Lesson Plan: Ecosystems and Food Webs

Here is a step-by-step guide to using this lesson plan in the classroom/laboratory. We have suggested these steps as a possible plan of action. You may customize the lesson plan according to your preferences and requirements.

Step 1: Topic introduction and discussion (Go to the Reading)

1. Use the reading, ‘What is an ecosystem?’ by Khan Academy, to introduce your students to the topic of natural ecosystems.
2. Use the text to define ecosystems and their components.
3. Describe the different types of ecosystems found in the natural world.
4. Use the tool to explain how matter and energy is conserved in ecosystems.
5. Further, discuss the stability and dynamics of an ecosystem- elaborate on the equilibrium within an ecosystem and how it responds to disturbances.
6. Use the text to describe the resistance and resilience of an ecosystem, in response to disturbances to its equilibrium.

7. Use another reading in the same resource, ‘Food chains & food webs’ to explain how food chains and food webs represent the flow of energy and matter within ecosystems.
8. Use the tool to define producers, consumers, decomposers and to describe trophic levels within ecosystems.
9. Explain what autotrophs and heterotrophs are and use the tool to describe primary, secondary, tertiary, quaternary, and apex consumers.
10. Discuss the energy transfer within these systems and their limiting factors.

11. Use the end-of-module quiz, ‘Practice: Food chains and food webs’, to assess student understanding of the topic of ecosystems and food webs.
12. Use the associated links (video or textual hints) to enable students to answer the questions correctly.

Optional: Use the two video micro-lectures included in this resource to improve students’ understanding of the defined topics.

Step 2: Discuss an example of an ecosystem affected by climate change

(Go to the Video and Associated Student Worksheet )

1. Use this educational resource, ‘Liz Hadly Tracks the Impact of Climate Change in Yellowstone’ by Howard Hughes Medical Institute (HHMI) Biointeractive, to discuss how the ecosystems of Yellowstone National Park, USA, are affected by climate change.
2. First, play the embedded video (7.5 min) to describe the impacts of warming temperatures on forest ecosystems.
3. Discuss, using the video, how this results in outbreaks of bark beetle populations that attack and destroy large areas of pine and spruce trees in the National Park.
4. Explain how the destruction of these trees disrupts a food chain involving squirrels (primary consumers) and bears (apex consumers), thus upsetting the energy flow within this ecosystem.
5. Use the video to describe how lowered water availability also affects aquatic biosystems that include amphibians in Yellowstone National Park.
6. Use the student worksheet to encourage classroom discussion and to evaluate students’ understanding of the impact of climate change on food webs and ecosystems.

Step 3: Extend understanding of the extent of Bark Beetle infestation (Go to the Infographic)

1. Use the interactive infographic, ‘Bark beetle ravages central Europe’s forests’ by Reuters, to discuss with your students, the extent of bark beetle infestation in the harvested timber from the forests of Central Europe, from the years 2012-2018.
2. Ask your students to investigate the cause-effect of higher incidences of beetle infestation in the data represented and encourage them to find a correlation, if any, to the prevailing climatic conditions for those countries.

Step 4 : Discuss further using the example of Bhutan’s efforts to prevent climate induced Bark Beetle infestation 

(Go to the Reading)

1. Use the technical note, ‘Predicting Bark Beetle Outbreaks using GIS, Climate and Phenology Data’ by Dr. Kaka Tshering and Chimi Tshering, Ugyen Wangchuck Institute for Conservation and Environmental Research (UWICER), Bhutan; and University of Natural Resources and Life Sciences, Austria; to explain to your students how global warming has impacted the ecosystems in the forests of Bhutan.
2. Use the text to discuss how frequent bark beetle outbreaks, amongst other reasons, have resulted in making many such ecosystems unstable.
3. To counteract this, explain how studies were carried out to simulate spatial and temporal distribution of bark beetle outbreaks with rise in temperature: using GIS, climate and phenology data.
4. Direct your students to read the entire document.
5. Finally, encourage classroom discussions on how this information can be used to preempt bark beetle outbreaks and protect the susceptible forest ecosystems of Bhutan.

Suggested questions/assignments for learning evaluation :

1. What is an ecosystem? Describe the components of an ecosystem and their functions.
2. What are the roles of food and water cycles in an ecosystem?
3. What are the challenges for an ecosystem? Discuss the role of climate.
4. What are biomes and how are they categorized?
5. What are food chains and food webs? Give suitable examples.
6. How do bark beetle populations cause disruptions in a natural ecosystem?
7. How has climate change influenced bark beetle outbreaks globally?

The tools in this lesson plan will enable students to:

1. describe the structure and function of an ecosystem
2. discuss the trophic levels of organisms within an ecosystem
3. evaluate biomes and their component food webs
4. apply their learning to real-world ecosystem challenges
5. describe how Bark Beetles destroy forest ecosystems
6. discuss climate change related Bark Beetle outbreaks globally

If you or your students would like to explore the topic further, these additional resources will be useful.