The Global Environment
Midterm Exam 1 Part B
Spring, 2022
Exam Front Page Instructions:
The following exam will test your ability to recall basic concepts and definitions as well as integrate the body of knowledge that you have accumulated during the first part of the semester.
The exam will consist of two (2) sections. SECTION A has 6 short answer questions. It will be worth 5 points each. These will be 4-5 sentence answers (about 50 words) or diagrams where necessary. SECTION B has 1 long essay question. These will be about a page long detailed answers (100 -150 words). It will be worth 20 points. Word limit is just an approximation for the answers. As long as the answer satisfies the question asked, you are good to go.
You have between (Feb 22nd- Feb 26th 11:30 pm) to complete the exam. Please feel free to ask questions if you do not understand any aspect of the exam. You can submit your answers as a word document or a pdf in the allotted folder by the due date. If you are using information from the web, mention their sources.
Section A: Short Answer and Diagrams (30 points):
Answer the following questions to the best of your ability. Be sure to provide specific details when answering questions and drawing diagrams.
1. What are five things you would do to cut waste in human societies by following principle of sustainability?
2. How can the extinction of bird species create a ripple effect through the rest of the ecosystem?
3. Use the second law of thermodynamics to explain why we cannot recycle the high-quality chemical energy stored in gasoline.
4. If anthropogenic processes introduce increasing amounts of atmospheric nitrogen to the biosphere and hydrosphere, where does that nitrogen go?
5. What can city planners do to make residents less dependent on cars, apart from providing public transit options?
6. How is it possible that countries with the same population size and affluence could differ in their environmental impacts?
Section B: Long Essay Question (20 points):
Be sure to be specific and provide details for your essay.
1. The “biological capacity” is the ability of the natural world to replenish its renewable resources and absorb the resulting waste products and pollution. Exceeding the biological capacity creates an “ecological deficit.” Discuss the potential future implications for the earth resulting from the fact that we are currently exceeding the earth’s biological capacity by about 50 percent.
The Environment and Sustainability
u Biotic factors
u (e.g. plants, animals, farms,
forests)
u Abiotic factors
u (include sunlight, air, water,
earth)
u Four spheres- life support
systems
u Environmental science studies
connections in nature
u How the earth works and has survived and
thrived
u How humans interact with the environment
u How we can live more sustainably
u Ecology
u Branch of biology focusing on interaction of
living things with their environment
u Ecosystem
Three Scientific Principles of
Sustainability
u Dependence on solar energy
u Biodiversity
u Chemical (nutrient) cycling
u Natural
capital
keeps humans and other species alive
and supports economies
u Natural
resources
: useful materials and energy in nature
u May be inexhaustible, renewable, or nonrenewable
(exhaustible)
u Ecosystem services
u Processes provided by healthy ecosystems
Key Components of Sustainability
u Natural resource examples
u Inexhaustible:
u A resource that never runs out or gets
depleted.
u Renewable:
u A resource that can be used
repeatedly and is replaced naturally.
u Nonrenewable:
u A resource that is not replenished with
the speed at which it is consumed.
Key Components of Sustainability
u Nutrient cycling is a vital
ecosystem service
u Human activities can degrade
natural capital
u Using renewable resources too
fast
u Overloading air, water, and
soil with wastes and pollutants
u Humans must provide solutions
to environmental problems
Three Additional
Principles of
Sustainability
u Full-cost pricing
u Win-win solutions
u A responsibility to future
generations
Countries Differ in Their Resource
Use and Environmental Impact
u More-developed countries
u Industrialized nations with high
average income per person
u 17% of the world’s population
u Use 70% of world’s natural resources
u Less-developed countries
u 83% of the world’s population
u Use about 30% of world’s natural
resources
u Many people have a better quality of life
u Have developed useful materials and products
u Life spans have increased
u Food supply is more abundant
u Exposure to toxic chemicals is more avoidable
u Humans have protected some endangered species and
ecosystems:
u Taken steps to restore cleared lands
u Businesses and governments work toward improving
environmental quality
u Environmental degradation
u Wasting, depleting, and degrading
u Human activities directly affect 83% of
earth’s land surface
u Urban development, crop and
energy production, mining, timber
cutting, and more
u Species are becoming extinct 100
times faster than in prehuman times
Degrading Commonly Shared Renewable
Resources: The Tragedy of the Commons
u Open-access resources
u Atmosphere, ocean and its fishes,
grasslands, forests, streams, and aquifers
u Cumulative effect of many people
exploiting a shared resource can degrade,
exhaust, or ruin it
u Solution: use resource at a rate well below
its sustainable yield
u Mutual agreement, or access regulation
u Ecological footprint
u The impact a person or community has on the environment
u Sustainability measure that relates to the Earth’s biocapacity
u The largest components: air pollution, climate change, and
ocean acidification due to burning fossil fuels for energy
u Ecological deficit
u Footprint is larger than biological capacity for replenishment
Our Growing Ecological Footprints
u Simple environmental impact model developed in the
1970s
u I = P x A x T
u I = Environmental impact
u P = Population
u A = Affluence
u T = Technology
u Some technologies are beneficial, some harmful
Cultural Changes Can
Increase or Shrink Our
Ecological Footprints
u Humans were hunter gatherers 10,000 years
ago
u Three major cultural events
u Agricultural revolution
u Industrial–medical revolution
u Information–globalization revolution
u Current need for a sustainability revolution
What Causes Environmental
Problems?
u Basic causes of environmental problems
u Population growth
u Unsustainable resource use
u Omission of harmful environmental costs in market
pricing of goods and services
u Increasing isolation from nature
u Competing environmental worldviews
Human Population is Growing at a
Rapid Rate
u Human population has grown
exponentially
u Current population: 7.9 billion
people
u By 2050, population could reach 9.8
billion
u We don’t know how many people
the earth can support indefinitely
Affluence and Unstainable
Resource Use
u Affluence results in increased resource consumption per
person
u Increases environmental degradation, wastes, and
pollution
u Positive aspects of affluence
u Better and widespread education
uIncreased awareness of environmental issues
u Money available to develop technologies with
beneficial environmental impacts
Exclusion of Harmful Environmental and
Health Costs
u Companies do not pay the environmental cost of
resource use
u Goods and services do not include the harmful
environmental costs
u Consumers lack information
u Companies receive tax breaks and subsidies
u Some subsidies encourage depletion of natural
capital
u Increasing populations in urban areas
u Lack of contact with nature
u Benefits of outdoor activities
u Better health
u Reduced stress
u Improved mental capabilities
u Increased imagination and creativity
u Sense of connection with the earth
Environmental worldview
Set of assumptions and values
Environmental ethics
Why should we care about the
environment?
Do we have an obligation to protect
other species against extinction caused
by human actions?
Should every person be entitled to equal
protection from environmental hazards?
