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What have we learned since Easter Island?
Transcript of What have we learned since Easter Island?
Colonized in 400 A.D.
POPULATION DECREASE (NRD = death rate >birth rate)
As population increases exponentially, natural resources decrease exponentially.
Sophisticated political structures fail.
Division of resources no longer shared.
Warfare over resources begins and population begins to decline (-FBL) “Corrective Loop”
On Easter Island, the population crash allowed resources to recover slowly, but never returned to the original k-capacity. Nature is resilient.
Global population is increasing exponentially (+FBL).
When will it crash? When humans exceed the global carrying capacity of the environment?
Population crash = -FBL so that natural resources may recover.
Signs of impending crashes
AIDS, pandemic outbreak threats, increased spread of disease and famine as global climates warm, increased global tension and warfare over resources (oil, water, etc…)
2,000 years ago...
...at the dawn of the first millennium A.D. the world's population was around 300 million people.
800 years later...
...the population had climbed to the landmark level of one billion people. Almost 65 percent of all people lived in Asia, 21 percent in a prospering Europe, and less than 1 percent in North America.
127 years later...
...the two-billionth baby was born. From 1920 to 1950, the population growth rate hovered around 1 percent a year. But beginning in the middle of the century, the advent of antibiotics and other public health advances profoundly altered life expectancy, increasing the number of children who would live to bear their own children.
33 years later...
...advances in medicine, agriculture, and sanitation had spread to many places in the developing world. By 1960, the global population reached three billion, and in the late 1960s the growth rate hit an all-time peak of 2.04 percent a year.
14 years later...
...new reproductive technologies had helped curb the growth rate. But with so many people already on the planet, a population "explosion" was under way, and the epicenters of the explosion lay in the developing world. The four-billionth baby was born in 1974.
13 years later...
...the five-billionth baby was born.
12 years later...
...around October 12, 1999, the six-billionth baby arrived. Today, Europe and Africa each hold about 12 percent of the world's population. Nine percent live in Latin America, 5 percent in North America. And, just as in 1800, Asia is home to the majority of Earth's inhabitants—roughly 61 percent, or more than 3.5 billion people.
Roughly 50 years from now
Over the next half century, our numbers will increase again, likely to a staggering nine billion people. Nearly all of this growth will take place in developing countries, where the demand for food and water already outstrips supplies.
1,000 years later...
...the population had risen by as little as 10 million. And well into the second millennium, it grew less than 0.1 percent each year. The numbers in Europe even fell in the 1300s—struck down by the Black Plague. But beginning in the late 18th century, the Industrial Revolution would raise living standards and spur growth.
Increased population = increase demand for resources:
demand for the food destroys the soil
minerals in soil are depleted
increased use of pesticides
overuse of fresh water
Global Atmospheric Changes
CO2 produced from fossil fuel burning acts like a blanket around the earth
Plants take CO2 out of the atmosphere though photosynthesis
6CO2 + 6H2O --> 6O2 + C6H12O6
Chemicals released from the surface of the earth destory our ozon shield
No stratospheric ozone, no protection from the UV rays of the sun
Loss of Biodiversity
Habitat destruction leads to a loss of many species starting with the plants
exact # of species lost is unknown because not all species are identified
Strong ecosystems need biodiversity
1959-1980: 25% of all prescription drugs from natural resources
wild species keep domestic species vigorous
Rachel Carson was a scientist who wrote Silent Spring in 1962.
It addressed the growing use of pesticides (DDT) and their unpredicted effects on the song birds
Original users of pesticides did not know that the posions used to kill insects would accumulate in other living things and kill them too.
More Cool Environmentalists:
John Muir - founded the Sierra Club
Ansel Adams - photographer
Aldo Leopold - Author (A Sand County Almanac)
Henry David Thoreau - Poet (Walden Pond)
Garrett Hardin - wrote Tragedy of the Commons
Levels of organization of matter
Plants and animals interacting with their abiotic environment. Ecosystems exist in biomes.
