Unit A: Interactions and Ecosystems

Introduction

• Definition of an ecosystem: an area where living things interact with other living and non-living things.
• The importance of understanding ecosystems for the well-being of Earth.
• Human actions can impact ecosystems both positively and negatively.

Section 1: Relationships Between Living Things and Their Environments

1.1 Defining an Ecosystem and Basic Needs

• Ecosystems: Composed of biotic (living) and abiotic (non-living) factors.
• Examples: Ocean, desert, puddle, rotting log.
• Basic Needs of Living Things:
  • Water: Essential for life, makes up a large portion of living organisms.
  • Food: Provides nutrients and energy.
  • Energy: Needed for all bodily functions and survival.
  • Oxygen: Required for energy release from food.
  • Suitable Living Conditions: Necessary for survival; varies among organisms.

1.2 Interactions Among Living Things

• Symbiotic Relationships:
  • Commensalism: One benefits; the other is unaffected (e.g., orchids on trees).
  • Mutualism: Both benefit (e.g., goby fish and snapping shrimp).
  • Parasitism: One benefits; the other is harmed (e.g., mosquitoes biting humans).

1.3 Human Impacts on Ecosystems

• Frank Lake: Wetland creation by Ducks Unlimited, using waste water from a meat-packing plant.
• Beaver Population in Yoho National Park: Decline due to fire management practices impacting tree growth.
• Garbage and Pollution: Human waste impacts ecosystems; solutions include recycling and sanitary landfills.

Section 2: The Flow of Energy and the Cycling of Matter

2.1 Interactions Among Producers, Consumers, and Decomposers

• Consumers: Organisms that consume other organisms for energy (Carnivores, Herbivores, Omnivores).
• Producers: Organisms that make their own food through photosynthesis.
  • Photosynthesis: Converts solar energy into chemical energy; produces oxygen.
• Decomposers: Break down dead matter, recycling nutrients.

Energy Flow in Ecosystems

• Photosynthesis: Plants convert sunlight into energy and release oxygen.
• Cellular Respiration: Process of energy release in living organisms using oxygen.

Decision-Making and Environmental Management

Activities

• Brainstorm and create plans to reduce human negative impacts on natural areas.
• Create mini-ecosystems in jars to observe interactions and changes.

Focus on Social and Environmental Context

• Consider how human activities impact ecosystems and how science and technology can help manage these impacts.
• Encourage critical thinking about the balance between human needs and ecosystem sustainability.

Conclusion

• Understanding ecosystems and their dynamics is crucial for maintaining Earth's health and making informed decisions.
• Science and technology play a key role in helping humans interact positively with their environment.