🌍 UNIT 9 NOTES (Biodiversity, Ozone, Climate Change)

🌱 The 6th Mass Extinction

  • Scientists believe Earth is currently in a 6th mass extinction

  • About 1,000 species lost per year

  • Main cause: human activity (habitat destruction, pollution, etc.)

🧬 Biodiversity & Species Categories

Key Definitions

  • Extinct species: no individuals left

  • Threatened species: likely to become endangered soon

  • Near-threatened species: may become threatened in future

  • Least concern species: widespread and abundant

  • Endemic species: found only in one specific area

🧬 Importance of Genetic Diversity

  • High genetic diversity = better survival

  • Low diversity → harder to:

    • adapt to environmental changes

    • resist diseases

🌎 Value of Biodiversity

Types of Value

  • Intrinsic value: value just for existing (ethical/moral)

  • Instrumental value: usefulness to humans

Ecosystem Services

  • Provisioning: resources we use (food, medicine)

  • Regulating services: natural processes (climate, water cycles)

  • Support systems:

    • pollination (bees, birds, bats)

    • pest control

⚠ HIPPCO (Causes of Biodiversity Loss)

  • H: Habitat loss

  • I: Invasive species

  • P: Pollution

  • P: Population growth

  • C: Climate change

  • O: Overharvesting

🌿 Invasive Species

Definitions

  • Exotic species: outside native range

  • Invasive species: spreads rapidly and harms ecosystem

Examples

  • Kudzu vine: blocks sunlight, kills plants

  • Zebra mussel: clogs pipes, outcompetes natives

  • Buffel grass: steals water from native plants

  • Silver carp: crowds out native fish

📜 Environmental Laws & Protection

  • CITES: controls trade of endangered species

  • Red List: tracks extinction risk

  • Lacey Act: bans illegal wildlife trade

  • Endangered Species Act (ESA): protects species & habitats

  • Marine Mammal Protection Act (1972): protects marine mammals

  • NEPA (1970): environmental impact assessments

  • OSHA (1970): worker safety from hazards

🌳 Protected Areas

  • Biosphere reserve: protected land with zones

    • Core zone: most protected, highest biodiversity

    • Buffer zone: limited human activity

    • Transition zone: human use allowed

☀ OZONE DEPLETION (from your slides)

🌍 Stratospheric Ozone

  • Protects Earth from UV radiation

  • Essential for life

⚠ Causes

  • CFCs (chlorofluorocarbons):

    • used in aerosols, refrigerators

    • break down ozone layer

⚠ Effects

  • More UV radiation reaches Earth

  • Causes:

    • skin cancer & cataracts (humans)

    • plant damage → reduced photosynthesis

🌡 CLIMATE CHANGE

🌬 Greenhouse Gases

  • Carbon dioxide (CO₂)

  • Methane (CH₄)

  • Nitrous oxide (N₂O)

  • Water vapor

  • CFCs

Key Ideas

  • CO₂ = most common

  • Methane = much stronger than CO₂

  • N₂O = long-lasting (100+ years)

  • CFCs = extremely powerful

📈 Evidence of Climate Change

  • Rising CO₂ levels (Keeling Curve)

  • Increasing global temperatures

  • Ice cores show past cooler climates

🌊 Consequences

  • Rising sea levels (melting ice + expansion)

  • Changing migration patterns

  • Altered plant flowering times

  • More droughts

  • Spread of diseases

🌊 Ocean Impacts

Ocean Warming

  • caused by greenhouse gases

  • leads to:

    • habitat loss

    • coral bleaching

Ocean Acidification

  • CO₂ absorbed → lowers pH

  • harms coral (can’t build shells)

🔁 Feedback Loops

  • Positive feedback: amplifies change (worsens warming)

  • Negative feedback: reduces change (stabilizes system)

Example:

  • Ice melts → less reflection → more heat absorbed → more melting

🌍 Climate Policies

  • Kyoto Protocol:

    • aimed to reduce emissions

    • U.S. signed but never ratified

  • Cap-and-Trade:

    • companies buy/sell pollution permits

  • Carbon sequestration:

    • storing carbon to reduce emissions

💰 Economics & Environment

  • Kuznets Curve:

    • pollution increases → then decreases as income rises

  • GDP:

    • total value of goods/services in a country

🌎 Worldviews

  • Anthropocentric: human-centered

  • Biocentric: all living things have value

  • Ecocentric: ecosystems as a whole matter

🌱 Sustainability

  • Stewardship: caring for Earth for future generations

  • Triple Bottom Line:

    • Profit

    • People

    • Planet

🌾 Sources of Greenhouse Gases

Nitrous Oxide

  • Human: agriculture

  • Natural: wet soils

Carbon Dioxide

  • Human: fossil fuels

  • Natural: volcanoes, decomposition

Methane

  • Human: livestock, rice fields

  • Natural: wetlands

CFCs

  • Human only: aerosols, foam

Water Vapor

  • Natural: evaporation

🧠 Quick Study Tips

  • HIPPCO = main causes of biodiversity loss

  • CFCs = ozone depletion

  • CO₂ = climate change driver

  • Biodiversity = stability

☀ How Photochemical Smog Forms

1. Start with Primary Pollutants

These are released directly into the air:

  • Nitrogen oxides (NOₓ) → from cars, power plants

  • Volatile organic compounds (VOCs) → from gasoline, paints, industrial chemicals

2. Sunlight Triggers Reactions

  • UV radiation from the sun hits these pollutants

  • This provides energy for chemical reactions

3. Ozone Formation (Secondary Pollutant)

  • NO₂ (nitrogen dioxide) breaks apart in sunlight

  • This leads to formation of ground-level ozone (O₃)

4. More Secondary Pollutants Form

Reactions with VOCs create:

  • Ozone (O₃)

  • PANs (peroxyacyl nitrates)

  • Other oxidants

These together = photochemical smog