4-02apes review Exam Review for Environmental Science-I
Fundamentally
the planet consists only of matter and energy.
To an environmental scientist the quality – high ex: coal or Al or low ex:
methane and mineral ores is important.
The driving force for quality of matter is entropy. Entropy always
proceeds towards a state of high entropy in which matter is poorly organized.
Biogeochemical cycles describe the flow of
matter through the environment. The
common theme is to have a reservoir an assimilation in which the matter is used
by the living components and degradation in which it is released an available
once again.
Hydrological
cycle- Water cycle
Assimilation-
via absorption by plants and animals
Release-
as plants loose water via transpiration and animals exhale during respiration.
Assimilation-
via photosynthesis and as producer materials are transferred up the food chain.
Release-
respiration of plants and animals, decomposition of organic matter during
combustion ex: burning coal.
Reservoirs-
as atmospheric N2, in the soil as NH4+ _________, NH4 _________, NO2- and
NO3- __________, __________.
Assimilation-
plants absorb nitrogen as nitrates or ammonium, passes up food chain.
Nitrogen
fixation turns atmosheric nitrogen to ammonium via rhizobium, atmospheric
nitrogen can be turned into nitrates via lightning or electrical discharge.
Nitrification
turns ammonium to nitrites and nitrates via nitrifying bacteria.
Release-
denitrifying bacteria convert nitrates back to nitrogen (denitrification) and
detritis bacteria turn organic sources e.g amino acids, proteins to ammonium
ions, also excretion of metabolic wastes as ammonia and urea.
Phosphorous
cycle-an essential plant nutrient which also is implicated in eutrophication.
Reservoirs-
rocks as phosphorous, phosphate
Assimilation-
plants absorb phosphate PO4-3 from soil.
Release-
during decomposition of animals, plants.
Energy
forms – kinetic, EMR, heat, potential always degrade as well but proceed from a
concentrated energy form to one in which less energy is transferred as it
flows. Hence the quality is also
important--- high ex: nuclear vs
low geothermal. Two fundamental laws of energy govern:
1. First law of conservation
2. Second law of efficiency --- in
ecosystems about 10% is the maximum that can be tansferred each time( 90% loss
to heat). The loss of energy transfer
usually is seen as waste heat.
Environmental impacts ---- we have arrived at
through-put societies in which resources are depleted and sustainability is
threatened. Solution:
change to a low waste, recycle approach in which is energy is conserved
and high quality matter and energy are not wasted when lower quality can be
substituted.
|
Tables
& Figures: Table
3-2 Fig 2-8,2-9,2-10,2-11,2-12,2-13,
3-7,3-8,3-9,3-10,3-12,3-14,3-15,3-16,3-17,3-18, 3-22 |
All
ecosystems are impacted by both biotic
and abiotic components.
Earth’s
crust is the top 2% of the planet.
Oceans cover the abyssal floor with a ridge system. Deep ocean trenches have some of the richest
minerals and strangest biodiversity. The
continental system “floats” on the core and consists of mountains and craton
(non-mountainous). The crust is the
storehouse of minerals (ores), below which lies the mantle and core. Plate tectonics explains the changes that
have occurred in our lithosphere (crust and mantle top). These plates undergo convergence, divergence
and transformation. Large scale crustal
movement forms mountains while external forces; sun, wind, etc can also change
the earth’s surface. Weathering-wind
rain, erosion-via wind and rain which causes movement or loss and mass wasting-
via rockslides and mudflows.
The
rock cycle illustrates the cycling of matter.
Three main types of rocks are igneous—granite, lava which result from
magma escaping make up the bulk of the earths crust.
Sedimentary---limestone,
gypsum form from layered deposits of eroded soil ex:
Metamorphic—coal,
slate forms when rocks are heated and melt under high pressures.
Natural
hazards consist of earhquakes, vocanic activity, floods, subsidence. All of these can lead to a loss of
biodiversity, habitat and resource quality e.g. water quality or air pollution.
Mining
of Resources poses many environmental problems including:
Erosion,
air/water pollution, scarring of land, subsidence, leachates (acids), habitat
destruction. Which can result from open
pit, strip, surface and dredging operations to extract the minerals which have
economic value.
|
Tables & Figures: Fig 5-17,5-18 |
Chapter 5 Evolutionàbiodiversity
In
order to fully appreciate biodiversity it is helpful to investigate the origins
of life on earth. There are two
fundamental types of organisms—prokaryotes that lack an organized nucleus
ex: bacteria. Eukaryotes which have an organized nucleus
and comprise almost all other organisms (plants, animals, protists).
