AP Exam

Part III

Marine Ecosystems

• Coastal- occur near shore where tides and currents are always changing, causing a mixture of nutrients.

• Zone is from the high tide mark of shorelines to the continental shelf.

• Organisms include: coral (in tropical regions), zooplankton, phytoplankton, crustaceans, echinoderms, dolphins, sharks, etc..

Marine Ecosystems

• Esturaries- Animals in these areas must be able to adapt to a rapid and constant change in salinity.

• Rich in nutrients

• Excellent spawning and breeding grounds for fish, crustaceans and birds.

Inland Wetlands

• Water levels vary from standing water in the wet season to none during the dry season or during droughts. Include marshes, swamps and bogs.

• Differentiate between a marsh, swamp and bog

Marine Ecosystems

• Open Ocean- These areas occur beyond the continental shelf .

• Deep water up to 11,000 meters

• Zones below 200 m are dark, cold, and poor in nutrients.

Legislation Regarding Aquatic Environments

• Alaska National Interest Lands Conservation Act, 1980• Designated certain public lands in Alaska as units of the

National Park, National Wildlife Refuge, Wild and Scenic Rivers, National Wilderness Preservation, and National Forest Systems, resulting in general expansions of all systems.

• Created 79.54 million acres of refuge land in Alaska.• 27.47 million acres were designated as wilderness.

• Anadromous Fish Conservation Act, 1965• Conservation, development and enhancement of

anadromous fish, including those in the Great Lakes

• Anadromous fish are those that are born in fresh water, migrate to salt water to grow into adults and return to fresh water to spawn.

• Examples: salmon, smelt, striped bass, sturgeon

• Catadromous fish- live in fresh water and enter salt water to spawn.

Additional Legislation

• Convention for the Conservation of Antarctic Marine Living Resources (CCAMLR), 1980-

• Management of all southern ocean fisheries. • Fish & Wildlife Act, 1956• Emphasis on the commercial fishing industry,

but also adheres to every citizen’s right to fish for pleasure and enjoyment.

• Fish and Wildlife Coordination Act, 1980• Authorized financial and technical assistance to

the states for the development, revision, and implementation of conservation plans and programs for non-game fish and wildlife

• Great Lakes Fish and Wildlife Restoration Act, 1998

• Marine Mammal Protection Act, 1972• Conservation of marine mammals with

management vested in the Department of Commerce for cetaceans (whales, dolphins, and porpoises) and pinnipeds (seals, sea lions, walrus) other than the walrus.

• A sterile male technique of pest control:• A. relies on the use of phermones, chemicals

that attract fertile males away from reproductively capable females.

• B. Is often effective because females of many insect species breed only once during their lifetime.

• C. Relies upon genetic engineering techniques to produce infertile males.

• D. Uses male animals that are sterilized by treatment with Bacillus thuringiensis bacterium.

• E. Can cause eggshell thinning in some bird species.

Aquatic Review

• A mixture of fresh and saltwater is known as

• A. brackish

• B. Gray water

• C. Black water

• D. Connate water

• E. Lentic water

International Acts

• Antarctic Treaty – signed Dec. 1, 1959/ enforced June 23 1961

• Antarctica is the only continent with no nations.  While seven nations (not including the United States) have made claims to Antarctica, no single nation controls any part of the continent. The Antarctic Treaty governs the actions of people in Antarctica. 12 nations listed in the preamble signed the Antarctic Treaty on 1 December 1959 at Washington, D.C. The Treaty entered into force on 23 June 1961.

• Cairo Conference on Population & Development- Sept. 1994

• The United Nations International Conference on Population and Development (ICPD) was held from 5-13 September 1994 in Cairo, Egypt. During this two week period world leaders, high ranking officials, representatives of non-governmental organizations and United Nations agencies gathered to agree on a Programme of Action. Main Point- Population Control

• Kyoto Conference-1997• Sponsored by the United Nations• Held in Kyoto, Japan• Result:• 1)Agreement among 10 nations requiring

greenhouse gas emissions reduction, especially carbon dioxide, to 5% below 1990 emissions by 2010. Developing nations’ reductions are voluntary.