Climate - average temperature over time
Weather - daily variations in temperature & precipitation
Microcliamte and other Abiotic factors
Biomass & Biomass Pyramids
All biomass gets its energy from the sun
Only 10% of energy from one trophic level moves to the next trophic level
Energy released is high potential energy molecules (like glucose) then converted into low potential energy molecules (like carbon dioxide)
**Concept of eating lower on the biomass of the pyramid**
Temperature, light, oxygen, carbn dioxide, precipitation
zones of stress
limits of tolerance
range of tolerance
Synergistic effects - the interaction of two or more factors is greater than the sum of the effects when each acts alone. Examples: pollution & disease
Energy is measured in calories
Calorie - amount of heat needed to raise 1 gram of water 1 degree celsius
1st Law of Thermodynamics
Energy cannot be created nor destroyed, only change forms (light to chemical)
2nd Law of Thermodynamics
Energy transformations increase disorder (entrophy) of the universe.
Heat is the lowest grade of energy.
flowers & insects
Habitat v Niche
Ecosystems & How they work
Recycle or die (Death and decay)
All matter is recycled through the lithosphere, hydrosphere, and atmosphere
Nothing is created, nothing is destroyed
All stable ecosystems recycle matter and get erergy from the sun.
Atoms - basic units of matter
(electrons, protons & neurons
Chemical bonds - how atoms are held together (ionic & covalent)
Molecule/Compound - two or more atoms bonded together
pH scale - base/alkaline & acid
C-C bonds and/or C-H bonds
They can be natural (compounds that make up living things) or synthetic (man-made compounds)
Photosynthesis - very inefficient (only 1% of the energy from the sun is used)
Moving fossil fuels (which took millions of years to form) to the atmosphere (in hundreds of years) is the major component of global warming
Main reserve in the atmosphere
Living things must get nitrogen from ammonium (NH4) or nitrate (NO3)
N from the atmosphere must be fixed:
change N2 into ammonium or nitrate
Rhizobium (bacteria living in roots of legumes)
Burning fossil fuels
No gas phase
only solid and liquid
man-made fertilizers contain organic phosphates
because P is a limiting factor in aquatic systems, it leads to eutrophication
The rainforest is very good at recycling P, except for when we cu it down...
Top 6 most abundant elements in LIVING THINGS (not in order)
Top 8 elements in the earths crust (in order)
O, Si, Al, Fe (iron), Ca, Na (sodium), P, Mg
Only silly apes in college study past midnight
Fires in Ecosystems
maintain balance of species and energy in ecosystems over the long run
beneficial because it provides nutrients for the soil
Must create new soil for plants to grow
the first plants to come in are called pioneer species (lichens, moss, microbes)
Succession - One species gradually replaced by another in an ecosystem
primary - new ecosystem where there were no living things before (cooled lava, receded glacier, mud slide)
secondary - ecosystem used to be there (fire, humans clear an area)
Aquatic - lakes taken over by terrestrial ecosystem
Climax ecosystem in balance only changes if major interference
Why do species change?
Environmental resistance and biotic potential
Selective pressure on mutations
Speciation (creation of a new species based on reproductive isolation)
(space and time for evolution)
geological time scale
Mutations are naturally random events
Genetic Trait - only passed down if an organism reproduces
Population Growth Rates
(b) crude birth rate - number of birth per 1000 individuals
(d) crude death rate - number of deaths per 1000 individuals
(r) growth rate - natural rate of increase in population expressed as percent per years (of this number is negaive, the population is shrinking
rate = birth - death
but other factors affect population growth in a certain area...
r = (birth - death) + (immigration - emigration)
If the growth rate is 1% and the population size is 10,000, how many years will it take to get a population of 40,000?
