APES Test Review for Topics 4.6 - 4.9 and 5.1-5.3, 8.1, 8.5, 8.7, and 8.8

Experiment Review

• Some of the MCQs & part of the FRQ have an experimental scenario in which you will have to determine the following components: independent variable, dependent variable, control group, experimental group, and constants (also referred to as controlled variables)

• Independent variable → refers to what the experimenter is manipulating/changing 

(e.g. temperature, concentration of a substance, etc.) 

• Dependent variable —> refers to what the experimenter is measuring (what data is the person collecting – e.g. number of surviving organisms for each temperature) 

• Control group - a group that doesn’t receive the treatment/manipulation; for example: if an experimenter is testing to see how an increase in DDT concentration affects a population of mosquitoes, then a control group would contain a sample of mosquitoes not exposed to DDT

• Experimental group(s) - one or more groups that receive a treatment/manipulation; for example: using the DDT, the experimenter could expose 10 mosquitoes to .5% DDT, he/she could expose another group of 10 mosquitoes to 1.0% DDT, and etc.

• Constants (also referred to as controlled variables) - these are variables that have to remain the same for both the control group and the experimental group(s); it is important to keep these variables the same so that they do not influence the results. 

There will be a few dimensional analysis problems in the MCQ section.

   Tips: 1) circle, underline, or write out what you are trying to solve for → make sure you focus on the unit(s) that the problem wants you to solve for

            2) for the givens indicated in the problem, write them out using a “divider line —”  

                If a given states, “2.3 Liters of corn kernels are needed to produce 1 kilogram of corn syrup”

                You should write it as 2.3 L of corn kernels  or it could be written as 1 kg of corn syrup

                                                    1 kg of corn syrup                                           2.3 L of corn kernels

            3) Remember, you can only multiply the numbers across in a setup.

There will be a few Percent Change Problems: Final value - Initial value x 100 = ____%

                                                                               Initial value

Topic 4.6 - Watersheds

• Land area that drains into a body of water; 

• Watershed can be affected by vegetation (vegetation that borders an aquatic environment is great at absorbing some pollutants), the type of soil that supports vegetation and slope of the watershed (steeper slopes tend to speed the movement of pollutants into a body of water); 

• Human activities have a negative impact on watersheds: logging - increase sediment pollution in a water body, storm drains pollutants, industrial sites - runoff of industrial point source pollutants, farmland/ranchland- runoff of fertilizer, animal wastes, and etc.

Topic 4.7 - Solar Radiation and Earth’s Seasons

• Angle of incidence (angle of Sun’s rays hitting the Earth’s surface;

• The Earth’s surface most perpendicular to the Sun receives the greatest amount of solar radiation- for example: the equator is the most perpendicular to the Sun

• Latitudinal degrees::  Equator = 0⁰, Tropic of Cancer - 30⁰ N, Tropic of Capricorn - 30⁰S, Arctic Circle - 60⁰N ,Antarctic Circle - 60⁰S

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• Earth tilts at 23.5 degrees (the tilting is the reason for seasons happening); Northern Hemisphere Winter solstice (Dec. 21-22) - shortest day of the year; Polar Night (Arctic receives 24 hours of darkness)); Vernal Equinox (March 20-21) - equal day and night lengths; Summer Solstice (June 20-22) - longest day of the year; Midnight Sun - Arctic receives 24 hours of daylight; Autumnal Equinox - September 22-23

Topic 4.8 - Earth’s Geography and Climate

• Large bodies of water stabilize land temperatures nearby due to the fact that water has a high specific heat + high movement to migrate the warmer temperatures into its location to maintain a constant temperature (water takes a longer time to increase its temperature); land, on the other hand - has a low specific heat + no movement - land is unable to migrate warmer temperatures inward to maintain a constant temperature (land has a quicker temperature increase); examples of large bodies of water - Great Lakes, Gulf of Mexico, & Mediterranean Sea; ocean water currents’ temperatures influence land temperatures

• Rainshadow effect - the leeward side of a high mountain that doesn’t receive rainfall (it has dry and desert-like conditions)- leeward is the side of a mountain further away from an ocean; the windward side of a mountain that faces a large body of water will receive high rainfall due to ocean breezes carrying moisture onto land that condenses into rain droplets (it is wet and has an abundance of vegetation) 

Topic 4.9 - El Nino and La Nina

• El Nino (occurs every 3-7 years) near equatorial Pacific Coast of South America - during an El Nino, easterly trade winds stall & may even reverse - warm sea surface waters remain near Pacific coast of South America - no upwelling occurs (upwelling usually occurs when cold water rises to the surface when tradewinds force warm water to move west across Pacific Ocean - cold water bring nutrients and dissolved oxygen to the surface (upwelling produces vibrant food chains & fishing industry thrives) - cooler & wetter conditions happen in the southeastern U.S. and unusually dry weather in the northern U.S., Canada, southern Africa, and Southeast Asia. 

