Transcript APES Review!

APES Review!
4/24/08
Introduction
Environment, biotic, abiotic
 Thomas Malthus and Paul Ehrlich:
predicted massive population increases
and subsequent problems
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Environmental science is about
sustainability, which requires us to live
in such a way as to maintain Earth’s
systems for the foreseeable future
Designing Experiments
have a hypothesis that you want to test
 Make sure to have a control group that is
not tested in order to compare
 Only test 1 variable at a time!
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Basic Information
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Properties of water:
– strong cohesion (helps transport of chemicals)
– can resist temperature change
– Solid form is less dense than liquid (ice floats)
– Bonds well (dissolves many molecules)
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pH scale: <7= acid, >7=base
Basics on Energy
Potential energy is energy of position and
kinetic energy is energy of motion
 First law of thermodynamics: the total
energy of the universe remains constant
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– Ex) the potential energy of the water behind a dam
equals the kinetic energy of its eventual movement
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Second law of thermodynamics: the nature
of energy will change from a more ordered to
less ordered state
– As we burn a log, the energy is released as heat and
light, becoming more disorganized
Basics on Energy
Photosynthesis: plants, or autotrophs,
convert sunlight energy and CO2 into
glucose and O2
 Cellular respiration: all organisms
convert glucose into ATP energy and CO2
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Energy Basics
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Energy efficiency: the amount of energy
that is useful from one step to the next
– A coal power plant is 38% efficient
– Beef cattle are 7% efficient, chickens are 33%
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Productivity is the amount of biomass
that is produced by a community
Basic Ecology Information
A species is a group of organisms with
similar enough genetic makeup to be able
to reproduce successfully
 A population is an interbreeding group of
organisms that lives in the same area
 A community is a group of
interdependent populations
 An ecosystem is composed of biological
communities and their physical
surroundings
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The biogeochemical cycles
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The carbon cycle
1. photosynthesis captures CO2 to form
glucose. animals eat glucose
2. cellular respiration converts glucose into
CO2
3. CO2 is captured and dissolved by the
oceans
4. Organisms use the carbonate ion to form
sediments
5. When organisms die, they may be
compressed into fossil fuels
6. Fossil fuels are burned to produce CO2
The biogeochemical cycles
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The nitrogen cycle
1. Nitrogen fixation converts nitrogen gas into
ammonia through bacterial action
2. Nitrogen gas can form NO2 through
combustion and later combined with water to
form acid rain
3. Nitrification turns ammonia into nitrite and
nitrate ions
4. Nitrates are used by plants to form proteins
5. Plant proteins are eaten by animals
6. Animals decompose to form ammonia
through ammonification
The biogeochemical cycles
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The phosphate cycle
– There is no gaseous phase unlike
other cycles
1. Phosphates are used in plants and
animals
2. Decaying organic matter puts
phosphates in soil
– This is often used as fertilizers
3. Animals and plants pick up phosphates
to use
The biogeochemical cycles
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The sulfur cycle
1. Sulfur is used to construct proteins
2. Living cells are compressed into fossil
fuels, which release SO2 when
combusted
3. SO2 combines with water vapor to
form acid rain
4. Sulfate ions are taken in by plants to
form proteins
5. Volcanic eruptions produce sulfides
The biogeochemical cycles
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The water cycle
– Characterized by changes in the physical
state, rather than chemical reactions
– Powered by solar energy and by gravity
– A large amount of water is stored as
groundwater in aquifers
The biogeochemical case studies
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Wastewater treatment and nitrogen
– Plants need to be careful to have bacteria
convert all the ammonia into nitrate ions,
which are later removed
Earth Systems and Global Processes
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Convection is the circulation of material
that occurs when the density of material is
changed upon warming or cooling
– Energy from the Earth’s core heats the
mantle, which then rises and cools as it
contacts the crust—this drives tectonic action
– Ocean currents are also driven by differences
in temperature and salinity
Earth Systems and Global Processes
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Convection in the atmosphere
– Energy from the sun from is as UV light and is
mostly absorbed by ozone; eventually all
energy is reradiated as infrared radiation
 More solar energy hits the equator than other
regions
– Coriolis effect—circular air movements that
create surface winds
Plate tectonics
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Plate tectonics describes the movements of
the Earth’s lithospheric plates
– Divergent boundaries occur where magma
is pushed up and new crust is produced;
produces rift valleys and sea floor spreading
– Convergent boundaries occur when two
plates meet and one dives under the other
through subduction; forms mountains and
trenches
– Transform boundaries occur when two
plates slide past each other; causes
earthquake faults
The rock cycle
Igneous rocks are formed from magma that
has solidified
 Sedimentary rocks are formed through
weathering and deposition
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– Mechanical weathering takes place when a force is
applied to break up a rock