Differing Environmental Views
Human-centered
environmental
worldview
Life-centered Earth-centered
What Is an
Environmentally
Sustainable Society?
u Living sustainably
u Live off the Earth’s
natural income
without depleting
or degrading the
natural capital that
supplies it
Learn from nature Protect natural capital
Do not waste
resources
Recycle and reuse
nonrenewable
resources
Use renewable
resources at a rate
slower than nature
can replenish them
We Can Live More Sustainably
INCORPORATE HARMFUL HEALTH
AND ENVIRONMENTAL IMPACTS IN
MARKET PRICES
PREVENT FUTURE ECOLOGICAL
DAMAGE AND REPAIR PAST
DAMAGE
FIND WIN–WIN SOLUTIONS TO
ENVIRONMENTAL PROBLEMS
ACCEPT RESPONSIBILITY TO PASS
THE EARTH ON TO FUTURE
GENERATIONS IN A CONDITION AS
GOOD AS OR BETTER THAN WHAT
WE INHERITED
What is an Environment?
Environmental Science
Key Components of Sustainability
Key Components of Sustainability
Key Components of Sustainability
Humans Protecting the Environment
We Are Living Unsustainably
Our Growing Ecological Footprints
IPAT – Another Environmental Impact Model
Isolation from Nature
Differing Environmental Views
Differing Environmental Views
We Can Live More Sustainably
We Can Live More Sustainably
SCIENCE, MATTER, ENERGY, AND
SYSTEMS
WHAT IS SCIENCE?
Science is:
• A field of study focused on discovering how nature works
– happens at a variety of scales
• Using that knowledge to describe what is likely to happen
in nature
• Based on the assumption that events in the natural world
follow orderly cause-and-effect patterns
• Patterns can be understood through observations (by use
of our senses and with instruments that expand our
senses), measurements, and experimentation
SCIENTISTS:
• Identify a problem for study
• Gather relevant
data
• Propose a hypothesis that explains the
data
• Gather data to test the hypothesis
• Modify the hypothesis as needed
The process is known as the scientific method
HYPOTHESES
What is a “hypothesis”?
• A “hypothesis” is an idea or explanation that is tested through study and
experimentation.
• Examples:
• Problem: The amount of light in the room effects test scores of the students.
Hypothesis: If we increase the amount of light during studying, student’s performance on test
scores will decrease.
• Problem: Too many deer found in residential areas.
Hypothesis: Deer prefer to stay closer to human settlements.
SCIENTISTS
•
modify, or revise, the hypothesis as needed.
• Scientists share their results
SCIENTIFIC THEORIES AND LAWS: THE MOST
IMPORTANT AND CERTAIN RESULTS OF SCIENCE
• Scientific theory
• Widely tested and supported by evidence
• Scientific law or law of nature
• Well-tested, widely accepted description of what happens repeatedly
and in the same way in nature
WHAT IS MATTER?
• Matter is anything that has mass* and takes
up space.
• It exists in three physical states – solid, liquid, and
gas.
• *Mass=the constant amount of matter/material in
something. Often measured in g or kg. (NOT the
same as weight, which depends on gravity)
• Exists in three physical states: solid, liquid, or gas
MATTER CONSISTS OF ELEMENTS AND
COMPOUNDS
• Two chemical forms: elements and
compounds
• Elements
• Have unique properties
• Cannot be broken down chemically
into other substances
• Known elements arranged in a chart called
periodic table of the elements
MATTER CONSISTS OF ELEMENTS AND
COMPOUNDS
• Most matter consists of Compounds
• Two or more different elements held together in fixed proportions
• Example = H20 (hydrogen and oxygen)
ELEMENTS AND COMPOUNDS ARE MADE OF
ATOMS, MOLECULES, AND IONS
• Atomic theory
• All elements are made of atoms
• Atom is the smallest unit of matter into which an element can be divided
and still have distinct chemical properties
• Subatomic particles
• Nucleus of the atom
• Protons have positive charge
• Neutrons have no charge
• Negatively charged electrons orbit the nucleus
ELEMENTS AND COMPOUNDS ARE MADE OF
ATOMS, MOLECULES, AND IONS
• Each element has a unique atomic number
• Same as number of protons in nucleus
• Example: Carbon (C): 6 protons in its nucleus and an atomic
number of 6
• Example: Uranium (U): 92 protons, atomic number of 92
• Most of an atom’s mass is in its nucleus
• Electrons have very little mass compared to protons and
neutrons
ELEMENTS AND COMPOUNDS ARE MADE OF
ATOMS, MOLECULES, AND IONS
• Mass number
• Number of protons plus neutrons in nucleus
• Example: Carbon atom has 6 protons and 6 neutrons in its nucleus – its mass
number is 12.
• Example: Uranium atom has 92 protons and 143 neutrons – its mass number
of 235.
• Isotope
• Form of an element with same atomic number but different mass number
• Each atom of an element has the same number of protons in its nucleus
• The number of neutrons in an element’s nucleus can change
• Therefore, the mass numbers can also change
ELEMENTS AND COMPOUNDS ARE MADE OF
ATOMS, MOLECULES, AND IONS
• Molecule
• Combination of two or more atoms of same or
different elements
• Held together by chemical bonds
• Molecules are basic building blocks of many
compounds.
• Examples – water, hydrogen gas, and methane
ELEMENTS AND COMPOUNDS ARE MADE OF ATOMS,
MOLECULES, AND IONS
• Ions
• An atom or a group of atoms (a molecule) with
one or more net positive (+) or negative (−)
electrical charges from losing or gaining
negatively charged electrons
• Ions are attracted to other ions with opposite
electronic charges (+ to -, and – to +), which
leads to ionic bonding and the creation of ionic
compounds.
• Example: salt (sodium (Na+) chloride (Cl-))
ELEMENTS AND COMPOUNDS ARE MADE OF
ATOMS, MOLECULES, AND IONS
• Acidity
• Measure of comparative amounts of hydrogen ions (H+) and hydroxide
ions (OH–) in a volume of water solution
• Measured with pH
• Neutral solution has pH equal to 7
• Acidic solution has pH < 7 (more hydrogen ions than hydroxide ions)
• Basic solution has pH > 7 (more hydroxide ions than hydrogen ions)
ORGANIC COMPOUNDS ARE THE
CHEMICALS OF LIFE
• Organic compounds
• Contain at least two carbon atoms
• Exception: methane (CH4)
• Types
• Hydrocarbons
• Simple carbohydrates
• Macromolecules: complex organic molecules
• Complex carbohydrates, proteins, nucleic acids,
and lipids
MATTER COMES TO LIFE
THROUGH CELLS, GENES,
AND CHROMOSOMES
• Cells
• Fundamental units of life
• All organisms have one or more cells
• Genes
• Sequences of nucleotides within DNA
• Instructions called genetic information
• Create inheritable traits
• Chromosomes: composed of many genes
MATTER CAN CHANGE
• Physical change
– No change in chemical composition
– Example: crushing a bottle,
chopping wood, and melting ice
• Chemical change
– Change in chemical composition
– Example: Carbon dioxide
LAW OF CONSERVATION OF MATTER
• We can change elements and compounds from one physical or chemical form
to another
• We cannot create or destroy atoms
WHAT IS ENERGY AND WHAT ARE ITS FORMS
• Energy: ability to do work
• Kinetic energy
• Energy of movement
• Electromagnetic radiation
• Thermal energy
• Potential energy
ENERGY COMES IN MANY FORMS
• Kinetic energy is matter in motion.
