AP Environmental Science Course Review Part 2 

Unit 2: The Living World - Biodiversity (Friday, April 30th)

Evolution

• Genetic changes in a population of species overtime

• Adaptation: inherited traits that helps an organism better survive

• Natural selection: some organisms are better able to survive and reproduce than others 

• Coevolution: 2 populations of species influence each others evolution over a long period of time

  • Poisonous newt + poison-resistant snake

• Mutations: genetic changes in DNA that occur randomly and can encourage evolution

Types of Selection

Speciation

• When a population ends up breaking into 2 populations in some way

• Allopatric speciation: species are separated by a physical barrier and cannot cross-breed, leading to independent evolution and speciation

• Sympatric: species are NOT separated but changes in behavior leads to lack of mating and eventual speciation

Types of Species

• Indicator: alters us to changes in the environment earlier than either species due to their sensitivity to changes (ex. frogs)

• Foundation: alters the environment in a way that influences other species (ex. Elephants that push trees, create paths in savanna)

• Keystone: species that exert a large influence over an ecosystem and is dependent on by many other species (ex. otters)

• Generalist species: occupy broad niches, eat a variety of food, can withstand varying conditions (ex. mice)

• Specialist species: occupy specific narrow niches often with species food sources, sensitive to changes and more prone to extinction should conditions change (ex. koala)

Primary VS. Secondary Succession

• Intermediate disturbance hypothesis: Ecosystems can withstand a moderate amount of disturbance and it often increases biodiversity more than a low/high amount of disturbance

  • A high amount of disturbance>> extinctions

Biodiversity 

• Higher biodiversity = higher ecosystem/population resilience to disturbance

• Species diversity: number and variety of species contained in a habitat

• Species richness: number of species specifically

• Species evenness: refers to whether or not species are in equal abundance

  • A rainforest would have high species evenness (lots of species + not one dominates)

  • Pine forest has low species evenness (pine trees are majority in ecosystem)

Island Biodiversity

• Larger islands have greater biodiversity than smaller islands as do islands that are closer to the mainland

• Larger islands have higher rates of migration of NEW species from the mainland as do closer islands than smaller islands and islands away

Range of Tolerance

• Different types of changes in the ecosystems that an organism can withstand

• Optimum range doesn't affect them

• high/low= physiological stress or death (having to do w salinity, temp, DO, pH, etc)

Unit 3: Population (Saturday, May 1st)

Life Strategies

Growth Patterns

• Population growth is limited by resource availability

  • Resources are always finite

  • When resources are abundant, population growth increase

  • When resources are scarce, unequal distribution may result in increased mortality + decreased fecundity (ability to produce new offspring)

• Overshoot: refers to when a pop exceeds the carrying capacity of an ecosystem

  • Can result in environmental consequences such as resource degradation or dieback of population

• Logistic Growth

  • As population approach limits on food/water/resources; carrying capacity (K) slows down pop growth

  • After approaching K, they'll be around stable

• Exponential Growth

  • A lot of pop experiences early in their population

  • No limits on food/resources

• Carrying Capacity: the maximum number of individuals the habitat can support based on food, water, and other resources (density-dependent factors)

  • Carrying capacity can change as available resources change

  • If populations overshoot carrying capacity, the lack of resources will result in a decline in pop #

Survivorship Curves

• Type 1: longer lives, most make it to maturity, low infant deaths, less offspring produced, higher parental vcare

  • Ex. People, k-selected species

  • Increasing mortality with age

• Type 2: equal chance of dying at any point in life

  • Ex. birds

• Type 3: high infant deaths, those that do make it usually survive to adulthood, offspring often over-produced

  • R-selected species

Age Structures

• Rapid growth: 

  • wide pyramid with wide base (lots of younger individuals and likely lots of future growth)

  • Top is skinny: little access to medical care 

• Slow growth:

  • Lots of older individuals>loner life span and increased access to medical care

• Zero growth:

  • Rectangular shaped; TFR is at replacement level (2.1)

• Negative growth/decline

Total Fertility Rate

• TFR: the numbers of babies on average that women in a country have (ages 15-45)

• Replacement fertility: 2.1 (replaces mom and dad), leads to population stabilization

  • Higher TFR in less developed countries, lower TFR in more developed countries

• Factors affecting TFR: medical care, jobs for women, death (infant), literacy in women, labor (needed for child labor), birth control access, government policies/laws

Population Math/Calculations

• Population growth rate= (birth rate + immigration) - (death rate + emigration)/total pop) x 100

• Doubling Time= 70/r; r=growth rate

• Birth rate (as a %): (total births/total population) x 100

  • Crude birth rate (per 1,000)=  (total births/total population) x 1000

• Death Rate (as a %): (total deaths/total population) x 100

  • Crude Death rate (per 1,000)= (total deaths/total population) x 1000

• Global population growth rate (r) = (CBR/1000-CDR/100) x 100

• National population growth rate (r) - ((CBR+immigration)-(CDR+emigration))/10

• Percent rate of change: (new-old)/(old) x 100

Demographic Transition Model

• Characteristics of developing countries:

  • Higher infant mortality rates

  • More children in workforce

  • Lower life- expectancy

  • Lower rates of access to modern medicine, education, safe drinking water, and sanitation

• 
  

• Stage 1 Pre-industrial: high BR and DR

  • Ex. not good living condition, struggling economy, war-torn country

  • agrarian/agricultural (more children=financial benefit from farms)

• Stage 2 Transitioning: dropping DR, still high BR

  • Life span begins to increase

  • Rapid pop growth

• Stage 3 Industrial: low DR, declining BR

  • Pop growth begins to slow down

  • Increased education/opportunities increases age of first pregnancy decreasing # of children born per woman, more children=financial burden; increased average ay m marriage, increased access to contraception + family planning

• Stage 4 Post-industrial: BR approaching DR

  • TFR may fall below RLF

  • Pop growth may be near 0, or negative

• Human population growth (or decline) in a geographic area is influenced by:

  • Birth rates, infant mortality rates, death rates, access to family planning, access to education, age at marriage

• Globally, human population growth is limited by: 

  • Earth’s carrying capacity, food supply (population growth tends to grow exponentially but food supplies grow linearly- Malthusian’s theory)

Population growth can be affected by density-dependent or density-independent

• Density dependent: factors affect a population more as the population size increases

  • Access to clean water, access to clean air, availability of food resoeces, disease transmission, territory size

• Density-independent: factors that affect a population at the same rate, no matter what the population size

  • Major storms (hurricanes, tornadoes, tsunamis, etc); fires; prolonged heat waves; doughts

Unit 4: Earth Systems and Resources (Friday, May 7th)

