APES Test 6 Flashcards
- What are the major steps in the carbon cycle?
The major steps include photosynthesis, respiration, decomposition, burial and sedimentation, extraction, exchange, and combustion. Carbon moves between the atmosphere, oceans, soil, and organisms in these steps.
- Describe the steps of the nitrogen cycle.
The nitrogen cycle involves nitrogen fixation, nitrification, assimilation, ammonification, and denitrification. Nitrogen moves between the atmosphere, soil, and organisms through these processes.
- Plants require nutrients like nitrogen and phosphorus. What process allows them to obtain these nutrients?
Plants obtain nitrogen through nitrogen fixation (conversion of atmospheric nitrogen into usable forms) and phosphorus through uptake from soil or water.
- What are the main steps of the phosphorous cycle?
The main steps include weathering of rocks, leaching into soil and water, uptake by plants, and return to soil through decomposition. Phosphorus does not have a gaseous phase and primarily cycles through terrestrial and aquatic environments.
- Identify and describe the different soil horizons and their characteristics.
O Horizon (Organic Layer) – Contains decomposed/undecomposed organic material like leaf litter and humus; nutrient-rich.
A Horizon (Topsoil) – Mix of organic matter and minerals; fertile, dark, and supports plant growth.
E Horizon (Eluviation Layer) – Leached layer; lighter in color due to loss of minerals like iron and clay.
B Horizon (Subsoil) – Accumulates leached minerals; denser with lower organic content.
C Horizon (Parent Material) – Weathered rock fragments; minimal organic matter.
R Horizon (Bedrock) – Solid rock layer; unweathered, serves as the foundation for soil formation.
- How can soil be eroded? What methods can be used to prevent soil erosion on farms?
Soil erosion can occur through water, wind, or human activity like agriculture. Methods to prevent erosion include contour plowing, terracing, cover cropping, and planting windbreaks.
- What does soil permeability refer to? What does it mean if soil has a low permeability? What does it mean if soil has high permeability?
Soil permeability refers to its ability to allow water and air to pass through. Low permeability means water movement is restricted, leading to potential waterlogging. High permeability means water moves freely, which can lead to leaching of nutrients.
- Sand, clay, and silt make up soil. Describe how each of these contributes to properties of soil, such as its permeability.
Sand improves permeability due to large particles allowing water movement. Clay reduces permeability due to small particle size and compaction. Silt contributes to soil fertility and water retention.
- Describe how soil can be amended with sand and clay to adjust the permeability of the soil.
Adding sand increases permeability in clay soils, while adding clay increases water retention in sandy soils. Balancing these amendments improves overall soil structure and water management.
- What were the pros and cons of the Green Revolution and industrialized agriculture?
The Green Revolution increased food production but led to environmental degradation, loss of biodiversity, and dependence on synthetic inputs. Industrialized agriculture improved efficiency but raised concerns about soil erosion, water use, and pesticide use.
- Identify agricultural practices that increase environmental concerns like soil erosion and eutrophication.
Practices include monoculture, excessive fertilizer use, improper irrigation, and deforestation for agriculture. These contribute to erosion and nutrient runoff into water bodies.
- Identify agricultural practices that decrease environmental concerns like soil erosion and eutrophication.
Practices like crop rotation, cover cropping, integrated pest management, and conservation tillage help reduce erosion and nutrient pollution while promoting soil health.
- What are the pros and cons of using genetically modified seeds/crops?
Pros include increased crop yield and resistance to pests, while cons include potential environmental risks, loss of biodiversity, and socio-economic concerns for small farmers.
- Describe the different irrigation methods, as well as the pros and cons of each.
Irrigation methods include surface, drip, and sprinkler. Surface irrigation is inexpensive but inefficient. Drip irrigation is precise but costly. Sprinkler irrigation is versatile but can lead to soil erosion and water wastage.
- How efficient is each of the irrigation methods? Which methods are more prone to cause soil salinization? Why?
Drip irrigation is the most efficient, followed by sprinkler, and surface irrigation is the least efficient. Surface irrigation can cause soil salinization due to water evaporation leaving salts behind.
- What are the pros and cons of using pesticides?
Pros include increased crop yield and pest control. Cons include environmental pollution, harm to non-target species, development of pesticide resistance, and human health risks.
- What is the pesticide treadmill?
The pesticide treadmill refers to the cycle of increasing pesticide use to combat resistant pests, leading to more resistant pests and continued use of stronger pesticides.
- Identify and describe the different methods for raising livestock. Include the pros and cons of each.
Methods include intensive (confined feeding operations) and extensive (grazing systems). Intensive farming increases efficiency but raises animal welfare and environmental concerns. Extensive farming promotes natural behaviors but requires more land.
- What are the environmental concerns related to the raising of livestock?
Concerns include land degradation, deforestation for pastureland, water consumption, methane emissions contributing to greenhouse gases, and grain use for animal feed impacting food security.
- What is integrated pest management?
Integrated pest management (IPM) is a holistic approach combining biological, cultural, and chemical methods to manage pests while minimizing environmental impact and economic cost.
- Describe the biological and cultivation controls that can be used as part of integrated pest management.
Biological controls use natural predators or parasites to control pests, while cultivation controls modify crop rotation or planting schedules to disrupt pest lifecycles. Both methods reduce reliance on chemical pesticides.
- Identify and describe different sustainable agricultural practices that minimize environmental consequences in comparison to traditional/industrial agricultural practices.
Practices include organic farming, agroforestry, permaculture, and precision agriculture. These methods promote soil health, biodiversity, and resource efficiency while reducing chemical inputs and environmental impact.
- What are endocrine disruptors?
Endocrine disruptors are chemicals that interfere with hormone systems in organisms, affecting growth, development, and reproduction.
- What are the most common effects of endocrine disruptors? What type of changes would you expect in organisms and ecosystems where endocrine disruptors are present?
Effects include reproductive abnormalities, developmental disorders, and altered behavior. Organisms and ecosystems exposed to disruptors may experience reduced fertility, skewed sex ratios, and population declines.
- What causes eutrophication in aquatic ecosystems?
Eutrophication is caused by excess nutrients, primarily nitrogen and phosphorus, entering water bodies from sources like agricultural runoff, sewage, and industrial waste. These nutrients promote excessive algal growth, disrupting aquatic ecosystems.
- Describe what happens in aquatic ecosystems when eutrophication takes place (what happens to photosynthesis, different species, amount of dissolved oxygen, etc.).
Eutrophication leads to rapid algal blooms that block sunlight, reducing photosynthesis for submerged plants. As algae die and decompose, bacteria consume oxygen, causing hypoxia (low oxygen levels). This results in fish kills, loss of biodiversity, and ecosystem collapse.
- What is a persistent organic pollutant (POP)?
A POP is a toxic chemical that resists degradation and persists in the environment for long periods. Examples include DDT, PCBs, and dioxins, which accumulate in living organisms and pose health risks.
- Which trophic level will have a higher concentration of persistent organic pollutants (POPs) stored in fatty tissues?
Top predators in the food chain, such as large fish, birds of prey, and mammals, have the highest concentration of POPs due to biomagnification.
- Define bioaccumulation.
Bioaccumulation is the process by which a substance, such as a pollutant, builds up in the tissues of an individual organism over time.
- Define biomagnification.
Biomagnification is the increasing concentration of a substance, like a toxin or pollutant, as it moves up through the trophic levels of a food chain.
- Describe the difference between bioaccumulation and biomagnification.
Bioaccumulation occurs within a single organism over its lifetime, while biomagnification refers to the increasing concentration of substances as they pass up the food chain from prey to predator.
