Env. Ethics, Trophic Transfer, Water Pollution +

• The exam will consist of ~45 questions.
• It will cover material from Labs 2-6.
• The question formats will be multiple choice, true/false, fill in the blank, and short answer.
• Topics include Environmental Ethics & Scientific Method, Trophic Transfer of Energy I & II, Blue-Green Infrastructure Water Pollution, and Aquatic Ecological Assessment & Trophic Transfer of Energy.

Environmental Ethics

• Moral principles that guide our interactions with the environment and its biota.
• The field developed in the 1970s.
• Intrinsic value means a thing has value "in itself," or "for its own sake."
• Extrinsic value is the monetary or quantifiable value of a utility of something.

Host Plant Specialists

• Organisms adapted to the chemical defenses of specific plants.
• Native insects will mostly not eat non-native plants.
• A native plant has evolved within the local food web and exists with other plants and animals within that web.
• Insects are the organisms that "run the world."
• An increase in native insect diversity can lead to an increase in native plant diversity.

Scientific Method

• The five steps are observe, hypothesize, experiment, conclude, and share results.
• A hypothesis is a statement providing a tentative answer that is falsifiable.
• Scientists cannot prove a hypothesis to be true, but it can be supported or disproved.
• A research hypothesis (H₁) is a prediction of what is causing an event.
• The null hypothesis (H₀) is the negation of the research hypothesis.
• Example: If the research hypothesis is "Fertilizer will increase algae growth in ponds," the null hypothesis is "Fertilizer will not increase algae growth in ponds."
• An independent variable is manipulated to cause an effect, response, and/or change (e.g., fertilizer).
• A dependent variable is the effected, responsive, and/or changed variable as a result of a manipulated independent variable (e.g., algae cells).
• A control variable is an unmanipulated variable that provides a comparison or baseline to detect changes caused by a dependent variable (e.g., pond water without fertilizer).
• Significance is determined by the p-value:
• If p-value < 0.05, reject the null hypothesis, and there is a significant difference.
• If p-value ≥ 0.05, "fail to reject" the null hypothesis.
• The three types of significance are statistical, biological/ecological, and social.

Additional Info on Env Ethics

• Replicates are important in experiments to account for natural variation.
• Two books/articles that helped to launch the environmental movement were Tragedy of the Commons and The Land Ethic.
• Native insects require native plants because they have evolved together over thousands of generations.
• Scholarly articles are typically written by a scholar and feature headings/subheadings.

Trophic Transfer of Energy I: Photosynthesis & Producers

• Heterotrophs obtain carbon by consuming other living organisms; “héteros” means “different."
• Consumers are another term for heterotrophs.
• Autotrophs fix carbon via photosynthesis; "autos" means "self."
• Producers are another term for autotrophs.
• Photosynthesis uses carbon dioxide, light energy, and water.
• Cellular respiration uses glucose (CO) and oxygen to create ATP (chemical energy).
• Photosynthesis produces glucose (C₆H₁₂O₆) and oxygen (O₂).
• Cellular respiration produces carbon dioxide (CO₂) and water (H₂O).
• Photosynthesis occurs when light is present.
• Cellular respiration occurs at all times in all living organisms.
• Photosynthesis occurs in the chloroplasts of plant organelles.
• Chlorophyll is the pigment that captures light energy from the sun.
• Sequestered carbon is carbon stored in living tissue and organic matter.
• Dissolved oxygen (DO) presence can be measured as a proxy for photosynthesis.
• Water with low DO is hypoxic, while water with no DO is anoxic.
• The diurnal DO cycle refers to DO increasing during the day and decreasing at night.

