Biology Essentials: Ecosystems

Introduction

• Presenter: Mr. Andersen
• Topic: Ecosystems
• Example Ecosystem: Greater Yellowstone Ecosystem

Levels of Ecology

• Bebekpo Acronym:
  • Biosphere
  • Biome
  • Ecosystem
  • Community
  • Population
  • Organism

Definition of Ecosystems

• Components: Biotic and abiotic characteristics in an area.
• Example: Yellowstone National Park established in 1872 to protect geothermal features.
• Range: Includes parts of Wyoming, Montana, and Idaho.
• Significance: One of the most pristine ecosystems in the Northern Hemisphere.

Ecosystem Dynamics

Energy and Matter

• Energy: Comes from the sun.
• Matter: Needs to be recycled, especially carbon.

Primary Productivity

• Definition: Amount of biomass produced by producers in an area.
• Measurement: Grams of carbon per meter² per year.
• Influences: Nutrients availability, light.
• Examples: High primary productivity in oceans, coniferous forests, rainforests.

Food Chains and Food Webs

• Food Chain: Linear representation of feeding relationships.
• Food Web: Complex network showing all feeding connections.
• Trophic Levels:
  • Level 1: Producers (e.g., algae)
  • Level 2: Primary consumers
  • Level 3: Secondary consumers
  • Level 4: Tertiary consumers

Population Dynamics

Growth Patterns

• Exponential Growth: Initial rapid increase.
• Limiting Factors: Scarcity of resources, competition.
• Carrying Capacity (K): Maximum population size an ecosystem can support.
• Example: Wolves in Yellowstone reaching logistic growth.

Predator-Prey Relationships

• Example: Wolves and elk in Yellowstone.
• Impact: Wolves affect elk population; predator-prey dynamics lead to equilibrium.

Human Impacts on Ecosystems

Case Study: Whitebark Pine

• Impact of Climate Change:
  • Decreased Population: Whitebark pine sensitive to warming.
  • Effects on Food Chain: Affects squirrels and grizzly bears.
  • Human-Induced Changes: Rapid changes affect entire ecosystems.

Conclusion

• Ecosystems: Delicate and maintain equilibrium through feedback loops.
• Challenges: Human activities can disrupt natural balance quickly.