70/rate = 70/1% = 70 years to double
In 70 years the doubling time will be 20,000
In 1 DT => 20,000
In 2 DT => 40,000
(70 years)(2) = 140 years
In 140 years the population will be 40,000
SHOW YOUR WORK
Developed v Developing Countries
Developed Countries (Canada, US, Australia, Western Europe
Developing Countries (Latin America, China, Africa)
1/5 of the world's population in lives in absolute poverty, illiterate, lack clean H20 and don't have enough food
80% of world's population lives in developing countries and their population is growing
Total fertility = average # of children born per woman
For developed countries = 2.1
For developing countries = 2.6
Fertiliey of 2.0 = replacement level
Under 2.0 = shrinking population
Over 2.0 = growing population
Soils (Dust Bowl, Porosity and Permeability Labs)
Sand 2.0 - .02 mm
Silt .02 - .002 mm
Clay .002> (some microscopic)
Loam (40%sand - 40%silt - 20% clay
Loam is theoretically the ideal soil
Classes of soil
Mollisols - very fertile, dark, found in temperate grasslands, best agricultural soil, Deep A horizon
Oxisols - soil or tropical and subtropical rainforest layer of iron and Al oxide oxides in B horizon, little O horizon
Alfisols - weathered forest soil, not deep, but developed OAE horizons + B typical temperate forest biome. Needs fertilizer for agriculture.
Aridsols - dry lands + desert, lack of vegetation, lack of rain -> unstructured vertically, irrigation leads to salinization b/c of high evaporation
The primary use for fresh water in the US is agriculture
In our homes, we use the most fresh water to wash, clean and flush
The typical person in an industrialized nation uses 700-1000 gallons per week
The Ogallala Aquifer
Excellent example of human interference with the water supply
The water in the lake was diverted from the lake to the city of Los Angeles. It became a salt bed.
Increased salt concentration due to evaporation
Three Gorges Dam in China
China needs to meet the growing demand for energy
Huge environmental impact
Hundreds of thousands of people will be displaced (not to mention the ecosystems which will be flooded)
Greenhouse gas emissions from fossil fuels
other air pollutants from fossil fuels
pollutions from pesticides sprays
loss of fertility
increased runoff and flooding from land cleared to grow crops
fish kills from pesticide runoff
surface and groundwater pollution from pesticides and fertilizers
over fertilization of lakes => eutrophication
Major environmental effects of food production
loss and degradation of habitat from clearing grasslands and forests and draining wetlands
fish kills from pesticide runoff
killing of wild predators to protect live stock
loss of genetic diversity from replacing thousands of wild crops strains with a few monoculture strains
nitrates in drinking water
pesticides residues in drinking water, food and air
contamination of drinking and swimming water with disease organisms from livestock wastes
The Green Revolution
To Eliminate hunger by improving crop performance
Movement to increase yields by using:
new crop cultivators
do not eliminate famine
population still increasing
increase cost of production
an increased negative environmental impact
didn't work for everyone
Protection of Biodiversity & Ecosystems
Threatened - if the trend continues, the species will be endangered
Endangered - of the trend continues, the species will be extinct
Pharmaceuticals and native plants --> approximately 25% of drugs used as medicines come from natural plant sources
The Exxon Valdez Oil Spill (1989) --> 300,000 birds died as a result of that particular oil spill. The area, Prince William Sound is still recovering
A keystone species holds a community together, when it disappears, so does the biological community. Elimination of a keystone species dramatically alters the structure and function of a community.