• Energy of movement
• Examples: running water, a ball rolling down a hill, electrons flowing through a wire
(electricity), light, and a mass of air moving (wind)
ENERGY COMES IN MANY FORMS
• Kinetic energy is matter in motion.
• Electromagnetic radiation is energy that travels in the form of
waves.
• Example: visible light and the spectrum of electromagnetic radiation
from the sun
• Light is made of photons which are produced when atoms heat
up.
• Light travels in waves
• Light is the only form of energy visible to the human eye.
ENERGY COMES IN MANY FORMS
• Kinetic energy is matter in motion.
• Heat/Thermal energy is the total kinetic energy of all moving atoms, ions, or molecules in
an object, a body of water, or a volume of gas such as the atmosphere.
• If the atoms, ions, or molecules in a sample of matter move faster, the matter will
become warmer.
• When two objects at different temperatures make contact with each another, heat
flows from the warmer object to the cooler object.
• Heat is transferred through radiation, conduction, and convection.
ENERGY COMES IN MANY FORMS
• Radiation is the transfer of heat energy through space by
electromagnetic radiation in the form of infrared radiation.
• Heat from the sun reaches the earth
• Heat from a fireplace transfers to the surrounding air
• Conduction is the transfer of heat from one solid substance
to a cooler one when they are in physical contact. Energy
moves from hot to cold.
• Touching a hot object
• Electric stove burner heats a pan
• Convection is the transfer of heat energy within liquids
or gases when warmer areas of the liquid or gas rise to
cooler areas and cooler liquid or gas takes its place.
ENERGY COMES IN MANY FORMS
• Potential energy
• Stored energy is potentially available for use.
• Examples: a spring, carbon in coal, and water behind a dam
• Can be changed into kinetic energy
WHAT IS ENERGY AND WHAT HAPPENS WHEN IT
UNDERGOES CHANGE?
• Whenever energy is converted from one form to another in a physical or chemical
change:
• No energy is created or destroyed when converted from one form to another (first law of
thermodynamics/Law of Conservation of Energy)
• You end up with lower quality or less-usable energy than you started with (second law of
thermodynamics)
• Lower quality energy is usually in the form of heat flowing into the environment.
• The temperature drops to the point that quality is too low to do much useful work.
ENERGY CHANGES OBEY TWO SCIENTIFIC LAWS
• Energy efficiency
• Measure of how much work results from a unit of
energy put into a system
• Improving efficiency reduces waste
• Estimate: 84% of energy used in the U.S. is wasted
• Unavoidably because of second law of
thermodynamics (41%)
• Unnecessarily (43%)
ENERGY IS RENEWABLE AND NONRENEWABLE
• Renewable energy
• Gained from resources that are replenished
by natural processes in a relatively short time
• Nonrenewable energy
• Gained from resources that can be depleted
and are not replenished by natural processes
within human time scale
ENERGY IS RENEWABLE AND NONRENEWABLE
• Solar energy
• 99% of the energy that keeps us warm and supports plants and other organisms
• Commercial energy
• Energy sold in the marketplace
• Supplements sun’s energy
• 90% comes from burning fossil fuels
• Oil, coal, and natural gas
WHAT ARE SYSTEMS AND
HOW DO THEY RESPOND
TO CHANGE?
• System
• Set of components that interact in a regular way
• Examples: human body, a cell, a TV set, and an
economy
• Systems have inputs, flows, and outputs of matter,
energy, and information
• Feedback can affect their behavior
SYSTEMS AND
FEEDBACK LOOPS
• Feedback
• Any process that increases or decreases a
change to a system
• Positive feedback loop
• Causes system to change further in the
same direction (can lead to tipping point).
• Example: Decreasing vegetation in a
valley causes increasing erosion and
nutrient losses that in turn cause more
vegetation to die, resulting in more erosion
and nutrient losses.
SYSTEMS AND FEEDBACK LOOPS
• Negative, or corrective, feedback loop
• Causes system to change in opposite
directions
• Example: Air conditioner goes on until a
specific temperature is reached and then
goes off and the house starts to warm until it
reaches a specified temperature and turns the
air conditioner on
SYSTEMS AND FEEDBACK LOOPS
• Most systems in nature use negative feedback to enhance long-term stability.
• Ecological tipping point
• Natural system stuck in positive feedback loop can reach this point
• Beyond this point, system changes so drastically it suffers from severe
degradation or collapse
Scientists
Matter Consists of Elements and Compounds
Elements and Compounds Are Made of Atoms, Molecules, and Ions
Elements and Compounds Are Made of Atoms, Molecules, and Ions
Elements and Compounds Are Made of Atoms, Molecules, and Ions
Elements and Compounds Are Made of Atoms, Molecules, and Ions
Elements and Compounds Are Made of Atoms, Molecules, and Ions
Energy comes in many forms
Energy comes in many forms
Energy Comes in Many Forms
Energy Is Renewable and Nonrenewable
Systems and Feedback Loops
Systems and Feedback Loops
Ecosystems: What Are They and How
Do They Work?
How Does the Earth’s Life-Support
System Work?
u Major components of the earth’s life-support system
u Atmosphere (air)
u Hydrosphere (water)
u Geosphere (rocks, minerals, and soil)
u Biosphere (living things)
Earth’s Life-Support System Has Four
Major Components
u Atmosphere
u Innermost layer is the troposphere
uContains the air we breathe
u Stratosphere: contains ozone layer
uFilters sun’s harmful UV radiation
u Hydrosphere
u All water vapor, liquid water, and ice
u Oceans contain 97% of the planet’s water
Earth’s Life-Support System Has Four
Major Components
u Geosphere
u Upper portion of crust contains nutrients
organisms need to live, grow, and
reproduce
u Contains nonrenewable fossil fuels
u Biosphere
u Parts of atmosphere, hydrosphere, and
geosphere where life is found
u One-way flow of high-quality energy from the sun that
supports plant growth and warms troposphere (greenhouse
effect)
Three Factors Sustain the Earth’s Life
Cycling of nutrients through parts of the biosphere
Gravity holds the earth’s atmosphere and enables
movement and cycling of chemicals through air, water,
soil, and organisms
What Are the Major Components
of an Ecosystem?