Representatives--
Protists—diatoms,
amoebas, algae
Fungi-
molds, mushrooms, yeasts
Plants-
monocots, dicots, angiosperms, gymnospersm
Animals-
invertebrates, vertebrates, mammals, amphibians, reptiles. Aves
Evolution-
probably a result of changing earth in 2 phases; chemical evolution shere the early
earth consists of carbon dioxide, methane and ammonia which convert to nucleic
acids and amino acids with u.v. radiation or conversion at thermal vents under
high heat or even brought in by metoerites.
Followed by biological evolution; once formed nucleic acids probably
sequenced into RNA, DNA, protobionts and eventually photosynthetic bacteria as
the earth changed from an oxygen poor environment to oxygen rich. Currently earth at 4.7 billion years.
Main
evolutionary terms-
Microevolution- small changes in DNA
sequences e.g. antibiotic resistance or pesticide resistance.
Macroevolution- large changes that happen
slowly over time results in new species.
Evidence
for evolution/speciation-
Fossils,
homologous structures, embryology, molecular biology
Evolutionary
mechanisms- mutations via radiation, chemicals, chance and natural selection in
which changes in DNA provide a positive or negative advantage. If the advantage is passed on the DNA
survives; Natural Selection (Darwin and Wallace) populations evolve.
Diversifying- uncommon traits are
best e.g. white or black
Stabilizing- average traits are
best e.g. grey
Directional-uncommon trait becomes
the norm e.g. sickle cell and malaria
The
populations with the new traits (DNA) must become geographically isolated and
reproduce only within that group. If not
the alternative is extinction—gradual or punctuated.
|
Tables & Figures: Fig 5-9,5-10,5-12,5-13,5-21 |
Chapter 4Population Dynamics
Population
changes- Change in reproducing populations are controlled by the carrying
capacity of the system.
Organisms
make up our biodiversity that is found in ecosystems. To keep these populations in balance both
abiotic—ex: drought and biotic—ex: predator-prey relationships provide stress. Populations are controlled by:
Biotic
potential-
growth*
Environmental
resistance-
decline*
Density
dependent-competition
for food
Density
independent-
flood, fires
·
PROVIDE FEED-BACK LOOP
Zero
Pop Growth- no net change or Births + Immigration minus
Deaths and emigration.
Pop
curves-
J-
curve where the population hovers around
the carrying capacity.
S
–curve where the population is in exponential growth phase
Pop
Control strategies-
r-
short life span, small offspring in large numbers with a short lifespan ex: fish, insects
K-long
life span, long birth cycle few numbers with relatively large stable pop sizes.
Biodiversity-
is the variety of life forms; Importance--
Healthy ecosystems are diverse.
These systems have high net productivity.
Species
diversity refers to the variety of species within a region. Ex:
birds and mammals vs only mammals.
There is an unveven distribution based on elevation, temperature,
latitutude. Ecosystem diversity- found
in ecoystems. Cultural diversity- when
humans are in an ecosystem. Biodiversity
is controlled by the niche of the organism, the available resources,population
dynamics and the species interactions of
competition, predation, mutualisms (symbiosis and commensalism).
Interspecific
competition- between 2 or more species competing for the same resource.
Predator-prey---
between individuals not populations illustrate pos/neg feed back loops.
What
does the graph look like?
Symbiotic-
2 species in close relationships
Parasitc- harms the host, live on or
in the host
Mutualism-both species interact and both benefit
e.g. nutritional or protective ex: pollinators or cleaner fish.
Commensalism- one benefits and the
other is not harmed or helped ex. Clownfish
Successional
Patterns of population change- Change
over time usually involving plants.
Primary-
plants begin to grow on rocks and bare soil.
Lichens, mosses, grasses, shrubs, trees.
Secondary-
on land that has already undergone succession is now bare. Ex: clear cutting a forest. Hubbard-Brook study to see how succession is
effected by nutrient cycling.
Value
of biodiversity-
Immature
ecosystems have simple food webs, small plants and limited matter and energy
cycling.
Mature
ecosystem have mature systems with complex webs and nutrient cycling. Considered climax vegetation communities.
Successional
patterns can be disrupted e.g. fires, habitat destruction.
Ecosystem
benefits- water holding capacity, soil microbes, decomposers, nitrogen fixers,
photosynthetic output, climate stability, pollution clean up, homeostasis,
disaster recovery.
Bioresources-
provide food ~20 plants feed the world (corn, rice, wheat), fish
Provide
medicines, wood products, breeding stock (DNA), cultural diversity, recreation,
educational and research opportunities, and have intrinsic value.
|
Tables & Figures: Fig 4-2,4-4,4-5,4-6,4-15,4-16,4-17 |
Climate-
the long term weather primarily determined by temp and ppt and controlled by
air and wind circulation patterns and the topography of the land.
