APES FINAL EXAM REVIEW Important Equations Simple growth rate of a population N1= N0 + B - D+ I – E N0= Starting population, N1= Ending population B= Birth rate, D= Death rate, I= Immigration rate, E= Emigration rate

Intrinsic Rate (r) of increase for population growth r = B - D

Rate of change of population size dN = rN dN = N1- N0 dt

Net growth rate of a population (R0) R0 = N1 N0

Annual % rate of natural population change % = (B – D) x 100% 1,000

Doubling time for a population (rule of 70) dt=70/ annual % rate of change

*Human Impact I = P × A × T I = Human impact on the environment P = Population A = Consumption per person T = Environmental impact per unit of consumption

Chapters 1–3 (Introduction / Environmental Ethics and Economics / Environmental Policy)

British economist Thomas Malthus claimed that unless population growth were controlled by laws or other social structures, the number of people would outgrow the available food supply until starvation, war, or disease arose and reduced the population.

o Biologist Paul Ehrlich → "neo-Malthusian" He warned that population growth will have disastrous effects on human welfare in his 1968 book The Population Bomb

Garret Hardin wrote the essay, "The Tragedy of the Commons," which stated that resources that are open to unregulated exploitation will eventually be depleted.

Ecological footprint expresses the environmental impact of an individual or population in terms of the cumulative amount of land and water required to provide the raw materials the person or population consumes and to dispose of or recycle the waste the person or population produces.

o Developed by environmental scientists Mathis Wackernagel and William Rees in the 1990s o Citizens from wealthy, developed nations have much larger ecological footprints than

those from poorer, developing nations. Average US citizen has a ecological footprint of 9.5 hectares Average Chinese citizen has a ecological footprint of 1.5 hectares

o A sustainable ecological footprint per person is about 2 hectares, between that of an average Mexican and that of an average Chinese citizen

According to Thomas Kuhn, there are periodic upheavals in thought in which one scientific paradigm, or dominant view, is abandoned for another.

The Millennium Ecosystem Assessment, which was completed by many environmental scientists from nearly 100 nations, found that our degradation of the world's environmental systems is having negative impacts but with care and diligence we can still turn many of these trends around.

Sustainability is the principle that we must live in such a way as to maintain Earth's systems and its natural resources for the foreseeable future.

According to classical economics, which was founded by Adam Smith, individuals acting in their own self-interest may benefit society, provided that their behavior is constrained by the rule of law and by private property rights and operates within competitive markets

Neoclassical economics explains market prices in terms of consumer preferences for units of particular commodities.

Assumptions of neoclassical economics o Resources are infinite or substitutable o Long-term effects should be disregarded o Costs and benefits are internal

Experienced only by the buyer and seller Extern

alities are costs or benefits that involve people other than the buyer or seller.

External cost, or a negative externality, is a cost borne by someone not involved in a transaction. (i.e.—health problems, property damage, etc.)

o Growth is good

British economist John Stuart Mill hypothesized that as resources become harder to find and extract, economic growth would slow and eventually stabilize.

Ecosystem services are said to have nonmarket values, values not usually included in the price of a good or service.

In the US, legislation is created by Congress and it is either enacted or vetoed by the president, who heads the executive branch. The judicial branch, consisting of the Supreme Court and various lower courts, is charged with interpreting law. Decisions rendered by the courts make up a body of law known as case law.

Environmental justice is the fair treatment and meaningful involvement of all people regardless of race, color, national origin, or income with respect to the development, implementation, and enforcement of environmental laws, regulations, and policies.

Ecosystem services refers to how environmental systems naturally function in a manner that supports economies. (i.e.—purify air/water, cycle nutrients, provide pollination for plants, etc)

NEPA: National Environmental Policy Act o Established by President Nixon in 1970 o Created an agency called the Council on Environmental Quality o Required that an environmental impact statement (EIS) be prepared for any major federal

action that might significantly alter environmental quality.

EPA: Environmental Protection Agency o Established by President Nixon in 1970

o Charged with protecting human health and the environment, by writing and enforcing regulations based on laws passed by Congress

USDA: United States Department of Agriculture (USDA) o Responsible for developing and executing policies on farming, agriculture, and food.

Genuine Progress Indicator (GPI) accounts for benefits such as volunteerism and for costs such as environmental degradation and social upheaval.

Gross domestic product (GDP) accounts for the total monetary value of final goods and services produced in a country each year

Preservation ethic states that we should protect the natural environment in a pristine, unaltered state.

Conservation ethic states that humans should put natural resources to use but also have a responsibility to manage them wisely

Chapter 5 (Evolution, Biodiversity, and Population Ecology)

Golden toad in Costa Rica's Monteverde region o Extinct o Discovered in 1964 o Resided in lush forests above the village of Monteverde known as lower montane forests

or cloud forests. Much of the moisture they receive arrives in the form of low-moving clouds Climate change had a negative effect on cloud forests

Low-moving clouds rose

Higher temperatures

Dried the forest o Endemic to Monteverde forest, which became too dry for them to survive o Endemic species are most threatened by habitat loss

Natural selection is the process by which traits that enhance survival and reproduction are passed on more frequently to future generations that those that do not, altering the genetic makeup of populations through time.

Logic of natural selection: o Organisms produce more offspring that can survive o Individuals vary in their characteristics o Many characteristics are inherited by offspring from their parents

Some individuals will be better suited/adapted to their environment Better adapted individuals transmit more genes to future generation by producing

more offspring and/or offspring of high quality. Future generations will contain more genes, and thus more characteristics, of the

better-suited individuals.

Speciation: process by which new species are generated o Allopatric speciation: species formation due to the physical separation of populations over

some geographic distance o Sympatric speciation: species formation due to reproductive isolation within the same area

Levels of ecological organization: Biosphere → Ecosystem → Community → Population → Organism

K-selected species

o Large size o Slow development o Long-lived o Reproduction later in life o Few offspring o Parental care o Constant population size, close to carrying capacity

r-selected species o Small size o Fast development o Short-lived o Reproduction early in life o Many offspring o No parental care o Variable population size

Survivorship Curves

Zebra Mussels and Sea Otters

Zebra Mussels:

Invasive species – in the Great Lakes; scientific name: Dreissena polymorpha

Black-and-white shellfish, size of a dime; attach to hard surfaces

Open paired shells and feed on algae by filtering water through gills

Native to Caspian, Black, and Azov Seas

Discovered in 1988 in Canadian waters at Lake St. Clair – European ships discharged

ballast water containing mussels/larvae into Great Lakes

o Reach all 5 Great Lakes within two years

Enters Hudson River and Illinois River access to watershed covering 40% of US

1992 – reach Ohio, Arkansas, and Tennessee Rivers; 1994 – settle in waters of 19 US

states and 2 Canadian provinces

Larval stage is well-adapted for long-distance dispersal – drift for several weeks

Adults attach to boats/ships transported to other areas

In North America, the mussels didn’t encounter predators, competitors, and parasites that

limited pop. growth in Old World

Clog up water intake pipes at factories, power plants, wastewater treatment facilities, and

municipal water supplies

Can damage boat engines, degrade docks, foul fishing gear, and sink buoys used for

navigation US loses hundreds of millions of $ each year

Eat primarily phytoplankton deplete populations

o Phytoplankton = foundation of Great Lakes food web

o Depletion is bad for zooplankton and fish that eat both

Zebra mussels suffocate native mollusks by attaching to their shells

Filtering algae + organic matter from open water + deposit nutrients in feces nutrient

balance of community shifted to bottom and benefit species that feed there

o Cleared water sunlight penetrates more deeply spurred growth of large-leafed

underwater plants and algae

Introduction to Hudson river shows:

o Biomass of phytoplankton fell 80%

o Biomass of small zooplankton fell 76%

o Biomass of large zooplankton fell 52%

o Benthic invertebrates increased by 10%

Some organisms play bigger roles in communities than others:

Sea Otters:

Animal Farm: “Some animals are more equal than others”

Some species exert greater influence than others

Keystone species – a species that has particularly strong far-reaching impact

Often large-bodied secondary or tertiary consumers are considered keystone species

Top predators control herbivore populations, which could modify the plant community

Predatory starfish Pisaster ochraceus has great influence on community composition of

intertidal organisms on Pacific coast of NA

o When present, species diversity is high w/ several types of barnacles, mussels, and

algae

o When removed, mussels become numerous and displace other species suppress

diversity

Animals at high trophic levels (wolves, starfish, and sea otters) most often seen as

keystone species

Others attain status as “ecosystem engineers” – physically modify environment

o Beavers build dams and turn streams into ponds, flooding acres of dry land and

turning them to swamp

o Prairie dogs dig burrows that aerate soil and serve as homes for other animals

Zebra mussels would cause: Open-water fish harmed, but help littoral-feeding fish

o Organisms at bottom of food chain also keystone species – if removed, community

can change rapidly

Less likely since more species at lower trophic level – if 1 removed, others

can perform same functions

Sea otters consume sea urchins that eat kelp in nearshore environments of Pacific

o When present, urchin # down allows lush underwater forests of kelp to grow +

provide habitat for other species

o When absent, urchin pop. increases kelp devoured habitat destroyed

suppressed diversity

Live in coastal waters of Pacific; float on backs; feast on sea urchins

Nearly hunted to extinction for fur

o Regions w/ otters host dense “forests” of kelp

o Regions w/o otters – urchins eat kelp and create “urchin barrens” (empty seafloors)

Once recolonized by otters, kelp forests returned

Since 1991, orca predation on otters increased

Chapter 9 (Soil and Agriculture Review)

Agriculture arose about 10,000 years ago as the climate warmed following a period of glaciation.