u Ecologists study five levels of
matter
u Biosphere, ecosystems,
communities, populations,
and organisms
u Ecology assigns each organism to a feeding
level (trophic level)
u Organisms classified as producers or
consumers based on source of nutrients
Ecosystems Have Several
Important Components
u During photosynthesis, plants generate energy
and emit oxygen
u CO2 + H2O + sunlight → glucose + oxygen
u Producers (autotrophs) make needed nutrients
from their environment
u Consumers (heterotrophs) cannot produce the
nutrients they need
u Primary consumers (herbivores) eat plants
u Carnivores feed on flesh of other animals
u Secondary and tertiary (or higher) consumers
u Omnivores eat both plants and animals
Ecosystems Have Several Important
Components
u Decomposers
u Consumers that recycle dead plants and animals into chemical
nutrients like carbon and nitrogen that are released back into the
soil, air and water
u Directly absorb nutrients through external chemical and biological
processes
u Nutrients return to soil, water, and air
for reuse
u Bacteria, fungi and earthworms are big
decomposers
u Detritivores
uIngest and digest dead matter internally
Ecosystems Have Several Important
Components
u Producers, consumers, and
decomposers use chemical
energy stored in glucose
u In most cells, energy is
released by aerobic
respiration
u Using oxygen to turn
glucose back to carbon
dioxide and water
u Soil
u Complex mixture of rock, particles, mineral nutrients, organic
matter, water, air, and living organisms
u Soil formation begins with weathering of rock
u Various forms of plant and animal life begin living in the weathered
particles.
u Their waste and decaying bodies add organic matter and minerals
to the slowly forming soil.
u Mature soils contain several layers (horizons)
u Differ in texture, composition, and thickness
Soil Is the Foundation of Life on Land
u Soil is a renewable resource
u Renews very slowly
u Formation of one inch of topsoil
can take hundreds to thousands
of years
u Becomes nonrenewable if it is
depleted faster than it can be
replenished
u Protecting and renewing topsoil
is key to sustainability
Soil Is the Foundation of Life on Land
What Happens to Energy in an
Ecosystem?
u Energy flows through ecosystems in food chains and webs
u Food chain
u Movement of energy and nutrients from one trophic
level to the next
u Food web
u Network of interconnected food chains
What Happens to Energy in an
Ecosystem?
What Happens to Energy in an
Ecosystem?
u Every use and transfer of energy involves energy loss as heat
u Pyramid of energy flow
u 90% of energy lost with each transfer through metabolic
heat: why food chains and webs rarely have more than 4 or 5
trophic levels
u Less chemical energy for higher trophic levels
u About 2/3 of the world’s people survive by eating wheat,
rice, and corn at the first trophic level.
u Biomass
u Total mass of organisms in a given trophic level
What Happens to Energy in an
Ecosystem?
Some Ecosystems Produce Plant Matter
Faster than Others
Do
u Gross primary productivity
(GPP)
u Rate at which an ecosystem’s
producers (plants and
phytoplankton) convert solar
energy to stored chemical
energy
u Measured in units such as
kcal/m2/year
Some Ecosystems Produce Plant Matter Faster
than Others Do
u Net primary productivity (NPP)
u Rate at which an ecosystem’s producers
convert solar energy to chemical energy,
minus the rate at which they use the
stored energy for aerobic respiration
u The planet’s NPP ultimately limits the
number of consumers (including humans)
that can survive on the earth
Some Ecosystems Produce Plant Matter
Faster than Others
What Happens to Matter in an
Ecosystem?
u Matter in the form of nutrients cycles within and among
ecosystems
u Cycles driven by incoming solar energy and gravity
u Can be altered by human activity
u Nutrient Cycles
u Water, carbon, nitrogen, and phosphorus
u The water cycle collects, purifies, and
distributes the Earth’s fixed supply of
water.
u Renews water quality.
u The sun powers the water cycle.
u Incoming solar energy causes
evaporation.
u Gravity draws water back as
precipitation:
u Surface runoff evaporates to complete the
cycle
u Some precipitation is stored underground
as groundwater
u Some precipitation is converted to ice and
stored in glaciers
Water Cycle Sustains all Life
u Only 0.024% of the Earth’s freshwater supply is available to
humans and other species.
u The ways humans alter the water cycle:
u Withdrawing large amounts of freshwater from aquifers at rates
faster than nature can replace it
u Clearing vegetation (agriculture, road building), which increases
runoff
u Draining and filling wetlands for farming and urban development
Science Focus: Water’s Unique
Properties
u Properties of water
u Liquid over large temperature range
u Changes temperature slowly because it can
store a large amount of heat
u Takes lots of energy to evaporate
u Can dissolve a variety of compounds (also can
make it polluted)
u Filters out wavelengths of UV radiation and
protects aquatic organisms
u Expands when it freezes
Carbon Cycles among
Living and Nonliving
Things
u Carbon is the basic building block of
carbohydrates, fats, proteins, DNA,
and other organic compounds.
u Photosynthesis from producers
removes CO2 from the atmosphere
and aerobic respiration by
producers, consumers, and
decomposers adds CO2 .
u Some CO2 dissolves in the ocean
and is stored in marine sediments.
u Humans have added large quantities of CO2 to the atmosphere
u Faster rate than natural processes can remove
u Levels have been increasing sharply since about 1960
u Carbon from fossil fuels are being burned back into atmosphere
u Result is the warming atmosphere and changing climate
u Clearing vegetation reduces ability to
remove excess CO2 from the atmosphere
u Nitrogen is a critical nutrient for all forms of life.
u Nitrogen gas makes up 78% of the volume of the atmosphere.
u Useful forms of nitrogen are created in the nitrogen cycle:
u Created by lightning and specialized bacteria in topsoil and
bottom sediment of aquatic systems
u Used by plants to produce proteins, nucleic acids, and vitamins
u Bacteria converts nitrogen compounds back into nitrogen gas.
Nitrogen Cycle: Bacteria in Action
u Human alteration of the nitrogen cycle
u Burning gasoline and other fuels create nitric oxide,
which can return as acid rain
u Removing large amounts of nitrogen from the
atmosphere to make fertilizers
u Adding excess nitrates in aquatic ecosystems
u Human nitrogen inputs to the environment have risen
sharply and are expected to continue rising
Nitrogen Cycle: Bacteria in Action
Phosphorous Cycles through Water, Rock,
and Food Webs
u Phosphorus
u Another nutrient that supports life
u Cycles through water, the Earth’s crust, and living
organisms
u Major reservoir is phosphate rocks
u Cycles slowly
u Does not cycle through the atmosphere because
few of the compounds exist as gas
u Lack of phosphorus limits growth of producer
populations (plants)
Phosphorous Cycles through Water, Rock,
and Food Webs
u Phosphorus
u Human activities and impacts
uClearing forests
uRemoving large amounts of phosphate
from the Earth to make fertilizers
uErosion leaches phosphates into streams
Earth’s Life-Support System Has Four�Major Components
Three Factors Sustain the Earth’s Life
Three Factors Sustain the Earth’s Life
Ecosystems Have Several Important Components
Ecosystems Have Several Important Components
Soil Is the Foundation of Life on Land
Soil Is the Foundation of Life on Land
Soil Is the Foundation of Life on Land
What Happens to Energy in an Ecosystem?
What Happens to Energy in an Ecosystem?
What Happens to Energy in an Ecosystem?