4.1 Plate Tectonics

Plate Tectonics: Theory explaining the movement of the Earth’s rigid lithospheric plates is the result of convection processes in the underlying partially molten mantle

Earth’s Structure

• Core: Dense mass of solid nickel, iron, and radioactive elements that release heat

• Mantle: liquid layer of magma surrounding the core, kept liquefied by intense heat from core

• Asthenosphere: solid, flexible layer of mantle, beneath the lithosphere

• Lithosphere: thin, brittle layer of rock floating on top of mantle ( broken up into tectonic plates

• Crust: very outer layer of the lithosphere, Earth’s surface

Plate Boundaries

Divergent Plate Boundary: Plates move away from each other

• Rising magma plume from mantle forces plates apart

  • Forms: mid-oceanic ridges, volcanoes, seafloor spreading, and rift valleys (on land)

Convergent Plate Boundary:Plates move towards each other 

• Leads to subduction (one plate being forced beneath another)

  • Forms: mountains, island arcs, earthquakes, and volcanoes

Transform fault Plate Boundary: plates slide past each other in opposite directions

• Forms: earthquakes (occurs when the stress on lithospheric plates overcomes a locked fault, resulting in a release of energy)

Convection Cycles (Divergent): Magma heated by earth’s core rises towards lithosphere

• Rising magma cools & expands, forcing oceanic plates apart

  • Creates, mid ocean ridges, volcanoes, spreading zones or “seafloor spreading”

• Magma cools, and solidifies into new lithosphere

• Magma heated by earth’s core rises towards lithosphere

• Rising magma cools & expands, forcing oceanic plates apart

  • Creates, mid ocean ridges, volcanoes, spreading zones or “seafloor spreading”

• Magma cools, and solidifies into new lithosphere

Convergent Boundary - Subduction Zone 

Oceanic-Oceanic : one plate subducts underneath other

• Forces magma up to lithosphere surface, forming mid ocean volcanoes

  • Island arcs

• Off-shore trench 

Oceanic-Continental : dense oceanic plate subducts beneath cont. Plate & melts back into magma

• Forces magma up to lithosphere surface

• Coastal Mountains (Andes), Volcanoes on land, trenches, tsunamis

Continental-Continental one plate subducts underneath other, forcing surface crust upward (mountains)

• Ex: Himalayas

Transform Fault Boundary

• Plates sliding past each other in opp. directions creates a fault (fracture in rock surface)

  • Earthquakes = most common activity

  • Occurs when rough edges of plates get stuck on each other

  • Pressure builds as plates keep sliding, but edges stay stuck

  • When stress overcomes the locked fault, plates suddenly release, slide past each other and release energy that shakes the lithosphere

Ring of Fire: pattern of volcanoes all around pacific plate

• Offshore island arcs (Japan) 

Transform faults: likely location of earthquakes

Hotspots: areas of esp. hot magma rising up to lithosphere

• Mid-ocean Islands (iceland, Hawaii)   

4.2 Soil Formation & Erosion

Weathering: Breakdown of rocks into smaller pieces

• Physical (wind, rain, freezing/thawing of ice)

• Biological (roots of trees crack rocks)

• Chemical (acid rain, acids from moss/lichen)

• Weathering of rocks = soil formation

  • Broken into smaller and smaller pieces

  • Carried away and deposited by erosion

Erosion

• Transport of weathered rock fragments by wind and rain

• Carried to new location and deposited (deposition)

Soil Formation:

• Weathering of parent material produces smaller, and smaller fragments that make up geological/inorganic part of soil

  • Sand, silt, clay

  • Minerals

• From above

  • Breakdown of organic matter adds humus to soil

  • Erosion deposits soil particles from other areas, adding to soil

Soil Horizons 

O-Horizon: layer of organic matter (plant roots, dead leaves, animal waste, etc) on top of soil

• Provides nutrients and limits H2O loss to evap.

A-Horizon: aka topsoil; layer of humus (decomposed organic matter) and minerals from parent material

• A-Horizon has most biological activity (earthworms, soil microbes) breaking down organic matter to release nutrients

B-Horizon: aka subsoil; lighter layer below topsoil, mostly made of minerals w/little to no org. matter

• Contains some nutrients

C-Horizon: least weathered soil that is closest to the parent material, sometimes called bedrock

Loss of Topsoil: tiling (turning soil for ag.) + loss of vegetation disturb soil and make it more easily eroded by wind and rain

• Loss of top soil dries out soil, removes nutrients + soil organisms that recycle nutrients

Compaction: compression of soil by machines (tractors, bulldozers, etc.), grazing livestock, and humans reduces ability to hold moisture

• Dry soil erodes more easily

• Dry soil supports less plant growth, less root structure, leading to more erosion

Nutrient Depletion: repeatedly growing crops on the same soil removes key nutrients (N, P, K, Na, Mg) over time

• Reduces ability to grow future crops

Minimizing erosion of topsoil into surface water:

• maintain/plant vegetated buffers between surface waters and crop fields (creates habitats to maintain biodiversity)

  • Create retention ponds to capture eroded soil (recharges groundwater by slowing flow of runoff and allowing infiltration, maintains biodiversity)

  • Maintain cover crops on fields after harvests (provides nutrients to next crop)

  • Use no-till agriculture (reduces fuel requirements, reduces releases of greenhouse gases associated w mechanized agriculture>decreases global climate change)

• Soil helps filter and clean water that moves through them

• Soil Erosion into bodies of water can create turbidity, reduce the penetration of sunlight (reducing photosynthesis), and clog the gills of aquatic organisms

4.3 Soil Composition & Properties

•  Soil Particle Size, Texture, and Porosity

• Geologic (rock) portion of soil is made up of 3 particles

  • (biggest to smallest) Sand > silt > clay

• Soil Texture: is the % of sand, silt, and clay in a soil

  • Always adds up to 100% ex: 40-40-20

• B/c sand is bigger, it has bigger pores (empty spaces between particles)

  • This allows air + water to enter sandy soil easily

  • Clay has smallest pores, so it’s harder for air + water to enter clay-heavy soils

• Porosity is the amount of pore space a soil has

  • more sand in a soil = more porous/higher porosity (easier for water + air to enter)

  • more clay in a soil = less porous/less porosity (harder for water + air to enter)

Water

• Needs to hold water, but not too much

• Factors that increase H2O holding cap.

  • Aerated soil (biological activity)

  • Compost/humus/organic matter

  • Clay content

  • Root structure, especially natives

• Factors that decrease H2O holding cap.

