AP ENVIRONMENTAL SCIENCE UNIT 5 (LAND AND WATER USE)

tragedy of the commons

suggests that individuals will used shared resources in their own self-interest rather than in keeping with the common good, thereby depleting the resources

clearcutting

cutting down of almost all trees in a designated area, frequently followed by replanting within two years

weight the advantages and disadvantages of clearcutting

advantage: cost-effective

disadvantages: leads to soil erosion, increased soil and stream temperatures, and flooding

why are forests important and what happens when they are removed?

they contain trees that absorb pollutants and store carbon dioxide, if removed (through cutting and burning) there is a release of carbon dioxide which contributes to climate change

the green revolution

a shift to new agricultural strategies and practices in order to increase food production, with both positive and negative results.

what were some of the strategies and methods of the green revolution

mechanization, genetically modified organisms (GMOs), fertilization, irrigation, and the use of pesticides

genetically modified organisms (GMOs)

any plant, animal, or microorganism whose genetic material (DNA) has been deliberately altered using modern biotechnology or genetic engineering techniques

what does mechanization or farming increase?

profits and efficiency for farms and reliance on fossil fuels

explain tilling and environmental damage it causes

-the agricultural process of mechanically agitating or turning over the the soil to prepare it for planting

-soil erosion (tilling turns wears down the structure of soil which makes it easy to get carried away), release of greenhouse gases (tilling increases the decomp of organic matter, which releases stored carbon into the atmosphere), loss of soil fertility (tilling destroys the habitat of essential soil organisms, including earthworms, bacteria, and fungi)

explain slash-and-burn farming and the environmental damage it causes

-clearing forests by cutting trees and burning vegetation, with ash used to fertilize the soil

-deforestation and habitat loss, carbon emissions (destroying trees which sequester carbon), soil erosion (protection of soil is now gone), air pollution and smoke, and loss of biodiversity (burning kills crucial soil microbes, earthworms, and insects and reduce plant diversity)

how does the use of fertilizers cause damage to the environment?

nutrient runoff into waterways (causes agal bloom, that when algae die, their decomp consumes oxygen, which creates hypoxic (low oxygen) zones that kill aquatic life), greenhouse gas emissions (fertilizer produces nitrous oxide, contamination of groundwater (nitrates can leach into the soil into groundwater, affecting drinking water, which is dangerous for infants), air pollution (fertilizer application contributes to ammonia and ozone in the air, lowering air quality which affects plant growth)

soil erosion

the wearing away of the topsoil (the most fertile layer of the ground)

what does the largest use of freshwater go towards?

irrigation (70%)

drip irrigation

uses perforated (holes) hoses to release small amounts of water to plant roots (most efficient with about 5% of water lost to evaporation and runoff, expensive so it is used less)

flood irrigation

flooding of an agricultural field with water (low-cost but generally inefficient since it sees about 20% of the water lost to evaporation and runoff, can lead to waterlogging of the soil)

furrow irrigation

cutting furrows between crop rows and filling them water (in-expensive but inefficient since about 1/3 of water is lost to evaporation and runoff)

spray irrigation

involves pumping groundwater into spray nozzles across an agricultural field (more efficient than furrow and flood irrigation with only ¼ or less of the water lost to evaporation or runoff, more expensive than furrow and flood irrigation, requires energy to run)

waterlogging

when too much water is left to sit in the soil (raises the water table (the top level of the underground water supply) of groundwater and inhibits plants’ ability to absorb oxygen through their roots

salinization

occurs when the salts in groundwater remain in the soil after the water evaporates

what can salinization do to soil over time?

it can make soil toxic to plants

aquifers

an underground layer of water-bearing, permeable rock, gravel, sand, or silt that stores and transmits usable groundwater

what can happen to aquifers if they are overused for agricultural irrigation and what is an example?

-they can become severely depleted

-Ogallala Aquifer in the central United States

what is a consequence of using common pest-control methods such as pesticides, herbicides, fungicides, rodenticides, and insecticides?

organisms can become resistant to them through artificial selection

artificial selection

also known as selective breeding, humans purposefully choose specific plants or animals to to reproduce based on desirable traits (size, flavor, temperament) over generations (ex. breeding dogs)

what are the benefits of pest control?

decreases crop damage and increase crop yields

what are some common pest-control methods?

pesticide, insecticide, herbicide, fungicide, and rodenticide

what is a benefit and consequence of utilizing crops that are genetically engineered

-increased resistance to pests and diseases

-loss of genetic diversity of a particular crop if used for planting or other ways

concentrated animal feeding operations (CAFOs)

also known as feedlots, used as a quick way to get livestock ready for slaughter (crowded spaces, animals are fed grains or feed that are not as suitable as grass, they generate a lot of organic waste (can contaminate ground and surface water), less expensive than other methods which can keep costs down for consumers)

free-range grazing

allows animals to graze on grass during their entire lifecycle (meet from free-range grazing tends to be free from antibiotics and other chemicals used in feedlots, organic waste from these animals is used as fertilizer, requires large areas of land and the meat produced is more expensive for consumers)

true or false: meat production is less efficient than agriculture

true, it takes approximately 20 times more land to produce the same amount of calories from meat as from plants

overgrazing

occurs when too many animals feed on a particular area of land (causes loss of vegetation (which leads to soil erosion) and desertification)

desertification

the degradation of low precipitation regions toward being increasingly arid until they become deserts

what could decrease in the consumption of meat lead to? (there are several)

decrease in CO2, methane, and N2O (nitrous oxide) emissions; conserve water, reduce the use of antibiotics and growth hormones, and improve topsoil

what has overfishing led to and what are its consequences?