– Chemical weathering takes place through chemical
reactions, often with water
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Metamorphic rocks are formed as other rocks
are exposed to heat or pressure
Soil
Soil is formed from small particles of rock and
minerals
 Soil composition
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– Clay: very fine particles, impermeable to water
– Silt: fine particles that result from weathering
– Sand: course particles from weather; high water
permeability
– Humus: organic material in topsoil
– Loam: a mixture of the other types, good for
agriculture
Soil
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Soil profiles show the different layers of
material
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Soil conservation: Soil Conservation Act
– Erosion occurs when soil is moved; occurs
through water, wind, and salinization
– Decrease erosion through no-till farming,
trees to break wind, monitor soil nutrients,
decrease irrigation
The atmosphere
Mostly nitrogen, then oxygen, then water
vapor and other gases
 Layers: troposphere < tropopause <
stratosphere < mesosphere <
thermosphere/ionosphere
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Weather is caused by temperature,
pressure, and moisture
Global Climate Changes
Milankovitch cycles: changing of Earth’s orbit
around the sun, exposing different latitudes to
different amounts of sunlight over time
 Volcanic eruptions: put huge amounts of ash
into the atmosphere, blocking sun
 El Nino: as water moves in the surface of
equatorial waters, it is heated and evaporates,
causing increased moisture
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– Causes different amounts of moisture and
precipitation
Global Climate Changes
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Greenhouse effects: the increased
amounts of greenhouse gases causes
more infrared radiation to be captured
– Increased burning of fossil fuels has made
more CO2 than our natural processes can
absorb
Effects of Global Climate Change
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Reduces artic sea ice, increases the level of the
sea
Glaciers are melting, causing less freshwater
runoff for human use
High ocean levels will flood major population
centers
Spreads the range of disease-causing organisms
Causes migration of plant and animal species
Coral reefs undergo bleaching
Permafrost is melting
Causes more energetic storms
Species Interactions
Food webs: producers—primary
consumer—secondary consumer—tertiary
consumer—decomposers
 Keystone species have a particularly
strong impact on ecosystems
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– Often a large, tertiary consumer
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Succession shows the pattern of
restoration when an ecosystem is
disturbed
Species Interactions
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The niche is a species’ ecological role
– The niche is determined by competition
Predation: the process by which
individuals of one species hunt and kill
 Parasitism: one organism depends on
another for nourishment or other benefit
while causing the host harm
 Herbivory: animals feed on the tissues of
plants
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Species Interactions
Mutualism: two or more species benefit
from the interaction with one another
 Symbiosis: physical close mutualitistic
association
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– Ex) plant roots and fungi, bacteria in intestine
Amensalism: one organism is harmed
and the other is unaffected
 Commensalism: one species benefits
and the other is unaffected
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Evolution
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Evolution is the process of change in a
population over time
– Evolution occurs through the process of
natural selection, where the best
genetically adapted individuals survive and
reproduce
– Proposed by Charles Darwin
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The result of evolution is speciation
– Allopatric speciation is a result of
geographic barriers
Extinction
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The disappearance of a species from Earth
is called extinction
– Extinctions occur when rapid environmental
change occurs and species cannot adapt
– There have been 5 mass extinctions on Earth
– The K-T extinction occurred when the
dinosaurs were wiped out
The Biomes
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Biomes: a major region classified by its
dominant plant type
– Tundra: few trees, extreme cold, frozen
ground (permafrost)
– desert: very low moisture, adapted plants,
small animals
– grassland: medium rainfall, grazing animals
– Savannahs: tropical grasslands
– Chaparral: dry ecosystem with low woody
trees
The Biomes
– Temperate deciduous forest: trees loose
leaves every fall; even precipitation
– Taiga: boreal forests with long, snowy
winters and conifer trees
– Temperate rainforest: heavy rainfall; many
coniferous trees
– Tropical rainforest: heavy rainfall; warm
year-round; high biodiversity
The Biomes
Pelagic marine ecosystems: open
ocean;
phytoplankton→zooplankton→small fish
→top carnivores
 Benthic marine ecosystems: near the
bottom of the sea
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– Coral reefs: mutualistic relationship between
algae and marine inverterates, as well as
great biodiversity
The Biomes
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Benthic marine ecosystems
– Mangrove swamps: occur near the shore
where salt-adapted trees grown with their
roots in the water; tropical zones
– The abyss: great depths of the ocean
– Estuaries and salt marshes: interface
between ocean and rivers; brackish water;
high biodiversity
– Intertidal zones: regions between low and
high tides
The Biomes
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Coastal ecosystems
– Supratidal zone: beach area
– Barrier islands: islands created by wave action
Streams and rivers: major source of nutrients
comes from terrestrial sources
 Lakes and ponds: vary in nutrient levels
 Wetlands
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– Provide essential habitats