  • Compacted soil (machines, cows)

  • Topsoil erosion

  • Sand

  • Root loss

Nutrients

• N, P, K+, Mg2+, Ca+, Na+

• Factors that increase soil nutrients

  • Organic matter (releases nutrients)

  • Humus (holds and releases nutrients)

  • Decomposer activity (recycles nut.)

  • Clay (neg. charge binds pos. nutrients)

  • Bases (Calcium carbonate - limestone)

• Factors that decrease soil nutrients

  • Acids leach pos. charge nutrients 

  • Excessive rain/irr. leeches nutrients

  • Excessive farming depletes nut.

  • Topsoil erosion

Effect on Soil Fertility

• Soil that is too sandy (too permeable) drains water too quickly for roots + dries out

• Clay-heavy soil doesn’t let H2O drain to roots, or waterlogs (suffocating them) 

• Ideal soil for most plant growth is loam, which balances porosity or drainage, with H2O holding cap. (40% sand; 40% silt; 20% clay)

4.4 Atmosphere

• Nitrogen 78% Mostly in the form of N2 (unuseable to plants without being fixed)

Argon ~ 0.93%: Inert, noble gas

Oxygen ~ 21%: Produced by photosynthesis in plants & needed for human/animal respiration

Water Vapor ~ 0-4%: Varies by region & conditions; acts as a temporary GHG, but less concerning than CO2

CO2 ~ 0.04%: Most important GHG; leads to global warming

Removed from atm. by photosynthesis

Exosphere: Outermost layer where atm. merges with space

Thermosphere: Therm = hottest temp; 

• absorbs harmful X-rays & UV radiation 

• charged gas molecules glow under intense solar radiation northern lights (aurora borealis)

Mesosphere: Meso = for middle; 60-80 km, even less dense

Stratosphere:  “S” for second - 16-60 km; less dense due to less pressure from layers above

• Thickest ozone/O3 layer is found here; absorbs UV-B & UV-C rays which can mutate DNA of animals (cancer)

Troposphere: Tropo = change (weather occurs here) - 0-16 km, most dense due to pressure of other layers above it

• Most of atmosphere’s gas molecules are found here

• Ozone (O3) in the troposphere is harmful to humans (respiratory irritant) & damages plant stomata, and forms smog

Layers of earth’s atm. are based on where temp. gradients change with distance from earth’s surface

Thermosphere: temp. Increases due to absorption of highly energetic solar radiation

• Hottest place on earth (3,100oF)

Mesosphere: temp. decreases because density decreases, leaving fewer molecules to absorb sun

• Coldest place on earth (-150oF)

Stratosphere: temp. increases because top layer of stratosphere is warmed by UV rays (like pool surface)

Troposphere: temp. decreases as air gets further from warmth of earth’s surface (temp drops with altitude)

4.5 Global Wind Patterns

4 Properties that determine how air moves

1. Density: less dense air rises and more dense air sinks

   1. Warm air is LESS (more likely to rise) dense than cool air

   2. As warm air rises from the equator, it condenses and spreads out due to rotation of the earth (A Hadley Cell) (Hadley happens where its hot)

      1. The precipitation from the condensation falls between 0 and 30 N/S latitude creating tropical rainforest

      2. At 30 N/S, the dryer air sinks back down to the surface= deserts

2. Water Vapor Capacity: how much water vapor can air hold?

   1. Warm air can hold more water vapor 

   2. Saturation point: max amount of water vapor air can hold

   3. Temp goes up, saturation point goes up; temp goes down, saturation point goes down

3. Pressure: as air rises, pressure decreases

   1. Increase in attitude, decrease in pressure, volume increases, temp drops = adiabatic cooling 

   2. Pressure and volume inversely proportional

   3. Altitude increases, pressure increases, volume decreases, temp increases = Adiabatic heating

4. Latent Heat Release: water vapor in the air condenses to form precipitation, to warm up air

Coriolis Effect:

• Deflection of objects traveling through the atmosphere due to the spin of earth

  • Objects are deflected to the RIGHT in the northern hemisphere and to the LEFT in the southern

• The spinning of cyclonic storms (counterclockwise in the northern hemisphere and clockwise in the southern)=result of the coriolis effect

• Air at 30 degrees moves back to L pressure of equator

• West between 0-30 degrees moves from E>W

  • Because Earth spinning from W>E

• Wind between 30-60 movies W>E

  • Earth spins faster @ 30 degrees than 60 

• Throw ball from northern hemisphere(moving slower) > equator it moves to the right 

Global Wind Patterns

• Air moves out from 30 - 0 and 60 due to high pressure @ 30 and low pressure @ 0 and 60

  • Air rising @ equator = low pressure

  • Air sinking down at 30 = high pressure

• 0-30 winds blow E>W (EASTERN TRADE)

  • Drives ocean current clockwise in N hemisphere, counterclockwise in S hemisphere

• 30-60 winds blow W>E (WESTERLIES

  • Drives weather patterns of N America

4.7 Solar Radiation & Earth’s Seasons

• isolation : the amount of solar radiation ( energy from sun’s rays) reaching an area

Solar Intensity & Latitude:

• Depends on 

  • Angle: how directly rays strike Earth’s surface

  • The amount of atmosphere sun’s rays pass through

  • Equator = higher isolation than higher latitudes

• At high latitudes, sunlight must pass through more atmosphere & loses more of its energy

  • A given amount of solar energy is spread over a larger surface areas than at the equator

Solar Intensity & Season

• Orbit of earth around sun + tilt on axis changes angle of sun’s rays

  • Causes varying insolation, varying length of days, and seasons

  • Tilt of earth’s axis stays fixed during orbit

    • June/December solstices: N or S hemisphere is maximally tilted toward sun ( summer/winter(

    • March/Sept equinox: N and S hemispheres equally facing sun

Albedo

• The proportion of light that is reflected by a surface

• Surfaces with higher albedo reflect more light, and absorb less ( ice/snow)

  • Absorb less heat

• Surfaces with low albedo reflect less light, and absorb more (water)

  • Absorb more heat

• Positive feedback loop>>>

Albedo & Surface Temperature

• When sunlight is absorbed by a surface, it gives off infrared radiation (heat)

  • Areas with lower albedo, absorb more sunlight light/hear

• Urban Heat Island: urban areas are hotter than surrounding rural areas due to low albedo blacktop 

• Polar regions are colder due to high albedo

4.8 Earth’s Geography & Climate

Climate & Geography

• Climate is determined by insolation ( latitude>angle of insolation & atmosphere

• Higher latitudes receive less insolation ( cooler, less precipitation)

• Equator receives most intense insolation ( higher temp, air rises, high precip)

• Thermal inversion: cooler air at the surface becomes “trapped” by a later of warmer air above it

