AP Environmental Science Course Review Part 1 

80 mc questions in 90 minutes - 60% of exam score

3 FRQ in 70 minutes - 40% of exam score

• Question 1: design an investigation

• Question 2: analyze environmental problem + propose a solution

• Question 3: analyze environmental problem + propose solution doing calculations

Experimental Design Components

• hypothesis and/or predictions 

• identify the independent variable - what treatments will you apply 

• identify the dependent variable - what will you measure 

• identify several variables to be controlled (very important) 

• describe the materials you would use to conduct the experiment.  Be specific! 

• describe what you will actually do.  Give a specific list of steps you’d follow.

• describe how you will actually take and record data 

• describe how the data will be graphed and analyzed 

• state how you will draw a conclusion (claim-evidence-reasoning with comparison of outside sources) 

Math To-Know

Most Important APES Laws/Legislation

1963 (revised several times since) Clean Air Act (CAA): Includes provisions for: 

• Sulfur oxides, carbon monoxide, particulate material, volatile organic compounds, nitrogen oxides, ozone, lead

• Providing resources to study air in order to inquest about the issue of atmospheric pollutants.

• Setting enforceable regulations to limit emissions from stationary and mobile sources

• Developing programs to monitor and reduce acid deposition 

• Establishing a program to phase out the use of chemicals that deplete stratospheric O³ 

• Establishing a cap and trade (a system in which maximum allowable emissions are set for each industry; businesses that reduce their emissions to below the standards are awarded credits which they can sell to other businesses within their industry, creating economic incentive for reducing emissions).

1970 National Environmental Policy Act (NEPA): One of the first pieces of environmental legislation in the United States, NEPA was written to promote the idea of sustainability.

• Environmental Impact Statement (EIS): Any major federal agency must submit an EIS for any activity that may have a harmful impact on the environment. 

• 1970 Environmental Protection Agency (EPA): Formed under the Nixon Administration with the primary purpose of protecting human health and the environment and enforce environmental standards under a variety of state and local environmental laws. 

1972 (revised several times since) Clean Water Act (CWA): A response to the 1969 Cuyahoga River catching fire in Cleveland, Ohio. Its mission is to restore and maintain the chemical, physical, and biological integrity of Americaʼs waterways and make them “fishable and swimmable.” Provisions intended to reduce and prevent point and nonpoint sources of water pollution, although there are no provisions regarding groundwater protection.

1973 Endangered Species Act (ESA): A far-reaching act that provides protection for any species that is determined to be threatened with extinction. Provisions include strict enforcement of habitat protection, a ban on any activity which disturbs or endangers the life of a listed species, and a ban on the import or export of any individual organisms or product derived from an endangered species.  

1973 Convention on International Trade in Endangered Species of Wild Flora and Fauna (CITES): A multilateral treaty ensuring that international trade in specimens of wild animals and plants does not threaten the survival of the species in the wild and accords varying degrees of protection for more than 33,000 species. 

1974 Safe Drinking Water Act (SDWA): Focuses on maintaining the purity of any water source that may potentially be used as drinking water, including both surface and groundwater. 

1976 Resource Conservation and Recovery Act (RCRA): Also called the “Cradle-to-Grave Act,” sets specific regulations concerning the manufacture, transport, storage, use, and disposal of a host of hazardous chemicals. Its major provision requires extensive documentation at every step to ensure the hazardous wastes are disposed of properly. 

1980 Comprehensive Environmental Response, Compensation, and Reliability Act (CERCLA): Also called the Superfund Act, established to handle industrial contamination in sites where no direct individual or party could be help responsible. Imposed a tax on the chemical and petroleum industries and authorized the federal government to respond to the release of hazardous substances. Also created a trust fund for cleaning hazardous waste sites when no responsible party could be identified. 

1987 Montreal Protocol: A global effort and one of the greatest environmental success stories to date. Provisions include requiring participating nations to phase out the use of ozone-depleting chemicals (specifically CFCs) in favor of less harmful alternatives. 