Seasons-
determined by incoming solar energy and the uneven heating of the earth as the
earth rotates and tilts.
The
ENSO- “el nino” effect illustrates the impact of changing factors—nutrient
cycling is blocked in southern hemisphere and warm water sent to northern
hemisphere.
Atmospheric
gases have important impact on planet; water-stabilizes, carbon dioxide-global
warming, ozone- protects from UV.
The
limiting factors of water, incoming solar radiation, air, control the climates which vary with latitude
and altitude to produce distinct regions for ecosystems----Biomes.
Biomes
are individual but interconnected ecosystems.
Man has impacted these ecosystems and altered the worlds biomes ex: tropical rainforest deforestation(
Review
climatograms and major biomes including limiting factors, representative
species and environmental concerns.
|
Figures & Tables: 2-16,2-18,2-19,2-20 Fig 21-2,21-14 Table 2-3 |
Failure to maintain populations results in extinctions. Although, extinction is normal the accelerated rate due to human activity is not, estimates of 5-10 extinctions/ day are frequently cited. Key factors are:
habitat
loss and degradation
alteration
of environment,
man’s overhunting, fishing
pest control and introduction of non-native species
Not
all species are threatened with extinction.
Some are threatened (declining numbers) or endangered (few numbers). To stop extinction we must:
1. Protect habitat-Wilderness Act which allows
protection of undeveloped land, National
Wild and Scenic Rivers Act keep rivers free of development to be used
for recreation only.
U.S. Public Lands about 40% of the
land (most of which is in
National Forests- USFS control via
multiple use
National Resource Land- BLM control
via multiple use
National Parks-NPS control via
preserve, protect for recreation
National Wildlife Refuge- US Fish and Wildlife Service
limited use and protection of habitats as determined by dept. of interior
National wilderness- joint management areas to be
preserved
2. Protect endangered/threatened species with
the ESA (list, identify then prohibit hunting, injury or collection), Lacy Act
(prohibits transport of wild animals without permit) and CITES (international
treaty which requires permit to transport animals).
3. Manage/regulate populations- using wildlife
management principles of ecology, population dynamics.
Control
food supply, control hunting, establish refuges, ban whaling, etc.
Strategies
employed include:
Nature
conservancies- buy land and hold to preserve and protect habitat
Gene
banks- for a last resort prior to extinction
Botanical
gardens and zoos
Captive
breeding programs
|
Tables & Figures: Table 11-1,11-2,11-3, 12-1,12-2, Fig 11-8,11-9,11-10,11-11,11-12, 12-1,12-2,12-6,
12-7 |
Exam Review for Environmental Science-II
Chapter 6 & 7-
Population dynamics
The study of human population changes – the trends and causes.
%
changes = BR- DR/10
Doubling
Time = 70/ % changes ex: 70/3% = 35 yrs to double the population
Because
the world’s population has increased dramatically 3.2 billion from 1965 to 5.8
billion in 1996 population population trends have generated much interest and
concern.
Demographers
use population profiles to study trends.
Essentially a bar graph which shows age and % of population at
intervals. Ex:
Developing
countries Developed Constrictive
85 -- -- --
-- --
-------
40 -----
------
--------------
------- ----
------------------
5 ------------ --
--------
Used
to predict the goods and services that will be needed, funding of social
services and the forcasting of future birth and death rates. They give a snapshot view of what is going
on and are based on TFR and death rates.
Must be revised because they change over time. They indicate that overall world population
will grow, while some countries will or have begun a decline in population ex:
US, Japan
What
changes fertility rates?
Educational
level, wealth
%
of women in work force
rural
vs urban lifestyles
literacy
and educational level of women
infant
mortality
religion,culture,
social programs
birth
control options or lack of
The
major factor in increasing populations
has been death rates caused by-
Better
food distribution, health care, water quality, sanitation, lowering of infant
mortality.
Text and Figures-Table 6-1 |
Environmentally the goal is to provide energy at minimal cost to the environment.
To do
this a transition from fossil fuels and nuclear power which is in
finite supply and has impacts on air and water quality as well as hazardous
waste is required. Environmental goal is
to use renewable resources which have minimal or no environmental impacts.
Oil-
40% of our energy budget; although it is portable and is fairly inexpensive its
supply is dwindling and contributes to air pollution by emmiting CO, CO2, NOx
and particulates
Which
contribute to global climate change and acid rain.
