Biodiversity, Water, Soil, Food Production, Pest Control, Climate Change Notes

Chapter 6 – Wild Species and Biodiversity

• Types of Biodiversity:

  • Genetic Diversity: Variation within species.
  • Species Diversity: Variety of species in an ecosystem.
  • Ecosystem Diversity: Variety of ecosystems in a region.
  • Current Estimates: About 2 million species are described; estimates suggest 8-10 million species may exist.

• Value of Species:

  • Instrumental Value: Usefulness of species to humans (e.g., medicine, food, ecosystem services).
  • Intrinsic Value: Inherent worth of a species, regardless of usefulness to humans.

• Wild Genes and Agriculture:

  • Wild genes enhance cultivated crops' traits, such as disease resistance, drought tolerance, and yield.

• HIPPO Threats to Biodiversity:

  • Habitat Destruction: Primary cause of biodiversity loss.
  • Invasive Species: Non-native species that can disrupt local ecosystems.
  • Pollution: Various forms affecting biodiversity.
  • Population Growth: Human overpopulation impacts ecosystems.
  • Overharvesting: Exceeding ecosystem replenishment capacity.

• Conservation Approaches:

  • Protected Areas: National parks and reserves.
  • Endangered Species Act (ESA): Legal protections for threatened species.
  • Captive Breeding: Programs in zoos for endangered species.
  • Habitat Restoration: Efforts to restore damaged ecosystems.
  • International Treaties: Such as CITES to protect wildlife.

• Endangered Species Act (ESA):

  • Purpose: Protects species at extinction risk.
  • Three Key Elements:
  1. Listing of endangered/threatened species.
  2. Protection of critical habitat.
  3. Development of recovery plans for listed species.

Chapter 10 – Water: Hydrologic Cycle and Human Use

• Freshwater Availability:

  • Only 2.5% of Earth's water is freshwater; less than 1% is readily accessible for human use.

• Human Water Uses:

  • Agriculture: ~70%
  • Industry: ~20%
  • Domestic: ~10%
  • Sources: Surface water (rivers, lakes), groundwater (aquifers), and desalination.

• Hydrologic Cycle Loops:

  1. Evaporation: Water evaporates, forms clouds, and precipitates.
  2. Runoff: Water flows into rivers, lakes, and oceans.
  3. Groundwater: Water infiltrates soil, recharging aquifers.

• Impact of Deforestation/Urbanization:

  • Reduces water infiltration, increases runoff, causing floods and water shortages.

• Climate Change Effects:

  • Increased extreme weather, altered precipitation, and glacier melting.

• Case Studies:

  • Aral Sea: Overuse for irrigation leads to desertification.
  • Manupali River: Water shortages from unsustainable farming.

• Dams:

  • Benefits: Water storage, hydroelectric power, flood prevention.
  • Drawbacks: Disrupt ecosystems, displace people, alter sediment flows.

• Groundwater Resources:

  • Renewable: Rechargeable by precipitation.
  • Nonrenewable: Depleted faster than replenished, causing shortages.

• Water Use Types:

  • Consumptive: Water is lost (e.g., irrigation).
  • Nonconsumptive: Water returns to the system (e.g., hydropower).

• Problems with Water Diversion:

  • Alters ecosystems, displaces communities, disrupts fish migration.

• Groundwater Mining Issues:

  • Causes aquifer depletion, land subsidence, and increased salinization.

• Five Options to Meet Water Demand:

  • Conservation, desalination, recycling, rainwater harvesting, improved irrigation.

• Reducing Water Demand:

  • Implementing efficient practices in agriculture (drip irrigation), industry, and households.

• USA Household Water Consumption:

  • Direct: ~300 gallons/day; Indirect: ~2,000 gallons/day.

• Water Subsidies:

  • Encourage overuse by making water too cheap to conserve.

Chapter 11 – Soil Formation and Soil Loss

• Definitions:

  • Detritus: Dead organic matter.
  • Humus: Decomposed detritus in soil, vital for fertility.

• Soil as a Detritus-Based Ecosystem:

  • Relies on organic decomposition for nutrients and energy.

• Soil Profile Horizons:

  • O Horizon: Organic layer.
  • A Horizon: Topsoil.
  • B Horizon: Subsoil.
  • C Horizon: Parent material.
  • R Horizon: Bedrock.

• Soil Types:

  • Mollisols: Fertile, found in grasslands.
  • Oxisols: Nutrient-poor, tropical soils.
  • Alfisols: Moderately fertile, deciduous forests.
  • Aridisols: Desert soils with low organic matter.

• Challenges of Tropical Soils:

  • High rainfall leads to nutrient leaching; rapid decomposition limits organic buildup.

