Environmental Systems and Societies Study Guide Notes

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Welcome to the IB Academy guide for Environmental Systems and Societies SL.
Purpose:

• Provide concise and comprehensive revision material compiled by experienced teachers.

• Structure guides to ease the absorption of complex information via a step-by-step approach.

Approach:

• Distinguishes between skill (applying syllabus material) and understanding (conceptual grasp) which builds through practice.

• Encourages collaborative study with peers for effective knowledge reinforcement.

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Table of Contents

1. Systems and Models

   • Components, Types, and Energy within systems

2. Systems in the Natural World

   • Energy and matter flows, Biomes, Ecosystems, Biodiversity

3. Investigating Ecosystems

   • Experimental methods, Data collection rules, Measuring abiotic and biotic factors

4. Systems in the Human World

   • Population dynamics, Pollution, Human resource use

5. Humans and Biotic Impact

   • Biodiversity value and conservation strategies

6. Water, Soil and Food Production

   • Importance of water, soil types, Food production strategies

7. Energy and the Atmosphere

   • Energy management and pollution impacts

8. Climate Change and Sustainability

   • Climate issues, Mitigation and adaptation strategies

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Systems and Models

1.1 Components of Systems

• Storages: Represented as boxes (or shapes) that indicate stores of matter/energy.

• Flows: Transfers or transformations between storages, depicted by arrows (size reflects flow strength).

• Inputs/Outputs:

  • Inputs: Flows entering a system.

  • Outputs: Flows exiting a system.

• Boundaries: Lines that help define system limits.

1.2 Types of Systems**

• Open Systems: Matter and energy flow both in and out (e.g., ecosystems).

• Closed Systems: Only energy flows; matter remains constant (e.g., Earth as a whole).

• Isolated Systems: Neither matter nor energy flows in or out; hypothetical.

1.3 Energy within Systems**

• Laws of Thermodynamics govern energy flow:

  • Conservation of Energy: Energy cannot be created or destroyed, only transformed.

  • Entropy: Systems tend towards disorder over time, which affects energy availability along food chains.

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1.4 Feedback Mechanisms**

• Negative feedback loop: Stabilizes the system (counteracts changes).

• Positive feedback loop: Amplifies changes, potentially leading to instability and tipping points.

Tip: Systems tend toward stable equilibrium, but can experience oscillations.

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Systems in the Natural World

2.1 Flows of Energy and Matter

• The Sun: Average of 1400 W/m², entering Earth as shortwave radiation and leaving as longwave radiation.

• Greenhouse Effect: Necessary for maintaining life-sustaining temperatures; excessive gases contribute to global warming.

2.1.1 Solar Energy Impact**

• Plants convert only 0.06% of solar energy into usable chemical energy (photosynthesis).

• Energy transfer through food chains is inefficient — approximately 10% ecological efficiency at each trophic level.

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2.1.2 Energy Distribution**

• Energy from the Sun is not evenly dispersed; equatorial areas receive more energy leading to global climatic and weather patterns that influence ecosystems.

2.2 Biomes**

• Defined by solar input, precipitation, and temperature;

  • Tropical, Temperate, Polar biomes shaped by latitude-induced climatic patterns.

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Investigating Ecosystems (Experimental Methods)**

3.1 General Data Collection Rules:

• Define ecosystem location.

• Sampling must balance accuracy with practicality in size, repetitions needed depend on measured factors.

3.2 Measuring Abiotic Factors:**

• Employ tools like thermometers and pH meters to quantify factors like temperature, salinity, and dissolved oxygen across different ecosystems.

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Measuring Biotic Factors:**

• Sampling Methods: Use point quadrats and line transects to assess diversity and abundance in ecosystems. Samples should be random or systematic to ensure data accuracy.

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Species Abundance

• Capture-mark-release-recapture method (Lincoln Index) used for estimating population sizes: $Lincoln\, Index = \frac{n<em>1 \times n</em>2}{nm}$

  • where $n1$: first sample caught, $n2$: second sample, $nm$: marked recaptures.

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Species Diversity Measurement

• Simpson Index provides a measure of biodiversity; higher D indicates greater diversity:
  $D = \frac{N(N-1)}{\sum n(n-1)}$

• N is total number of organisms, n is count of each species.

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Humans and Their Effect on the Biotic World

5.1 The Value of Biodiversity

• Biodiversity's aesthetic, ecological, and economic values illustrate its significance to human survival and the stability of environments.

5.2 Conservation Strategies**

• Identification and protection of vulnerable species through legislation, community engagement, and sustainability practices are essential to maintain biodiversity.

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Climate Change and Sustainability**

8.1 Climate Change Initiatives

• Climate change driven by increased greenhouse gases necessitates global mitigation strategies, leading efforts to curtail emissions and adapt practices.

International Cooperation

• Coordinated efforts (e.g., Kyoto Protocol, Paris Agreement) showcase progress in addressing climate change, focusing on sustainability and resilience primarily among industrialized nations.