  • Increases intensity of surface air pollution

• mountains : disrupt wind, and produce rain shadow effect

• Oceans: moderate temp & add moisture to the air 

Rain Shadow

• A drier area of land next to a higher elevation, higher elevation (such as mtn.) blocks the precipitation from reaching the area

• Warm, moist air from ocean hits “windward” side of mts, rises, cools> lush, green vegetation

• dry air descends down “leeward” side of mtn, warming as it sinks

  • Leads to arid dry desert conditions

4.9 El Niño & La Nina

• El Nino (southern oscillation- ENSO) is a periodic, non-anthropogenic phenomenon that occurs in the southern pacficic ocean

  • Changes to patterns of rainfall, wind, ocean circulation occur that can cause climatic/environmental/economic disruptions 

  • Effects: Suppressed upwelling and less productive fisheries in SA; warmer winter in much of N America; decreased hurricane activity in atlantic ocean, increased precip/flooding in americas ( w coast esp)

• Effects of LA NINA: stronger upwelling and better fisheries in SA than normal; worse tornado activity in US & hurricane activity in atlantic; rainier/warmer/increased monsoons in SE Asia

Global Ocean Surface Currents

• Gyers: large ocean circ. Patterns due to global warming

  • Clockwise in N hemisphere, counterclockwise in S hemisphere

• E>W trade winds between 0-30 push eq. Current E >W

• Westerlies between 30-60 degrees and pushes mid lat. currents W>E

• Upwelling zones: areas of ocean where winds blow warm surface water away from a land mass, drawing colder/deeper water to replace it

  • Brings O2 + nutrients to surface = productive fishing

Thermohaline Circulation

• Connects all of world’s oceans, mixing salt, nutrients, and temp throughout

  • War, water from Gulf of MX moves toward North Pole

  • Cools & Evaporates as it moves towards poles

  • saltier/colder @ poles , is more dense making it sink

  • Spreads along ocean floor

  • Rises back up into shallow warm ocean current @ upwelling zones

Unit 5: Land and Water Use (Sunday, May 9th)

5.1 Tragedy of Commons (TOC)

• Individuals will used shared/public resources in their own self-interest, degrading them

  • Overgrazing, overfishing, water/air pollution, overuse of groundwater    

Why does it happen?

• When no one owns the resource, no one directly suffers the negative consequences of depleting/degrading/or overusing

• People assume others will overuse if they don't

• No penalty for overusing, degrading, polluting many public resources

Problems?

• Overfishing>fishery collapse>population crash(loss of income, starvation)

• Air pollution from coal power plants>bronchitis, asthma, increased healthcare costs

• Pesticide runoff from farms>contaminates drinking water

• Externalities: costs/benefits of a good or service that is not included in the purchase price

  • Can be + or -

  • Smell of local bakery= positive externality

  • Air pollution from a factory= negative externality 

How to Solve the TOC

• Many economists feel that private ownership or regulation is the solution to the problem of tragedy of the commons

• Private land ownership ( individual or gov)

• Fees or taxes for use

  • Permit system for grazing, logging

• Taxes, fines, criminal charges for pollution or shared air/soil/water resources 

  • Clean air act, clean water act, safe drinking water act

FRQ: The oceans of the world are often referred to as a commons. Identify one other such commons, explaining how human activities affect that commons, and propose a solution for managing that commons.

Forests are another example of commons in which humans cut down the trees for the purpose of making products or using the empty land for slash-and-burn agriculture to later abandon the area and decrease the stability and biodiversity of the forests/environments. To manage the commons, fees or permits may be imposed with increased security to prevent illegal activities. 

5.2 Clearcutting

• economically advantageous but>> soil erosion, increased soil/steam temperatures, and flooding 

• Forest benefits: filtering of air pollutants, removal & storage of CO2 from atm., habitat for organisms

• Timber is when it is cut down, lumber is when something is done to the wood

Timber Harvest Practices

• Clear-cutting: removing all or almost all the trees in an area

  • Benefits: most economical, often strands are replanted

  • Soil Erosion: caused by loss of stabilizing root structure, removed soil organic matter/nutrients from forests, deposits sediments in local streams and makes it more turbid (cloudy)

  • Reduction of carbon sequestration

  • Increase in climate change

  • Increased soil/stream temp: loss of tree shade increases soil temp, loss of tree shade along rivers/streams along with erosion of sediments warms them 

  • Flooding and landslides: logging machinery compacts soil, increased sunlight dries out soil, loss of root structure=erosion of topsoil and o orizon

    • Decreases H2O holding capacity of soil causing flooding and landslides

Tree Plantations: area where the same tree species are repeatedly planted, grown, and harvested

• Lowers biodiversity: mature forests replaced with single species forests; less species/habitat diversity

• All the trees planted at same time=all same age; lowers biodiversity b/c no dead trees for woodpeckers, insects, decomposers

Deforestation Consequences

• Reduces air filtering and carbon storing services

• Cutting trees down releases CO2 from decomposition of leftover organic material

• Slash and burn method of clearing land for agriculture by cutting trees/burning releases CO2, N2O, and water vapor into atmosphere (greenhouse gases)

Selective Cutting:

• Removal of single trees or small amounts of trees

• Optimum growth amount shade-tolerant species

• Less erosion, loss of biodiversity, etc

• Logging roads

1. Identify and explain one reasonable cause for a decline in the trout pop of the sophia williams river that is directly linked to the deforestation of the nearby forest

As the deforestation of the nearby forest occurs, the soil starts to loosen with no roots to hold them together making soil erosion and runoff occur more frequently bringing toxins and sediments to the rivers. As this occurs, the fish no longer have a suitable habitat because the increased aquatic particulate that irritates and clogs fish gills and kills the trout

2. Identify a law that could be applied tho the situation described above

A law that could be the clean water act 

3. Intact forests are an important part of the biosphere. Describe a regulating service forests provide

Regulating services forests provide include water filtration, stabilization of local climate, severe weather mitigation, carbon sink (when trees perform photosynthesis they take in carbon dioxide which becomes a part of their roots and stems), air quality maintenance,, water quality maintenance 

Describe TWO ecosystem services provided for humans by forests. Explain how clear-cutting would affect each ecosystem service you describe.

Forests give provisioning services through their wood used as fuel or other human activities- If clear-cutting were to occur, the loss of these goods produced by the forests would cause a shortage of resources. Another ecosystem service forests provide us is as a regulating service as forests are a great sink of carbon from the atmosphere while they regulate and produce oxygen for human use. With clear-cutting, there would be a higher amount of CO2 in the atmosphere (a greenhouse gas) which would lead to higher temperatures and result in the lower amount of CO2 being converted into oxygen for humans to take in.

