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Introduction to Ecology

• Ecology: the study of how living organisms interact with each other and their environment.

• Everything in ecology is connected; understanding these connections is essential.

• Exam information: do not schedule during class; utilize accommodations if needed.

Study Tips for the Exam

• Exam Format: Fifty questions; pace yourself.

• Key Advice: Slow down while answering, reading questions carefully.

• Questions may ask for incorrect answers; be mindful.

• Trust your instincts; don’t overthink answers.

Food Chains and Food Webs

• Food Chain vs. Food Web: Traditionally thought of as linear food chains; now viewed as complex food webs where species are interconnected through food relationships.

• Phytoplankton: Primary producers in the ocean, converting sunlight into chemical energy.

• Examples of food web connections:

  • Phytoplankton to krill to whales or to other consumers like seals and humans.

• Important nutrients like nitrogen and phosphorus are cycled through ecosystems (e.g., salmon migrating and impacting forest health).

Ecological Concepts

Ecological Tolerance

• Definition: the range of conditions an organism can withstand.

• Tolerance affects distribution; variations exist between species (e.g., temperature, moisture).

• Example: Stress from temperature extremes can kill temperature-sensitive plants or animals.

Niche

• Definition: the specific role and space an organism occupies in its environment, including its interactions with other species.

• Species can have fundamental and realized niches; competition influences their actual niche.

• Examples:

  • Coyotes vs. wolves: coyotes can live in areas where wolves control resources, limiting their own niche.

  • Foxes thriving in urban areas while coyotes dominate more rural regions.

Succession

• Definition: process of change in the species structure of an ecological community over time.

• Types of Succession:

  • Primary Succession: Occurs in lifeless areas (e.g., after a fire).

  • Secondary Succession: Follows disturbances that destroy existing community but leaves soil intact.

• Succession leads to complexity in ecosystems, influencing biodiversity.

• Species diversity is often higher in more complex ecosystems (e.g., coral reefs vs. open ocean).

Disturbance and Resilience

• Disturbances can benefit ecosystems; they can clear old growth, allowing younger plants to thrive.

• Resilience is the system's ability to recover from disturbances (e.g., forests after fire).

• Human impact: Habitat modifications, simplifications, and unwanted species can create new challenges in ecosystem dynamics.

Summary of Key Concepts

• Everything is interconnected in ecological systems.

• Understanding ecological tolerance helps explain species distribution.

• A niche encompasses both where a species lives and its role in the ecosystem.

• Successional changes reveal how ecosystems evolve, responding to time and disturbances.

• Recognize the importance of biodiversity and resilience in the face of environmental change.