Ecology Notes

Ecology 🌱 Life on Earth & Habitats

  • Habitat = place where an organism lives
    • Terrestrial (land)
    • Aquatic (water)
  • Atmosphere
    • 78% nitrogen
    • 21% oxygen
    • Blocks harmful UV radiation
    • Regulates temperature
  • Lithosphere
    • Rocks
    • Mountains
    • Ocean floor
  • Hydrosphere
    • All water on earth (97% in oceans)
  • Biosphere
    • Thin layer where life exists
    • Depends on resources

Ecosystem Basics 🌿

  • Ecosystem: The biological environment of a given area.
  • Living (biotic) + non-living (abiotic) parts in an area
  • Biotic factors
    • Producers (plants)
    • Consumers (animals)
    • Decomposers (fungi, bacteria)
  • Abiotic factors
    • Sunlight
    • Water
    • Temperature
    • Soil

Sustainability ♻

  • Sustainable = natural cycles without interruption
  • Artificial ecosystems need human help
  • Described by
    • Species
    • Temperature
    • Water depth
    • Rainfall

Flow of Energy 🌞

  • Sun = main energy source
  • More energy → more biodiversity
  • Food chain → simple, one path
  • Food web → complex, shows many feeding links
  • Energy pyramid → energy decreases at each level (broad base, narrow top)

Water Cycle 💧

  1. Evaporation → water turns to vapor
  2. Condensation → vapor cools into clouds
  3. Precipitation → rain, snow falls
  4. Transpiration → plants release water vapor
  5. Runoff → water returns to oceans/lakes
    • Human impact → pollution, overuse, disrupts balance

Nitrogen Cycle 🌿

  • Nitrogen gas (N_2) needs to be fixed → soil bacteria make ammonium & nitrate for plants
    • Aquatic: cyanobacteria does nitrogen fixing
    • Human impact → fertilizers, vehicle emissions, acid rain

Carbon Cycle 🌍

  • Carbon moves between atmosphere, living things, soil, oceans
  • Stored in fossil fuels, plants, oceans
  • Released by respiration, decomposition, burning fossil fuels

Photosynthesis & Respiration 🌻

  • Photosynthesis (plants) → sun + CO_2 + water → glucose + oxygen
  • Cellular respiration (animals) → glucose + oxygen → ATP (energy) + CO_2 + water
  • They complement each other!

Biodiversity 🌸

  • Variety of species & genes in an ecosystem
  • High biodiversity → more sustainable, resilient to stress
  • Low biodiversity → less resilient, more vulnerable
  • Threats → habitat loss, invasive species, pollution

Invasive Species ⚠

  • Non-native, harm ecosystems, outcompete natives, spread fast, no predators

Key Takeaways to Memorize ✅

  • Sun → base energy source
  • Matter cycles → water, nitrogen, carbon
  • Biodiversity = health & sustainability
  • Human activities can disrupt balance