• 2) Long term objective was to prevent emissions from human sources from interfering with the natural climate system.

• Montreal Protocol- 1987 (Amended in 1990, 92)

• Agreement to reduce air pollutants that destroy stratospheric ozone. CFCs, halons, carbon tetrachloride, and methyl chloroform--are to be phased out by 2000 (2005 for methyl chloroform).

• Rio Earth Summit- 1992• Held in Rio de Janeiro, Brazil.• Attendees: world’s leaders, politicians,

diplomats, etc.• Result of Summit: • 1)Attempts will be made to reduce

greenhouse gas emissions by the year 2000 to the 1990 levels

• 2) Developing countries will be given more and easier access to technology that minimizes environmental damage.

• UN Conference on the Human Environment, Stockholm (Capital of Sweden)- 1972

• The United Nations Conference on the Human Environment, having met at Stockholm from 5 to 16 June 1972,having considered the need for a common outlook and for common principles to inspire and guide the peoples of the world in the preservation and enhancement of the human environment

• Cities Treaty- 1976• Adopted by Congress in 1976, in an effort to

maintain and protect endangered populations in ancestral habitats, prohibits the removal of Asian elephants and other endangered species from the wild and their importation into the United States. The stresses on habitat and space, poaching and unregulated hunting have severely limited the ability of native populations to maintain enough genetic diversity to survive.

• Hadley cell model• Resides over the equator to the subtropics. It

causes dry are to absorb moisture as it descends

• The major environmental result of creating power through nuclear fuel is

• Storing its waste• Nuclear breeder reactors convert • Nonfissable U238 into plutonium• Integrated pest management is the concept that• All insects can be controlled by using a natural

biological or other natural controls

Pesticides

• Biocide - Kills wide range of organisms.• Herbicide - Kills plants.• Insecticide - Kills insects.• Fungicide - Kills fungi.• Acaricide - Kills mites, ticks, and spiders.• Nematicide - Kills nematodes (round worms)• Rodenticide - Kills rodents.• Avicide - Kills birds.• Algicides: Kills algae

• Chemical Classes• Inorganic Pesticides - Broad-spectrum, generally highly

toxic, and essentially indestructible. (arsenic - copper)– Generally neurotoxins

• Natural Organic Pesticides (Botanicals) - Generally plant extracts. (nicotene - phenols)

• Fumigants - Small molecules that gasify easily and penetrate materials rapidly. (carbon tetrachloride - ethylene dibromide)

• Chlorinated Hydrocarbons - Fast acting and highly toxic to sensitive organisms. (DDT - mothballs)

• Inhibit nerve membrane ion transport and block nerve signal transmission.

• Persistent - Tend to biomagnify.• Organophosphates - Extremely toxic to mammals, birds and

fish. (Malathion)

• 1939- DDT- dichlorodiphenyltrichloroethane created by Mueller. He received a Nobel Prize in 1948.– Advantage of DDT: Cheap, stable, soluble

in oil, and easily spread over a large area.• Highly toxic to insects, but relatively nontoxic

to mammals.

The Ecological Niche

• The role as species plays in an ecosystem• Habitat – the actual physical location where a

species lives• N-dimensional hypervolume- many conditions and

resources influence the maintenance, growth, and reproduction of an organism

• Fundamental Niche – full potential range of conditions and resources it could theoretically use if no competition

• Realized Niche – part of a fundamental niche an organism occupies

Generalists vs Specialists

• Generalists

– Have broad niches

– Live in many different places, eat variety of foods, wide range of environmental conditions.

