APES Agricultural Unit (Unit 5) Exam Review The exam will consist of about 45–50 multiple-choice questions only. (there will be questions from the 1s

APES Agricultural Unit (Unit 5) Exam Review 

The exam will consist of about 45–50 multiple-choice questions only. (there will be questions from the 1st semester). The exam will include Impacts of Mining Topic 5.9 and Sustainable Forestry Topic 5.17 There will be an FRQ after the test, BUT the FRQ will not be counted as part of the test grade. 

The terms biomagnification and bioaccumulation are on the test BUT POPs (persistent organic pollutants - Topic 8.7 is NOT on the test). Biomagnification occurs when a toxin’s concentration increases as it moves through a food chain, Bioaccumulation occurs when a toxin builds up within one organism.

*Ecological footprint is a measure of human impact on the environment and whether the impact is sustainable (in other words, humans ability to maintain the quality of a natural resource such as water, soil, air)

Review over Tragedy of the Commons Topic 5.1 Tragedy of the Commons

Tragedy of the Commons = when people overuse a common, shared resource with no regulation implemented that leads to a depletion of that resource

Review for Clearcutting - Topic 5.2 Clearcutting

Review ecological & economic services provided by trees - ecological - provides shade/cool temperatures for animals, absorbs CO₂ for photosynthesis (also helps with reducing global warming), trees absorbs water – prevents flooding from occurring in an area, etc.; economic - provides jobs for people for when touring a forest, jobs are also available for people to cut down trees (in sustainable manner)

Negative Impacts of Clearcutting on Terrestrial Environments:

- ↓ in soil stability (soil is more prone to erosion - with soil eroding, nutrients will also be transported away; ↑ in atmospheric CO₂ = leads to increase in global warming; ↓ in albedo  = very bad 😣 albedo refers to the reflection of sun’s rays off of surfaces, a decrease in albedo means that surfaces such as plain soil will increase absorption of Sun’s heat which leads to a warmer/hotter environment

Negative Impacts of Clearcutting on Aquatic Environments:

↑in turbidity (turbidity refers to the accumulation of sediment in water), ↓ in albedo (dark colored environments, like water, absorb sun’s heat), ↑in eutrophication

Review for GMO Topic 5.3 The Green Revolution - Review Daily Video 5.3

Green Revolution = movement from small scale, human labor farming to large scale, mechanized farming

Green Revolution features include: mechanized farming, monocultures (genetically modified crops), artificial selection, & Irrigation

GMO benefits - increase crop yield & quality, potential changes in pesticide use (farmers can insert gene(s) into seeds of crops that make the crops resistant to pesticides, pests, hot temperatures, cold temperatures, etc.,  increase in profits for farmers

GMO disadvantages - reduces biodiversity within crops and natural ecosystems;  pesticide use can kill non-target pests, requires machinery in applying fertilizer and pesticides (burning fossil fuels releases CO₂ - increases global warming; soil erosion), can also require a lot of irrigation for crops

Review for Impacts of Agricultural Farming (The Green Revolution) Topic 5.4 Impacts of Agricultural Practices - Review Daily Video 5.4

-Tilling - preparing the soil for planting seeds and growing crops - increases soil erosion

-synthetic fertilizers - water soluble & contain specific nutrients of nitrogen, phosphorus, and potassium - potentially could run off into an aquatic ecosystem → leads to growth of algae → growth of aerobic bacteria (use up most O₂) → fish kills - this is called cultural eutrophication

- uses lots of irrigation (groundwater used for irrigating crops) → leads to salinization (happens to crops grown in arid environments - the problem is that when water is evaporated, salt crystals are left behind and this causes crops & other vegetation to die and waterlogging (happens in temperate environments, when water settles above the soil - the problem is that plant roots can’t get access to oxygen in the air and as a result the crops could die)

- mostly uses pesticides (↓ biodiversity within the grown crop and in the area where the crop is grown)

Review for Irrigation Methods: Topic 5.5 Irrigation Methods - Review Daily Video 5.5 

Drip irrigation (most effective; uses perforated hoses; loses 5% of water to evaporation)

Flood irrigation (2nd most effective; flooding an agricultural field with water; leads to waterlogging, loses 20% of water to evaporation )

Furrow irrigation (least effective --involves creating “trenches” between rows of crops; loses a lot of water to evaporation; loses 30% of water to evaporation