Do
Some Ecosystems Produce Plant Matter Faster than Others Do
Some Ecosystems Produce Plant Matter Faster than Others
Water Cycle Sustains all Life
Water Cycle Sustains all Life
Human Disruption of the Carbon Cycle
Nitrogen Cycle: Bacteria in Action
Nitrogen Cycle: Bacteria in Action
Nitrogen Cycle: Bacteria in Action
Phosphorous Cycles through Water, Rock, and Food Webs
Phosphorous Cycles through Water, Rock, and Food Webs
Phosphorous Cycles through Water, Rock, and Food Webs
Biodiversity
Lecture 4
What Are the Major Types of Life on the
Earth?
• Every organism is composed of one or more
cells.
• Cell:
• Known as the “building blocks of life”
• Surrounded by a structure called the cell membrane
What Are the Major Types of Life on the
Earth?
• Classification based on cell structure
• Prokaryotic (bacterial cells)
• Cells enclosed by a membrane but containing no distinct nucleus or other internal parts
enclosed by membranes
• Eukaryotic
• All nonbacterial organisms
• Cells are encased in a membrane and have a distinct nucleus (a membrane-bounded
structure containing genetic material in the form of DNA) and several other internal parts
enclosed by membranes.
What Are the Major Types of Life on the
Earth?
Scientists group organisms into
categories based on their greatly
varying characteristics.
• Taxonomic classification:
• Domain, kingdom, phylum, class,
family, genus, and species
• Archaebacteria
• Eubacteria
• Protista (algae and protozoans)
• Plantae: Plants (mosses, ferns, and
flowering plants)
• Fungi (mushrooms, molds, mildew,
and yeasts)
• Animalia: Animals (invertebrates
and vertebrates)
• https://www.youtube.com/watch?v=kKwOlAqQoLk
Earth’s Organisms Are Many and Varied
• Species – group of organisms with characteristics that
distinguish it from other groups of organisms.
• Estimated 7–10 million species exist
• About 2 million species have been identified
• About half of those are insects
• Pollination is a vital ecosystem service performed by insects
• Biological control
• Biological diversity is the diversity of life on earth
• Four components:
• Species diversity
• Includes species richness (the number of different species) and evenness
(comparative abundance of all species)
• Genetic diversity
• Variety of genes in a population or species
• Ecosystem diversity
• Biomes: regions with distinct climates and species
• Functional diversity
• Biological and chemical processes, such as energy flow and matter recycling, needed
for the survival of species, communities, and ecosystems
• https://www.youtube.com/watch?v=b6Ua_zWDH6U
• Species diversity includes species richness (number of different species) and
evenness (comparative abundance of all species).
• If an ecosystem only has three species, its richness is low. But if there are an
equal number of each of the three species, the species evenness is high.
• Species richness is highest in the tropics and declines as we move toward the
poles.
• Most species rich environments are tropical rain forests, large tropical lakes,
coral reefs, and the ocean-bottom zone.
Species Diversity
Functional diversity is the biological and chemical processes, such
as energy flow and matter recycling, needed for the survival of
species, communities, and ecosystems.
-What is/are the organism(s) doing?
-How does it interact with other organisms and the environment
• Variety of genes in a population or species
• Genes contain genetic information that give rise to specific traits, or
characteristics, that are passed on to offspring through reproduction.
• Species have a better chance of surviving and adapting to environmental changes
if they have greater genetic diversity.
• Biomes: Regions with distinct climates and species
(terrestrial classification)
• tropical rainforests, temperate forests, deserts, tundra,
boreal forests, grasslands, and savanna
• Biomes differ in their community structure based on the
types, relative sizes, and stratification of their plant species
Ecosystem Diversity
• Large areas of forest and other biomes have a core habitat and edge habitats
with different environmental conditions and species, called edge effects
• Natural ecosystems within biomes rarely have distinct boundaries.
• Instead, one ecosystem tends to merge with the next in a transitional zone
called an ecotone
• Ecotone: a region containing a mixture of species from adjacent ecosystems along with
some migrant species not found in either of the bordering ecosystems
• Humans have fragmented many biomes into isolated patches with less core
habitat and more edge habitat that supports fewer species.
• Each species plays a specific ecological role called its niche
• Includes everything that affects survival and reproduction
• Water, space, sunlight, food, and temperatures
• What it eats
• How much water it drinks
• When it reproduces
• Niche is NOT the same as habitat, which is where a species lives
• Related to functional diversity component of biodiversity
•
are used to classify species into 2
categories:
• Generalist species
• Broad niche—wide range of tolerance
• Specialist species
• Narrow niche—narrow range of tolerance
Niches
• Further classification of niches depends on
the roles that species play in ecosystems:
• Native species normally live and thrive in a
particular ecosystem
• Nonnative species migrate or are accidentally
introduced into an ecosystem
• https://www.youtube.com/watch?v=spTWwqVP_2s
Niches
• Further classification of niches depends on the
roles that species play in ecosystems:
• Indicator species provide early warnings of
environmental changes
• Lichens, Trout
Niches
• Further classification of niches depends on the roles that species
play in ecosystems:
• Keystone species have a large effect on the types and abundance of
other species (such as pollination and population regulation)
• E.g., Saguaro cactus – habitat, food
• Species can play one or more roles in an ecosystem
• https://www.youtube.com/watch?v=JGcIp4YEKrc
What Are the Major Types of Life on the Earth?
What Are the Major Types of Life on the Earth?
Taxonomies
Kingdoms
Taxonomies video
What Is Biodiversity and Why Is It Important?
What is Biodiversity?
Species Diversity
Species Diversity
Functional Diversity
Genetic Diversity
Ecosystem Diversity
Major Biomes across United States
Ecosystem Diversity
What Role Do Species Play in Ecosystems?
What Role Do Species Play in Ecosystems?
Niches
Invasive Species
Niches
Niches
Lecture 5
• Biological evolution
• The process by which Earth’s life forms change
genetically over time
• Helps explain why there is such biodiversity
• Widely accepted scientific theory
• Natural selection
• Process by which
species
have evolved from earlier
species
Evolution Explains How Organisms Change
over Time
• Fossils
• Physical evidence of past organisms
• Preserved in rocks or ice
• Fossil record
• Entire body of fossil evidence
• Uneven and incomplete
• Estimate: fossils found so far represent only
1% of all species that have ever lived
Evolution Depends on
and
• Darwin and Wallace independently proposed the concept of
natural selection in 1850s.
• Biological evolution involves changes in a population’s genetic
makeup over generations.
• Populations, not individuals, evolve.