In traditional agriculture (or subsistence agriculture), farming families produce only enough food for themselves and do not make use of large-scale irrigation, fertilizer, or laboring animals.

In intensive traditional agriculture, farming families produce surplus food to sell in the market using draft animals, irrigation, and fertilizer.

Industrialized agriculture requires monocultures. o Monoculture → uniform planting of a single crop

By volume, spoil consists of around 50% mineral matter, up to 5% organic matter and the reminder comprising of pore space taken up by air or water.

Parent material is the base geological material in a particular location.

Weathering is the major contributor to soil formation; it describes the physical, chemical, and biological processes that break down rocks and minerals, turning large particles into smaller particles.

o Physical or mechanical weathering breaks down rock without causing a chemical change in the parent material.

o Chemical weathering results when water or other substances chemically interact with parent material.

o Biological weathering occurs when living things break down parent material by physical or chemical means.

Erosion oftentimes contributes to soil formation; it is the movement of soil from one area to another. o Helps form soil in one locality by depositing material it has depleted from another. o Prevalent when soil is stripped of vegetation, leaving the surface exposed to water and wind that

may wash or blow it away. o Detrimental → reduces the amount of life that a given area can sustain.

Biological activity contributes to soil formation through the deposition, decomposition, and accumulation of organic matter.

Partial decomposition of organic matter creates humus, a dark, spongy, crumbly mass of material made up of complex organic compounds.

o Soils with high humus content hold moisture well and are productive for plant life.

Soil formation is influenced by: o Climate

Soil forms faster in warm, wet climates. o Organisms

Burrowing animals such as earthworms aerate soil, add organic matter, and facilitate microbial decomposition. Plants add organic matter and affect a soil's composition and structure.

o Topographic relief Steeper slopes result in more runoff and erosion and in less leaching, accumulation of organic matter, and differentiation of soil layers.

o Parent material Chemical and physical attributes of the parent material influence properties of the resulting soil.

o Time Soil formation takes decades, centuries, or millennia.

Each layer of soil is known as a horizon and they are (in descending order): o O or organic horizon → uppermost layer consisting mostly of organic matter, such as

decomposing leaves o A horizon → consisting of inorganic mineral components such as weathered substrate, with

organic matter and humus from above mixed in. Referred to as topsoil, that portion of the soil that is most nutritive for plants

o E horizon → characterized by the loss of some minerals and organic matter through leaching Leaching is the process whereby solid particles suspended or dissolved in liquid are

transported to another location. o B horizon → subsoil; collects and accumulates minerals from above

Contains a greater concentration of minerals and organic acids leached from above than does the E horizon.

o C horizon → consists of slightly-altered or unaltered parent material o R horizon →parent material

Soil's cross-section as a whole, from surface to bedrock, is known as a soil profile.

Soil texture is determined by the size of particles. o Clay particles → <0.002 mm in diameter o Silt particles → 0.002 – 0.05 mm in diameter o Sand particles → 0.05 – 2 mm in diameter o Soil with a relatively even mixture of the three particles sizes is known as loam.

Soil texture influence soil porosity, a measure of the size of spaces between particles. o Finer the particles, the smaller the spaces between the them.

Chapter 10 – Agriculture, Biotechnology, and the Future of Food Central Case – Possible Transgenic Maize in Mexico

- Corn, a staple to our food supply dates back to 5500 years when the people of Oaxaca first

domesticated it

- Oaxaca remains one of the worlds center for its diversity of maize

- In 2001, scientists found genetically modified corn that was banned in Mexico.

- Corn is a transgenic plant and many people worried that these transgenes crops may crossbreed

with native crops therefore changing its genetic makeup

- Researchers found that these invading genes had split and spread throughout the maize

genome.

- US was considered a source of GM corn because transgenes can easily be spread with wind

pollination

Agricultural production is greater than population increase - 850 million people in developing countries do not have enough food

- Attaining food security is a goal for policymakers, ensuring everyone has food.

- A sustainable supply of food depends on maintaining healthy soil, water and biodiversity

- Although Paul Elrich and other scientists predicted that the growing population will outstrip the

food supply, we have actually reduced world hunger since 1970

- These advances come from increasing the ability to produce food, devoting more energy into

the production of food, increased use of fertilizers, increasing amount of cultivated land and

developing more productive crop and livestock through genetic engineering

- However, due to the decrease of grain crops, and decreased availability of arable land,

agricultural production may not continue to outpace the growing population

Undernourishment, Overnutrition, Malnourishment - Undernourishment – mostly in developing countries, receive less than 90% of their daily caloric

needs. Mostly due to economic issues, many people do not have the income to attain sufficient

amounts of food

- Overnutrition – In areas such as the US where food is abundant and people are sedentary,

adults tend to receive more calories than they need

- Malnutrition – lack of quality in food. Malnutrition can lead to disease causing bloating of the

abdomen, hair discoloration and reduced growth

Green Revolution increases agricultural production - Mid to late 20th century. Caused by the need to produce greater quantity and quality of food for

the growing population

- Agricultural scientists created methods to increase crop yields per unit area.

- An US cornfield upped its corn output fivefold in the 20th century, people saw this as a way to

end starvation

- Started in the 1940s when a specially bred type of wheat that produced larger seed heads and

larger yields was introduced tripling Mexico’s wheat production

Pros and Cons of Green Revolution - With the new grains, developing nations began using inorganic fertilizers on their fields and

using equipment powered by fossil fuels for irrigation

- While the total cultivated area expanded 33%, the energy input increased 80 times

- Intensive agriculture helped farmers harvest more crops and saved millions in India from

starvation.

- Its intensified use of already cultivated land reduced pressures to converting new lands.

- Since 1961, food production rose 150%, human population rose 100%, and new land converted

into agriculture increased 10%. Prevented deforestation and habitat conversion to some degree.

- Its techniques have had negative impacts on the environment in terms of pollution, salinization

and desertification.

- It also decreases biodiversity by planting crops in monocultures because fewer wild organisms

are able to live in monocultures

- Monocultures also narrow our diets, 90% of the food we consume comes from 15 crop species

and 8 livestock species.

- Oaxaca’s native diversity in maize is extremely important now that so much is lost to

monocultures.

Pests and Pollinators - Pests such as army worms have lower the yields of many crops and given farmers a hard time

for years

- Pests are any organisms that damage valuable crops and weeds are any plant that competes

with our crops, they have more detrimental effects on monocultures vs. traditional agriculture

- Pesticides have been developed to kill insects, plants and fungi. 900 million lbs of pesticide is

used in the US and since 1960, our use of pesticide has increased fourfold

Pests evolve resistance to pesticides - Due to natural selection, a small number of the microbes may have immunity to a pesticide, as

these genetically resistant pests mate with others, then the new population of pests will be

immune to the pesticide as well

- Industrial chemists are caught up racing with the pests to fight them off while they evolve

- Resistant pests can take a toll on the economy, the gummy stem blight destroyed two thirds of

Texas’s melon crop

Biological control - Biocontrol – the use of a predator to control a pest naturally

- Parasitoid wasps are used as biocontrol agents for caterpillars

- Bt is a natural pesticide that produces a protein that kills caterpillars and flies larvae.

Biocontrol agents may become pests - The introduction of a foreign organism introduces many risks because biocontrol has produced

unintended consequences such as animals becoming invasive and affecting a nontarget

organism.

- Moth was introduced to the Caribbean islands to rid of cactus pears but had spread to Florida

and are killing rare native cacti

- Biocontrol can be extremely effective in dealing with a problem but it can also have extremely

negative effects if it doesn’t work as planned

Integrated pest management - IPM – an i9ntegration of techniques that combine biocontrol, chemical methods and the close

monitoring of populations, habitat alteration, transgenic crops and more.

- Indonesia who originally heavily subsidized pesticide use realized that pesticides actually killed

off the natural enemies of a plant hopper that began devastating rice fields

- In 1986, the Indonesian government banned the importation of pesticides and ended subsidies

for pesticides and as a result, they saved $179 million annually and rice yields rose 13%

Insects pollinate crops - Most insects are harmless and some even essential to agriculture especially pollinators

- Pollination – male sex cells (pollen) fertilize female sex cells. It is required for plants to

reproduce and exist.

- Some plants such as conifers are pollinated by the wind; others such as flowers are pollinated by

hummingbirds and insects.

- While our staple crops are pollinated by wind, there are 800 documented cultivated plants that

require insects for pollination

- The alfalfa in the US great basin is pollinated by alkali bees. When farmers began plowing the

land and increasing pesticide use, the bees and alfalfa both declined.

Conservation of pollinators is vital - The European honeybee is being threatened by parasitic mites that have devastated their

population

- By reducing use of insecticides, pollinator populations can be maintained.

- Because some insecticides do not target only the “bad” bugs, other bugs that are vital to plants

are killed as well

- Planting flowering plants can also encourage the population of pollinators by giving them

protection.

Genetic modification of Food - Potential solutions in the 1980s and 1990s allow scientists to alter the genes of organisms.