5.3 The Green Revolution

• Shift in agriculture away from small, family operated farms to large, industrial-scale agribusiness

  • Increased use of mechanization, GMOs, irrigation, fertilizers, pesticides

  • Increased efficiency of lands, short-term profitability and food supply

    • Decreased world hunger and increased earth's carrying capacity

  • negative effects: soil erosion, biodiversity loss, ground or surface water contamination

Mechanization

• Increased use of tractors for plowing and filling fields and combines for harvesting=increased yield + profit

• Increased reliance on fossil fuels>emits GHG to atmosphere

• Heavy machinery also compacts soil, decreasing H2O holding capacity>makes topsoil prone to erosion

• Economies of scale: average costs of production fall as output increases

  • Large upfront expenditure justified by profits from increased production

  • Small farms cannot expend the up-front cost

Monoculture

• Easy to plant, maintain, harvest

• Only certain types of pests associated with this one crop

• DOWNSIDES: loss of habitat and biodiversity, loss of ancestral varieties, increased pros of catastrophic event

Energy subsidy

• Energy input per calorie of food produced

  • In US: 10 calorie energy input for every 1 calorie you consume

  • Energy input per calorie of food obtained is greater for modern agriculture practices than for traditional agriculture

  • Fossil fuel energy is primary energy subsidy for large-scale modern food production (to produce fertilizers/pesticides, to operate tractors, pump water for irrigation, harvest food and prepare for transport)

High-Yield Variety Crops

• hybrid/ genetically modified crops that produce a higher yield 

  • Hybrid: cross-pollinating different species or parent plants with ideal traits

• Increased yield and food stability in regions previously prone to famine ( india, pakistan, MX)

• GMOs: crops with new genes spliced into their genome

  • BT bacteria’s pesticide producing material is given to other crops

GMOs

• Genetically modified crops have genes for drought tolerance, pest resistance, faster growth, and larger fruit/grain

  • Increases profitability with few plants lost to drought, disease, or pests + larger plant size + yield/acre

  • All genetically identical so genetic diversity is decreased and susceptibility to diseases/pests is increased

Synthetic Fertilizer 

• Shift from organic fertilizers (manure/compost)>synthetic fertilizers (man made ammonium, nitrate, phosphate)

  • Increases yield/profit w more nutrients needed (N, P, K)

  • Excess nitrate, phosphate are washed fff fields into nearby waterway>eutrophication/algae blooms

  • Require ffs for production, releasing CO2

Irrigation

• Drawing water from ground or nearby surface water +  distributing it on fields = increase plant growth

  • Makes agriculture more possible in places that are  too dry

  • Can deplete groundwater esp aquifers

  • Overwatering can drown roots, no O2 access, and cause soil salinization (increase salt level in soils)

Pesticides

• Increase in use of synthetic pesticides: chemicals sprayed on crops that kills weeds, insects, rodents, etc that eat or damage crops

  • Increase yield and profit w few plants lost due to pests

  • Can wash off crops in runoff and kill or harm non-target species in local soils/waters

    • Ex. DDT thinned shells of bird eggs, esp eagles

1. Describe 1 environmental advantage and 1 environmental disadvantage of using GM crops

1 environmental advantage of using GM crops is higher yields per acre and less acreage needed which is a less loss of habitat, biodiversity. 1 environmental disadvantage of using GM crops is that GM crops w insect resistance may impact beneficial insects used for pollination, altered genes may impact human health w altered proteins and toxins

2. Describe 1 economic advantage and 1 economic disadvantage of using GM crops

1 economic advantage of using GM crops is the increased yield meaning there is an increased profit especially in places that could not grow crops before, reduced water loss that lowers associated costs. 1 economic disadvantage of using GM crops is that higher yields often lead to greater soil depletion, requiring higher costs of mitigation, decreased profit due to use of GM crops that gave increased fertilizer demand to reach yield potential

5.4 Impacts of Agricultural Practices

Arable land- capable of producing crops

Tilling:

• Bare soil>soil erosion, evaporation

  • Eutrophication, need for fertilizer

• Turned soil> impacts soil structure

• Turned soil>sequestered carbon released as CO2

• Eutrophication: overgrowth of algae

• Mechanized farming equipment>impact soil, emissions, fossil fuels (habitat loss, water usage to get ff)

Slash and Burn Agriculture

• Developing countries

• Typically tropical rainforests (low-nutrient soil)

• Subsistence (himself and family) farmers

• Ash used as fertilizer

• UNSUSTAINABLE

  • Nutrients provided by ash quickly used

  • Cut down new plot of land 4 crops

• IMPACTS: desertification (forests cannot grow back), soil erosion, decreased albedo, increased evaporation, decreased water infiltration

Synthetic vs Organic fertilizers

• N, P, K

• Organic is from animal waste 

• Synthetic fertilizers PROS:

  • Easy to transport/use, timed released, customizable

• Synthetic fertilizers CONS:

  • Water-soluble (runoff), often overused, does nothing to improve soil structure

• Organic fertilizer CONS:

  • Must be gathered, nutrient levels unknown, harder to use

• Organic fertilizer PROS:

  • Can be worked into soil (stays), contains partially digested vegetation>improves soil structure

5.5 Irrigation Methods

• furrow irrigation: trench dug along crops and filled with water

  • Easy, inexpensive and water seeps into soil slowly

  • 66% efficient, 33 lost to runoff and evap

  • Difficult to apply small amounts

• Flood irrigation: flood entire filled, easier but more disruptive to plants

  • PROS: Easy, inexpensive, mechanization not required

  • CONS: Requires water nearby, not for all plant types

  • Can waterlogged soil/drown plants

  • 80% efficient, 20 to runoff/evap

• Drip irrigation: most efficient, but also most costly

  • Over 95% efficient

  • Holes in hose allow water to slowly drip out

  • Avoids waterlogging and conserves water

  • Very expensive, requires mechanization, placements makes any other processes difficult

  • Most efficient irrigation technique for dry/semiarid climates since less water is lost to evaporation

  • Used in dry/semiarid climates because water resources are limited and drip uses less water than other methods to reduce water use-l

• Spray irrigation: ground or surface water pumped into spray nozzles

  • More efficient ( less water loss) than flood or furrow

  • More expensive (requires energy for pumps and movement of sprinklers). Mpzz;es can clog ( less sediment in water), machinery run with electricity/FF

Waterlogging

• Overwatering can saturate the soil, filling all soil pore space w water

  • nallow water into pores, so roots cant take in o2 they need

  • Can stunt growth/kill crops

• Solution: Drip irrigation. Soil aeration- poking holes or cores in soil to allow air in and water to drain through soil