Trophic Transfer of Energy II: Consumers

• The four ecological classifications from smallest to largest are species --> population --> community --> ecosystem.
• A species is a group of organisms with similar characteristics that breed to produce fertile offspring.
• A population is a group of individuals of the same species living in the same location at the same time.
• A community is a temporary association of different species living in the same location at the same time.
• An ecosystem is a biological community of interacting organisms and the environment.
• A food web is more complex than a food chain.
• Food chains represent a simplified, linear flow of energy.
• A food web consists of several chains and shows all possible flow paths of energy.
• A biomass pyramid quantifies the amount of energy passed onto each trophic level.
• The first law of thermodynamics- Energy is neither created nor lost as it changes from one form to the other.
• The second law of thermodynamics- Energy is not destroyed but changes in terms of quality as it is converted from one form to another
• 10% of the energy is transferred from one trophic level to the next. The remaining 90% is lost via movement, heat, respiration, and waste.
• A primary consumer is an organism that eats only autotrophs (herbivore).
• A secondary consumer is an organism that eats both plants and animals (omnivore), or an organism that eats only meat (carnivore).
• A tertiary consumer is an organism that eats secondary consumers (carnivore).
• A detritivore is an organism that consumes waste products or dead organisms.
• A decomposer is an organism that breaks down leaf litter and other non-living matter into inorganic molecules.
• Autotroph > Vegetarian > Omnivore > Carnivore is the most to least-energy efficient feeding strategies.

Blue-Green Infrastructure (BGI) & Water Pollution

• The hydrological cycle continuously renews and recycles water on Earth.
• Water pollution can come from point and non-point sources.
• Point source pollution comes from a single source and is easily identifiable.
• Non-point source pollution comes from multiple sites over large areas and is difficult to identify.
• The three types of water pollution are biological, chemical, and physical.
• Groundwater pollution is considered to be a more serious problem because it is longer lasting than surface water pollution.
• Biological pollution examples include disease-causing organisms, either direct or indirect.
• Chemical pollution types are natural (nutrients) and artificial (pesticides, fertilizers, heavy metals, acids, salts, chlorine, toxic elements, pharmaceuticals, etc.).
• Physical pollution examples include sediments, thermal (raising/lowering water temp), and solid waste.
• Eutrophication is a condition where increased nutrients (nitrogen and phosphorus) in water lead to large amounts of algae (blooms)
• This leads to hypoxic or anoxic conditions.
• Stormwater is rainfall across an area of land.
• Gray infrastructure refers to traditionally built structures around cities to help guide stormwater.
• Disadvantages include being impervious with limited drainage capacity, and increased flooding with heavy rain.
• Blue-Green Infrastructure (BGI) is a "nature-based" alternative to stormwater management.
• BGI Advantages:
• Environmentally friendly co-benefits aka "Stacking"
• Reduces flooding events/Allows water to slow down and penetrate soil
• Increased water storage
• Increased vegetation and habitats for animals/Offers on-site chemical pollution filtration
• Urban heat island mitigation
• BGI Examples:
• Rain gardens/Bioswales
• Native vegetation installed in rights-of-way/Wetlands
• Restored creeks and rivers/Cut or sloped curbs

Ecological Assessment and Trophic Transfer of Contaminants

• Habitat is the term that describes the natural environment where an organism lives, including abiotic (non-living) and biotic (living) factors.
• Biota is the term that describes all of the living organisms of a particular habitat.
• Benthic macroinvertebrates are good indicators of water quality because they are fairly sedentary, sensitive to disturbance, easy to identify, and easy to collect.
• A channel is the bed where a natural stream of water runs.
• Riffles are areas of a stream with faster flowing water, usually over rocks, with higher oxygen levels.
• Pools are areas of a stream where there is very little/no water flow (stagnant) with lower oxygen levels.
• A bank is land on either side of a stream or the land surrounding a pond or a lake.
• A riparian buffer is an area of land directly in contact with a water body; amount of vegetated land between the body of water and the first non-natural feature is also part of it.
• A reach is a designated portion of a stream or river.
• Sinuosity measures how curvy a stream channel is, i.e., bends in the stream.
• Erosion is the removal of material from one place to another by wind or water.
• The instream region refers to areas within the body of water.
• Substrate is the base on which an organism lives, i.e., the stream bottom.
• Aesthetics refers to a pleasing appearance or effect.
• Bioaccumulation is the gradual accumulation of pollutants in an organism over time.
• This occurs when organisms absorb more pollutants from the environment than the organism can break down.
• Biomagnification is the tendency of pollutants to concentrate as they move from one trophic level to the next.
• This means an increase in concentration of a pollutant from one level of a food chain to another.