1. Genetic variability
2. Natural Selection
Genetic Variability
• First step in evolution: Genetic variability
• Occurs through mutations
• Random changes in DNA as cells divide and DNA is copied
• Can be the result of exposure to external factors (like
chemicals and radioactivity)
• Some mutations can be beneficial, and others can be
harmful
• Some can result in heritable traits
Natural Selection
• Natural selection
• Environmental conditions favor increased survival and reproduction
of certain individuals in a population
• Survival of the fittest
Natural Selection
• Adaptive trait
• Improves the ability of an individual organism to survive and
reproduce at a higher rate than other individuals in a population
• Given prevailing environmental conditions
Evolution Depends on Genetic Variability and
Natural Selection
• Genetic resistance
• Example of natural selection at work
• Occurs when organisms have genes that can tolerate a chemical designed to kill them
• Resistant individuals survive and reproduce
• Some disease-causing bacteria have developed resistance to
antibacterial drugs (antibiotics)
Evolution Depends on Genetic Variability and
Natural Selection
• Human species adaptations
• Strong opposable thumbs
• Ability to walk upright
• A complex brain
Limits to Adaptation through Natural
Selection
• Adaptive genetic traits must precede change in the environmental
conditions
• A population’s reproductive capacity
• Species that reproduce rapidly and in large numbers are better able
to adapt
Myths about Evolution through Natural
Selection
• Five common myths
• Survival of the fittest means survival of the strongest.
• Evolution explains the origin of life.
• Humans evolved from apes or monkeys.
• Evolution is part of nature’s grand plan to produce perfectly adapted
species.
• Evolution by natural selection is not important because it is just a theory.
• New species arise in two
phases
• Geographic isolation
• Reproductive isolation
• New species arise in two phases
• Geographic isolation
• Occurs first
• Populations migrate or are separated
by some other cause
What Factors Affect Biodiversity?
• Reproductive isolation
• Mutation and change by natural
selection occurs in the geographically
isolated groups
• Eventually prevents breeding between
the groups
What Factors Affect Biodiversity?
• Tectonic plates affect evolution and the
distribution of life on earth
• Locations of continents and oceans have shifted
through geologic time
• Species move and adapt to new environments,
allowing speciation
• Earthquakes can separate and isolate
populations
• Volcanic eruptions can destroy habitats
• Artificial selection
• Selective breeding (or crossbreeding)
• Occurs between genetically similar species
• Not a form of speciation
• Slow process
• Genetic engineering
• Way to speed process of artificial selection
• Gene splicing
• Extinction
• Process in which an entire species ceases to exist
• Endemic species
• Found only in one area
• Particularly vulnerable to extinction
• Background extinction
• Typical low rate of extinction
• 0.0001% of all species per year
• Mass extinction
• Significant rise above background level
• 20–95% of species are eliminated
• Causes unknown but could include:
• Giant volcanic eruptions
• Collisions with meteors or asteroids
• Provides opportunity for evolution of new
species
• Five mass extinctions
• https://www.youtube.com/watch?v=GShGxrw4xOU&feature=emb_
title
Steps of Evolution
Genetic Variability
Natural Selection
Natural Selection
Evolution Depends on Genetic Variability and Natural Selection
How do New Species Arise?
What Factors Affect Biodiversity?
What Factors Affect Biodiversity?
What Factors Affect Biodiversity?
Geological Processes Affect Biodiversity
Artificial Selection and Genetic Engineering
Extinction
Extinction Eliminates Species
Video
Species Interactions,
Ecological Succession,
and Population Control
Lecture 6
• Five types of
species
interactions
affect resource use and species
population sizes in an ecosystem
• Competition
•
• Parasitism
• Mutualism
• Commensalism
• Most common interaction is
competition
• Interspecific competition
• Competition between
different species to use the
same limited resources
• Resource Partitioning
• Intraspecific competition
Predation
• Predator feeds directly on all or part of a member of another
species (prey)
• Strong effect on population sizes and other factors in ecosystems
• Methods of predation
• Walk, swim, or fly
• Camouflage
• Chemical warfare
• Coevolution
• Parasitism
• One species (parasite) lives on another organism
• Parasites harm but rarely kill the host
• Examples: tapeworms, sea lampreys, fleas, and ticks
• Mutualism
• Interaction that benefits both species
• Nutrition and protective relationship
• Not cooperation—mutual exploitation
• Example: clownfish live within sea anemones
• Gain protection and feed on waste matter left by
anemones’ meals
• Clownfish protect anemones from some predators
and parasites
Parasitism, Mutualism, and Commensalism
• Commensalism
• Benefits one species and has little effect on the other
• Examples:
• Epiphytes (air plants) attach themselves to trees (Pitcher Plant)
• Birds nest in trees
• https://www.youtube.com/watch?v=doB6fyzoO68
How Do Communities and Ecosystems Respond to
Changing Environmental Conditions?
• Ecological succession
• Normally gradual change in structure and species
composition in a given system
• Primary ecological succession
• Involves gradual establishment of communities of
different species in lifeless areas
• Need to build up fertile soil or aquatic sediments to
support plant community
• Takes hundreds to thousands of years
• Pioneer species such as lichens or mosses quickly spread
and release acids
Ecological Succession Creates and Changes
Ecosystems
• Secondary ecological succession
• Series of terrestrial communities or ecosystems develop in places with soil
or sediment
• Examples: abandoned farmland, burned or cut forests, and flooded land
Ecological succession is an important ecosystem service enriching biodiversity
• Population
• Group of interbreeding individuals of the same species
• Population size
• May increase, decrease, or remain the same in response to
changing environmental conditions
• Scientists use sampling techniques to estimate
What Limits the Growth of Populations?
• Population distribution varies over their habitats
• Most populations live together in clumps or groups
• Organisms cluster for resources
• Protection from predators
• Variables that govern changes in population size
• Births, deaths, immigration, and emigration
Several Factors Can Limit Population
Size
• Each population has a range of tolerance
• Variation in physical and chemical
environment under which it can survive
• Limiting factors
• Precipitation (on land)
• Water temperature, depth, clarity, and
other factors (in aquatic environments)
• Population density
• Density-dependent factors (parasites and
diseases spread easily, higher death rates;
finding mates in sexually reproducing
individuals is easy)
No Population Can Grow Indefinitely:
J-Curves and S-Curves
• Some species can reproduce
exponentially
• Reproduce at an early age
• Have many offspring each time they
reproduce
• Short intervals in between
reproductive cycles
• Produces J-shaped curve of growth
• Examples: bacteria and many insect
species
No Population Can Grow Indefinitely:
J-Curves and S-Curves
• Population growth in nature always limited
• Environmental resistance
• Sum of all factors that limit population growth
• Carrying capacity
• Maximum population of a given species that a particular habitat can sustain
indefinitely
• Overshoot results in population crash
No Population Can Grow Indefinitely:
J-Curves and S-Curves
• r-Selected species
• Species with capacity for a high rate
of population growth
• Examples: algae, bacteria, frogs,
most insects, and many fish
• May go through irregular and
unstable cycles in population sizes
Reproductive Patterns
• K-Selected species
• Species that reproduce later in life
• Have few offspring
• Have long life spans
• Examples: large mammals, whales,
humans, birds of prey, and long-lived
plants
• Can be vulnerable to extinction
• Survivorship curve
• Shows the percentages of members of population surviving at different ages
• Late loss (K-selected species)
• Early loss (r-selected species)
• Constant loss (many songbirds)
Humans Are Not Exempt from Nature’s
Population Controls
• Ireland
• Potato crop destroyed by fungus in 1845
• Killed one million people
• Bubonic plague
• Killed 25 million during the 14th century in densely populated European
cities
• Technological, social, and cultural changes have expanded earth’s
carrying capacity for the human species today
How Do Species Interact?
