absorbs heat that would otherwise dissipate
out into space. If there is more carbon dioxide in the
atmosphere, global temperatures are likely to
increase. It is possible that plants will respond to the
increased carbon dioxide and increased temperatures
with an increase in photosynthesis. Since carbon
dioxide is needed for photosynthesis, this could reduce
the amount of carbon dioxide in the atmosphere,
leading to cooler temperatures. Is this a positive or
negative feedback loop?
Identify and explain if it is a
negative or positive feedback loop
• Here are some examples related to ecosystems and
global climate change. Ice caps at the north and south
poles are very reflective -- the ice reflects light and
heat rather than absorbing it. If global warming occurs,
then the increase in temperature will cause polar ice to
melt, and the bare dark ground will absorb rather than
reflect heat. This additional absorption of heat will
further boost the temperature of the earth. Is this a
positive or negative feedback loop?
Lesson 3.2 Systems in Environmental Science
Spheres of Function
• Earth can be divided into spheres that are defined
according to their location and function.
Lesson 3.3 Earth’s Spheres
The movement of Earth’s plates has
formed the deepest ocean trenches
and the highest mountains.
Lesson 3.3 Earth’s Spheres
The Geosphere
• Rocks and minerals on and below Earth’s surface:
• Crust: Thin, cool, rocky outer
“skin”
• Mantle: Very hot and mostly solid
• Core: Outer core is molten metal,
inner core is solid metal
Rock formation, Ouray National Wildlife Refuge, Utah
Lesson 3.3 Earth’s Spheres
Plate Tectonics
• Crust and mantle are divided
into:
• Lithosphere: Crust and
uppermost mantle; divided into
tectonic plates
• Asthenosphere: Soft middle
mantle; heated by outer core
• Lower mantle: Solid rock
• Convection currents in the
asthenosphere move tectonic
plates.
• Collisions and separations of
the plates result in landforms.
Volcano lava
Lesson 3.3 Earth’s Spheres
Tectonic Plates
• There are three major types of plate boundary:
• Divergent
• Transform
• Convergent
Lesson 3.3 Earth’s Spheres
Divergent and Transform Plate
Boundaries
• Divergent boundaries:
Rising magma pushes
plates apart.
Divergent plate boundary
• Transform boundaries:
Plates slip and grind
alongside one another.
Transform plate boundary
Lesson 3.3 Earth’s Spheres
Convergent Plate Boundaries
• Plates collide, causing one of two things to happen:
• Subduction: One plate slides beneath another.
• Mountain-building: Both plates are uplifted.
Lesson 3.3 Earth’s Spheres
The Biosphere and Atmosphere
• Biosphere: The part of Earth in which living and
nonliving things interact
• Atmosphere: Contains the gases that organisms
need, such as oxygen; keeps Earth warm enough
to support life
Earth’s atmosphere, seen from space
Lesson 3.3 Earth’s Spheres
The Hydrosphere
• Consists of Earth’s water
Greenlaw Brook, Limestone, Maine
• Most of Earth’s water
(97.5%) is salt water.
• Only 0.5% of Earth’s
water is unfrozen fresh
water usable for drinking
or irrigation.
• Earth’s available fresh
water includes surface
water and ground water.
Did You Know? If it is depleted, groundwater
can take hundreds or even thousands of years
to recharge completely.
Lesson 3.3 Earth’s Spheres
The Water Cycle
Which of the following spheres
contains rocks and minerals
below earth’s surface?
59%
A. Biosphere
B. Crust
C. Lithosphere
D. Atmosphere
E. Geosphere
18%
18%
6%
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What type of boundary occurs
when rising magma pushes plates
apart
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A. Transform
B. Divergent
C. Convergent
D. Mountain-building
E. Subduction
What type of boundary occurs
when plates collide?
88%
A. Divergent
B. Transform
C. Convergent
D. Subduction
E. Mountain-Building
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The part of Earth in which living
and non living things interact
occurs in which sphere?
88%
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A. Hydrosphere
B. Biosphere
C. Atmosphere
D. Lithosphere
E. Geosphere
Lesson 3.4 Biogeochemical Cycles
A carbon atom in your body today may have
been part of a blade of grass last year, or a
dinosaur bone millions of years ago.
Fossilized bones in a
Colorado dig.
Lesson 3.4 Biogeochemical Cycles
Nutrient Cycling
• Matter cycles through the
environment.
• Matter can be transformed, but
cannot be created or destroyed –
Law of Conservation of Matter
• Nutrients, matter that organisms
require for life process, circulate
throughout the environment in
biogeochemical cycles.
Did You Know? Organisms require several
dozen nutrients, such as nitrogen, phosphorus,
and carbon, to survive.
Lesson 3.4 Biogeochemical Cycles
Nutrient Cycling
• Biogeochemical cycles – nutrients cycle endlessly
throughout the environment in complex cycles
• Carbon
• Phosphorus
• Nitrogen
• The water cycle also plays a part in all biogeochemical
cycles
Did You Know? Organisms require several
dozen nutrients, such as nitrogen, phosphorus,
and carbon, to survive.
Lesson 3.4 Biogeochemical Cycles
The Carbon Cycle
Lesson 3.4 Biogeochemical Cycles
The Phosphorus Cycle
Lesson 3.4 Biogeochemical Cycles
The Nitrogen Cycle
Which of following is NOT a
macronutrient
A. Carbon
B. Phosphorus
C. Hydrogen
D. Nitrogen
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Which cycle relies on bacteria?
A. Phosphorus
B. Carbon
C. Nitrogen
D. Cell Respiration
E. Photosynthesis
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