• Specialists

– Narrow niches

– One type of habitat, only one or two types of food

– More prone to extinction

– Advantage in constant environmental conditions

Types of Species

• Native species, exotic/alien species• Indicator Species – species that serve as early

warnings that a community or ecosystem is being damaged (Birds)

• Keystone – role in ecosystem is more important than abundance, play pivotal roles in structure, function, and integrity of ecosystem b/c critically linked to large number of other species

Competition and Predation

• Interspecific competition – two or more species compete for limited resource, can harm competing species

• Predation – one species feeds directly on all or part of living organisms. Predator benefits, prey is harmed

• Symbiosis – long-lasting relationships, species live in intimate association– Parasitism – parasite feeds on host– Mutualism – both benefit– Commensalism – one benefits, other is neither

harmed nor helped

How do species compete?

• Interspecific competition results when niches overlap. One species must:

– Migrate to another area– Shift its feeding habits– Suffer a sharp population decline– Become extinct in that area

Species compete in two ways• Interference – one species limits another's access

to resource, member establish a territory• Exploitation – competing species have = access

Principle of Competitive Exclusion

• Two species require the same resource cannot coexist indefinitely in ecosystem where there is not enough of that resource to meet the needs of both species.

Species have reduced competition by:• Resource partitioning – the dividing up of

available resources• Character displacement – species develop

physical or behavioral characteristics or adaptations allowing them to use diff resources

Predator and Prey Interaction

• Predators feed on prey, do not live in or on prey. (+) feedback system for predator limited by (-) feedback when prey populations fall below certain minimum.

• benefits prey: eliminates sick, weak, agedPredators increase chances of getting meal:• Pursuit – run fast to catch prey, keen eyesight, hunt in

packs• Ambush – camouflagePrey defend themselves against predators by:• Run, swim, fly fast, keen sight or sense of smell• Chemical warfare – chemicals that are poisonous• Warning coloration – predators know animal is bad tasting• Mimicry – species take on appearcnce of poisonous animal

Symbiotic species Interactions

• Parasitism:– Parasitoids – parasites that kill hosts as part of life

cycle (used by farmers for pests)– Endoparasites – live inside host– Ectoparasites – live outside host

• Mutualism:– Nutritional Mutualism – lichens: photosynthetic algae

and chlorophyll- lacking fungi. They cannot live apart, aka obligatory mutualism.

– More common when resources are scarce• Commensalism:

– Redwood sorrel benefits from growing in the shade of tall redwood trees

Ecosystem Structure

• Physical appearance

• Niche structure

• Species diversity

• Species abundance

An ecosystems respond to change

• Ecological succession – gradual change in species composition of given area.

• Primary – gradual establishment of biotic communities (lifeless, soil-less area)– Pioneer species – lichens and mosses– Early successional plants – close to ground, break up rock and

make soil– Midsuccessional- herbs, grasses, low shrubs– Late successional - trees

• Secondary – reestablishment of biotic community. Begins where natural community has been disturbed, but soil sediment remains. Ex. Abandoned farmlands, burned forests etc.

How do species replace each other?

• Facilitation – species behave in such a way that facilitates growing of other species. Ex – legumes convert nitrogen to nitrates making soil more suitable

• Inhibition – early species hinder establishment and growth of other species

• Tolerance – ate successional plants are unaffected by plants at earlier stages of succession

What is the role of Disturbance in succession?• A disturbance is a discrete event in time that disrupts an

ecosystem• Natural disturbance – fires, hurricanes, floods• Intermediate disturbance hypothesis – communities that

experience frequent disturbance have greatest diversity of species

Ecological Stability and Sustainability

• Stability is maintained only by constant dynamic change in response to changing environmental conditions

• Inertia – ability of living system to resist disturbance • Constancy – ability of system to maintain certain size within limits

imposed by available resources• Resilience – ability of system to bounce back after external

disturbanceThe signs of ill health in a stressed ecosystem:

– Drop in primary productivity– Increased nutrient loss– Decline of indicator species– Increased populations of insect pests– Decline in species diversity– Present of contaminants

General Information

• Pests: any species that competes with us or food, invades lawns and gardens, destroys wood in houses, spreads disease, or is a nuisance

• Pesticides: Chemicals developed to kill organisms that we consider undesirable– Insecticides: insect-killers– Herbicides: weed-killers– Fungicides: fungus-killers– Nematocides: roundworm-killers– Rodenticides: rat- and mouse-killers

Co-evolution

• Plants have been producing chemicals to ward off herbivorous predators for ~225 million years. As herbivores adapt, so thy don’t starve, plants adapt so that they survive. This is an example of co-evolution.