Coal-
23% this source is higher in quality, has a more abundant supply but also
contributes to air pollution and must be mined which increases environmental
impacts.
Natural
gas-20% also LNG and LPG we have more natural gas than oil. It is cleaner burning than oil and is
transportable as well. Better choice
than oil.
Nuclear
Power- 10%
of power in US. Historically
controversial.
Nuclear
power comes from fission of U235 which emits radiation and other
trasmutation products. This reaction
puts out many times more energy than chemical fuels (oil, coal, etc). It is very efficient, emits less CO2,
has a relatively good safety record overall.
Negatives are cost, radiation, storage of wastes, terrorism threats and
the limited supply of U235 which has made breeder reactors a
frequent proposition as an alternative.
Primary concern for most citizens is risk of cancer from exposure of
radiation (somatic cells) or birth defects ( germ cell). The handling and storage of nuclear waste
products from all sources has been of concern.
high-
spent fuel from reactors (1000’s of years)
Transuranic-processing
wastes
Low-
hospitals and university reactors
Wastes
are processed by:
Incineration-
low level
Compaction
Solidification
Storage
on site or in underground facilities-transuranic and spent fuel
Renewable
energy alternatives- prior to considering renewable options energy conservation is an
often overlooked strategy (Note: the primary driving force of conservtion came
about in the 1970’s with the OPEC oil embargo) in addition to wise energy
matching.
Passive
and active solar collectors for heating. Water and Space Heating. Uses solar collectors or orients the house in
a favorable location to trap sunlight.
Solar
powered electricity- photovoltaic cells—used locally, solar trough
collectors—used commercially.
Hydropower- Dams; require large water flows can also have
environmental impacts, loss of habitat, potential for flooding.
Windpower-
requires large area and of course wind.
Potential problems from noise and loss of wildlife (birds).
Solar
production of Hydrogen fuels- using photovoltaic electricity to split water and
capture hydrogen as a clean burning portable fuel.
Synthetic
fuels—convert biomass to alcohol and use in place of gasoline. Many countries do this well ex:
Brazil and New Zealand.
Non-Solar-
Geothermal-
requires access to geothermal vents, high cost and often variable output.
Tidal
Power- few possibilities, nevertheless always mentioned as an alternative.
|
Tables and Figures- Fig 13-4, 13-6, 13-9, 13-10, 14-2, 14-5, 14-6,
14-8, 14-9, 14-10, 14-11, 15-4,15-7,15-14 thru 15-17, 15-24 Table 13-1, 13-2, 13-3, 14-1, 14-2 |
|
|
The
atmosphere consists of 3 layers; troposphere from the surface to 17 km here
significant water vapor is present and our weather patterns are formed. The stratosphere is from 17km to 50km where
the same gases are found in less abundance, it is in this region that UV is
absorbed by ozone and turned into oxygen.
The last layer above 50km is the mesophere where the atmosphere
transitions into space.
Pollution
sources-
Natural
occuring---forest fires, volanic activity, dust
Man
made—
Primary- released directly
ex: CO, CO2, SO2,
NO, HC’s particulates
Secondary- via chemical reactions
CO or CO2 + H2O à HCO3 weak acids
SO2 or SO3
+ H2O à H2SO3
and H2SO4 strong
acids
NO and NO2 +
water à HNO2 and HNO3 strong acids
3
O2 à 2 O3 under influence of light, UV at ground level
NOx + O3 + HC
form photochemical oxidants withlight and heat (PAN)
Others- inorganics ex: aspestos
Organics- ex: pesticides, solents
Radiation- from coal burning and
radon
Heat- from combustion of fuels
Noise- transportation and
industry
Sources of Pollutants-
Transortation (50%), Industry13%,
Stationary28%
Air pollution is often
geographical- for example industrial is usually in northeast, photochemical is
often in the west e.g. Los Angeles.
Imporving Air Quality has been a
top priority in the US and California.
1970- Clean Air Act set standards
for 4 pollutants with a 90% reduction goal
ammendments in 1977,1990 have
brought in waivers, RACT and MACT which
has improved air quality
immensely—ex: catalytic converters, precipators, filters,
scrubbers and separators
Global Atmospheric Changes-
Acid Rain- from SO2 or SO3 + H2O à H2SO3
and H2SO4 strong
acids
NO and NO2 +
water à HNO2 and HNO3 strong acids
Emissions are concentrated
geographically and primarily effect streams and lakes in which organisms are
sensitive to varying pH levels. PH less
than 5.6 is considered acid rain by the EPA.
pH = - log of H+ ex: 1 x 10-3 H+
represents a pH of 3 Note- log
In addition property, crop damage
is signficant.