1997 Kyoto Protocol: Developed at a world summit to address measures for reducing greenhouse gas emissions. No real progress was made; when the US announced it would not sign the protocol the whole movement lost support

1938 Delaney Clause of Food, Drug, and Cosmetic Act: chemical additives “found to induce cancer in man” or in animals could NOT be approved for use in foods by the FDA

Unit 1: The Living World- Ecosystems 

1.1 Introduction to Ecosystems

• Presence of a species may be influenced by:

  • Fundamental niche: range of abiotic factors it can tolerate

  • Ability to disperse

  • Interactions with other species

    • Competition, predation, mutualism, commensalism

• Competition: the struggle of individuals to obtain a limiting resource

• Competitive exclusion principle: two species competing for the same limiting resource cannot coexist (CAN LEAD TO RESOURCE PARTITIONING)

• The process of partitioning reduces competition between 2 species

  • Temporal: species use same resource at different time

  • Spatial: species reduce competition by using different habitats

  • Morphological: evolution of different body shapes or size

• Predation: the use of one species as a resource by another species

• True predators: kill their prey

• Herbivores: consume plants as prey

• Parasites: live on or in the organism they consume

  • Typically only consume part of their host, single parasites rarely cause death

  • Parasites that cause disease in the hosts are pathogens

• Parasitoids: lay eggs inside other organisms

  • When hatch, larva slowly consume the host from inside out, causing the hosts death

• Mutualism: interspecific interaction where both species benefit (acacia tree and ants)

• Commensalism: ons species benefits but the other is neither harmed nor helped (clownfish /anemone)  

• Parasitic:   one benefits and the other organism is harmed

1.2 Terrestrial Biomes

Tundra Biome

• Cold & treeless, with low growing vegetation

• Arctic tundra – N most regions of N. Hemisphere

• Very short growing season (4 months during summer)

  • Upper layer of soil thaws, creating pools of standing water- ideal habitat for mosquitoes

• Permafrost- underlying subsoil, impermeable, permanently frozen- prevents deep rooted  plants

• Little precipitation

• Plants: lichen, moss, woody shrubs

• Soil: slow rate of decomposition resulting in accumulation of organic matter in the soil over  time with relatively low levels of soil nutrients

Boreal Forest (Taiga) Biome

• Coniferous (cone bearing) evergreen trees (Ex: Pine and Spruce)

  • Evergreen- green year round

• Europe, Russia, N. America

• Plant growth constrained by temperature

• Decomposition a slow process (cold) & low nutrient content in  waxy needles – thick layer of organic material but soil low in  nutrients

• Some deciduous trees- lose leaves (Ex: Birch, Maple, Aspen)

• Extensively logged for pulp, paper, and building materials

Temperate Rainforest Biome

• Mid-latitude- west coast of N. America from Northern CA to Alaska

• Ocean water is source of water vapor

• Mild summers and winters

• 12 month growing season (almost)

• Coniferous trees most common (Ex: Spruce, Cedar, Fir, Hemlock, Redwoods)

• Redwoods (Sequoia sempervirens)

• Ferns and mosses (can live in nutrient poor soil) are found under trees

• Nutrients released are uptaken by trees or leached out by abundant rain

Temperate Seasonal Forest Biome

• Deciduous trees

• Warm summer & cold winter

• Eastern USA, Japan, Europe, China

• Warm summers favor rapid decomposition

• Soils have more nutrients because deciduous  leaves decompose faster

• Historically one of first biomes to be converted to  agriculture

Woodland/Shrubland Biome

• Hot/dry summers and mild/rainy winters

• Southern CA = chaparral

• Wildfires

• Fire dependent plant species

• Drought resistant shrubs (Ex: yucca, scrub oak, sagebrush)