- While it may hold a promise to input more nutrients in food and lessen the impact of agriculture

on the environment, it also poses unknown risks

Recombinant DNA - Genetic engineering – the manipulation of an organisms genetic material by adding, deleting or

changing segments of its DNA

- GM organisms – organisms that have been genetically engineered using recombinant DNA

technology

- Recombinant DNA – DNA is broken up from multiple organisms and then its segments are

spliced together to produce certain desirable traits into genomes of organisms that lack them

- In the study of E.coli, scientists isolated the plasmids from the bacteria while DNA from the gene

of interest is removed from another organism, this gene is inserted into the plasmid to form

recombinant DNA which enters the new bacteria reproducing many copies of this desired gene

- Transgenic organisms contain DNA from other species.

- Biotechnology creates transgenic organisms derived from other species

- Recombinant DNA and biotechnology has helped us produce medicine, understand the causes

of cancer and other diseases

Genetic Engineering - Altering the genetic makeup of plants is not new, early farmers have selected plants and animals

that had desirable traits for years

- However, techniques used for GM organisms differs from selective breeding

- Selective breeding mixes genes of individuals of the same species while recombinant DNA mixes

genes of different species

- Selective breeding is based on the natural process of selection while genetic engineering is more

like mutation

Biotechnology - Since GM technology was first developed in 1970, scientists have debated whether it was safe

- After deemed safe, GM seeds rose quickly. Today, over two thirds of the US harvest of soybeans

and corn are genetically modified

- US, Argentina, Canada, Brazil and China account for 96% of GM crops

Impacts of GM crops - People worry that GM crops may be dangerous to eat. They are also afraid that they may escape

and damage nontargeted organisms or transfer not other plants creating super weeds

- Precautionary principle – we should not take any action until it is well understood

- A study n Britain showed that GM crops provide long term financial benefits. Another study

showed that there were little human health risks however its effects on ecosystems should be

tested. A third study found areas with GM oil seed supported less biodiversity while those with

GM maize supported more.

Debate over GM foods - - ethical issues people have about not messing around with natural food have played a role on

the debate despite that our agricultures has already been through thousands of years of

selective breeding

- Many also believe that big businesses such as Monsanto or Syngenta create GM technologies

which threaten the independence of a small farmer and creates a lack of control over ones food

- These same corporations also conduct the safety of GM organisms making it somewhat

unreliable

- Many GM crops have expressed herbicide tolerance while traits that benefit farmers such as

increased nutrition are not commercialized

- When Monsanto first developed its GM products in 1980, they tried to reassure the public by

getting the US government to regulate the industry

- Later, a growth hormone that increased milk production in cows was produced which alarmed

the public

- Schmieiser fought Monsanto in court when accused of planting roundup ready soybeans

without a contract while really it was due to the pollen blown into his field from a neighbors

field

- Social, economic, legal and political factors have created the opposition in the European Union

due to the de facto moratorium of GM foods which blocked the importation of US agricultural

goods prompting the US to bring up the issue to the WTO

- Zambia refused US food aid because they were worried that the transgenic crops would travel

to their land since they rely on exporting food to Europe who bans GM crops

- GM crop manufacturers aim to increase profits and reduce hunger but activists disagree about

the problems and risks that some solutions pose

Transgenic contamination of Native Maize - Quist and Chapela ignited controversy over transgenic corn DNA in Mexican maize

- Their i-PCR technique used to report this may have been unreliable

- Gene flow is possible between transgenic corn and Mexico native corn.

Crop diversity

- Diversity in genes provides resistance to disease and pests

- Monocultures can destroy entire crops and crop diversity

- Accidental interbreeding can decrease diversity of local plants

- We have already lost a lot of crop diversity. The wheat variety in china has dropped from 10000

to 1000 and the diversity of fruits and vegetables in the US have dropped 90%

- Loss of crop diversity is caused by consumers who want uniform and standardized foods for

appeal and convenience

- Storing and collecting seeds can preserve crop diversity

- Seed banks contain six million seed samples which have to be planted periodically to renew its

stock

Livestock and Poultry - The choice to eat animal products have environmental, social and economic impacts

- Our consumption of meat and animal products have increased since our wealth and global

commerce has increased

- Global meat production has increased fivefold and per capita meat consumption has

- Doubled

Feedlot Agriculture - Industrial agriculture has created new methods for raising livestock

- Feedlots – factory farms (CAFO’s) that deliver energy rich food to animals that live in a crowed

environment.

- Feedlots are necessary for countries that have a high meat consumption because it allows for

greater production

- It benefits the environment by taking animals off large land and concentrating into one area

which prevents overgrazing and soil degradation

- However, it produces a huge amount of waste that can pollute the air and water. A typical steer

eats 3000 lbs of grain and generates 50 lbs of manure per day

- The dirty conditions can cause disease which antibiotics are used to attack

- These impacts can be lessened if it is properly regulated and managed, feedlot manure can be

injected into the ground and used as fertilizer

Food choice = Energy choice - 90% of energy is lost when energy moves through trophic levels. Energy that is fed to cows gets

lost from its digestion and metabolic activities.

- A vegetarian diet is more energy efficient because we are taking foods from a lower food chain

directly instead of wasting that energy to an animal

- Some animals convert energy into milk, eggs or meat more efficiently than others.

- Scientists measure this based on the amount of land used, while chicken and eggs used the least

land, beef requires the most.

- We feed 45% of our global grain production to animals, the energy used to grow this grain could

be used to grow better crops

- We can feed livestock crop residues so resources are not gone to waste

Aquaculture - We rely on fish farms for food. Aquaculture provides a third of the worlds fish population

Benefits - Small scale aquaculture can be sustainable and a reliable source of protein

- Large scale aquaculture increases a nations food security

- Reduces the fishing pressure on overharvested fish and the by catch (unintended catch)

- Is safer and uses less fossil fuels than commercial fishing

- Very energy efficient, produces 10 times more fish per unit area than those harvested from an

open ocean

Negative impacts - Densely compacted farmed animals increases risk of disease which reduces food security

- Produces a lot of waste from uneaten food that gets decomposed

- Need to grow grain to bait which reduces energy efficiency. May also be fed other wild fish

which can put a stress on the wild fish population

- If farmed aquatic organisms escape, they can spread diseases and outcompete native fish.

Transgenic fish may also interbreed with native fish which increases the extinction rate

Sustainable Agriculture

- Industrialized agriculture poses many problems including the degradation of soil, increased

reliance on fossil fuels and other problems from pesticide use, genetic modification, intensive

feedlots and aquaculture operations.

- Though it is necessary to feed our growing population, we must practice less intensive methods

of raising animals and crops

- Sustainable agriculture – agriculture that does not deplete soils faster than they form. Farming

that doesn’t reduce soil, water, and genetic diversity.

- Low input agriculture – uses less pesticides, fertilizers, growth hormones, water, and fossil fuels.

Relies on organic agriculture – biological approach (biocontrol)

Increasing organic agriculture - USDA has a criterion for foods to be considered organic.

- Organic food only consists of 1% of food expenditures but increased 20% annually from 1989

reaching $25 billion

- The demand of organic food and land used for organic farming is increasing.

- Consumers favor organic produce because of the skeptism toward pesticide use and to prevent

the environmental factors that inorganic food poses.

- One of Britain’s largest supermarkets vowed only to sell organic food at no greater price and

some textile manufacturers are promoting organic cotton

- Government incentives also helped to convert seven million hectares of land to organic.

- Studies have shown that in the long run, lower inputs and higher market prices are more

profitable

Organic Farming - Conventional fields used 50% more fertilizer while producing 20% more produce than organic

fields.

- Tested on four fields with different conventional and organic aspects.

- Organic field’s recieved 35-50% less fertilizer and 97% less pesticide while yield 80% of what the

conventional field produced after 20 years.

- Scientists believe that organic farms conserve soil quality better keeping soil fertile

- They found that organic farming produced soils that contained more naturally occurring

nutrients and had more microbial life (more biodiversity) vs. the conventionally farmed soil.

Locally supported agriculture - Farmers markets – communities support small scale farmers by buying fresh produce

- Community supported agriculture – consumers pay farmers for their share of yield

Cuba - After breaking up with the USSR, it lost 75% of its total imports forcing them to go organic

- Government encouraged people in cities to grow gardens and use oxen instead of tractors

- Was highly successful and may encourage other nations to farm the same way

- Organic agriculture alleviates problems from high input agriculture.

- The choice is up to the consumer to decide.