Competition for Resources
Predation
Parasitism, Mutualism, and Commensalism
Parasitism, Mutualism, and Commensalism
What Limits the Growth of Populations?
No Population Can Grow Indefinitely: �J-Curves and S-Curves
No Population Can Grow Indefinitely: �J-Curves and S-Curves
Reproductive Patterns
Reproductive Patterns
Species Vary in Their Life Spans
Lecture 7
Past and Current
Population
Growth are Very
Different
” Every second, on average, four or five
children are born, somewhere on the
earth. In that same second, one or two
other people die.
” In 2011 the United Nations announced
that we had reached 7 billion people,
having added the most recent billion in
only 12 years. We’re now growing at 1.05
% per year.
” Rate of population growth has slowed since 1960 to
1.05%
” World’s population is still growing
” In 2015, 241,000 people were added every day
” Human population growth is unevenly distributed
geographically
” 2% added to more developed countries
” 98% added to less developed countries
” People are moving from rural to urban areas
” In 2018, 55% of the world’s population lived in urban areas,
and it is increasing
” Urban dwellers are living in less developed countries where
resources for dealing with the growing population are
limited
Perspectives on
Population
Growth
As with many topics in environmental
science, people have widely differing
opinions about population and
resources.
Some believe that population growth
is the ultimate cause of poverty and
environmental degradation.
Others argue that poverty,
environmental degradation, and
overpopulation are all merely
symptoms of deeper social and
political factors.
The worldview we choose to
believe will profoundly affect our
approach to population issues.
” We are approaching, or may have surpassed, the
earth’s carrying capacity.
” Maximum number of people who could live in
reasonable freedom and comfort indefinitely, without
decreasing the ability of the earth to sustain future
generations
” Joel Cohen, at Rockefeller University reviewed published
estimates of the maximum human population size the
planet can sustain. 300 years of thinking, converged on a
median value of 10 to 12 billion.
” David Pimental states that “By 2100, 12 billion miserable
humans will suffer a difficult life on Earth.”
Many Factors Determine
Population Growth
Demography encompasses vital statistics about
people, such as births, deaths, and where they live,
as well as total population size.
” Population size increases through births and
immigration
” Decreases through deaths and emigration
” Key factor that determines population size
” Average number of children born to women in a
population (total fertility rate)
” Crude birth rate
” Number of live births per 1,000 people in a population
per
year
” Crude death rate
” Number of deaths per 1,000 people in a population per
year
” Population change = (Births + Immigration) – (Deaths
+ Emigration)
” Replacement-level fertility rate
” Average number of children a couple
must bear to replace themselves
” Approximately 2.1
”Higher than 2 because some children
die before reaching reproductive
years
” Total fertility rate (TFR)
” The number of children born to an average
woman in a population during her entire
reproductive life.
” This rate varies due to education, access to
modern health care, and religious practices.
”Between 1955 and 2018, the global TFR
dropped from 5 to 2.4
”To eventually halt population growth, the
global TFR must drop to the fertility
replacement level of 2.1
Predicting
Population
Change
” Human population size in 2050 is estimated to be between
7.8 billion and 10.8 billion people
” Factors influencing the range of estimates
” Reliability of current population estimates
” Assumptions about trends in fertility
” Different organizations who estimate populations use
different methods and data
” Importance of children as part of the labor
force
” Especially in less developed countries
” Cost of raising and educating children
” Availability of pension systems
” Urbanization
” Educational and employment opportunities for
women
” Average age at marriage
” Availability of reliable birth control methods
” Religious beliefs, traditions, and cultural norms
” Life span is the oldest age to which a species is known to survive.
”The average age that a newborn infant can expect to attain in any given
society.
” Worldwide, average life expectancy rose from 48 to 72 yrs between 1955
and 2018.
” Infant mortality rate
”Number of babies out of every 1,000 who die before their first birthday
” Poverty is the single most important factor affecting life expectancy.
” Factors that cause high infant mortality:
” Insufficient food, poor nutrition, and infectious disease.
” The movement of people into and out of
specific geographic areas
” Reasons for migration
” Jobs and economic improvement
” Religious persecution or ethnic conflict
” Political oppression or war
” Environmental refugees
How Does a Population’s
Affect Its Growth or Decline?
o Age structure is the number and percentages of males and females in
young, middle, and older age groups in a population.
o It is an important factor in determining how fast a population grows or
declines.
Age Structure
” Age structure categories
” Pre-reproductive (ages 0–14) – too young to have kids
” Reproductive (ages 15–44)
” Post reproductive (ages 45 and older)
” Country with large percentage of people younger than age 15 will experience rapid population
growth
” Global population of seniors expected to triple between 2018 and 2050
” Most future population growth will happen in less developed countries because of youthful age
structure and rapid population rates.
” Graying of the world’s population is due to declining
birth rates and medical advances that have
extended life spans.
” As the percentage of people over 65 increases, more
countries will experience population declines.
” Slow population decline is generally manageable.
” Rapid decline leads to economic problems:
” Proportionally fewer young people working
” Labor shortages
” Some countries with rapidly declining populations:
” Japan, Germany, Italy, Bulgaria, Hungary, Romania,
Cuba, and Portugal
How Can We Slow Human Population
Growth?
” There is argument on whether population growth needs to slow:
” Some say environmental degradation can be linked to population growth
” Ways to slow human population growth:
” Reduce poverty through economic development
” Elevate the status of women
” Encourage family planning
” Demographic transition:
” As countries become industrialized and economically developed, poverty declines (this results in
populations that tend to grow more slowly).
” Several countries are experiencing a stabilized or declining population.
” Reducing poverty is key to improving human health and stabilizing the population.
” It takes 4 stages.
o Economic and social conditions
change mortality and births.
o Stage I represents the conditions in a
premodern society.
o Malnutrition, illness, accidents and
other hazards keep high death rates
but high birth rates keep population
relatively constant.
o Economic development in Stage II
brings better jobs, medical care,
sanitation, and a generally improved
standard of living, and death rates
often fall very rapidly.
o Birth rates may rise at first, with money
and nutrition, people might want more
children. Later, birth rates fall as
people concentrate their resources on
fewer children.
o Note that populations grow rapidly
during Stage III when death rates
have already fallen but birth rates
remain high.
o Population may go one or more
rounds of doubling before coming to
balance again.
o Stage IV represents conditions in
developed countries, where the
transition is complete and both birth
rates and death rates are low, often a
third or less than those in the
predevelopment era.
o Most of northern and western Europe
went through a demographic transition
in 19th and early 20th century.