Soil Salinization

• Salinization process of salt building up in soil over time

• Groundwater used for irrigation naturally has small amount of salt

  • Water evap, salt left behind in soil>dehydrating plant roots and preventing growth

• Solution: drip irrigation, soil aeration, flushing w fresh water, switching to freshwater source

Global Human Water Use

• Industrial: power plants, metal/plastic manufacturing

• Municipal: households ( toilets, shower, drinking water)

• Agriculture: water for livestock irrigation water for crops

Aquifers & Groundwater

• Groundwater: H2O is stored in pore space of permeable rock and sediment layers

• Aquifers: usable groundwater deposits for humans

  • Replenished by groundwater recharge (rain water percolating down through soil into aquifer)

  • Unconfined aquifers recharge quickly

  • Confined aquifer recharge are longer-term water deposits that recharge more slowly

  • Ogallala aquifer: farmers drawing water from aquifer>water levels losing more than it is being replenished

Depletion of Aquifers

• Cone depression: forms when water table is lowered by excessive pumping, depleting water and drying nearby wells

• Saltwater intrusion: excessive pumping near coast lowers water table pressure>allowing saltwater to seep deeper into groundwater

FRQ about soil salinization: 

Soil salinization occurs when groundwater is used for irrigation and as the water evaporates, salt is left behind in the soil which can become toxic for the plants. A solution to prevent or remediate soil salinization is to switch to a freshwater source in order to flush out the salt and keep using the less salty alternative. But one disadvantage of this solution is that it is very expensive and is not economically profitable to be spending so much on a freshwater resource.

5.6 Pest Control Methods

Pesticide Use and Overuse:

• Pesticide treadmill: continuous use of pesticides that increase/stronger concentration and have unintended effects on the environment

Problems

• Increasing use> runoff (kills organisms in water, contaminated drinking water); carried by wind to other areas, entry through wells

  • Killing of bees needed for pollination, biomagnification (storing of persistent of lower trophic level effect on apex predator)

Use

• Reduce impacts of pests> maximizing yield of crops, increasing profit not affected by mold, insects etc.

• Chemical Control with: pesticides, herbicides, fungicides, rodenticides, insecticides

• 
  

5.7 Meat Production Methods

Meat overconsumption

• When countries are developing they eat more meat

Land Use

• Takes a lot of land (25% land on earth)

Animal waste and Emissions

• Lots of animals raised for meat>lots of animal waste

• Cows emit methane> GHG

Animal Waste

• Increase turbidity>>Decrease in aquatic primary productivity, decrease in albedo

• Increase in water temperature>>decrease in dissolved oxygen (DO) levels

• Increase in organic matter/nutrient load>>increase in decomp by aerobic bacteria, decrease in DO levels, eutrophication

• Soil Compaction, soil erosion

Reducing Meat Consumption

• Reduce CO2, methane, N2O emissions, conserve water, reduce use of antibiotics and growth hormone, improve topsoil 

CAFOs (concentrated animal feeding operation)

• CAFOs can raise cattle, chickens, turkeys, pigs, sheep, goats, or any other livestock for consumption by humans

• Large but efficient (to serve demand for meat)

  • Keeps meat production costs down= more affordable meat for consumers

  • BUT can lead to density-dependnet pathogenic infections; increased nmethane production, and acid-resistant E. coli

• Crowded, create a lot of waste^^^ (animal waste section)

Free range grazing

• Allows animals to graze on grass during their entire lifecycle

  • Allows animals to eat grass, the food they are designed to eat

  • Means less antibiotic use and less antibiotic residue in the meat

  • Uses animal waste as a natural fertilizer for the forage

• Free range grazing and land use>more land area, non native organisms interfering, costs more, not using growth hormone

  • Requires large areas of land

  • May lead to overgrazing and land degradation

  • Leads to higher meat prices for consumer

Overgrazing

5.8 Impacts of Overfishing

Overfishing has led to extreme scarcity of some fish species, which lessens biodiversity in aquatic systems and harm people who depend on fishing for food and commerce

• Longline: long line with evenly lined hooks held by flotation devices dragged behind ships (28 mi long)

  • Pro: efficient (lots of fish w 1 pass), 

  • Con: overfishing if unregulated, non-target species than intended will eat and get hooked

• Drift net/gill net: long net set at varying depths pulled by ships/boats (caught by gills)

  • Pros: efficient

  • Cons: can lead to overfishing, can catch unintended organisms

• Purse seine: massive net that has 2 drawstrings, catch entire school of fish, draw bottom and top shut to draw up fish

  • Pros: efficient

  • Cons: can lead to overfishing, can catch unintended organisms

• Trawling: net shaped like cone that is dragged through water

  • Pros: efficient

  • Cons: can lead to overfishing, can catch unintended organisms, erased DESTROYS HABITAT AS ITS DRAGGED ALONG BOTTOM

• Sonar: locating school of fish, seafloor

  • Pros: more money, fish

  • Cons: interferes w navigational systems of aquatic mammals like whales 

• Bycatch: non target species

  • Processed w rest of everything, tossed back out

Making fishing more sustainable

• Catch limits based on MSY (maximum sustainable yield)

• Limit age/size of fish caught

• Modify techniques to reduce bycatch

• laws/treaties that protect critical species: US Endangered Species Act; Convention on International Trade in Endangered Species of Wild Flora and Fauna

• Modified fishing techniques: TED is a turtle exclusion device on trawling nets 

 FRQ: describe commercial practices and explain the role it plays in the depletion of marine organisms

• Bottom trawling is when you drag a net or line with hooks along the bottom of the ocean that destroys the benthic habitat and catches many non target species

• Sonar uses sound waves to locate fish or see the bottom that allows ships to locate larger school of fish quickly and target them as well as throw off animals using their navigational systems like whales to wash up on the shore

Identify 1 international regulation or US federal law that applied to the harvesting of marine food resources and explain how it helps to manage marine species

• Endangered Species Act-

• The convention on international trade in endangered species of wild flora and fauna

Identify and explain a way other than passing a law or signing an international treaty, to reduce overfishing of a fish species

• Set a catch limit for each commercial fishing company in a country, setting a MSY for an entire country would ensure there will be enough fish to reproduce and replenish fish stocks

• Offer incentive to commercial fishing companies and countries that fish sustainable, incentivizing can motivate corporations and countries to shift towards using more sustainable fishing methods

5.10 Impacts of Urbanization

• Urban sprawl: change in pop distribution from high pop density areas>low density suburbs that spread into rural lands

• Urbanization: shift from lifestyle on agricultural, rural>non agricultural jobs that has high pop density

  • Pro: mass transit (reduced FF emission), activity level up, more efficient use of space, less land impact