Chapter 11 Outline Saving the Siberian Tiger:

Roamed across Asia from Turkey to northeast Russia and Indonesia; within past 200 yrs,

humans have stripped them from most of their historic range

Of survivors, Siberian tiger is largest cat in world

Siberian tiger = Amur Tiger; last refuge is in Sikhote-Alin Mountains of Russian Far East

For thousands of years held prominent place in native language/lore – called “Old Man”

(royalty/guardian of mountains + forests)

Russians hunted them for sport and hides; poachers begin to sell body parts to China +

other Asian countries

o Used in traditional medicines and aphrodisiacs

Road building, logging, and agriculture begin to fragment tiger habitat international

conservation groups get involved

Our Planet of Life

Growing human pop. and resource consumption are putting pressure on flora and fauna

Biodiversity encompasses several levels

species diversity – expressed in terms of the # or variety of species in the world or

particular region

o species richness - # of species

o evenness/relative abundance – extent to which #s of individuals of different

species are = or skewed

species generation - + species richness; extinction - - species richness

taxonomists classify species based on organism’s physical appearance and genetic

makeup King Philip Comes Over For Great Snacks

o kingdom phylum class order family genus species

biodiversity also exists in form of subspecies (populations of a species that occur in

different geographic areas and differ from one another in some characteristics)

o results when divergence doesn’t proceed far enough to create separate species

o denoted with a 3rd

part of scientific name

Siberian tiger = Panthera tigris altaica

1 of 5 subspecies of tiger still surviving

Genetic diversity – encompasses the differences in DNA composition among individuals

within species and populations

Provides raw material for adaptation to local conditions

Tigers: diversity of genes for coat thickness – Bengal tiger: thin coat in warmer climate,

Siberian tiger: thick coat in cold climate

Populations w/ more genetic diversity may stand better chances of persisting b/c variation

better enables them to cope w/ env. change

Populations w/ depressed genetic diversity may be more vulnerable to disease and may

suffer inbreeding depression (when genetically similar parents mate and produce

weak/defective offspring)

Ecosystem diversity – refers to the # and variety of ecosystems; diversity of biotic

community types/habitats within some specified area

If area is large, scientists may consider geographic arrangement of habitats, communities,

or ecosystems at landscape level

Measuring biodiversity is not easy:

Scientists often express biodiversity in terms of most easily measured component: species

diversity, in particular species richness

So far, 1.7-2.0 million species of plants, animals and microorganisms have been

identified/described; estimates for total # range from 3-100 million, our guess is 5-30

Species not evenly distributed among taxonomic groups – insects show predominance

over all other forms of life

40% of insects are beetles; beetles outnumber all non-insect animals and all plants

Our knowledge of species #s is incomplete

o Some areas of Earth remain little explored – barely sampled ocean depths,

hydrothermal vents, or tree canopies and soils of tropical forests

o Many species are tiny and overlooked – include bacteria, nematodes

(roundworms), protists, fungi, and soil-dwelling arthropods

o Many organisms are difficult to identify – ones that were thought to be identical

turn out to be multiple species

Frequent w/ microbes, fungi, + insects; sometimes w/ birds, trees, whales

TERRY ERWIN! – 1982: fogged rainforest trees in Central America w/ clouds of

insecticide, then collected insects, spiders, and other arthropods as they dies and fell from

trees

o Concluded that 163 beetle species specialized on tree species Luehea seemannii

o If typical, then world’s 50k tropical tree species contain 8,150,000 beetle species

+ 20 million arthropod species (beetles are 40% of all arthropods)

o If canopies hold 2/3 of all arthropods, then arthropod species in tropical forests

would be 30 million

o Many assumptions were involved + follow-up studies have revised the estimate ↓

Biodiversity is unevenly distributed:

Living things distributed across planet unevenly

Some groups of organisms only contain few species, while others contain many

Some groups have given rise to many species in relatively short period of time through

adaptive radiation

Species diversity varies according to variety

o Tropical dry forests and rainforests tend to support more species than tundra and

boreal forests

o Variation in diversity by biome is related to 1 of planet’s most striking patterns of

species diversity

Species richness generally increases as one approaches the equator –

latitudinal gradient

1 of most obvious patterns, yet 1 of most difficult to explain

Plant productivity + climate stability play key roles in phenomenon of latitudinal gradient

o Greater amounts of solar energy, heat, and humidity at tropical latitudes more

plant growth support larger 3s of animals

o Stable climates of equatorial regions help ensure a single species won’t dominate

ecosystems, but numerous species will coexist

o Varying conditions favor generalists (species that can deal w/ wide range of

circumstances but don’t do singe thing well)

o Stable conditions favor organisms w/ specialized niches that do certain things

well

Polar/temperate regions may be lacking in species b/c glaciation events repeatedly forced

organisms out of these regions towards more tropical latitudes

Biodiversity Loss and Species Extinction

Extirpation – disappearance of a population from a given area, but not globally

o Tiger has been extirpated from most of its historic range

o Erosive process that can lead to extinction

Extinction is a natural process:

Extirpation + extinction occur naturally – if not, there would be millions of creatures that

had vanished from Earth before humans

Around 99% of species that ever lived are extinct

Background extinction rate – most extinctions preceding appearance of humans have

occurred 1 by one for independent reasons

Earth has experienced five previous mass extinction episodes:

Each have eliminated more than 1/5 of life’s families and at least half of its species

Best known is K-T mass extinction

If current trends continue, then modern era (Quaternary period) may see extinction of

more than half of all species

Humans set the sixth mass extinction in motion years ago:

Sailors documented extinction of dodo on Indian Ocean island of Mauritius

In NA, Carolina parakeet, great auk, Labrador duck, and passenger pigeon have gone

extinct; and probably Bachman’s warbler and Eskimo curlew

California condor, Kirtland’s warbler, whooping crane, and ivory-billed woodpecker

teeter on brink of extinction

Species extinction by humans precede written history

o Ppl hunted species to extinction for thousands of years

o Wherever humans go, extinction occurs ******

Current extinction rates are much higher than normal:

Species loss accelerating as pop. growth and resource consumption put strain on habitats

and wildlife

Decade ago: 1500 of world’s leading scientists reported to UN that in preceding 400

years, 484 animal and 654 plant species were known to go extinct; 30k plant + animal

species faced extinction

2005: scientists calculated that current global extinction rate is 100 to 1000 times greater

than the background rate; projected that rate would increase tenfold or more in future

To keep track of current status of endangered species, World Conservation Union

maintains Red List – updated list of species facing high risks of extinction

o Since 1996, total # of vertebrate animals listed climbed by more than 6%

Actual #s of species extinct and threatened are greater than known #s

Biodiversity loss involves more than extinction:

Extinction only tell part of story of biodiversity loss

Larger part is decline in population sizes of many organisms

o Declines in #s are accompanied by shrinkage of species’ geographic ranges

o many species today are less numerous and occupy less area than before

Frogs, toads, and salamanders are decreasing drastically + in abundance

o Recent studies implicated wide array of factors

4 primary causes of species extinction: (global climate change about to be 5th

)

o habitat alteration – farming replaces diverse natural communities

grazing modifies structure + species composition of grasslands

either type of agriculture can lead to desertification

clearing forests removes resources

hydroelectric dams turn rivers into reservoirs upstream and affect water

conditions and floodplain communities downstream

urbanization + suburbanization

o few species benefit

o Greatest cause of biodiversity loss today – 83 % for mammals, 85 % for birds

Area of prairie habitat has been decreased by more than 99%

o Invasive species – have pushed native species to extinction

Soma have been accidental – include aquatic organisms (zebra mussels)

transported among continents in ballast water of ships

Animals that escaped from pet trade

Weed seeds that cling to socks as we travel

o Others intentional – ppl brought food crops, domesticated animals, and other

organisms (unaware of consequences)

o Species native to islands are especially vulnerable to disruption from introduced

species b/c native species were in isolation for so long w/ few parasites, predators,

and competitors not evolved defenses necessary to resist invaders

o Most organisms introduced to areas die out, but the few that survive do really

well, esp. if w/o predators + parasites or competitors

o Pollution – negative affect in several ways

Air pollution can degrade forest ecosystems

Water pollution can adversely affect fish/amphibians

Agricultural runoff can harm terrestrial and aquatic species

Heavy metals, PCBs, endocrine-disrupting compounds and other toxic

chemicals can poison people and wildlife

o Overharvesting – high intensity of human hunting/harvesting can lead to

extinction for some species

Siberian tiger (again…)

o Political freedom that came w/ Soviet Union’s breakup brought freedom to

harvest Siberia’s natural resources w/o regulations/rules

Coincides w/ economic expansion in Asian countries

Early ‘90s: boom in poaching + increases in logging of Korean pine

forests

Climate change – emissions of CO2 + “greenhouse gases” trap heat in atmosphere and

cause avg. temps to warm worldwide

o modifies global weather patterns + increases frequency of extreme weather

events

o Scientists foresee these events – global climate change; will accelerate and

become more severe until we reduce emissions from fossil fuels

o Droughts put stress on populations and warmer temps are forcing species to

move towards the poles and higher altitudes

All 5 influenced by human pop. growth and rising per capita consumption

Growth in pop. and growth in consumption are ultimate reasons behind proximate threats

to biodiversity

Benefits of Biodiversity

Scientists offered # of tangible pragmatic reasons for preserving biodiversity – show how

it supports human society

Many ppl feel organisms have intrinsic right to exist and ethical/aesthetic dimensions to

biodiversity cannot be ignored

Biodiversity provides ecosystem services free of charge:

Some things can be free as long as we protect living systems that provide them

Intact forests provide clean air + buffer hydrologic systems against flooding/drought,

native crop varieties provide insurance against disease + drought; abundant wildlife

attracts tourists + boosts economies

o All are ecosystem services

“According to UNEP, biodiversity:

o Provides food, fuel, and fiber

o Provides shelter + building materials

o Purifies air and water

o Detoxifies + decomposes wastes

o Stabilizes + moderates Earth’s climate

o Moderates floods, droughts, winds, and temp extremes

o Generates + renews soil fertility + cycles nutrients

o Pollinates plants

o Controls pests + diseases

o Maintains genetic resources as inputs to crop varieties, livestock breeds, and

medicines

o Provides cultural + aesthetic benefits

o Gives us means to adapt to change”

Organisms + ecosystems support vital processes humans cannot reproduce

Biodiversity helps maintain ecosystem function:

High levels of biodiversity tend to increase stability of communities/ecosystems

o Also increases resilience of ecological systems

If keystone species is extirpated or driven extinct, other species may disappear or face

significant pop. changes

o Often top predators are keystone species

Most vulnerable to human impact

Biodiversity enhances food security:

Genetic diversity within crop species is valuable

o In ’95, Turkey’s wheat crops received $50 billion worth of disease resistance

from wild wheat strains

Biodiversity provides drugs and medicines:

Ppl made medicines from plants for centuries

Many of today’s drugs are from studying chemical compounds in plants

Rosy periwinkle – produces compounds that treat Hodgkin’s disease and a deadly form

of leukemia

Biodiversity provides economic benefits through tourism and recreation:

Biodiversity also = source of income

o Visitors spend $$ at local businesses, hire guides, + support parks that employ

local residents

o Ecotourism bring jobs + income to areas that could be poverty-stricken

Ecotourism = vital source for nations like Costa Rica, Australia (reefs!), and Kenya

(savanna)

o US gets millions of visitors for national parks

People value and seek out connections with nature:

Some ppl argue that there is deep importance to biodiversity

Biophilia – “connections human beings subconsciously seek w/ the rest of life”

o Affinity for parks, pets, hiking interest, etc.