First Generation Pesticides

• Sulfur: used as an insecticide since 500 BC

• Arsenic (As), lead (Pb), and mercury (Hg) by the 1400’s

• Nicotine sulfate: extracted from tobacco leaves in the 1600’s

• Pyrethrum: obtained from the heads of chrysanthemum flowers

• Rotenone: from the root of the derris plant

Second Generation Pesticides• About 2.5 million tons of pesticides are used yearly worldwide. In

the US, about 630 different biologically active (pest-killing) ingredients and 1,820 inert (inactive) ingredients are mixed to make 25,000 different pesticides products.

• DDT: 1939, entomologist Paul Mueller discovered that DDT was a potent insecticide. It soon became the world’s most-used pesticide.

• Broad-spectrum agents: toxic to many species• Selective-spectrum agents: effective against a narrowly defined

group of organisms• Persistence: length of time in which pesticides remain deadly in the

environment• Biomagnification:

• Spoil– Unwanted rock and other waste materials produced

when a material is removed from the earth's surface or subsurface by mining, dredging, quarrying, and excavation

• Overburden– Layer of soil and rock overlying a mineral deposit.

Surface mining removes this layer

• Open-pit mining– Removing minerals such as gravel, sand, and metal

ores by digging them out of the earth's surface and leaving an open pit.

• Area strip mining– Type of surface mining used where the terrain is flat

• Dredging– Type of surface mining in which chain buckets

and draglines scrape up sand, gravel, and other surface deposits covered with water

• Contour strip mining– Form of surface mining used on hilly or

mountainous terrain

• Depletion time– The time it takes to use a certain fraction,

usually 80%, of the known or estimated supply of a nonrenewable resource at an assumed rate of use

• Petrochemicals– Chemicals obtained by refining (distilling) crude oil.

They are used as raw materials in manufacturing most industrial chemicals, fertilizers, pesticides, plastics, synthetic fibers, paints, medicines, and many other products

• Tar sand– Deposit of a mixture of clay, sand, water, and varying

amounts of a tarlike heavy oil known as bitumen. Bitumen can be extracted from tar sand by heating. It is then purified and upgraded to synthetic crude oil

• Ore– Part of a metal-yielding material that can be

economically and legally extracted at a given time

• Shale oil– Slow-flowing, dark brown, heavy oil obtained when

kerogen in oil shale is vaporized at high temperatures and then condensed. Shale oil can be refined to yield gasoline, heating oil, and other petroleum products

• Breeder nuclear fission reactor– Nuclear fission reactor that produces more nuclear

fuel than it consumes by converting nonfissionable uranium-238 into fissionable plutonium-239

• Kerogen– Solid, waxy mixture of hydrocarbons found in oil

shale rock. Heating the rock to high temperatures causes the kerogen to vaporize. The vapor is condensed, purified, and then sent to a refinery to produce gasoline, heating oil, and other products

• Net energy– Total amount of useful energy available from an

energy resource or energy system over its lifetime, minus the amount of energy used (the first energy law), automatically wasted (the second energy law), and unnecessarily wasted in finding, processing, concentrating, and transporting it to users

How do minerals form?

• Magma crystallizes

• Sedimentary process1. Sedimentary sorting

2. Precipitation

3. Groundwater evaporates, leaving salts that precipitate

• Weathering process1. Water dissolves and removes soluble

ions

2. Residual deposits form

What are the environmental impacts of using mineral

resources?

• Scarring of land

• Collapse of land over underground mines

• Erosion of toxic mineral wastes

• Acid mine drainage

How is oil extracted and processed?