• Soil low in nutrients from winter rains

• Agriculture: grazing animals and deep rooted crops like grapes to make wine

Temperate Grassland

• Cold/harsh winters & hot/humid winters

• Great Plains of N. America = prairies

• S. America = pampas

• Central Asia/E. Europe = steppes

• Fires

• Plants: grasses & nonwoody flowering plants

• Long growing season & rapid decomposition –  nutrient rich soil

• 98% of tall grassland in USA has been converted  to agriculture

• Short grass prairie is converted to growing wheat

and grazing cattle

Tropical Rainforest

• Warm/wet @ 20° N/S latitude

• ITCZ

• High productivity, extremely high decomposition rate

• Soils lose nutrients quickly

• Slash and burn agriculture

• More biodiversity per hectare than any other terrestrial biome

• Plant: epiphytes (hold small pools of water to support an aquatic ecosystem)

Tropical Seasonal Forest/Savanna

• Lion King!

• Warm temperature & wet season/dry season

• Dense stands of shrubs and trees

• Grazing & fire discourage growth of smaller woody plants

• Warm temperature promotes decomposition but low rain prevents plants  from using soil nutrients

Subtropical Desert

• Hot/extremely dry

• Plant adaptations: small or nonexistent leaves modified into spines, thick  waxy outer layer, most photosynthesis occurs in plant stem

• Less than 10 inches of rain/year

1.3 Aquatic Biomes

• Freshwater biomes: streams, rivers, ponds, lakes that are used for drinking water

• Marine biomes: oceans, coral reefs, marshlands, and estuaries

  • Algae in marine biomes supply a large portion of the Earth’s O2 and take in CO2 from the atmosphere

• The global distribution of nonmineral marine natural resources such as dif fish varies because of the combination of salinity, depth, turbidity, nutrient availability, and temperature

• Streams: the faster a stream flows, the greater the amount of dissolved oxygen in it

• Rivers: water moves slower in a river and debri settles on the bottom
  
  

  • Usually have more nutrients and less dissolved oxygen

• Littoral zone: shallow area of soil and water near the shore where algae/emergent plants grow

• Limnetic zone: open water, where rooted plants can no longer survive

  • Phytoplankton are the only photosynthetic organisms, extends to as deep as sunlight can penetrate

• Profundal zone: zone where sunlight cannot penetrate so producers cannot survive

• Benthic zone: muddy bottom of a lake or pond beneath the limnetic or profundal zone

• Oligotrophic: low levels of organic matter

  • Tend to be deep and clear, oxygen rich bottom supports cold water fish like trout, phosphorus is limiting

• Mesotrophic: more organic matter

  • Oxygen level in lake bottom is low

• Eutrophic: high levels of organic matter

  • Abundant plant growth, poor clarity, oxygen poor bottoms

Freshwater Wetlands

• Aquatic biomes that are submerged or saturated by water for at least  part of each year, but shallow enough to support emergent  vegetation.

  • These include swamps, marshes, and bogs.

• Swamps: wetlands with emergent trees

• Marshes: wetlands that contain primarily  non woody vegetation, like cattails and sedges

• Bogs: acidic wetlands that typically contain  sphagnum moss and spruce trees

Marine Biomes: salt marshes, mangrove swamps, intertidal zones, coral reefs, open ocean

Mangrove Swamp

• Occur along tropical and subtropical coasts

• Tree roots submerged in water

• Trees are salt tolerant

• Help protect coast from erosion & storm  damage!!!

• Falling leaves produce nutrient rich  environment

• Provide sheltered habitat for fish and shellfish

Estuaries

• Area where a river meets an ocean

• Mix of salt and freshwater

• Located near coastlines, border land

• Extremely fertile

• Nutrient levels are higher than both salt and freshwater 

Salt Marsh

• Found along the coast in temperate climates  and contain non woody emergent vegetation.

• The salt marsh is one of the most productive  biomes in the world.