Do we have ethical obligations toward other species?:

Nothing immoral in humans using resources and consuming other organisms

But we have conscious reasoning ability and can control actions more ppl believe

organisms have intrinsic value + inherent right to exist

Conservation Biology: The Search for Solutions

More and more ppl perceive need to do something to stem loss of biodiversity

Conservation biology arose in response to biodiversity loss:

Conservation biology – scientific discipline devoted to understanding the factors, forces,

and processes that influence loss, protection, and restoration of biodiversity

o Arose as biologists become alarmed at degradation of natural systems

Applied + goal-oriented science; central to env. science

Conservation biologists work at multiple levels:

Integrate understanding of evolution + extinction w/ ecology + dynamic nature of env.

systems

At genetic level – study genetic attributes of organisms, generally to infer status of pop.

Minimum viable population size – how much genetic variation can be lost b4 running into

problems (ex. Interbreeding depression)

Island biogeography theory is a key component of conservation biology:

Equilibrium theory of island biogeography – explains how species come to be

distributed among oceanic islands

Predicts the # of species on an island based on its size + distance from nearest mainland

o # of species results from balance btwn # added by immigration + # lost through

extinction

o Greater distance means fewer species colonize it

Large islands more species at equilibrium than small islands

# of species doubles if island size goes up 10fold

o Species-area curves

Should endangered species be the focus of conservation efforts:

ESA - forbids anyone from destroying endangered species/habitats

o Forbids trades in products made from endangered species

o Birds have recovered – ex. Bald eagle

Opponents say ESA places more value on life of an endangered organisms than that of a

person

o Also from landowners

Canada – SARA – stress cooperation w/ landowners

Captive breeding, reintroduction, and cloning are single-species approaches:

Captive breeding – individuals can be raised, then reintroduced to wild

Cloning – DNA from an endangered species is inserted into cultured egg w/o nucleus +

egg is implanted into closely related species (surrogate mother)

Some species act as “umbrellas” for protecting habitat and communities:

Particular species are used as tools to conserve communities/ecosystems

Promoting flagship species is evident in WWF

International conservation efforts include widely signed treaties:

1973: Convention on International Trade in Endangered Species of Wild Fauna and Flora

(CITES) – bans international transport of body parts of endangered species (UN)

’92: Convention on Biological Diversity – conserve biodiversity, use biodiversity in

sustainable manner, and ensure fair distribution of biodiversity’s benefits

o Provides incentives for biodiversity conservation

o Managing access to and use of genetic resources

o Transferring technology, including biotechnology

o Promoting scientific cooperation

o Assessing effects of human actions on biodiversity

o Promoting education/awareness

o Provide funding for critical activities

o Encourage every nation to regularly report on biodiversity conservation efforts

UNEP identified # of accomplishments

Biodiversity hotspots pinpoint areas of high diversity:

map hotspots – prioritize regions that are most important globally for conservation

endemic – found nowhere else in the world

o location must contain at least 1500 endemic plant species to qualify as hotspot

o must have already lost 70% of habitat due to human impact

Community based conservation is increasingly popular:

developing nations come to view national environmentalism as neocolonialism

community-based conservation – biologists actively engage local ppl in efforts to

protect land/wildlife

Innovative economic strategies are being employed:

debt-for-nature swap – conservation organization raises $ and offers to pay off a portion

of developing country’s debt in exchange for promise to set aside reserves, fund env.

education, and better manage protected areas

conservation concession – nations often sell concessions to foreign multinational

corporation – allow them to extract resources Conservation International now pays

nations for concessions for conservation

Chapter 14 (Environmental Health and Toxicology)

Study and practice of environmental health assesses environmental factors that influence human health and quality of life.

Physical hazards occur naturally in our environment. o Natural disasters → earthquakes, floods, volcanic eruptions, blizzards, landslides, etc. o Ongoing natural phenomena → UV radiation, etc. o Common practices have increased our vulnerability to certain physical hazards.

Deforesting slopes→ greater risk of landslides

Chemical hazards include synthetic chemicals and chemicals produced naturally by organisms.

Biological hazards result from ecological interactions among organisms. o Infectious diseases such as malaria, cholera, and influenza

Cultural hazards result from the place we live, our socioeconomic status, our occupation, and our behavioral choices.

Infectious diseases are the second-leading cause of death worldwide, accounting for 26% of all deaths per year.

o Account for close to half of all deaths in developing nations, but for very few deaths in developed nations

Discrepancy due to differences in hygiene conditions and access to medicine, which are tightly correlated with wealth

o Respiratory infections, AIDS, diarrhea, tuberculosis, malaria, and childhood diseases, such as measles, account for 80% of deaths.

Notable toxins/pollutants o Radon o Lead o Asbestos

Widely used in building insulation and other products Causes lung cancer and asbestosis (lungs cease to function)

o Polybrominated diphenyl ethers (PBDEs) Widely used in consumer products such as computers, televisions, plastics, etc. Persist and accumulate in living tissue Endocrine disruptors

May effect brain and nervous system development o Polychlorinated biphenyls (PCBs)

Used in coolants and insulating fluids for transformers and capacitors Endocrine disruptors Banned by the US in 1979 and around the world by the Stockholm Convention on

Persistent Organic Pollutants of 2001

Toxicants, or toxic agents, come in various types: o Carcinogens

Cause cancer Difficult to identify

o Mutagens Cause mutations in the DNA of organisms

o Teratogens Cause harm to the unborn (i.e.―birth defects) Thalidomide → developed as a sleeping pill and to prevent nausea during

pregnancy, caused birth defects in thousands of babies. o Allergens

Overactivate the immune system, causing an immune response when one is not necessary

o Neurotoxins Assault the nervous system

o Endocrine disruptors Interfere with the endocrine system, or hormone system. Many are so similar to some hormones in their molecular structure and chemistry

that they "mimic" the hormone by interacting with receptor molecules just as the actual hormone would.

One common type involves the feminization of male animals

In global distillation, pollutants that evaporate and rise high into the atmosphere at lower latitudes, or are deposited in the ocean, are carried preferentially toward the poles by atmospheric currents of air and ocean currents of water.

o Polar organisms take in more than their share of toxicants

Pesticide drift refers to the airborne transport of pesticides

Bioaccumulation refers to the buildup of toxicants in the tissues of an animal

Biomagnifcation refers to the magnification of the concentration of toxicants in an organism caused by its consumption of other organisms in which toxicants have bioaccummulated

Chapter 15 (Freshwater Resources)

Only 2.5% of Earth's water is considered freshwater. o 1% of freshwater is surface water o 20% of freshwater is groundwater o 79% of freshwater is tied up in glaciers and ice caps

Freshwater ecosystems: o Rivers and streams

Water from rain, snowmelt, or springs runs downhill and converges in small channels, forming streams, creeks, or brooks, which eventually combine and merge into rivers.

Tributary → smaller river flowing into a larger one Watershed → area of land drained by a river and all its tributaries Floodplain → areas near a river's course that are flooded periodically

o Wetlands (including marshes, swamps, and bogs) Provide ecosystem services by slowing runoff, reducing flooding, recharging

aquifers, and filtering pollutants. Marshes → shallow water rich in vegetation Swamps → shallow water rich in vegetation, occur in forested areas Bogs → ponds covered with thick floating mats of vegetation

o Lakes and ponds Bodies of open standing water Littoral zone → region ringing the edge of a water body Benthic zone → bottom layer of a water body Limnetic zone → layer of open water through which sunlight penetrates in a water body Profundal zone → layer of open water that sunlight does not penetrate in a water body

Groundwater is contained within aquifers

Aquifers are porous, spongelike formations of rock, sand, or gravel that hold water. o Water table → boundary between an aquifer's upper layer, or zone of aeration (contains

pore spaces partly filled water), and its lower layer, or zone of saturation (completely filled with water).

o A confined/artesian aquifer exists when a water-bearing porous layer of rock, sand, or gravel is trapped between upper and lower layers of less permeable substrate (often clay); water under great pressure

o An unconfined aquifer has no upper layer to confine it; water is under less pressure and can be readily recharged by surface water.

Chapter 17 (from a review book)

Composition of the Atmosphere:

- 78% Nitrogen, 21% Oxygen, 0-4% water vapor, rest is argon, carbon dioxide, neon,

helium, and methane

- Wind pollution natural sources: wind erosion, volcanoes, and waste from living

organisms are main sources. Also, include pollen and forest fires.