– Reservoir for flood waters
– Natural water treatment process
Biodiversity
Genetic biodiversity refers to the
variety of genes within a population
 Species biodiversity refers to the
number of species in an ecosystem
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– Benefits: helps ecosystem stability, medicines,
aesthetic value, etc
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Ecosystem biodiversity refers to the
variety of biome types
Endangered Species
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Generally have characteristics that make it
vulnerable
– Logistic population growth
 Long life span, large body, carnivore, low
reproductive rate
– Requires a large amount of land per animal
– Specialist species
– Low genetic diversity
– Competes for resources with a dominant
species
– Low tolerance for pollution and/or human
activity
Introduced Species
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Invasive species are non-native
organisms that alter communities
substantially and become dominant
– No limiting factors to regulate their population
– Often difficult to remove or control
– Often on islands
Protecting Biodiversity
The Endangered Species Act
 National parks and forests
 Wetland protection/range management
 Wildlife corridors between parks
 land reclamation
 Captive breeding programs in zoos
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Biodiversity case studies
Wolves restored to Yellowstone park
 Overharvesting for seafood markets
 Silent Spring shows the impact of
pesticides on biodiversity
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Population Definitions
Fertility: a measure of the actual number
of offspring produced
 Fecundity: the physical ability of an
organism to reproduce
 Natality: the production of new
individuals
 Morbidity: level of illness in a population
 Mortality: measure of actual number of
individuals that die
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Population Definitions
Survivorship: the number of people in a
given age bracket who remain alive
 Life expectancy: probable number of
years an individual will survive
 Life span: longest length of life reached
 total growth rate: sum increases to the
population
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Population Growth
Growth = (birth + immigration) – (death
+ emigration)
 Exponential growth: when a population
increases by a fixed amount (j-curve)
 Logistic growth: population rises sharply
at first but then levels off (s-curve)
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– Levels off when a population reaches its
carrying capacity
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Doubling Time = 70 / % growth
Biotic Potential
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K-selected species are large, slow
reproduction, lots of parental care
– Ex) humans, mammals, etc
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R-selected species are small, short-lived,
with quick reproduction
– Ex) insects, rodents
Characteristics of populations
Population size
 Population density
 Population distribution: random, uniform,
or clumped
 Sex ratios
 Age structure
 Birth and death rates: survivorship curves
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Factors that affect human population size
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Increase size
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Social factors: status, comfort, pride
Financial factors: source of labor, security
Fertility factors: high infant mortality
Cultural factors: producing an heir, etc
Reduce size
– Personal freedom and educational opportunities for
women
– Socioeconomic status
– Materialism
Human Age Structure Diagrams
Demographic Transition
Evolution of populations from high birth/
death rates to low birth/death rates
 Stage 1: high birth and death rates
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– Little access to birth control, high infant
mortality
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Stage 2: high birth rates, death rates fall—
high population growth
– Improved medical care and sanitation
– Better food distribution
Demographic Transition
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Stage 3: birth and death rates fall—
population growth is constant
– Increased birth control, wealth increases,
higher education
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Stage 4: low birth and death rates—steady
population size
Air Pollutants
Primary pollutants: harmful to humans
in the form in which they are emitted
 Secondary pollutants: become toxic
after they are released
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– Ex) ozone
Nitrogen oxides
Description: formed when N2 is
combusted at high temps
 Sources: ½ from anthropogenic sources,
mostly automobiles
 Effects: acid rain, causes increased plant
growth (eutrophication and decreased
dissolved oxygen)
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Sulfur oxides
Description: has that damages tissues
 Sources: combustion of coal
 Effects: acid rain, causes breathing
difficulties
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Carbon oxides
Description: CO2 and CO most common
 Sources: burning fossil fuels
 Effects: CO2 causes global warming, CO is
toxic to humans
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Volatile Organic Compounds (VOCs)
Description: easily vaporized and can react
for form ground-level ozone
 Sources: cleaning fluids, paints, oil, etc
 Effects: can be carcinogens, irritants,
neurotoxins, etc
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Particulate Matter
Description: solid or liquid particles
suspended in the air; includes ash, dust,
smoke, etc
 Effects: irritates the lungs, may be toxic
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Metals and Halogens
Description: lead and mercury are the
most concerning metals, and CFCs are
important halogens
 Sources: atmospheric lead comes from
gasoline, mercury comes from coal power
plants, CFCs from coolants
 Effects: lead and mercury lead to brain
damage
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– Mercury will bioaccumulate