Spray irrigation (3rd most effective; uses “sprinkler” type of water systems; loses 25% of water to evaporation)

Review for Pest Control Methods (Pesticides) Topic 5.6 Pest Control Methods

Insecticides - chemicals used to kill insects

Herbicides - chemicals used to kill weeds

Broad-spectrum - pesticides don’t just kill targeted pest but all sorts of organisms

Persistent pesticides - organic (lipid-soluble) pesticides like DDT; why are they persistent? these pesticides can diffuse across an organism’s cells and reside within the cells → Bioaccumulation (makes it very difficult for organisms to get rid of the pesticides within them)

Biomagnification - occurs when a persistent chemical (that can’t be digested or broken down naturally) moves up a food chain; as the chemical moves up the food chain, its concentration increases (reason why top predators have more toxic chemicals within them than lower trophic level organisms)

Nonpersistent pesticides - water-soluble pesticides - example: sulfur

Pesticide treadmill - farmers continuously invest more money into using pesticides that continue to be ineffective due to some pests in the population being resistant

Resistant pest organisms - already possess genes that make them resistant to pesticides

Review problems with using pesticides (Topic 5.6) - some pests within population are already resistant to pesticides due to random mutations within their genes; pesticide treadmill problem for farmers; pesticide kills/harms non-target pests

Review for Meat Production Methods: Topic 5.7 Meat Production Methods

-feedlots or CAFOs (confined animal feeding operations) - animals grown in small spaces; ranchers use growth hormones (make them bigger) and antibiotics (supposed to make them resistant to bacterial infections); problems? -- animal wastes has E.coli - not good for using as a fertilizer and could end up contaminating surface/groundwater;  development of resistant bacterial strains; cows release methane gas - greenhouse gas; overgrazing (if cattle are given grass)

Review for Impacts of Overfishing: Topic 5.8 Impacts of Overfishing

Methods of Commercial Fishing:

-long-line (a long string/rope with hooks to capture fish)

-drift net/gill net - (looks like a volleyball net)

- purse-seine - (looks like a drawstring bag, but contains 2 drawstrings - good for capturing school of fish)

- trawling - (looks like a cone - dragged along the bottom of the ocean)

- Sonar - uses sound waves (by a Sound Navigation Technology) reflected by fish to detect them and then capture them 

Problems with Commercial Fishing:

-overfishing (tragedy of the commons), capturing non-target animals (bycatch)

- possible solutions? Develop an aquaculture (fish farm), set limits such as only allowing 50% of the population to be fished → this is the maximum sustainable yield used to maintain the population size

Review for Urbanization: Topic 5.10 Urbanization

Urbanization - shift from agricultural, rural jobs to high density areas (cities)

Urban sprawl - when people move out away from high density areas

Benefits of Urbanization: Mass transits, better usage of small land space (build up not outward), 

Drawbacks of Urbanization: loss of vegetation to build roads which are mostly impermeable surfaces (leads to flooding, less recharging of groundwater, & pollution of surface waters), increase of air pollution - due to more automobiles, factories combusting fossil fuels and releasing air pollutants; “heat island effect” - occurs when roads made of asphalt (dark surface color) are good at absorbing the Sun’s rays causing these densely populated areas to be extremely hot

Impacts of Mining: Topic 5.9 Impacts of Mining

- Ore - soil/rock deposit that contains a mineral or coal  (e.g. gold, diamonds, phosphorus

- Refining - a process that removes the impurities from ores

- 3 types of Surface Mining:

1. Open pit mining - Earth’s surface is dug in to form a “crater” 

2. Strip mining - Earth’s surface is “scraped” by machinery

3. Mountain-top removal - involves using explosives (mainly used for extracting coal)

- Subsurface mining - is more expensive; only used when a target mineral is hard to access

- Overburden - soil covering ores

- Spoils - are the overburden removed from ores

- Tailings - are the removed impurities during the process of refining 

- Environmental Problems that occurs with Mining:

1. Removal of vegetation during mining process leads to soil erosion and removal of species habitats

2. Trucks that build roads to mining sites may bring in invasive species

3. Machinery used in mining typically burn gasoline and emits air pollutants and greenhouse gases (e.g. CO₂)--> traps heat (infrared radiation) within the troposphere -> melting of polar ice caps/glaciers (removing species habitats), rising sea levels due to the melting of land ice could flood coastal areas containing species habitats