1. Primary oil recovery– Drill well, pump out lighter crude oil that

flows out through pores

2. Secondary oil recovery– Pump high-pressure water into well to

force out heavier crude oil

3. Tertiary oil recovery– Superheated steam forces out oil– Detergent dissolves heaviest oil, which

can then be pumped out

What are components of a nuclear fission reactor?

• Core: contains fuel rods• Uranium oxide fuel: uranium-238• Control rods: move in and out of reactor

to absorb neutrons• Moderator: slows neutrons so that chain

reaction keeps going• Coolant: circulates to remove heat and

produce steam for electricity

What types of energy do we use? Global and in U.S.

• Oil: 30% (40% in US)

• Coal: 22% (22% in US)

• Natural gas: 23% (22% in US)

• Nuclear power: 6% (7% in US)

• Hydropower, geothermal, solar, wind: 6% (5% in US)

• Biomass: 12% (4% in US)

Chapter 15

1. CAFE: (Corporate Average Fuel Economy) requires new cars to meet certain average fuel efficiency standards, averaged over all cars produced. Between 1973 and 1985, the average fuel efficiency doubled for new American cars and rose 37% for all passenger cars on the road because of CAFE.

Chapter 171. NAPAP: (National Acid Precipitation Assessment Program)

established in 1980 to 1. coordinate government acid deposition research, 2. assess the costs, benefits, and effectiveness of the country’s acid deposition legislation and control program, and 3. report its findings to Congress.

2. Clean Air Act: passed in London in 1952, then by Congress in 1963, but did not have much effect until a stronger version of the law enacted in 1970. The Clean Air Act of 1970empowered the federal government to set air pollution emission standards for automobiles and industries that each state was required to enforce. Stricter emissions standards were imposed by amendments to the Act in 1977 and 1990. Emissions of the six most common outdoor air pollutants decreased by 31% between 1970 and 1998

The Case for Pesticides• Pesticides save human lives: Since 1945, DDT and other

insecticides have probably prevented the premature deaths of at least 7 million people from insect-transmitted diseases.

• Pesticides increase food supplies and lower food costs: About 55% of the world’s potential human food supply is lost to pests before or after harvest. Without pesticides, these losses would be worse, and could cause the prices of food in the US to rise nearly 50%.

• Pesticides increase profits for farmers: Overall, for every dollar spent on pesticides, there is an increase in US crop yields worth approximately two dollars.

• Pesticides work faster and better than alternatives: Pesticides control most pests quickly and at a reasonable cost.

• The benefits overpower the health risks: Safer and more effective pesticides are being developed.

The Case Against Pesticides• Genetic resistance: Insects can develop immunities to pesticides in just a few years.• Broad-spectrum insecticides kill good organisms: This includes killing natural

predators and parasites that may have been maintaining the population of a pest species at a reasonable level.

• Unexpected outcome: wiping out natural predators can also unleash new pests whose populations the predators had previously held in chick, causing other unexpected effects

• The pesticide treadmill: A situation where farmers are forced to pay more for a pest control program that often becomes less effective as a genetic resistance develops

• Although the use of synthetic pesticides has increased 33-fold since 1942, it is estimated that more of the US food supply is lost to pests today than in the 1940’s.

• The estimated environmental, health, and social costs of pesticide use in the US range from $4 billion to $10 billion per year

• Alternative pest control practices could halve the use of chemical pesticides on 40 major US crops without reducing crop yields.

• A 50% cut in US pesticide use would cause retail prices to rise by only about .2% but would raise average income for farmers about 9%.

Environmental Effects

• Less than 2% of the insecticides applied to crops by aerial spraying or by ground spraying actually reach the target pests

• Some pesticides can harm wildlife: DDT had harmful effects in the environment when it biologically magnifies in food webs. This resulted in certain birds being listed on the endangered species list in the US because of fatal effects.

• Each year 20% of honeybee colonies in the US are wiped out by pesticides, while another 15% are damaged, costing farmers over $200 million annually.

Human Health Effects

• An estimated 25 million agricultural workers in developing countries are seriously poisoned by pesticides each year. 220,000 deaths result.

