Today:

•Reminders on the Take-home Final

•Intro to Ecological Principles

•Thinking About Wolves…, Group Quiz 6If you finish early, work with me or your colleagues on your final draft.

Due Thursday!

Next: Thinking About Next: Thinking About EcologyEcology

What is “ecology”?What sorts of

questions does ecology seek to

answer?

Thinking About EcologyThinking About Ecology

Ecology encompasses a wide-range of inquiries, including:

Organismal Ecology

Population Ecology

Community Ecology

Ecosystem Ecology

Landscape Ecology

The Biosphere!

Thinking About EcologyThinking About Ecology

Ecology is not Environmental Science! (Although Environmental Science pulls

heavily from Ecology!)

“To keep every cog and wheel is the first precaution to intelligent tinkering.”

- Aldo Leopold

Thinking About Ecology: Thinking About Ecology: Community EcologyCommunity Ecology

Competing Principles in Community Ecology:

The Rivet Modelvs

The Redundancy Model

Thinking About Ecology: Thinking About Ecology: Community EcologyCommunity Ecology

How do we know?

We need to understand a

species’ ecological niche: the total use of biotic and

abiotic resources in its environment.

Thinking About Ecology: Thinking About Ecology: Community EcologyCommunity Ecology

A species’ ecological niche is often heavily influenced by competition (the competitive

exclusion principle)

Thinking About Thinking About Ecology: Ecology:

Community Community EcologyEcology

An organism’s role in a community

can also be described by its trophic level.

Thinking About Thinking About Ecology: Ecology:

Community Community EcologyEcology

The trophic relationships in a

community can be visualized in a food

web

Are there any limits the length of a food

web? If so, why??

A Typical Biomass Pyramid:A Typical Biomass Pyramid:

Thinking About Ecology: Community Ecology

Energy Transfer in an Ecosystem:Energy Transfer in an Ecosystem:

Thinking About Ecology: Community Ecology

Thinking About Ecology: Thinking About Ecology: Community EcologyCommunity Ecology

Thinking About Ecology: Thinking About Ecology: Community EcologyCommunity Ecology

Possible Limitations:

1. The Energetic Hypothesis

2. The Dynamic Stability

Hypothesis

Thinking About Ecology: Thinking About Ecology: Community EcologyCommunity Ecology

Key Players in Community Dynamics:

1. Dominant species (high abundance or biomass)

2. Keystone species (pivotal role in community)

3. Foundation species (alter the structure or dynamics of their environment; facilitators)

Thinking About Ecology: Thinking About Ecology: Community EcologyCommunity Ecology

Other Useful Ideas:

Biotic Potential

and

Environmental Resistance

Thinking About Ecology: Thinking About Ecology: Community EcologyCommunity Ecology

Keystone species exert influence on a

community’s structure by virtue of their ecological niches.

How do we figure out who the keystone

species are??

Analyzing the Analyzing the Impact of Impact of

Keystone SpecieKeystone Speciess

Thinking About Ecology: Thinking About Ecology: Community EcologyCommunity Ecology

Thinking About the Gray Wolf

Reintroduction in Yellowstone