Global Warming-
Carbon dioxide levels have
increased by 20-30% since 1800’s with a small temperature rise occuring
also. Other gases implicated are methane
and water vapor. Long term impact is
uncertain and hotly debated including extreme views of flooding, etc.
Ozone Depletion-
The significant loss of ozone due
to chlorfluorcarbons. First identified
in 1985 in which Antarctica ozone hole observed. Important to note that Cl and F can break
down many ozone molecules and remains in the atmosphere for years.
CCl4 à Cl*
Cl* + O3 à ClO2 + O*
ClO2 à Cl* + O2
Etc, etc……
Importance--- ozone layer blocks UV
which protects humans, animals.
Possible links to skin cancers,
cataracts with scant data to support effects.
Tables and Figures-
Fig 21-2,
21-3, 21-4, 21-5, 21-6,21-9,21-10,,21-12, 21-11, 21-18, 21-19, 22-3, 22-5,
22-12, 22-13, 22-14, 22-15, 22-16, 22-18, 22-20, 22-21, 22-23, Table
21-1, 21-2, 21-3, 21-5, 22-1, 22-2 |
Chapters 9 & 18 - Water
and Water Pollution-
First lets review some important properties of
water.
High m.p., high b.p., surface tension, high specific
heat, density that changes with temperature, a polar molecular which is an
excellent solvent.
94-97% in oceans, 3-4% underground aquifers, 1.5% polar
ice
Of which only about 05% is used by humans
47% agricultural, 44% industrial 4-10% other
Distribution of water-
Uneven, often shortages due to drought, floods,
overdraft, salt water intrusion
Dams, reservoirs, import, desalinate and conserve,
cloud seeding
Review methods to increase
supply EX:
Dam- Plus=
stop floods, generate electricty, recreation, increase farming
Neg=
displaces habitat, alters ecosystems, displaces people, can cause flooding
Overdraft- Plus= more water is available, local
Neg=depletion, subsidence, salt water
intrusion
Water
Pollution-
based on principle that water does not meet a “standard” as with air pollution.
Organic
wastes—bacteria, pathogenic sewage cause
high BOD
Inorganic-acids,
metals, fertilizers causes toxic acid
rain effects and or algal blooms leading to eutrophication.
Organics(chemicals)-solvents
and petrochemicals lowers water quality
below “standards”
Thermal
pollution- waste heat electric power generators
can lead to alteration of ecosystems and changes in biodiversity.
Sediments-particulates
that do not dissolve and can affect photosynthesis and respiration (C-O cycle)
Point-
single source ex: power plant or oil
refinery
Non-Point-
multiple sources ex: fertilizers and air pollution can both emit
nitrates
Agricultural pollutants
contribute the largest impact to
streams and lakes
Contaminants ex:
acid rain, industrial sources—leaking
tanks, illegal dumping, landfill seepage (leachates),mining and even introduction of non-native species
can effect water ecosystems. Main
concern is contaminated drinking water supplies.
Effects: High BOD, biomagnification of water soluble
compounds, eutrophication
Solutions: dilution, chemical treatment, ban chemicals,
erosion control, legislation
1974
Safe Drinking Water Act established maximum levels of contaminants.
1972,
1987 Clean Water Act- prohibits dumping into lakes, streams to make safe for
fishing and swimming.
Sources-
municipal wastes, industrial, agricultural runoff, air pollutants and oil (the
most visible but smallest contribitor).
Primarily enters wetlands, estuaries at large population centers.
Solution-
Clean up sewage before it enters the oceans by:
Primary
treatment where the solids are physically remove and the water is allowed to
settle for 8hrs….remove sludge and transfer water to
Secondary
treatment where bacteria remove most of the dissolved organics at this point
the water can be used on golf courses, etc.
water then sent to primary treatment where bacteria, and chemicals such
as chlorine or ozone are used at this point meets drinking water standards
however it can only be used to recharge aquifers and for irrigation.
Oil-
Pollution
Case
study is the Exxon Valdez in which sever habitat destruction has occurred that
has take app 10 years to return to “normal”.
Most oil pollution is natural or from accidental leakage. 50% comes from oil on land from dumping down
into drains.
Effects
are variable due to wind, tides, etc.. immediate--toxic, short term—oil on
feathers and long term—ocean bottoms, shellfish effects can be observed. Clean up by mechanical, chemical and
biological methods.
|
Tables and Figures- Fig 9-1, 9-3, 9-8, 9-11, 9-10, 9-13, 9-14, 9-16,
9-18, 18-2, 18-7, 18-11, Table 18-1, 18-3 Earth Watch pg 444 |