Review for Introduction to Sustainability: Topic 5.12 Introduction to Sustainability

Sustainability refers to maintaining a natural resource (e.g. air, water, soil, vegetation, organisms) so that future generations will have enough of that resource. Input = Output (Use of that resource = replenishment of that resource)

Review for Methods to Reduce Urban Runoff: Topic 5.13 Methods to Reduce Urban Runoff

The 2 main goals are to recharged our groundwater and lessen the input of pollutants into our waterways: keep vegetation in place, use permeable road/street surfaces, increase public transportation, build-up not out

Review for Integrated Pest Management - Topic 5.14 Integrated Pest Management

Integrated Pest Management uses a combination of physical, biological and chemical methods to control a pest population. Biological method uses a natural predator of the pest; physical methods include crop rotation, intercropping, covering crops with nets - the goal is to protect the crops;  a chemical method incorporates the usage of small amounts of pesticides. 

Review for Sustainable Agriculture methods: Topic 5.15 Sustainable Agriculture

- Preventing soil erosion - no-till or minimum tilling - no or minimum usage of tractors, tools to till the soil, contour farming (farming on hills - rows of cropland are created across the hills - slows down water velocity) & terrace farming (farming on steps, tiers, slows down water velocity), windbreaks (uses trees to block crops exposure to wind) cover soil with vegetation (or mulch); 

- Review the Soil Unit - for example, soil horizons (O,A,E,B,C), 3 soil textures: clay, sand, silt; remember that clay is more effective for water-holding capacity and providing nutrients for plant growth (cation-ion exchange capacity); sand is more effective for water permeability and porosity, soil triangle

- Improving Soil Fertility - add organic nutrients to soil instead of using synthetic fertilizers - use natural organic matter - such as animal wastes, dead plant biomass, use compost as a soil fertilizer, crop rotation (one season - produce and harvest a crop - such as corn, then put in soybeans or any other legume to return nutrients to the soil - legume family of plants - peanuts, soybeans have nitrogen-fixing bacteria in their roots that return nitrogen compounds to the soil)

- Irrigating crops - use drip irrigation doesn’t require as much groundwater to water plants; use crops naturally adapted/tolerant of dry environments

- Getting rid of pests - use natural predators of pests or use physical control methods

- consumers should purchase locally grown and/or organic crops (organic crops were grown without using pesticides, synthetic fertilizers, and they are mostly non-genetically modified 

Sustainable ranching - raising cattle, etc. by using grass-fed feed BUT the rancher should use rotational grazing (move cattle from one pasture to another) so that the cattle doesn’t deplete the entire grass in a particular area

-Aquaculture Topic 5.16 Aquaculture

Aquaculture refers to farming of fish, shellfish, with the intent of selling the fish for profit; 

Pros of aquaculture: 1) less time consuming and less expensive (no fuel needed. Less human labor involved)than catching wildfish, 2) less “space” is needed for fish farms

Cons of aquaculture: 1) farmed fish can escape and breed or compete with natural fish, 2) farmed fish wastes can pollute waterways (since these fish are in a more concentrated area, 3) farmed fish can develop lethal, resistant bacterial infections because they are given antibiotics 

Sustainable Forestry - Topic 5.17 Sustainable Forestry

- use selective tree cutting instead of clear-cutting (e.g. choose a variety of mature trees when removing the timber - unprocessed wood, lumber is processed/transported wood)

- replant trees 

- buy and use timber that was sustainably sourced and certified (e.g. companies that use selective cutting, they don’t log in ecological sensitive or highly biodiverse areas, and when they transport timber, they limit ecological disruption and soil compaction)

- reuse/repurpose/recycle wood products - www.reusewood.org 

- incorporated integrated pest management - use a variety of methods to control pest population - such as use natural predators, set pest traps, manual weeding, remove diseased trees (so that bacteria/viruses populations don’t rise within a tree stand), thin underbrush, use prescribed burns (intentional set fires to remove excess understory vegetation and underbrush (e.g. shrubs, bushes, or small trees growing underneath large trees) – this removes fuel that can easily be ignited by high heat and high winds, also prescribed burns reduce pest and disease populations