Ecosystem

**1. Fundamentals of Ecosystems:**
– Definition: An ecosystem consists of all organisms and abiotic pools they interact with.
– Components: Biotic and abiotic elements linked through nutrient cycles and energy flows.
– Scale: Processes occur at various scales, determined by the processes being studied.
– Origin: Coined by Arthur Tansley in 1935 emphasizing material transfers between organisms and environment.
– Study Scale: Hutchinson and the Odum brothers contributed to the systems approach to ecosystem study.

**2. Ecosystem Processes and Components:**
– Rainforest and desert ecosystems showcase biodiversity.
– Flora and fauna play essential roles in ecosystem dynamics.
– Processes: Energy and material flow within ecosystems.
– Examples: Gambia River and Baja California desert exhibit diverse ecosystems.
– External Factors: Climate, parent material, and topography shape ecosystem structure.

**3. Threats, Restoration, and Sustainability:**
– Ecosystem Goods: Water, food, fuel, and medicinal plants.
– Ecosystem Services: Hydrological cycles, air and water cleaning, pollination.
– Human Impacts: Pollution, habitat loss, invasive species.
– Restoration: Vital for achieving Sustainable Development Goals.
– Sustainable Management: Crucial for conserving ecosystem functions.

**4. Primary Production and Energy Flow:**
– Primary Production: Organic matter production through photosynthesis.
– Energy Flow: Transfer of energy and carbon through ecosystems.
– Decomposition: Leaching, fragmentation, chemical alteration of dead material.
– Decomposition Rates: Influenced by temperature, moisture, soil properties.
– Dynamics and Resilience: Ecosystems’ ability to withstand disturbances and recover.

**5. Nutrient Cycling and Biodiversity:**
– Nitrogen Cycling: Nitrogen fixation, decomposition, nitrification, denitrification.
– Biodiversity: Drives ecosystem functioning, influences species interactions.
– Study Approaches: Theoretical, long-term, comparative, manipulative approaches.
– Human Interactions: Impact ecosystems, depend on goods and services.
– Degradation and Decline: Growing human population, economic valuation, transdisciplinary approaches.