Many small offspring
Little or no parental care and protection of offspring
Early reproductive age
Most offspring die before reaching reproductive age
Adapted to unstable climate and environmental conditions
High population growth rate (r)
Population size fluctuates wildly above and below carrying capacity (K)
Low ability to compete
Early successional species
Fewer, larger offspring
High parental care and protection of offspring
Later reproductive age
Most offspring survive to reproductive age
Adapted to stable climate and environmental conditions
Lower population growth rate (r)
Population size fairly stable and usually close tocarrying capacity (K)
High ability to compete
Late successional species
Fossil Fuels (Non-renewable Resources)
Coal - several hundred years
Natural Gas - at least 50 year supply in the United States
Oil - about a decade until supplies peak... (today 4/27 $112. 33/barrel)
Important Energy Facts
1700-1800 fire wood
1950 - today Crude Oil ("production of crude oil" = withdrawing it from reserves
We currently get 50% of our crude oil from foreign sources
Alaska pipeline built to help increase producton of domestic crude oil (ANWR)
Types of coal: Peat (not coal)-> Lignite (brown coal) -> bituminous coal (soft coal with high sulfur) -> Anthracite (hard coal with low sulfur - burns "clean)
The most important fossil fuel in the American Economy
Production: local ecosystems damage possible (Gulf Oil Spill 4/2010)
Transport: oil spills cause local and regional ecosystem damage (Exxon Valdez 1989)
Use: Photochemical Smog, particulates, acid precipitation, carbon dioxide)
Production: ecosystem damage, reclamation difficult (cookie mining lab), acid mine runoff, mine tailings, erosion, black lung, radon
Transport: energy intensive because of weight and number of train cars needed
Use: Fossil Fuel with the largest source of carbon dioxide and greatest quantity of contaiminants, largest volume of waste, acid precipitation
Possibly a transition fuel between fossil fuel and alternative energy sources
Production: Local ecosystem damage possible if oil or coal is part of the deposit
Transport: can be explosive
Use: produces the least air pollutants of all the fossil fuels
Electricity is a secondary energy source because it relies on another energy source to create th electricity
Basic production of electricity-boil water to produce steam to turn turbines to generate electron flow through a wire
Examples of primary sources for electrical production (20% from nuclear; 57% from coal; the rest is oil, geothermal, solar, wind, hydroelectric (no boiling water required for these (solar, wind, hydro necessary)
Pros: no CO2 emissions, no particulate emissions
Cons: Radiation can lead to damaged DNA, costs, radioactive waste (where do we put it?) thermal pollution
Basically - the splitting of uranium's nucleus gives off heat that can be used to boil water and turn a turbo generator to create electricity
Naturally ocurring Uranium is mined
Fusion - the combination of 2 atoms to form a larger atom (we are not here yet - we are in the before fusion years)
Fission - splitting an atom
Nuclear Regulartory Comission is the US governmental agency that regulates nuclear power plants
Radioisotope = unstable radioactive isotope
Uranium 235 has 92 protons and 143 neutrons. It is radioactive and used as fuel in nuclear reactors
When U235 is hit be a neutron, it is split (fission) into two smaller elements such as Kr and Ba plus three neutrons which sustains the chain reaction
Most (99.3%) of the naturally ocurring uranium is U238
For a nuclear reactor, this must be purified to 4% U235 and 96% U238 (VERY expensive)
How does a Power Plant operate?
a. water moderator - slows down neutrons
b. neutron - absorbing material - control rod
c. fuel rods - approximately one third replaced each year
d. Heat transfer system
e. Cooling System
f. Redundant safety systems
a. 4/26/86 (just had the 25th anniversary of the event)
c. Complete meltdown
Three Mile Island
b. Pennsylvania (50 miles from NYC)
c. partial meltdown, no one known to be hurt
All fuel rods are still in cooling ponds at commercial nuclear facilities
Proposed site for disposal - Yucca Mountain (no longer being considered)
sunlight, wind, falling water, geothermal
NOT fossil fuels, NOT nuclear
Active Solar Heating
Photovoltaic (PV) panels can be used to convert the energy from the sun into electricity
Electrons from the silicon in the PV panel are "pushed" through a wire by photons from the sun creating an electric current
Passive Solar heating:
large south-facing windows, heavy drapes to trap heat at night, interior bricks to trap heat
Shade windows in the summer to block light
Even though back up systems are required, and solar heating many only lessen the need for heating oil a few %, it will help us adapt to diminishing supplies
A dam is built across a large river to create a reservoir. The higher the head, the greater the amount of power that can be generated. Water is stored in a reservoir during low electricity production. Water is released and flows are controlled as electricity demands peak. Water spins the turbines in the “powerhouse”. Electricity is distributed to end user.