• Naturally occurring wetlands wound within  the intertidal zone

• Ecosystem service: absorb storm surge

Intertidal Zone

• Band of coastline the exists between  high and low tide

• Range from steep and rocky to  broad and sloping mudflats

• Stable environment when  submerged during high tide

• Harsh conditions during low tide  when organisms are exposed to  direct sunlight, high temperatures  and desiccation

• EX: barnacles, sponges, algae,  mussels, crabs, sea star

Coral Reef

• Found: warm shallow waters beyond shoreline

• Earth’s most diverse marine biome

• Coral- tiny animals the secrete layer of limestone (calcium carbonate) to form external  skeleton

• Animal lives inside this tiny skeleton with tentacles that draw in plankton and detritus

• Coral lives in water that is relatively poor in nutrients and food

  • Therefore have a relationship with single celled algae that live in the tissue of corals called  zooxanthella

  • Algae use CO2 captured during photosynthesis to produce sugar and nutrients… then  release this to the coral animal

  • Coral gains energy from sugar… and the algae gets CO2, nutrients and a safe place to live

• Coral bleaching

  • When algae in coral die- without algae the coral dies

  • Cause: turbidity, ocean temperature increase, pollution, tourism, ocean

Open Ocean

• How deep the light penetrates depends on the amount of sediment & algae  suspended in the water

• Will not exceed 200 m (approximately 650 feet)

• Is divided into zones

  • Photic- light

  • Aphotic- no light

  • Benthic- bottom

• Photic zone: relatively shallow part of the ocean above the drop-off of the continental shelf

  • Enough sunlight for photosynthesis, approximately 200 m/660 ft in depth

• Intertidal zone: area where the ocean meets the land between high and low tides

• Pelagic zone: sometimes called the open zone 

• Salinity, depth, temperature, turbidity (loss of transparency), nutrient availability in the ocean varies

1.4 The Carbon Cycle

• Carbon has 2 stages: the fast stage associated with living organisms

  • Slow stage: associated with dead organisms (fossil carbons)

• 1. When plants carry out photosynthesis the use CO2 from the atmosphere

  • Plats release some of the CO2 back into the atmosphere with cellular respiration but keeps most of it within their plant tissues

  • 2. The plant will die or be eaten by another organism that will die; the dead matter contains carbon will be processed by decomposers and exist in soil so more plants can use it

    • Decomposition: microbes, bacteria, fungi break down organic matter and release CO2 (aerobic decomp), CH4 (anaerobic decomp)

• 1. Carbon exchange occurs in the ocean: the ocean absorbs some CO2 form the atmosphere and release CO2 back into the atmosphere

  • Sedimentation: the CO2 combines with calcium ions in the water to form calcium carbonate that sinks to the bottom of the ocean and accumulated

  • Dissolved CO2: CO2 DISSOLVES into the ocean from the atmosphere and moves between atmosphere and ocean via direct exchange

• Ocean is the largest carbon sink 

• Sequestration: storage of carbon in biomass, sediments, limestone, fossil fuels

1.5 The Nitrogen Cycle

• Nitrogen, phosphorus, potassium, calcium, magnesium, and sulfur

• Most reservoirs in which nitrogen compounds occur hold them for relatively short periods of time 

• Atmosphere is the major reservoir of nitrogen (78% of the air on Earth)

• nitrogen/phosphorus: often a limiting nutrient

  • Limiting nutrient: often required for the growth of the organisms but available in a lower quality than other nutrients

• Nitrogen (N2 in air is useless to organisms and must be fixed into usable form: nitrate, nitrite, ammonia)

• Nitrogen Fixation: N2>NO3

  • Bacteria in roots of legume

  • Usable form for plants (nitrite)

  • When animals eat these plants usable nitrogen is acquired (assimilation)

• Ammonification: when plant/animal dies or excrete waste, microorganisms covert their N compounds to ammonia

• Nitrification: most plants cant use ammonia so they convert it tinto nitrate (NO3)

  • One group of soil bacteria change ammonia to nitrites

  • Another group of bacteria convert nitrites to nitrates

• Denitrification: other bacteria convert ammonia, nitrate, and nitrite back into N2 - returning into the atmosphere