- Anthropogenic sources: Primary pollutants (initially released are harmful), secondary

pollutants (become toxic eventually, i.e: photochemical smog after sunlight catalyzes

formation of oxidants and acids), fugitive emissions (number of nonlocalized sources i.e:

dust from soil erosion or mining)

- Criteria Pollutants:

1. Nitrogen oxides: formed when combined with oxygen, reddish brown, comes from

power plants and transportation vehicles, acid rain damages water ways and wildlife,

remediation- combust at a lower temperature or use pure oxygen rather than air

2. sulfur: corrosive gas that damages tissues of plants and animals, reacts with water to

form sulfuric acid (MAJOR component in acid rain), produced in the combustion of

coal, can cause breathing problems, use low-sulfur coal

3. carbon: carbon dioxide and monoxide are colorless and odorless, and produced from

the combustion of carbon, and dioxide can lead to global warming and monoxide is

toxic to humans because it binds more to hemoglobin molecule and prevents

transportation of oxygen to tissues

4. volatile organic compounds (VOCs): react to form ground-level ozone and come

from evaporation of crude oil, paints, dry cleaning adhesives, etc. Some are

carcinogens, irritants, and neurotoxins and have the most air pollutants. Need more

afterburners that combust completely.

5. particulate matter: also known as aerosol (suspended particles in atmosphere) like

ash, dust, smoke, pollen, and mildew, from nonhuman sources such as volcanoes and

forest fires. It reduces visibility but also irritates lungs and can be removed by using

bag filters or electrostatic precipitators.

6. metals and halogens: enter as volatile gases, oxides, or particulate solids most

dangerous are lead and mercury, CFCs catalyze conversion of atmospheric ozone

into oxygen, lead is from gasoline, mercury from coal fired power plants, CFCs from

propellants, lead and mercury lead to nerve damage, mercury bioaccumulation, and

CFCs skin cancer.

7. photochemical oxidants: secondary pollutants synthesized with sun *ozone

Non criteria pollutants: not regulated but still harmful

Indoor Air Pollution: four major types are asthma triggers, toxic building materials, radon gas,

and carbon monoxide.

Asthma Triggers: affects millions of Americans, triggered by secondhand smoke, dust mites,

pets, molds (clean house for dust mites and cockroaches as well as control moisture for mold)

Building Materials: some toxic compounds used in building construction include volatile organic

compounds (VOCs) such as formaldehyde

Radon: radioactive gas that is a by-product of the decay of uranium and other radioactive

elements, second leading cause of lung cancer in the U.S, reduced air pressure inside than

outside can draw gas into the home, try to prevent it from coming in

Carbon monoxide: colorless, odorless gas that competes with oxygen for binding site on the

hemoglobin molecule in red blood cells, created from incomplete combustion

Other outdoor pollutants: para-dichlorobenzene is carcinogenic; methylene chloride used in paint

stripper and thinner can cause nerve disorders and diabetes

Effects of Air Pollution: 50,000 die from air pollution related illness, cities more dangerous

Lung irritation: caused by strong oxidizers in air pollution, suspended particulates penetrate deep

into lungs and can trigger inflammatory response and asthma,, smoking largest cause of lung

cancer.

Effects of Air Pollution on Ecosystems:

- Acid rain: shift in pH of aquatic environment can harm animals , increase the leaching of

metals can harm plants, nutrients can leach out of soil and enter groundwater

Ozone Depletion: tend to be depleted in cold Antarctic area because cold temperatures create

clouds of ice crystals on stratosphere

Weather & Pollution:

1. grasshopper effect is by the convection cycles in the atmosphere and the variable

solubility of toxins in water at different temperatures. Result is that toxins tend to be

more apparent in warmer climates and released as precipitation in colder climates.

2. inversions and heat domes- inversion when a blanket of warm air prevents mixing of

cooler air underneath (two types: subsidence and radiation), heat domes occur in urban

areas where asphalt absorb a lot of heat which is re-radiated and creates an island of heat

Case summaries: noxious gases are regularly emitted from volcanoes in Hawaii, volcanic smog

known as vog irritates skin and the mucous membranes of eyes, nose, and respiratory tract.

Chapter 18

-Central Case: Rising Temperatures and Seas May Take the Maldives Under: Because of global climate

change, the tropical Maldives could soon be submerged by rising seas. Nearly 80% of the land area is

less than 39 inches above sea level. High seas could flood large areas of land, infect the drinking water,

and deplete the fish population. A tsunami hit the Maldives, and it suffered a greater economic shock

than any other nation.

-weather is an area’s short term atmospheric conditions

-climate is an area’s long term pattern of atmospheric conditions

-global climate change: changes in Earth’s climate, involving aspects such as temperature, precipitation,

storm frequency, and intensity

-global warming is an increase in Earth’s average surface temperature and thus is only one aspect of

global climate change

-fossil fuel combustion and deforestation are largely responsible for the current modification of Earth’s

atmosphere and climate

-the sun, atmosphere, and oceans shape climate and keep the Earth warm

-as Earth’s surface absorbs solar radiation, the surface increases in temperature and emits radiation

-greenhouse gases: gases that absorb infrared radiation from Earth’s surfaces that re-remit infrared

energy of slightly different wavelengths, warming the atmosphere

-greenhouse effect: the warming of the troposphere and Earth’s surface

-global warming potential is the relative ability of one molecule of a given greenhouse gs to contribute

to warming

-carbon dioxide is the primary greenhouse gas

-other greenhouse gases, like methane and nitrous oxide add to global warming

-water vapor is the most abundant greenhouse gas in the atmosphere

-aerosols and other elements may exert a cooling effect on the lower atmosphere

-other factors influence climate, such as the milankovitch cycles and oceanic circulation

-milankovitch cycles: variations in the Earth’s rotation and orbit around the sun that result in slight

changes in the relative amount of solar radiation reaching Earth’s surface at different latitudes over the

long term

-oceanic circulation shapes climate because it moves energy from one place to another

-el nino: conditions are triggered when equatorial winds weaken and allow warm water from the

western pacific to move eastward, preventing cold water from welling up in the eastern pacific

-la nina: cold surface waters extend far westward in the equatorial pacific

-environmental scientists have developed a number of methods to decipher clues from the past to learn

about Earth’s climate history

-proxy indicators tell us about the past

-earth’s ice caps and glaciers hold clues about past climate

-direct atmospheric sampling tells us about the present

-Understanding El Nino and La Nina: scientists thinking that the warming of global air and ocean surface

temperature is affecting ocean movement. Scientists monitor the development of these storms with an

array of wind and temperature sensing buoys.

-Scientists Use Pollen to Study Past Climate: Scientists learn about climate by studying vegetation in

specific places. Pollen and larger plant parts in sediments tell scientists about past plant communities

-coupled general circulation models help us understand climate change

-Coupled general circulation models are computer programs that combine what is known about weather

patterns, atmospheric circulation, atmosphere-ocean interactions, and feedback mechanisms to

simulate climate processes

-intergovernmental panel on climate change: scientific information concerning global climate change

through a series of reports

-they asses information relevant to question of human induced climate change

-the IPCC report summarizes evidence of recent changes in global climate and says that there is an

increase in atmospheric concentrations of greenhouse gases

-sea level rise and other changes interact in complex ways

-warming temperatures cause glaciers to shrink that increase water flow and sea level

-higher sea levels lead to beach erosion, coastal flooding, and intrusion of saltwater into aquifers

-the IPCC project future climate change as well as discuss the history of climate

-climate changes pose threats for farmers and forests in terms of draught and temperature

-if the temperature increases, most tropical areas will see decrease crop production

-warmer temperatures and longer growing seasons at higher latitude could potentially increase

agricultural productivity

-in regions where climate change increases precipitation and steam flow, erosion and flooding could

alter the structure and function of aquatic systems

-flooding could increase pollution of freshwater ecosystems

-human health could be affected with heat stress, respiratory ailments, expansion of tropical diseases,

sanitation problems, injuries and drowning from storms, and hunger related ailments

-the majority of scientists think that human activity is the primary reason for climate change

-there are different components are debated over in the scientific community

-scientists agree that climate change is occurring, but disagree on the roles played by clouds, water

vapor, soot and sulfate aerosols, vegetative carbon sinks, and the oceans.

-some challenge the scientific consensus by arguing that climate change is not a problem

-the media is presenting global warming and more even and two-sided than it actually is

-there are arguments over how individuals should respond to climate change

-electricity is the largest source of U.S. greenhouse gases

-we can conserve electricity through efficient technologies

-there are also renewable sources of electricity that individuals should invest in

-the government in working on automotive technology to save electricity

-people can also drive less and use public transportation to save electricity

-u.n. framework convention on climate change: a document that outlined a plan for reducing

greenhouse gas emission to 1990 levels by the year 200 through a voluntary, nation-by-nation approach

-kyoto protocol: an outgrowth of FCCC that was drafted in 1997 in Kyoto, Japan, which mandates

signatory nations to reduce emissions of six greenhouse gases to levels equal to or lower than those of

1990

-some feel climate change demands the precautionary principle

Chapter 19 (Fossil Fuels: Energy and Impacts)

Fossil fuels are highly combustible substances formed from the remains of ancient organisms.

Coal = organic matter + high pressure

Coal comes in different qualities o Peat

Organic material that is broken down anaerobically but remains wet, near the surface, and not well compressed

Precursor stage to coal Widely used as a fuel in Britain and other locations Forms coal as it decomposes further and becomes more deeply buried under

sediments, which causes the water content to decrease and the carbon compounds to be packed more tightly together.

o Lignite o Subibtuminous o Bituminous o Anthracite

Coal is mined at the surface (strip-mining) and underground (subsurface mining) o Subsurface mining

Shafts are dug deeply into the ground and networks of tunnels are dug or blasted out to follow coal seams in order to mine underground coal deposits.

o Strip-mining Use of heavy machinery to remove huge amounts of earth to expose coal or

minerals, which are mined out directly.

