Ecology Lecture Notes

Introduction

• The current living environment differs significantly from the childhood environment.
• Emphasis on the abundance of trees and presence of termites.
• Termites, despite their negative reputation for damaging wood, play crucial ecological roles:
  • Breaking down dead plant matter.
  • Returning nutrients to the ecosystem.
  • Being part of food chains.

Major Concepts in Ecology

• Ecology: Study of interactions within environmental systems, including organism interactions with each other and their environment.

Food Chains and Food Webs

• Food Chains:
  • Start with autotrophs (producers) making their own food.
  • Energy flow indicated by arrows pointing towards the consumer.
  • Hierarchy from primary consumers to apex consumers.
• Energy Pyramid:
  • Base: Producers
  • Subsequent levels: Primary, secondary, tertiary consumers.
  • 10% Rule: Only about 10% of energy is passed to each subsequent trophic level.

Biodiversity and Food Web Complexity

• Biodiversity: Variety and number of species in a given area.
• Food Webs:
  • Illustrate complex interactions between organisms.
  • Changes in species populations can affect others in the web.
• Importance of decomposers like bacteria and fungi.

Ecological Relationships

• Symbiotic Relationships:
  • Parasitism: One organism benefits, the other is harmed (e.g., fleas on rabbits).
  • Mutualism: Both organisms benefit (e.g., termites and gut bacteria or protists).
  • Commensalism: One benefits, the other is unaffected (e.g., barnacles on whales).

Nitrogen and Carbon Cycles

• Nitrogen Cycle:
  • Nitrogen Fixation: Conversion of atmospheric nitrogen to ammonia/ammonium.
  • Nitrification: Conversion of ammonia/ammonium to nitrates/nitrites.
  • Ammonification: Decomposition returns nitrogen to the soil as ammonia/ammonium.
  • Denitrification: Conversion of nitrates/nitrites back to nitrogen gas.
• Carbon Cycle:
  • Carbon as a building block of life and its presence in reservoirs.
  • Photosynthesis: Carbon dioxide used by producers.
  • Respiration: Release of carbon dioxide by organisms.
  • Impact of fossil fuel burning and greenhouse gases like carbon dioxide.

Human Impact on Biodiversity

• Greenhouse Gas Emissions:
  • Burning fossil fuels increases atmospheric carbon dioxide.
  • Ocean warming and acidification affecting marine life.
• Habitat Destruction:
  • Deforestation and its consequences like soil erosion.
  • Impact on aquatic habitats from water rerouting or dams.
• Invasive Species:
  • Introduction of non-native species disrupting local ecosystems (e.g., Formosan termites, lionfish).
• Overharvesting:
  • Unsustainable fishing impacting trophic levels and biodiversity.

Positive Human Efforts

• Examples of conservation and biodiversity support efforts:
  • Reforestation
  • Species conservation programs
  • Sustainable practices

Conclusion

• Importance of recognizing and improving efforts towards biodiversity conservation.
• Encouragement to stay curious about ecological issues.