-extreme scarcity of some fish species

-lessen biodiversity in aquatic systems and harm people who depend on fishing for food and commerce

what happens when more accessible ores are mined to depletion?

mining operations are forced to access lower grade ores, which results in increased use of resources that can cause increased waste and pollution

surface mining

the removal of large potions of soil and rock (called overburden) in order to access the ore underneath

overburden

large portions of soil and rock that is in the way of mining ores

strip mining

type of surface mining which removes the vegetation from an area, making the area more susceptible to erosion

slag and tailings

mining wastes (including the rocks and soil that were removed to access the ore, and waste) that remain when when the minerals have been removed from the ore

what is the purpose of mining?

it helps provide low cost energy and material necessary to make products

what are the consequences of mining for coal?

destroyed habitats, contamination of ground water, and release of dust particles and methane

urbanization can lead to what consequences?

depletion of resources and saltwater intrusion (the movement of saltwater into freshwater aquifers) in the hydrologic cycle

what happens when coal reserves get smaller due to a lack of easily accessible reserves?

it becomes necessary to access coal through subsurface mining (extraction of minerals deep below earths surface by creating tunnels and shafts) which is very expensive

how does urbanization affect the carbon cycle?

through the use of fossil fuels and landfills, which increasing the amount of carbon dioxide in the atmosphere

impervious surfaces

human-made structures (roads, buildings, sidewalks, and parking lots) that do not allow water to the reach the soil, leading to flooding

urban sprawl

the change in population distribution from high population density areas to low density suburbs that spread into rural land, which leads to potential environmental problems

ecological footprints

they compare resource demands and waste production required required for an individual or a society

sustainability

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

what are some environmental indicators that can guide humans to sustainability?

biological diversity, food production, average global surface temperatures and CO2 concentrations, human population, and resource depletion

sustainable yields

the amount of renewable resource that can be taken without reducing the available supply

what are some ways to increase water infiltration and reduce urban runoff?

replacing traditional pavement with permeable pavement, planting trees, increased use of public transportation, and building up, not out

integrated pest management (IPM)

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

what are some of the methods used for integrated pest management?

biological, physical, and limited chemical methods such as biocontrol, intercropping, crop rotation, and natural predators of pests

biocontrol

using natural enemies (predators, parasitoids, or pathogens) instead of conventional chemical pesticides to manage pests

intercropping

practice of growing two or more crops simultaneously in close proximity on the same fields to manage pests

crop rotation

the practice of growing a series of different types of crops in the same area across a sequence of growing seasons

the use of integrated pest management (IPM) reduces….?

the risk pesticides pose to wildlife, water supplies, and human health

advantages and disadvantages of integrated pest management (IPM)

-minimizes disruptions to the environment and threats to human health

-it can be complex and expensive

what is the goal of soil conservation?

to prevent soil erosion

what are some different methods of soil conservation?

contour plowing, windbreaks, perennial crops, terracing, no-till agriculture, and strip cropping

contour plowing

farmers plow and plant across a slope, following its elevation contour lines rather than u and down (reduces soil erosion)

windbreaks

linear plantings of trees, shrubs, or fences designed to reduce wind speed (provides protection from soil erosion)

perennial crops

plants that live for more than two years, often for decades, without needing to be replanted annually (reduces erosion)

terracing

transforming steep, sloped land into a series of flat, step-like platforms for farming (prevents erosion)

no-till agriculture

growing crops without disturbing the soil through plowing or tilling (reduces soil erosion)

strip cropping

agriculture technique that divides fields into long, narrow, alternating strips of different crops

what are strategies to improve soil fertility?

crop rotation and the addition of green manure and limestone

green manure

fast-growing crops, grown specifically to be incorporated into the soil while still green (acts as a natural improver of soils chemical and physical properties)

limestone

also known as calcium carbonate, may be added to soil to raise pH, neutralize acidity, and reduce toxicity in sour, acidic ground

rotational grazing

the regular rotation of livestock between different pastures in order to avoid overgrazing in a particular area

aquaculture

the controlled cultivation of aquatic organisms like fish, shellfish, and algae in fresh or saltwater

why has aquaculture expanded?

it is highly efficient, requires only small areas of water, and requires little fuel

what are two major consequences of aquaculture?

it can contaminate wastewater, and fish that escape may compete or breed with wild fish

what happens when the density of fish in aquaculture increases?

there is an increase in disease incidences, which can be transmitted to wild fish

what are some method of reducing deforestation?

reforestation, using and buying wood harvested by ecologically sustainable forestry techniques, and reusing wood

what are some methods to protect forests from pathogens and insects?

integrated pest management (IPM) and the removal of affected trees

prescribed burn

a method by which forests are set on fire under controlled conditions in order to reduce the occurrence of natural fires