Oil = organic matter + heat + high pressure

Half of the available oil reserves may already be depleted.

Amount of time remaining oil will last = Remaining reserves / Annual rate of production o Also known as the reserves-to-production ratio or R/P ratio

Oil is extracted through drilling o Primary extraction

Initial drilling and pumping of available oil As much as two-thirds of a deposit may remain after primary extractions

o Secondary extraction Solvents are used or underground rocks are flushed with water or steam to

remove additional oil in a deposit More expensive than primary extraction

Geologist M. King Hubbert predicted that US oil production would peak around 1970.

Crude oil is refined through distillation o Different components boil at different temperatures.

Gasoline Diesel fuel Heating oil Jet fuel Heavy fuel oil Liquefied petroleum gas Other products

Heavy oil is converted into lighter oil through processes collectively referred to as "cracking" o Thermal cracking

Long-chained molecules are broken into smaller chains by heating in the absence of oxygen

o Catalytic cracking Catalysts, substances that promote chemical reactions without being consumed by

the, used to control the cracking process. Results in the increase in the amount of a desired lighter product from a given

amount of heavy oil o Fluidized catalytic cracking

Most widely used from of cracking today A finely powdered catalyst that behaves like a fluid is fed continuously into a

reaction chamber with heavy oils.

Chemical composition of oil can be changed through catalytic reforming. o Uses catalysts to promote chemical reactions that transform certain hydrocarbons that are

slightly heavier than gasoline.

Octane rating reflects the amount of compression gasoline can go undergo before it spontaneously ignites.

o An octane rating of 92 indicates that a gasoline blend is equivalent to a mixture of 92% octane and 8% heptane.

o Gasoline that has a high octane rating is preferred because high compression engines are more powerful than low-compression engines

Nations can become dependent on foreign oil o United States very dependent on oil

Imports 65% of the crude oil it uses Close relationship with Saudi Arabia, which has 22% of world oil reserves Diversified its sources of crude oil to counter dependence on a few major suppliers

Receives much oil from non-Middle Eastern nations

Natural gas o Biogenic gas formed at shallow depths by the anaerobic decomposition of organic matter

by bacteria o Thermogenic gas formed due to compression and heat underground

"Fracking" or hydraulic fracturing results in the creation of fractures in rocks which are intended to increase the output of a well.

o Formed by pumping the fracturing fluid into the wellbore at a rate sufficient to increase the pressure downhole to a value in excess of the fracture gradient of the formation rock.

o Detrimental effect on environment due to the movement of gases and toxic chemicals to the surface and mishandling of the waste.

Generation of electricity o Coal is the primary fuel source used to generate electricity in the United States 1. Pieces are coal are crushed and blown into a high temperature furnace 2. Heat from the combustion of coal boils water and the resulting steam turns a turbine (a

rotary device that converts the kinetic energy of a moving substance such as steam into mechanical energy), generating electricity by passing magnets past copper coils

3. Steam is then coiled and condensed in a cooling loop and returned to the furnace o "Clean coal" technologies help filter out pollutants from the combustion process

Amount of a fossil fuel in a deposit that is technologically recoverable and economically feasible to remove under current conditions is termed the proven recoverable reserve of that fuel.

Chapter 20 (Conventional Energy Alternatives)

Biomass energy was the first energy source humans used

Biomass is still the leading energy source in much of the developing world

Fuelwood and other traditional biomass sources constitute nearly 80% of all renewable energy used worldwide

Major sources of biomass energy o Fuelwood o Charcoal o Manure from domestic animals

o Crops grown specifically for biomass energy production o Crop residues (such as corn stalks) o Forestry residues (such as wood waste from logging) o Processing wastes (such as solid or liquid waste from sawmills, pulpmills, and papers

mills) o Components of municipal solid waste

Biomass is only renewable if it is not overharvested

Potential for deforestation makes biomass energy less sustainable than other renewable sources.

Some new biomass sources can be burned efficiently in power plants in a similar way to fossil fuels to produce biopower.

Biofuels are derived from biomass.

Many new biomass sources are the waste products of preexisting industries or processes. (i.e.— Sweden & woody debris from the forest products industry)

Some plants are specifically grown for producing biofuels. o Fast-growing grasses (bamboo, fescue, and switchgrass) o Oil-producing groups (corn and soybeans) o Fast-growing trees (poplar and cottonwood)

Two main types of biofuels are ethanol and biodiesel

Ethanol is produced as a biofuel by fermenting biomass (carbohydrate-rich crops such as corn) o Carbohydrates are converted to sugars and then to ethanol. o 1 bushel of corn creates only 9.4 L (2.5 gal) of ethanol

Ethanol is widely added to gasoline in the US to reduce automotive emissions.

E-85 is a mix of 85% ethanol and 15% gasoline and it powers flexible fuel vehicles that are currently produced by US automakers.

In Brazil, ethanol from sugarcane accounts for 44% of all automotive fuel used.

Biodiesel is produced from vegetable oil, used cooking grease, or animal fat, which is mixed with small amounts of ethanol or methanol (wood ethanol) in the presence of a catalyst.

Most biodiesel is used in Europe.

Biodiesel can be mixed with regular petrodiesel o B20, a 20% biodiesel mix, is common.

Biomass is increasingly being combined with coal in existing coal-fired power plants in a process called co-firing.

o Up to 15% of the coal can be substituted with biomass. o Relatively easy and inexpensive

Gas produced by microbes which decompose biomass can be burned in a power plant's boiler to generate electricity.

o "Landfill gases" such as methane o "Biogas" produced in anaerobic digestion facilities

Heating biomass in the absence of oxygen results in pyrolysis, which produces a mix of substances including a liquid fuel called pyrolysis oil, which can be burned to generate electricity.

Biomass energy is essentially carbon-neutral, releasing no net carbon into the atmosphere. o Carbon released is the carbon obtained from the atmosphere by photosynthesis

Advantages of biomass energy o Reduce dependency on imported fuels o Least expensive type of fuel for burning in power plants

o Reduces emissions of air pollutants such as nitrogen oxides and sulfur dioxide.

Negative environmental impacts of biomass energy o Indoor air pollution → health hazards o Deforestation o Soil erosion o Desertification o Diminishing biodiversity o Crops specifically grown to produce biofuel use precious land

Hydroelectric power, or hydropower, is the use of the kinetic energy of moving water to turn turbines and generate electricity.

Most hydropower is derived through the storage technique where water is impounded in reservoirs behind concrete dams that block the flow of river water and then letting that water pass through the dam.

In the run-of-river approach electricity is generated without greatly disrupting the flow of river water. o Sacrifices the reliability of water flow across seasons that the storage approach

guarantees.

Hydropower accounts for 2.2% of the world' primary energy supply and 16.2% of the world's electricity production.

Canada, China, Brazil, the United States, and Russia are the top five consumers of hydropower.

Advantages of hydropower o Renewable as long as precipitation falls from the sky and fills rivers and reservoirs o Clean → No CO2 emissions

Large reservoirs may release methane as a result of anaerobic decay in deep water

Negative environmental impacts of hydropower o Damming rivers destroys habitat for riverside wildlife as riparian areas above dam sites are

submerged and those below dam sites often become starved of water. o Disrupts natural flooding cycles of rivers → Prevents river floodplains from receiving fresh

nutrient-laden sediments o Thermal pollution o Dams usually block the passage of fish and other aquatic creatures

Hydropower is not likely to expand very much more → expected to decline between now and 2030 o Most river that offer opportunities for hydropower have already been dammed.

In the US, 98% of river appropriate for dam construction already are dammed, the remaining 2% are protected under the Wild and Scene Rivers Act.

o Greater awareness of the ecological impacts of dams

Nuclear energy is the energy that holds together protons and neutrons within the nucleus of an atom. o Harnessed by converting it to thermal energy.

For fission to begin in a nuclear reactor, the neutrons bombarding uranium are slowed down with a substance called a moderator, usually water or graphite.

Control rods, made of a metallic alloy that absorbs neutrons, are placed into the reactor among the water-bathed fuel rods.

o Absorb the excess neutrons produced when uranium nuclei divide, so that on average a single uranium atom from each nucleus goes on to split another nucleus.

o Moved into and out of the water to maintain the fission reaction at the desired rate

Nuclear waste disposal is a problem o Currently, nuclear waste is held in temporary storage at nuclear power plants. o Spent fuel rods are sunken in pools of cooling water to minimize radiation leakage. o Many plants are expanding their storage capacity by storing waste in thick casks of steal,

lead, and concrete. o Yucca Mountain was chosen as the disposal site for spent fuel rods and other high-level

waste Unpopulated, lying 23 km from the nearest year-round residences Stable geology, with minimal risk of earthquakes Dry climate should minimize water infiltration through the soil, reducing chances of

groundwater contamination Water table is deep underground, making groundwater contamination less likely Groundwater does not connect with groundwater elsewhere, so that any

contamination would be contained Location, on federal land, can feasibly be protected from sabotage

Three Mile Island accident, 1979 o Through a combination of mechanical failure and human error, coolant water drained the

reactor vessel, temperatures rose inside the reactor core, and metal surrounding the uranium fuel rods began to melt, releasing radiation.

Referred to as a meltdown. o Brought under control within days

Chernobyl disaster, 1986 o Explosions destroyed the reactor and sent clouds of radioactive debris into the

atmosphere. o Soviet authority was slow to evacuate residents of the area o Killed 31 people directly and sickened or caused cancer in many more.