Improving Women’s Lives Helps Reduce Birth
Rates
” Women have fewer children if:
” Educated
” Able to earn an income
” Society does not suppress their rights
” Women:
” Do most of the domestic work and childcare
” Provide unpaid health care
” Have fewer rights and educational opportunities than men
” Family planning allows couples to determine the number and spacing
of their children.
” Birth control usually means any method used to reduce births including
celibacy, delayed marriage, contraception, and methods that prevent
embryo implantation and other methods like induced abortions.
Successful Family Planning Programs Often
Require Significant Societal Changes
” Important societal changes to affect population growth include:
” Improved social, educational, and economic status for women.
” Improved status for children.
” Acceptance of calculated choice as a valid element in life in general and in fertility
in particular.
” Social security and political stability that give people the means and the confidence
to plan for the future.
” The knowledge, availability, and use of effective and acceptable means of birth
control.
Access the text alternative for these
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Human Populations Grew Slowly Until Recently
Human Population Growth
What is the Carrying Capacity for Humans?
The Human Population Can Grow, Decline, or Stabilize
Fertility Rates
Total Fertility Rate is Impacted by Culture
People Want Children for Many Reasons
Fertility is Influenced by Culture
Life Expectancy is Rising Worldwide
Migration
Age Structure
Age Class Histograms
Aging Populations Can Decline Rapidly
Economic Development
Stage I
Stage II
Stage III
Stage IV
Family Planning Gives Us Choices
Fertility Rates by Country
Lecture 8
More Than Half of the World’s People Live in Urban
Areas
” Urbanization
” Creation and growth of urban and suburban
areas
55% of people live in such areas
” Urban growth
” Rate of increase of urban populations
” Immigration from rural areas
” Pushed from rural areas to urban areas
” Pulled to urban areas from rural areas
” Three major trends
” Proportion of global population living in urban areas is
increasing
” Number and sizes of urban areas are increasing
” Megacities: more than 10 million residents
” Hypercities: more than 20 million residents
” Poverty is becoming increasingly urbanized
” Mostly in less-developed countries
Three Major Urban Trends
” Three phases between 1800 and 2015
” Migration from rural areas to large
central cities
” Migration from large central cities to
suburbs and smaller cities
” Migration from North and East to South
and West
” Aging infrastructure
” Deteriorating services
” Urban sprawl
” Low-density development on the
edges of cities and towns
” Contributing factors to U.S. urban sprawl
” Abundant, affordable land
” Automobiles
” Federal and state funding of highways
” Inadequate urban planning
” Suburban sprawl destroys forests, wetlands,
and cropland
” Forces people to drive almost
everywhere
” Contributed to economic deaths of many
central cities
” Cities
” Centers of economic development,
innovation, education, technological
advances, social and cultural diversity,
and jobs
” Better medical care than rural areas
” Recycling economically feasible
” Reduce stress on wildlife habitats
” Mass transportation typically available
” Large ecological footprints
”Consume 75% of the world’s resources
” Lack of vegetation
” Water problems
”Runoff, flooding, wetland degradation
” Pollution and health problems
”Air and water pollution
”Solid and hazardous wastes
Urbanization Has Disadvantages
” Excessive noise
” Noise pollution impairs or interferes with
hearing, and causes stress and accidents
” Local climate effects and light pollution
” Cities tend to be warmer, rainier, foggier, and
cloudier than rural areas
” Urban heat island
” Artificial light has affected some species
(disorientation, natural behavior, higher
predation levels, disrupts light sensitive cycles,
higher mortality rates).
” Slums
” Areas dominated by dilapidated housing
” Squatter settlements and shantytowns
Scavenged materials, on unoccupied land
without the owner’s permission
” Terrible living conditions
Lack basic water and sanitation
High levels of pollution
Cities Can Grow Outward
or Upward
” Compact cities
” Hong Kong, China
” Tokyo, Japan
” Mass transit
” Dispersed cities
” The United States and Canada
” Car-centered cities
” Advantages
” Mobility and convenience
” Provides jobs
” Production and repair of vehicles
” Supplying fuel
” Building roads
Pros and Cons of Motor Vehicles
” Disadvantages
” Accidents kill 1.25 million people per
year globally and injure another 50
million
” Kill 50 million wild animals and
pets per year
” Largest source of outdoor air pollution
” Helped create urban sprawl and car
commuter culture
” Traffic congestion
” Full-cost pricing–environmental gas tax
” Consumer education
” Funds for mass transit and bike lanes
” Opposition from car owners and industry
” Raise parking fees
” Charge tolls on roads, tunnels, and
bridges
” Car-sharing networks
” Foot power
” Bicycles
” Buses
” Heavy-rail systems
” Subways, elevated rail, and metro trains
” Light-rail systems
” Streetcars, trolleys, and tramways
” Rapid-rail system between urban areas
” Land-use planning
”Governments control uses of certain parcels of land by legal and
economic methods
” Zoning
”Land designated for certain uses
”Mixed-use zoning
” Set of policies and tools that encourage
environmentally sustainable development
” Uses zoning laws to channel growth and
reduce ecological footprint
” Reduces dependence on cars
” Discourages sprawl
” Many European countries
” High taxes on heating fuel and gasoline
encourages compact cities
Preserving and
Using Open Space
” Urban growth boundary
” U.S. states: Washington, Oregon, and
Tennessee
” Greenbelts
” Canadian cities: Vancouver and
Toronto
” Western European cities
” Municipal parks
” U.S. cities: New York City and San
Francisco
” Conventional housing development
” Rows of houses on standard-size lots
” Cluster development
” Mixed housing types and green space
” New urbanism: environmental
sustainability
” Walkable, bike friendly neighborhoods
” Mixed use and diversity
” Quality urban design; smart transportation
” Sense of community
” Eco-city (or green city)
” New model for urban development
” People-oriented, not car-oriented
” Walk, bike, or use mass transit
” High percentage of MSW reused, recycled, or
composted
” Tree planting
” Vertical farms
” Environmental justice
” Ecological capital of Brazil
” Superb bus rapid-transit system
” 85% of the city’s commuters
” Streams and parks
” Recycling programs
” Care for the poor
” High literacy rate
” Population increased fivefold since
1965
” 50–150 people come together to design and
live in more ecologically, economically, and
socially sustainable villages in rural and
suburban areas
” Solar and wind power
” Energy-efficient housing
” Organic farming
” 2014: more than 400 eco-villages in over 70
countries
Three Major Urban Trends
Three Major Urban Trends
Urbanization in the United States
Urban Sprawl
Urban Sprawl
Urbanization Has Advantages
Urbanization Has Disadvantages
Urbanization Has Disadvantages
Poverty and Urban Living
Pros and Cons of Motor Vehicles
Pros and Cons of Motor Vehicles
Reducing Automobile Use
Alternatives to Cars
Conventional Land-Use Planning
Smart Growth
New Urbanism
The Eco-City Concept: Cities for People, Not Cars
The Eco-City Concept in Curitiba, Brazil
Eco-Villages