• In developed countries an estimated 300,000 farm workers suffer from pesticide-related illnesses yearly. 250,000 Americans get sick each year from home misuse of pesticides.

• Approximately 13% of vegetable and fruits consumed in the US may contain illegal pesticides and levels of approved pesticides above their legally allowed limits.

• At least 75% of the active ingredients approved for use in US pesticide products cause cancer in test animals.

Pesticide Regulation in the US• All commercial pesticides must be approved by the EPA for general or restricted use• When a pesticide is legally approved for use on fruits or vegetables, the EPA sets a

tolerance level, which specifies the amount of toxic pesticide residue that can legally remain on the crop when the consumer eats it.

• According to a National Academy of Sciences study, federal laws regulating the use of pesticides in the US are inadequate and poorly enforced by the EPA, FDA, and USDA

• Exposure to pesticide residues in food causes 4,000-20,000 cases of cancer per year in the US

• A 1993 study of pesticide safety by the US National Academy of Sciences urged the government to do the following things:

– Make human health the primary consideration for setting limits of pesticide levels allowed in food

– Collect more an better data on exposure to pesticides for different groups, including farm workers, adults, and children

– Develop new and better test procedures for evaluating the toxicity of pesticides, especially for children

– Consider cumulative exposures of all pesticides in food and water, especially for children, instead of basing regulations on exposure to a single pesticide

Progress Made with the Passage of the 1996 Food Quality Protection

Act• Requires new standards for pesticide tolerance levels in

foods, based on a reasonable certainty of no harm to human health

• Requires manufacturers to demonstrate that the active ingredients in their pesticide products are safe for infants and children

• Allows EPA to apply an additional 10-fold safety factor to pesticide tolerance levels to protect infants and children

• Requires the EPA to consider exposure to more than one pesticide when setting pesticide tolerance levels

• Requires the EPA to develop rules for a program to screen all active and inactive ingredients for their estrogenic and endocrine effects by 1999.

Solutions

• Cultivation practices– Crop rotation – Planting rows of hedges or trees around fields

to hinder insect invasions– Adjusting planting times so that major insect

pests either starve or get eaten by their natural predators

– Planting trap crops to lure pests away from the main crop

Solutions cont.

• Genetically resistant plants– Plants and animals that are genetically resistant to

certain pests insects, fungi, and diseases can be developed

– Genetic engineering can be used to build pest resistance into crops and thus reduce the need for pesticides

• Using natural enemies to help control pests– Biological control using predators, parasites, and

pathogens to regulate pest populations

• Using biopesticides to control pests

Solutions cont.

• Insect birth control, sex attractants, and hormones– Males of some insect pest species can be raised in

the laboratory, sterilized by radiation or chemicals, and then released into an infested area to mate unsuccessfully with fertile wild animals

– Hot water: the ‘Aqua Heat’ machine sprays boiling water on crops to kill weeds and insects

– Radiation: exposing certain foods after harvest to gamma rays emitted by radioactive isotopes will extend food shelf life and kill harmful insects, parasitic worms, and bacteria

Integrated Pest Management• Integrated pest management (IPM): in this approach, each crop and its

pests are evaluated as parts of an ecological system. Then a control program is developed that includes a mix of cultivation and biological chemical methods applied in proper sequence with the proper timing.

– The overall goal is not to eliminate pest populations but to reduce crop damage to an economically tolerable level.

– IPM requires expert knowledge about each pest situation, and is much slower acting than conventional pesticides.

– Although long-term costs are typically lower than the costs of using conventional pesticides, initial costs may be higher.

– Scientists urge the USDA to promote IPM by the US by:• Adding a 2% sales tax on pesticides and using revenue to fund IPM research and

education• Setting up a federally supported IPM demonstration project on at least one farm in

every county• Training USDA field personnel and county farm agents in IPM so that they can help

farmers use this alternative• Providing federal and state subsidies to farmer who use IPM• Gradually phasing out subsidies to farmers who depend almost entirely on pesticides,

once effective IPM methods have been developed for major pest species