Chapter 21 (New Renewable Energy Alternatives)

New renewable energy sources currently provide only 0.5% of our global primary energy supply

Transition to renewable energy cannot be immediate due to technological and economic barriers o Most renewables lack adequate technological development and infrastructure to transfer

power on the required scale

Passive solar energy collection is the most commonly used way to harness solar energy. o Buildings are designed and building materials are chosen to maximize direct absorption of

sunlight in winter while keeping the interior cool in the summer.

Active solar energy collection makes use of technological devices to focus, move, or store solar energy.

One passive solar design technique involves the use of an overhang, the installation of low, South-facing windows to maximize sunlight capture in the winter, and the use of thermal mass, which are materials that absorb heat, store it, and release it later.

Solar panels or flat-plate solar collectors, which are usually installed on rooftops, harness solar energy.

o Consist of dark-colored, heat-absorbing metal plates and are covered with glass planes. o Water, air, or antifreeze solutions are run through tubes that pass through the collectors,

transferring heat throughout a building.

Active solar energy is being used for heating, cooling, and water purification in Gaviotas, a remote town in the high plains of Colombia far from any electrical grid.

Strength of solar energy can be magnified by gathering sunlight from a wide area and focusing it on a single point

o Utilized in solar cookers, which are simple, inexpensive portable ovens that use reflectors to focus sunlight onto food and cook it.

o Utilized in large-scale solar “farms” where mirrors concentrate sunlight onto a receiver atop a tall “power tower.” From the receiver, heat is transported by fluids piped to a steam-driven generator to create electricity.

Photovoltaic (PV) cells collect sunlight and convert it to electrical energy directly by making use of the photovoltaic, or photoelectric effect. This effect occurs when light strikes one of a pair of metal plates in a PV cell, causing the release of electrons, which are attracted by electrostatic forces to the opposing plate.

Photovoltaic cells can be connected to batteries that store the accumulated charge until it is needed.

Funding for solar power, specifically PV systems, increased following the 1973 oil embargo but decreased as oil prices declined.

Use of solar energy has grown by nearly one-third annually worldwide since 1971

Sales of PV cells are increasing --- by 25% oer year in the US and by 63% annually in Japan, which uses PV roofing tiles widely.

Solar power is especially attractive to developing countries, many of which are rich in sun but poor in infrastructure.

Advantages of solar power o Inexhaustible energy source o Amount of solar energy reaching Earth’s surface should be enough to power the entire

world once solar technology is adequately developed o Quiet o Safe o Contain no moving parts, thus requiring little maintenance o Does not require a turbine or generator to create electricity. o Allow for local, decentralized control over power o In developing countries, solar cookers enable families to cook food without gathering

fuelwood Lessen people’s daily workload Reduce deforestation Low cost

Power from the wind can be harnessed by using wind turbines, mechanical assemblies that convert wind's kinetic energy into electrical energy

Wind blowing into a turbine turns the blades of the rotor, which rotate the machinery inside a compartment called a nacelle, which sits atop a taller tower. Inside the nacelle are a gearbox and a generator. The gearbox converts the rotational speed of the blades into much higher rotational speeds, which provide adequate motion for the generator to produce electricity.

Offshore wind turbines are becoming increasingly popular o Less air turbulence over water surfaces than over land surfaces o Winds speeds on average are roughly 20% greater over water than over land

Advantages of wind power o Produces no emissions once it is constructed o Wind turbines produce 23 times as much energy as they consume o Allows small areas to be more self-sufficient o Landowners can lease their land for wind development, which provides them with extra

revenue while also increasing property income tax for rural communities o Low maintenance costs

Disadvantages of wind power o Intermittent o Some areas are windier than others o New wind projects often face public opposition due to aesthetic reasons o Optimal wind power locations are not always located near population center that need the

energy o Wind turbines pose a threat to birds and bats, which can be killed when they fly into the

rotating blades

Geothermal power plants use the energy of naturally heated water to generate power.

Naturally heated groundwater can be used to power steam turbines and then piped and used to heat homes, etc.

Advantages of geothermal power o Reduces emissions relative to fossil fuel combustion

Disadvantages of geothermal power o Produce a minute amount of emissions → one-sixth of the CO2 produced by plants

powered by natural gas o Geothermal sources may not be sustainable o Water of geothermal sources contain salts and minerals that corrode equipment and

pollute the air o Limited to areas where the energy can be tapped

Hydrogen gas (H2) for fuel can be obtained by forcing various substances to release their hydrogen atoms, which requires an input of energy.

o In electrolysis, electricity is used to split hydrogen atoms from the oxygen atoms of water molecules.

Produces pure hydrogen Does not emit any pollutants

Leakage of hydrogen from the production, transport, and use of the gas could possibly deplete stratospheric ozone and lengthen the atmospheric lifetime of the greenhouse methane.

Environmental impact of a hydrogen-based energy system will depend on the source of the electricity used and the source of the material for hydrogen.

Hydrogen fuel drives electricity generation in a fuel cell, creating water as a waste product. 1) Atoms of hydrogen are stripped of their electrons 2) Electrons move from a negative electrode to a positive one, creating a current and

generating electricity 3) Hydrogen ions pass through a proton exchange membrane 4) Hydrogen ions combine with oxygen to form water molecules

Advantages of hydrogen and fuel cells

o Abundant supply of hydrogen o Hydrogen is clean and nontoxic to use o Pure water and heat may be the only waste products from a hydrogen fuel cell o Under pressure, hydrogen is no more dangerous than gasoline in tanks o Hydrogen fuel cells are energy-efficient.

35% to 70% of the energy released in the reaction can be used Efficiency of fuel cells can rise to 90% if the system is designed to capture heat as

well as electricity o Fuel cells are silent and nonpolluting o Fuel cells will generate electricity whenever hydrogen fuel is supplied

Ocean stores thermal energy

Ocean thermal energy conversion (OTEC) relies on the difference in temperature between the surface water and the deep water of the ocean

In the closed cycle, warm surface water is piped into a facility to evaporate chemicals such as ammonia that boil at low temperatures. These evaporated gases spin turbines to generate electricity. Cold water piped in from ocean depths then condenses the gases so they can be reused.

In the open cycle, the warm surface water is evaporated in vacuum and its steam turns the turbines and then is condensed by the cold water.

Chapter 22 (Waste Management)

Waste refers to any unwanted material or substance that results from a human activity or process.

Municipal solid waste → nonliquid waste from homes, institutions, and small businesses.

Industrial solid waste → nonliquid waste that is not hazardous from the production of consumer goods, mining, petroleum extraction and refining, and agriculture.

Hazardous waste → toxic, chemically reactive, flammable, or corrosive.

Components of waste management: o Minimizing the amount of waste we generate o Recovering waste materials and finding ways to recycle them o Disposing of waste safely and effectively Reduce, Reuse, Recycle, Recover, Dispose

Most effective way to manage waste is to minimize the amount of material that enters the waste stream

o Make indu8strial practices more efficient o Minimize packaging for products o Purchase "green" products o Reuse items o Recycle items o Compost materials at home o Municipal composting

Paper products comprise the largest component of the municipal solid waste stream in the US, followed by yard trimmings, food scraps, and plastics.

Each US citizen generates close to 1 ton of solid waste each year.

In sanitary landfills, waste is buried in the ground or piled up in large, carefully engineered mounds. o Waste is layered along with soil, which speeds decomposition, reduces odor, and lessens

infestation by pests. o Leachate, a liquid that results when substances from the trash dissolve in water as

rainwater percolates downward, is collected and treated. Landfill managers are required to maintain leachate collection systems for 30

years after a landfill has closed. o Groundwater is monitored for contamination o Landfill gas produced by anaerobic bacteria may be recovered

Resources Conservation and Recovery Act (RCRA) specify how waste should be added to landfills.

Disadvantages of landfills o Liners can be punctured o Leachate collection systems eventually cease to be maintained o Kept dry to reduce leachate, but the bacteria that break down material thrive in wet

conditions o Difficult to find suitable areas to locate landfills → NIMBY

Incineration, or combustion, is a controlled process in which mixed garbage is burned at very high temperatures.

o Incinerating waste reduces its weight by up to 75% and its volume by up to 90%

Incineration results in air pollution. o Scrubbers chemically treat the gases produced in combustion to remove hazardous

components and neutralize acidic gases, such as sulfur dioxide, turning them into water and salt.

o Particulate matter, referred to as fly ash, is physically removed from incinerator emissions in a system of huge filters known as baghouse and also through electrostatic precipitators.

Recycling comprises of: o Collection and processing of recyclable materials by municipalities and businesses o Use of recyclables by industry to manufacture new products o Consumer purchase of products made from recycled materials.

In curbside recycling, trucks pick up recyclable items in front of houses in conjunction with municipal trash pick-up.

In recovery facilities (MRFs), collected items are sorted, cleaned, shredded, and prepared for reprocessing

American consumers are not "closing" the recycling loop because they are not buying recycled goods.

Ways consumers can reduce waste: o Donate used items to charity o Reuse boxes, paper, plastic wrap, plastic containers, etc. o Rent or borrow items. o Buy groceries in bulk

Primary means of hazardous waste disposal are landfills, surface impoundments, and injection wells. o Surface impoundments are ponds in which liquid hazardous waste is stored o In deep-well injection, hazardous wastes are injected into wells that have been drilled deep

beneath the water table, reaching into porous rock.