• Urban Blighet/Urban Decay: decline in urban neighborhoods due to taxpayers moving out>leads to loss of tax dollars that reduce city services, an increase in abandoned buildings and increase in crime

• Urbanization can lead to depletion of resources and saltwater intrusion in the hydrologic cycle

• Urbanization through the burning of fossil fuels and landfills affects the carbon cycle by increasing the amount of CO2 in the atmosphere

• Impermeable surfaces>can’t recharge water/groundwater, runoff

  • Heat island effect; more veg=cooler temp; less veg=higher temp

FRQ: describe 2 causes of urban sprawl

• Transportation: increased use/reliance on automobiles, improved roads, lower gas prices promote driving, 

• Quality of life: desire for property/yard/lower density, better quality suburban schools

Discuss 2 human health effects associated with urban sprawl;

• Increased air pollution: asthma, bronchitis

• Less exercise due to auto travel time/commuter diet: obesity, diabetes

• Increased driving: personal injuries due to automobile use/crashes

Describe 2 steps a municipality could take to encourage emart growth in order to limit urban sprawl

• Transportation: subsidize mass transit to encourage less automobile use

• Tax incentives/reduced taxes for living in city

5.11 Ecological Footprints

• Ecological footprint: a measure of how many resources a person uses, expressed in an area of land

  • 5 variables: carbon footprint>energy; built-up land>settlements; forests>timber and paper; cropland and pasture>food and fibers; fisheries>seafood

• Less developed/developing countries have lower ecological footprint than developed countries

• Factors to consider in calculation of ecological footprint: cropland, grazing lands, fishing grounds, forested areas, built-up (urbanized) lands, carbon demand

5.12 Introduction to Sustainability

• Sustainability refers to humans living on Earth and their use of resources without depletion of the resources  for future generations

  • Indicators: biological diversity, food production, average global surface temp, CO2 concentrations, human pop, and resource depletion rates

• Biological diversity> healthier ecosystems are resistant to disturbances

• Food production> poor practices lead to soil degradation and water pollution

• Global surface temp and CO2 concentrations>excessive CO2 increases global temp creating climate change

• Human pop> exponential growth stresses the planet

• Resource depletion> will this resource be available in the future

• Sustainable Yield: The amount of a renewable resource that can be taken without reducing the available supply (50% of carrying capacity)

5.13 Methods to Reduce Urban Runoff

Consequences of urban runoff

• Decreased infiltration (groundwater recharge) from impervious surfaces

• Rain washes pollutants into storm drains and & local surface waters

  • Pollutants & effects: 

    • Salt (plant/insect death)

    • Sediment (turbidity)

    • Fertilizer (eutrophication)

    • Pesticides

    • Oil & gas (suffocate fish/kill aq insects)

Solution: Permeable Pavement

• Specifically designed to allow stormwater to infiltrate & exchange ground water

  • Decreases runoff, decreasing pollutants carried into storm drains & into local surface water

  • Decreases likelihood of flossing during heavy rainfall

  • More costly

Solution: rain garden

• Garden planted in urban areas, especially surrounding a storm drain

• Decreases runoff by allowing it to soak into garden soil surrounding storm drain

•  Creates hab for pollinators

Solution: public transit

• More cars on road= more pollutants on streets to runoff into storm drains and local waters

• More cars=more lands and parking lot (impervious surfaces) and more stormwater runoff

• Public transit decreases urban runoff, pollutants on road, CO2 emissions and 

Solution: Building Up, not Out

• Building vertically decreases impervious surfaces (decreasing urban runoff)

• Can be combined with green roof or rooftop garden to further decrease runoff

• Sequesters co2 and filters air pollutants

  • Plants absorb

5.14 Integrated Pest Management (IPM)

• A combination of methods used to effectively control pest species while minimizing the disruption of the environment

  • Goal is to reduce the amount of chemical pesticides used to reduce the pesticide treadmill and poisoning of non-target species and humans

• Biological controls: introduction of natural pest predators

• Physical controls: barriers that protect crops

• Chemical controls: poisons that kill pest species

• Crop Rotation: switching crops in harvests

• Intercropping: cultivation of 2+ crops grown at same time (2 pests w common predator)

  • By switch crops, pest species many not accumulate that warrant pesticide use

• THE USE OF CHEMICAL PESTICIDES CAN CAUSE HARM 2 ENVIRONMENT (kills non-targets wildlife, contaminates water supplies, affects human health)

• IPM PROS:

  • Decreases amount of chemical pesticides sprayed on crops, economic savings, sustainable, targeted, minimizes loss of pollinators, minimize health risk, decreases pesticide resistance

• IPM DRAWBACKS: 

  • Complex, slow, expensive

• The use of IPM reduces the risk that pesticides pose to wildlife, water supplies, and human health

• IPM mimizies disruptions to the environment and threats to human health BUT is complex and expensive

5.15 Sustainable Agriculture

Preservation of soil is essential to maintaining sustainable food production practices

• Contour Plowing: Preserved natural topography of the land and leaves oil intact (less soil erosion)

• Windbreaks (adding trees): Reduces wind erosion that may blow soil away

• Strip cropping: Harvesting one crop at a different time will leave one crop holding the soil in place 

• Terracing: hill or mountain; decreases the velocity of water going downhill>>reducing soil erosion

• No till agriculture: leave soil in place and does not loosen it so it can resist erosion

• Perennial crops: crop roots hold soil together year-round, does not have to be replanted

Practices that improve soil fertility include:

• Crop rotation: may replenish soils of nutrients naturally (ex. Legumes add nitrogen to the soil)

• Green manure: adds bulk and Nitrogen, Phosphorus, Potassium to soil that slowly decomposes

• Limestone: addition of limestone adds valuable calcium to soil and increases pH making soils more alkaline

Overgrazing is unsustainable in food production

• Overgrazing: extensive grazing that causes damage to plants (leads to soil erosion and destruction of pasturable fields)

• Rotational Grazing: the cycling of livestock around a particular part of their pasture to not overgraze 1 area (allows the cover crop to replenish and hold soil in place)

FRQ: describe 1 agricultural practice that can lead to the degradation of agricultural land

• plowing/tilling the soil increases soil erosion (by breaking up the soil structure) and reduces fertility

• Using monocultures or the growing of 1 crops over and over again will deplete the soil of the needed nutrients

• Overgrazing by livestock leads to a loss of soil cover and increases soil erosion without the top cover to hold it in place

Describe a potential solution or technique that can prevent or reduce degradation of agricultural land

• Contour plowing uses the contours of the land to minimize soil erosion

• Terracing, growing crops on side of hills or mountains in a series of steps reduces soil erosion

