C.2 Communities and Ecosystems

Essential Idea

• Changes in community structure affect and are affected by organisms.

Understandings

1. Most species occupy different trophic levels in multiple food chains.

2. A food web shows all the possible food chains in a community.

3. The percentage of ingested energy converted to biomass is dependent on the respiration rate.

4. The type of stable ecosystem that will emerge in an area is predictable based on climate.

5. In closed ecosystems energy but not matter is exchanged with the surroundings.

6. Disturbance influences the structure and rate of change within ecosystems.

Applications

1. Conversion ratio in sustainable food production practices.

2. Consideration of one example of how humans interfere with nutrient cycling.

Skills

1. Comparison of pyramids of energy from different ecosystems.

2. Analysis of a climograph showing the relationship between temperature, rainfall and the type of ecosystem.

3. Construction of Gersmehl diagrams to show the inter-relationships between nutrient stores and flows between taiga, desert and tropical rainforest.

4. Analysis of data showing primary succession.

5. Investigation into the effect of an environmental disturbance on an ecosystem.

Key Vocabulary

• Trophic levels

  • Food chain

  • Food web

• Biomass

  • Ingested energy - respiration

  • Sustainable food production

    • Conversion ratio

• Biome

  • Taiga, Desert, Tropical rainforest

  • Nutrient stores vs. flows

  • Climate dependent

    • Climograph

  • Climax community

    • Stable ecosystem

      • Disturbance

• Closed ecosystem

Textbook Reading and/or Activities

Click HERE for a pdf of chapter 9.

• Pages 440-462

  • Worked Example (p.442)

  • Worked Example (p.444)

  • Worked Example (p.445)

  • Worked Example (p.446)

  • Worked Example (p.447)

  • Worked Example (p.448)

  • TOK (p.448)

  • Challenge Yourself (p.448)

  • Worked Example (p.450)

  • Challenge Yourself (p.454)

  • Challenge Yourself (p.457)

  • Worked Example (p.458)

  • Worked Example (p.459)

  • Challenge Yourself (p.459)

  • TOK (p.461)

  • Exercises (p.462)

Notes

C.2 Communities and Ecosystem

A detailed set of notes, prepared by Bob Smullen, examining U1-U6, A1-A2 and S1-S5.

i-Biology Notes

A detailed set of notes, created by Stephen Taylor, examining U1 - U6 and S1 - S5.

Bioknowledgy Notes

A detailed set of notes, created by Chris Paine, examining the same IB learning expectations (because it's mostly the same) as the i-Biology Notes linked above.

Bob Smullen Ecology Review

A series of questions, prepared by Bob Smullen, to help check your understanding of both Topic 4 and Option C based on Ecology. This is VERY GOOD practice.

Learning Activities

Virtual Lab - DO and Aquatic Primary Productivity

This virtual lab, by Pearson, will help clarify the process by which different indicators can be used to measure primary productivity in aquatic plants.

Calculating Productivity

This activity, prepared by Newport High School, will help you improve your ability to calculate productivities from data.

Constructing Climographs

This activity will provide an opportunity to practice drawing climographs and to interpret their information.

Supplemental Reading

Abiotic vs. Biotic

This reading (<15 mins), prepared by Diffen, clearly outlines the differences between abiotic and biotic components of the environment. It includes a relevant SlideShare and two videos to help clarify each concept.