Environmental systems and societies IB

• What are the foundational concepts in Environmental Systems and Societies (ESS) related to ecosystems?

  First and Second Laws of Thermodynamics, Entropy, Equilibrium, Feedback mechanisms, and Energy flow.
• What does the First Law of Thermodynamics state?


  • Energy cannot be created or destroyed.
  • Energy can only be transformed from one form to another.
  • In ecosystems, energy enters from the sun and is transferred through trophic levels.
• How does energy flow through ecosystems according to the First Law of Thermodynamics?


  Energy enters from the sun and is transformed through different trophic levels without being lost.
• What does the Second Law of Thermodynamics state?


  Some energy is lost as heat during transformations, leading to increased entropy.
• What is the implication of the Second Law of Thermodynamics for energy transfer in ecosystems?


  Energy transfer is inefficient, with energy lost as heat at each trophic level.
• What is entropy in the context of ecosystems?


  Entropy is a measure of disorder or randomness in a system.
• How do ecosystems move in terms of entropy over time?


  Ecosystems tend to move from low entropy (organized) to high entropy (disordered) without constant energy input.
• What are the two types of equilibrium in ecosystems?


  • Static Equilibrium: No change, rare in nature.
  • Dynamic Equilibrium: Fluctuating but stable, absorbs small disturbances.
• What is positive feedback in ecosystems?


  Positive feedback amplifies changes, driving the system away from equilibrium.
• Can you give an example of positive feedback in ecosystems?


  In global warming, melting ice reduces reflective surfaces, causing more heat absorption.
• What is negative feedback in ecosystems?


  Negative feedback stabilizes a system by counteracting changes.
• How does predator-prey interaction illustrate negative feedback?


  If prey populations increase, predator numbers rise, but as predators consume prey, prey numbers decrease, stabilizing the system.
• How does the First Law of Thermodynamics manifest in ecosystems?


  • Sunlight provides energy for producers through photosynthesis.
  • Plants convert light energy to chemical energy (glucose).
  • Energy is transferred through herbivores to carnivores.
• What percentage of energy is typically transferred from one trophic level to the next?

  About 10% of energy is transferred; the rest is lost as heat.
• Why do food chains rarely exceed four or five levels?

  There’s not enough energy to sustain higher levels due to energy loss at each trophic transfer.
• What is complexity in ecosystems?


  • Refers to the number of species and interactions.
  • More complex ecosystems are more resilient.
  • They have multiple pathways for energy and nutrient flow.
• How does stability relate to complexity in ecosystems?


  Ecosystems with higher complexity are often more stable and can return to equilibrium after disturbances.
• How do the First and Second Laws of Thermodynamics connect to ecosystem stability?


  • They explain energy movement and loss as heat.
  • Greater entropy requires constant energy input to maintain order.
  • Feedback mechanisms help ecosystems maintain stability despite disturbances.
• What is the primary source of energy for most ecosystems?

  Solar energy.
• How is solar energy input measured in ecosystems?


  It is measured in joules per square meter per second.
• How much solar energy input is typically received in direct sunlight?


  Around 1,000 joules per square meter per second.
• How does a plant utilize solar energy?


  Plants perform photosynthesis, converting solar energy into chemical energy stored in glucose.
• What happens to the energy absorbed by a plant during photosynthesis?


  Only about 10% is converted into chemical energy; the rest is lost as heat.
• How much energy is typically stored as biomass when a herbivore consumes food?


  About 10% of the energy consumed is stored as biomass.
• What are common energy outputs in an open ecosystem?


  Heat loss to the environment and energy loss through waste or migration.
• How does energy flow through trophic levels in an ecosystem?


  • Producers absorb energy from sunlight.
  • Primary consumers eat producers and receive energy.
  • Secondary consumers eat primary consumers and receive energy.
  • Energy transfer is inefficient, with losses at each level.
• What is the relationship between energy inputs and outputs in an ecosystem?


  Energy inputs must equal energy outputs plus any energy stored within the ecosystem.
• Why is maintaining a balance of energy inputs and outputs crucial for ecosystems?


  It is essential for sustaining life and maintaining ecosystem dynamics.