• La Nina (tradewinds moving northwest from South America are stronger than usual -southeastern U.S. experiences unusually dry weather whereas northern U.S., Canada, southern Africa, and Southeast Asia experience wetter weather; during La Nina, eastern equatorial Pacific Ocean (near the coast of Peru) experience upwelling (cold water at the surface that has high levels of nutrients)

• El Nino is followed by a La Nina - El Nino can last for 3-6 months

Topic 5.1 Tragedy of the Commons

- Key Terms that need to be reviewed:

1. Tragedy of the Commons - overuse of a shared, common resource that leads to depletion

2. Common Resource - public, shared resource used by all - land, air, water

3. Private Resource - resource owned by 1 individual or a family

4. Review methods implemented to maintain shared resources such as:

Have rules (licenses, permits, quotas)

Ensure compliance of rules (fines, suspensions)

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Topic 5.2 Clearcutting

-removal of all trees in a location

-Key Terms that need to be reviewed:

1. Ecological and economic services provided by trees

2. Negative Impacts of Clearcutting on a terrestrial environment:

Carbon cycle - ↑CO₂ in atmosphere - enhances global warming

↓Soil stability 

↓albedo (albedo refers to the reflection of sun’s rays) = decrease in albedo results in  absorption of sun’s rays (heat).     

3. Negative Impacts of Clearcutting on an aquatic environment:

↑turbidity, ↑water temp. (trees provide shade, less trees =  ↑water temp.), ↑eutrophication, 

↓primary productivity (due to ↑turbidity, ↑water temp.), ↓dissolved oxygen for animals, ↓biodiversity/habitats

Topic 5.3 Green Revolution

- Key Terms to Review

  - Green Revolution – movement from small-scale, human labor farming to large-scale, machinery-mechanized farming

  - goal is to ↑ crop production to feed a lot of people 

  - Green Revolution Features
    1) Use of machinery (mechanization)

     2) Monoculture (producing one type of crop) ← GMO

     3) Use of artificial/synthetic fertilizer

     4) Possible heavy amounts of irrigation

  - GMOs vs artificial selection - GMOs involves the insertion of desired genes into an organism

                                                - artificial selection involves humans breeding different strains/species of

                                                  plants or animals to produce a desired hybrid

  - GMO benefit - can insert genes into organisms that help them tolerate environmental conditions 

                            such as heat, salt, cold, or even pesticides

  - GMO drawbacks - synthetic/artificial fertilizers may still be needed, leads to eutrophication in aquatic ecosystems, the use of pesticides to protect the GMO crops will lead to pests becoming resistant to the pesticide, use of pesticides may kill harmless pests, & GMOs will decrease biodiversity within the crop that is being grown

Topic 8.1 Sources of Pollution

• Point sources of pollution - enter the environment from a single source and are clearly defined; examples are pipes, drainage, and factory smokestacks, wastewater treatment plants, oil refineries, leaking underground gasoline storage tanks

• The Clean Water Act requires industries to get a permit from the state and/or EPA before they can discharge any effluent (point source of pollutants) into a body of water

• Nonpoint sources of pollution - is pollution that cannot be traced back to a single point, CAFOs, property or a single pipe; contaminants come from many sources accumulating over a wide area until if impairs water quality; unfortunately, nonpoint sources of pollution are not regulated by the Clean Water Act

• Examples of nonpoint sources of pollution are agricultural lands and residential areas where they have runoff of excess amounts of fertilizers and pesticides; water running off of parking lots, roads, & lawns may carry toxic chemicals, oils & grease

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Topic 8.5 - Eutrophication 

• Algal blooms - increase in aquatic vegetation growth due to influx of fertilizer runoff (nitrates & phosphates) 

• Sources of eutrophication - farms, feedlots, sewage treatment plants, & detergents

• Oligotrophic -little to no nutrients in water (clear water; high levels of dissolved oxygen)

• Eutrophic - high nutrients in water- mostly from runoff of fertilizer (tends to be murky; low levels of dissolved oxygen) 

• Hypoxia - death of aquatic animals (like fish) because of lack of oxygen in water

• Oxygen sag curve - refers to declining levels of dissolved oxygen due to increased growth of aerobic bacteria; runoff of fertilizer → algae growth → algae produce oxygen → causes an increase in aerobic bacterial growth → aerobic bacteria use up the oxygen for cellular respiration and leave hardly no oxygen for other aquatic consumers

Topic 8.7 Persistent Organic Pollutants (POPs)

• Examples are DDT and PCBs - they are organic (made of carbon), persistent (can’t be broken down), nonpolar (can diffuse across cell membranes since membranes are nonpolar/hydrophobic), they all contain chlorine atoms (the carbon and chlorine atoms have a strong bond and this helps maintain the stability of the pollutants in the environment) and are artificially made in a lab 

• Most of these are pesticides; although PCBs are also by-products of industries making transformers, capacitors 

Topic 8.8 Bioaccumulation and Biomagnification 

• Bioaccumulation occurs when a toxin builds up within one organism - due to the organism consuming more than one prey/vegetation and also the toxin tends to be nonpolar which makes it easier for the toxin to diffuse across the organism’s cell membrane

•  Biomagnification occurs when toxin moves from one trophic level to another; the highest trophic level receives the greatest concentration of toxin; for example ospreys & bald eagles - consume several prey that already have an amount of toxin within their bodies.