• Perennial crops remain in the soil year-round and can survive for several years which reduces the need for replanting and improving or disturbing the structure of the soil which limits soil erosion

5.16 Aquaculture

• Aquaculture: the farming of fish, shellfish, mollusks, crustaceans or aquatic plants by an individual or corporation with the intent to sell the farmned organisms to consumers for profit

  • Can occur in both marine and freshwater environments, depending on organism farmers

  • China is leader in aquaculture production in marine and freshwater environments

• Aquaculture has expanded b/c it is highly efficient, requires only small areas of water, requires little fossil fuel inputs

• AQUACULTURES HELPS REDUCE OVERFISHING AND PROVIDES AFFORDABLE, HIGH-QUALITY PROTEIN TO HUMANS EFFECIENTLY AND W LESS FOSSIL FUEL INPUTS

• CONS: can waste from organisms/uneaten food pellets can contaminate waterways and fish that escape may compete or breed w wild fish

  • Density of fish in aquacultures can lead to disease incidence which can be transmitted to wild fish

• Aquaculture as an environmental solution:

  • Advantages: provides high-quality protein to growing human pop; provides stable income to fisherfolk w less risk than open-water; less acreage and less water; fewer fossil fuel input needed than terrestrial agriculture

  • Disadvantages: nitrogenous waste can pollute waterways>>eutrophication; Uneaten feed can pollute waterways>water-quality issues; escaped farmed organisms can interbreed or compete w wild organisms; diseases/parasites from densely packed farned pop can spread to wild; medication to control disease in farmed can pollute waterways

FRQ: describe an advantage of aquaculture that helps minimize natural resource use

• Less water, less fossil fuel inputs (minimizes natural resource use)

Identify a disadvantage of aquaculture and describe how that disadvantage might lead to an unintended environmental consequence

• Escape of farmed organisms can lead to competition and change to the wild organisms due to competition and interbreeding (foodweb change, diversity)

5.17 Sustainable Forestry

Forest ecosystem services: food, medicine, fuel, fiber, timer, carbon sequestration, air purification, water purification, flood and erosion control, maintenance of biodiversity, recreation, aesthetic and cultural value

• Sustainable forestry: refers to a collection of methods that attempt to reduce the human impact of harvesting trees and using forest resources

Methods for mitigating deforestation

• Reforestation:  intentional restocking of existing forests/woodlands that  have been depleted

• Using and buying wood harvested by ecologically sustainable forestry techniques:

  • Selective harvesting of trees, prohibiting logging in ecologically sensitive or highly biodiverse areas of forested land, transportation of felled trees via techniques that lessen ecological disruption and soil compaction

• Reusing/repurposing/recycling wood

Methods to protect forests from pathogens and insects include:

• Integrated Pest management (IPM): continual monitoring of health of tree stands, thinning of underbush, knowledge of common pest species, understanding economic pest threshold, setting pest traps/manual weeding, biological control w natural predators, chemical control w repellents/pesticides/herbicides (last resort)

• Removal of affected trees: helps slow spread of infestations in a stand

• Prescribed burn: method by which forests are set on fire under controlled conditions to reduce the occurrence of natural fires

  • Fire removes excess understory plants, dead tree limbs, needles, branches

  • Selective removal can reduce severity of natural forest fires by reducing the amount of dry matter available as fuel/help reduce pest infestations

• Sustainable forestry methods

  • Increase the economic costs of using forest resources and reduce profit margins for timber companies

  • Require forestry workers to be trained on how to properly use these techniques

  • PRO of mitigation of deforestation: preserves biodiversity, preserved critical ecosystems services that forests provide, economically supports organizations and timber companies that employ sustainable methods, reusing wood reduced need to cut new timber

  • PRO of using IPM/selective tree removal for pest management: ensures forestry workers are closely monitoring tree stands; reduces impact of pesticide/herbicide use on non-target species, soil, water; reduces likelihood of trophic structure disruption from pest eradication; more closely mimics natural balance of ecosystem

  • PRO of prescribed burns: lessen the severity of naturally-occurring fires by removing underbrush and debris; encourage new growth of nntaive species; help manage pest species

FRQ: provide 1 reason why fire-suppression policies lead to increased beetle activity

• Fire-suppression means that the undergrowth is not burned where pests usually breed 

• When the pest accumulate in the undergrowth, it affects the mature trees more>and in a forest that is not allowed to burn, there are more mature trees 

Explain how prescribed burns might mitigate the impact of mountain pine beetles on forests

• Prescribed burns would burn the understory in a forest that would reduce pest populations

• Help clear understory so that smaller saplings can come up which will make a mix of tree growth and not a majority of large trees that are preferred by the beetles

A national forest service intern recommends using a combination of IPM methods and selective tree removal to reduce beetle pop>>>

Explain 2 advantages of this approach that would justify its use by the forest service for beetle control

• It reduces the effect of chemical pesticides on nontarget species

• Selective tree removal means keeping the biodiversity of the forest intact b/c only diseased trees are removed

Unit 6: Energy Resources and Consumption (Saturday, May 22nd)

1 MBTU= 1,000,000 BTU

6.1 Renewable vs Nonrenewable Energy Sources

• Nonrenewable energy sources are in a fixed amount and involve energy transformation that cannot be easily replaced

  • Fossil fuels: fossilized remains of ancient biomass that take millions of years to form

    • Coal, oil, natural gas

  • Nuclear: energy generated from uranium or other radioactive fuels

• Renewable energy sources are those that can be replenished naturally, at or near the rate of consumption, and rescued

  • Depletable renewables can run out if overused (biomass)

  • Nondepletable renewables do not run out if overused (solar, wind hydroelectric, )

Fossil fuels

• Derived from biological material that fossilized millions of years ago

• Form in anaerobic conditions (swamps)

  • oil/gas trapped in rocks

Renewable Energy

• Rate of consumption:

  • Rate of use must be at or below rate of regeneration for renewables

  • Fossil fuels will run out because they take far longer to regenerate than the rate we use them

FRQ: explain whether or not biomass is a renewable energy source + justify

Biomass is a renewable energy source because it can be replenished naturally at a rate near consumption but can be depletable and run out if overused

• Non-renewable energy resources – Resources that have a finite amount available on Earth for human use.

• Non-depletable resources – Resources that cannot be used up on a human time scale.

• Potentially renewable resources – A resource that can be sustained on Earth as long as consumption does not outpace growth/replenishment.

• Renewable resources – Broad category for non-depletable and potentially renewable resources.

• Potential energy is stored energy and includes chemical, nuclear, gravitational, or mechanical energy. 

• Kinetic energy is energy created from movement and includes radiant energy, thermal energy, sound, motion and electrical energy.