• Assimilation: producers take up N in form of ammonia, ammonium, nitrate, nitrite, and incorporate it into their tissues

• Natural way to fix nitrogen: lightning

• 2 plants that fix nitrogen: legumes, rye (grass)

• Nitrate is a limiting nutrient essential to plant growth- burning soil vegetation increases nitrate levels , so testing would would allow the scientist to measure how much the levels are increasing by burning to help determine the impact of wildfires on plant growth and succession

1.6 The Phosphorus Cycle

• No atmospheric component (is a limiting factor)

  • Limitation imposed on return from the oceans to land to make phosphorus scarce in aquatic and many terrestrial ecosystems ( limiting factor)

• Found as phosphate (PO4 3): mineralization of organic phosphorus back into inorganic phosphorus >slow cycle in rocks

• N & P runoff and algal bloom= hypoxic

• Major reservoirs of phosphorus: rock and sediment that contain phosphorus-bearing minerals 

1.7 The Hydrologic Cycle

• Powered by the sun> movement of water in its various solid, liquid, and gaseous phases between sources/sinks

• Oceans are the primary reservoir of water at the Earth’s surface, with ice caps/groundwater as smaller reservoirs 

• 1. Heat from sun causes water to turn into water vapor>rise into atmosphere

  • Water from ground>air by either evaporating from body of water or ground or plants can release water through transpiration

• 2. Once in atmosphere, comes down to Earth in form of precipitation

  • Can result in surface runoff (water slides from the and back into body of water); percolation (water will be absorbed by the ground and become part of groundwater stores); plants uptake to use for photosynthesis

1.8 Primary Productivity

• Primary productivity: rate at which solar energy is converted into organic compounds via photosynthesis over a unit of time

• Gross primary productivity (GPP): total rate of photosynthesis in a given area

• Net primary productivity (NPP): rate of energy storage by photosynthesizers in a given area after subtracting the energy lost to respiration

  • Measured in units of energy per unit area per time (ex. kcal/m^2/yr)

• Producers capture about 1% of available energy via photosynthesis> GPP

  • About 60% of GPP is for respiration

  • 40% of GPP for growth/reproduction

• Productivity is highest where temperatures are warm and water/solar energy are abundant

• After drastic change (hurricane, fire, etc.) the amount of NPP tells us if the new system is more/less productive than the previous system

1.9 Trophic Levels

• Law of conservation of matter

  • Matter cannot be created or destroyed but it can be transformed

  • Matter is constantly moving between the living and nonliving world

• Autotrophs/producer

• Heterotrophs/consumer

• Herbivore /primary consumer

• Carnivore / secondary consumer

• Tertiary consumer

• Detrivore: feed on the dead and decomposing organic matter by oral ingestion

• Decomposer: organisms that decompose organic material

• Scavenger: consume dead animals

• Biomass: total mass

  • Amount of biomass present in an ecosystem at a particular time in its standing crop

  • Proportion of consumed energy that can be passed from one trophic level to another is ecological 

1.10 Energy Flow and the 10%

• The 10% rule is the transfer of energy from one trophic level to the next, only about 10% of the energy is passed on

  • The loss of energy that occurs when energy moves from lower> high trophic levels can be explained through the laws of thermodynamics

• First law of thermodynamics: This is the law of conservation of energy. The law states in a closed system energy cannot be created or destroyed, it can only be transformed from one form to another. 

• Second law of thermodynamics: The second law of thermodynamics states that every time energy changes form it increases entropy. Entropy is the amount of disorder in a system.

1.11 Food Chains and Food Webs

• Food web: model of interlocking pattern of food chains that depict the flow of energy and nutrients in two+ more food chains

• Keystone species: a species that plays a far more important role in its community than its relative abundance might suggest

• Negative feedback loop= output from a system moving in one direction acts as input

  • Moves system in the other direction

  • Input and output neutralize one another/stabilizes the system

• Positive feedback loop: causes system to change further in the same direction (further from normal)