– CFCs decrease ozone protection
Photochemical oxidants
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Description: secondary pollutants that are
synthesized with the aid of solar energy
– Includes ozone
Sources: often nitrogen oxides
 Effects: ozone is highly reactive when in
the troposphere and causes lung damage
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Indoor Air Pollutants
Asthma triggers: secondhand smoke, dust,
etc
 Toxic building materials: VOCs, heavy
metals, asbestos
 Radon gas: radioactive gas that is
produced within the Earth and enters
homes
 Carbon monoxide: decreases oxygen
levels in tissues; created by incomplete
combustion of fuel
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Human Water Use
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agriculture > industrial > municipal
Dams can be used to control water flow
and to produce electricity
 Water diversion projects change the flow
of rivers and bring water to cities
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Water pollutants
Pathogens: highest threat to human health
 Oxygen-demanding wastes: the addition
of nutrients or human wastes allows algae to
grow; then they die, the organisms that
decompose them use up the oxygen in the
water
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– Biological Oxygen Demand (BOD) is a good
estimate of the load of oxygen-consuming
organisms
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Inorganic wastes: suspended particles and
dissolved ions such as acid deposition
Water Pollutants
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Suspended particles: includes sediment from
erosion and runoff
Dissolved ions: includes heavy metals and
calcium
Heavy metal ions: usually extremely toxic and
may bioaccumulate
Toxic organic wastes: may come from dumps
or fuel, as well as natural sources such as red
tides
Thermal pollution: decreases dissolved
oxygen levels; often comes from power plants
Removing toxic wastes
Physical methods: vaporization, filtration,
UC disinfection, reverse osmosis
 Chemical methods: acid neutralization,
precipitation, or hydrolysis
 Biological methods: bioremediation,
wetlands, bacterial decomposition
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Water pollution control
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Clean Water Act
– Make all waters “fishable and swimmable”
– Require discharge permits of major polluters
– Identify toxic pollutants and remove them
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Reduce emissions of nitrogen and sulfur dioxides
Modify agricultural practices to reduce runoff
Treat wastes more effectively
Decrease silt runoff from urban areas
Reverse river channelization
Land Use
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Tragedy of the commons: personal
good supersedes the public good
– Garrett Hardin
– Case study: Easter Island—used all of the
public resources until they were gone
– Case study: overharvesting of fish or
deforestation
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Ecological Footprint: the sum total of
the impact a human has on the Earth,
including the resources used
Land Reuse
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Conservation: not using and protecting
resources
Preservation: providing a reserve of resources
for the future
Restoration: bringing a damaged ecosystem
back to its natural condition
Remediation: using chemical, biological, or
physical methods to remove pollutants
Reclamation: using large water projects to
bring water to otherwise un-arable lands
Mitigation: finding as solution to a problem
Human Nutritional Needs
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Undernourishment—getting fewer calories
than needed to survive
– Famines are massive incidents of
undernourishment, often caused by political
or economic upheaval, or environmental
devastation
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Overnutrition—in the US we eat an
average of 1000 extra calories per day
Human Nutritional Needs
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Malnourishment—inability to acquire
adequate vitamins and nutrients
– Kwashiorkor—lack of protein
– Anemia—lack of iron; prohibits oxygen
traveling in tissues
– Goiter—iodine deficiency
– Vitamin A deficiency—harms vision
– Scurvy—vitamin C deficiency
Land Degradation
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Desertification: converting farmable
grassland into non-arable desert
– Often occurs when land is over farmed and
organic material is removed
Erosion: soil is moved
 Fertilizer Use: adds inorganic materials to
soil
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– Often causes water pollution
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Energy use: depends on fossil fuels
Land Degradation
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Pesticide use
– Toxicity to nontarget species (animals and
humans)
– Pest resistance
– Types: inorganic, chlorinated hydrocarbons
(DDT), organophosphates, botanic pesticides
– Integrated pest management (IPM) uses a
variety of management techniques
Mining
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Extraction
– Surface mining—dig an open mine, displacing large
amounts of soil
– Subsurface mining—underground mines; more risks
to miners
– Well—used for liquid or gaseous deposits
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Processing
– Gold is extracted by spraying with solvent, often toxic
cyanide
– Uranium is processed, creating huge amounts of toxic
waste
– Aluminum extraction from bauxite ore requires large
amounts of energy
Mining Reclamation
The Surface Mining Control and
Reclamation Act requires that coal mining
operations reclaim sites after mining
 Involves the return of the overburden
(land removed)
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– Then, topsoil must be put down and plants
grown
– Tailings must be removed to stop toxic and
acidic runoff
Skipped pgs 123-144—human health
 Skipped pg 181-182—sewage treatment
 195-205 (building and urbanization)
 Energy chapter
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