• Bare Soil Impacts:

  • Erosion by wind/water results in desertification.

• Salinization:

  • Salt buildup from irrigation negatively affects crops.

• Fertilizer Needs:

  • Organic: Manure and compost (slow release).
  • Inorganic: Synthetic fertilizers (quick boost, risk of runoff).

Chapter 12 – Production and Distribution of Food

• Hunger Definitions:

  • Hunger: Lack of food.
  • Undernourishment: Insufficient calories.
  • Malnutrition: Poor diet lacking essential nutrients.

• Overnourishment and Obesity:

  • Result of excessive food intake, especially in affluent nations.

• Farming Types:

  • Subsistence Agriculture: Small-scale, sustainable.
  • Industrialized Agriculture: High-yield but depletes soil/requires chemicals.

• Green Revolution Overview:

  • Technological advancements leading to increased food production (e.g., high-yield crops, fertilizers).
  • Limitations: Environmental damage and biodiversity loss.

• Components & Costs of Green Revolution:

  • Five Components:
  1. High-yield varieties.
  2. Synthetic fertilizers.
  3. Pesticides/herbicides.
  4. Mechanization.
  5. Expanded irrigation.
  • Environmental Costs: Soil erosion, water pollution, decline in pollinators, greenhouse gas emissions.

• Sustainable Farming Practices:

  • Crop rotation, organic fertilizers, reduced pesticide use, water conservation, and soil conservation.

• Permaculture Definition:

  • A holistic farming method mimicking natural ecosystems, aiming for sustainability and regeneration.

• Case Study: Japanese Rice Farmer:

  • Utilized ducks and fish to control pests without chemicals; maintained a closed-loop ecosystem.

• CAFOs (Concentrated Animal Feeding Operations):

  • Industrialized farms with high livestock density, posing environmental and health risks.

• Genetically Modified (GM) Crops:

  • Engineered for better yield/resistance; concerns about health, biodiversity, and corporate control.

Chapter 13 – Pests and Pest Control

• Pest Control Philosophies:

  1. Chemical Control: Quick fixes that don't address causes.
  2. Ecological Control: Sustainable methods that manage populations naturally.

• Pesticide Poisoning Effects:

  • Acute: Nausea, dizziness, headaches, seizures.
  • Chronic: Cancer, endocrine disruption, neurological damage.

• Resistance & Outbreak Issues:

  • Pests evolve resistance, requiring stronger chemicals; pesticides kill natural predators leading to resurgence of other pests.

• Pesticide Treadmill:

  • Cycle of increasing pesticide use due to resistance.

• Bioaccumulation & Biomagnification:

  • Bioaccumulation: Toxins build up in organisms.
  • Biomagnification: Concentration increases up the food chain.

• Ecological Pest Control Categories:

  1. Cultural: Crop rotation, resistant crops.
  2. Physical: Traps and barriers.
  3. Biological: Introduce natural predators.
  4. Chemical: Natural pesticides.

• Integrated Pest Management (IPM):

  • Combines multiple methods for sustainability. Four Steps:
  1. Identify pest problem.
  2. Monitor levels/damage.
  3. Choose control methods.
  4. Evaluate effectiveness.

• Organic Food Definition:

  • Grown without synthetic fertilizers, pesticides, GMOs, or artificial additives.

Chapter 18 – Global Climate Change

• Weather vs. Climate:

  • Weather: Short-term atmospheric conditions.
  • Climate: Long-term patterns over years.

• Greenhouse Effect:

  • Greenhouse gases trap heat, warming the Earth.
  • More GHGs lead to increased warming.

• Major Greenhouse Gases:

  • Carbon dioxide (CO₂), Methane (CH₄), Nitrous oxide (N₂O).

• Evidence of Global Warming:

  • Rising temperatures, melting glaciers, and increasing extreme weather.

• Future Climate Change Impacts:

  • More severe storms, droughts, ocean acidification, food shortages.

• Impact on Developing Countries:

  • Increased resource scarcity, leading to displacement and conflict.

• Mitigation vs. Adaptation:

  • Mitigation: Reducing GHG emissions (e.g., renewable energy).
  • Adaptation: Adjusting to climate effects (e.g., building seawalls).

• Ethics in Climate Change:

  1. Responsibility: Who caused it?
  2. Fairness: Who suffers most?
  3. Future Generations: What do we leave behind?

• Predicted Climate Impacts for California:

  • More heatwaves, less snowpack, rising sea levels affecting communities.

• Vocabulary:

  • Adaptation: Adjusting to changing climates.
  • Mitigation: Reducing emissions.
  • Detritus: Dead organic material in ecosystems.
  • Humus: Decomposed substance enriching soil.