Biomass – organic matter in plants produced through photosynthesis and can be burned directly as a solid fuel or converted into a gas or liquid fuel.
Geothermal Energy - Heat contained in underground rocks and fluid that can be tapped for energy.
Extract dry steam, wet steam or hot water and can be used to heat space or water.
“Potentially renewable resource”
22 countries currently use geothermal, it supplies 1% of world energy. In the USA (44% geothermal energy produced worldwide) geothermal electricity is produced mostly in Hawaii, California, Nevada, and Utah.
Risks & Pests:
Borneo (DDT - The day they paracheuted cats into Borneo
Hazard: Anything that causes:
1. Injury, disease, or death to humans
2. Damage to property
3. Destruction of the environment
Cultural Hazard: a risk that a person chooses to engage in
RISK: The probability of suffering as a result of a hazard
PERCEPTION: What people think risks are
Leading cause of cancer in the US
Can cause cancer, lung disease, a bigger risk of death in addition with other types of pollution
Highest Health Risk in the US
Integrated pest management includes:
a. adjusting environmental conditions
b. chemical pesticides
c. disease resistant varieties
d. Crop rotation
e. biological controls
Insecticides kill plants, mammals, fish, birds
A broad spectrum pesticide is effective towards many types of pests
DDT accumulates in fat body tissue of animals
DDT was not used for handling weeds
DDT is, persistent, synthetic organic compound and a subject to biomagnifications in food chains
Lyme disease can be processed to human through the bite from an infected tick
Mosquitoes cause malaria, the vector for Plasmodium
The protozoan of the genus Plasmodium is the causative agent of malaria
lack of access to safe drinking water is a major cause of disease transmissions in developing countries.
Epidemiology is the study of presence, distribution and control of a disease in a population
Morbidity is the incidence of disease in a population
Mortality is the incidence of death in a population
Sewage treatment is the common practice
in the 1970, many cities were still dumping raw sewage into waterways
In 1972, the Clean Water Act provided funding for upgrading STP
Currently water ways are much cleaner
1^ (primary) & 2^ (secondary)
primary treatment - allow grit to settle
separate sludge from water
secondary (biological treatment) - bacteria feeds on the organic material
trickling filters contain bacteria --> removes the raw sludge from the water
RAW SLUDGE MAY CONTAIN HEAVY METALS
(it may need tertiary treatment to remove the toxic chemicals)
Home Septic Systems
do not use chlorine
do use a settling tank to settle organic solids
lets waste water percolate into the soil bacterial composition
Municipal Solid Waste
210,000,000 tons of municipal solid waste (MSW) are disposed of annually in the United States
Most of the waste is paper
55% of MSW is disposed of in landfills
17% of MSW is combusted, mostly in waste-to-energy (WTE) combustion facilities.
The best solution for solid waste problems is to reduce waste at its source
More than 75% of MSW is recyclable
What else can we do?
organic compounds with a halogen (bromine, iodine, etc.) replacing a hydrogen
used as pesticides
used to make plastic
resistant to biodegration
synthetic organic compounds
DIOXIN (mainly cause by burning PVC pipe - medical waste)
linked to cancer
Layers of the Atmosphere
Composition of the atmosphere
78% Nitrogen gas
20% oxgen gas
less than 2% - water vapor, argon gas, carbon dioxide (0.04%) & trace gases
Global Climate Change
Ozone - Good up high - bad nearby!!
Trophosphereic ozone is BAD
If we breath it, it causes lung damage
it is also a ghg
Stratospheric ozone is GOOD
It shields us from the harmful UVB rays of the sun
Ozone depletion is the thinning of the ozone layer (mostly over the South Pole)
Stratosphereic ozone is like sunblock for the earth
Get lots of sleep this weekend - don't cram the night before...be confident you have prepared your self to this point!
Be here by 7:00 on Monday - the exam STARTS AT 7:15!!!!