Teaching Sequence

5 minutes – Tune In: Activating prior knowledge
10 minutes – Find Out: Exploring food webs
35 minutes – Take Action: How might climate change affect food webs?
10 minutes – Reflection

Work through this resource material in the following sequence:

Tune In: Activating prior knowledge

Step 1. Break students into groups of two or three and invite them to answer the following questions. Students should work together to discuss their ideas, however each student is responsible for recording these ideas on their own Student Worksheet:

What is a food chain?
What is a food web?
How are food chains and food webs different?

Step 2. Invite the class to come together and share their answers.

Use the definitions below to clarify student understanding on these questions:

A food chain is a way of representing one series of relationships within a food web by showing links between producer and consumers.
A food web is a way of showing all the interconnecting food chains within an ecological community.
Source: http://wwf.panda.org/

Explain to students that they will be exploring food webs in more detail throughout the rest of this lesson.

Find Out: Exploring food webs

Step 1. Display the following food chain image:

Now share this image of a food web:

Both images above are available in the following factsheet; Food Webs for Display.

You can see from this food web that the flow of energy goes in many directions, weaving and winding around each other. You can also see that, generally, the smaller animals at the bottom of the food web have a greater number of predators, and the number of predator-prey relationships decreases the further up the food web you go.

Step 2. Break the class into pairs or small groups and give each group a copy of the Food Web Worksheet. Each group needs to work together to add in the arrows that will show the flow of energy within the food web.

Step 3. Once complete, groups can pair up with another group to share their responses. You can also use this Food Web Worksheet Answers.

Take Action: How might climate change affect food webs? Determining the impact, using phenology

Step 1. Break the class into groups of four or five. Students will now research and create a rough sketch of a food web for species in their local area. Students can use the ClimateWatch app or website to identify species in their area, as well as field guides available online or in your library.

Step 2. Once students have created their food web, groups need to think about and investigate how climate change might affect the species in their food web.

OPTION A. Students can select one of the following scenarios (also available on the Student Worksheet), and describe how this scenario would affect their food web (example responses provided):

Rising annual temperatures cause spring to arrive 10 days earlier
Example response – Flowering plants bud too early for the insects who would normally assist in pollination to have hatched causing pollination rates to drop significantly, affecting those animals that rely on those plants for food and resources.
Rising annual temperatures cause winter snow to melt 15 days earlier
Example response – Frog and fish eggs in creeks receiving melting snow are washed away before eggs have had the chance to hatch, affecting those animals – such as fish – who normally feed on these animals.
An extended drought causes winter rains to arrive four weeks later
Example response – Smaller plants and grasses have used up all their water reservoirs, animals use up their reserves of food, affecting those species that rely on these plants and animals for food and pollination.
OR
– Extended dry conditions may cause extreme fires, resulting in loss of food and habitat, leading to population decline or extinction.
A severe spring storm damages vegetation
Example response – Damaged nesting sites means that bird and small mammals suffer a drop in numbers, affecting the predators of these animals and the plants that rely on these animals for pollination.
Warmer temperatures see an outbreak of disease affecting reptiles
Example response – Reptiles that normally feed on rodents and insects suffer a decline in numbers, meaning that rodent and insect populations boom.
A once in a century marine heatwave starts to happen.
Example response – Increased ocean temperatures cause coral reef bleaching, resulting in loss of habitat and increased algae, not suitable for coral reef fish to feed upon, reduced fish for humans to eat.

OPTION B. Students can create their own scenario based on the information provided on the ClimateWatch app or website, as well as other online resources available.

Invite students to write down their scenario and describe, in writing, how their scenario will affect their food web using the following questions to guide them (also available on the Student Worksheet):

What is your climate change scenario?
What species will be immediately affected by this scenario?
What species will be affected later on?

Step 3. Using the information they have collected and created about their food webs, each group will now create a classroom demonstration. This demonstration requires groups to provide:

An image (sketch is fine) and name for each species in their food web on an A6 sized piece of paper
A written version of their scenario and the impacts that can be read out loud to the class.

Sample scenario: Heavy rainfall in the areas around the wetland see an unusually high level of water enter the wetland. Some of this water has flown off a farm and contains pesticides and herbicides designed to protect crops from infestations of damaging disease and insect infestations. Unfortunately, the herbicides and pesticides also harm some of the organisms in the wetland, in particular the water fleas and green algae, both of which completely die out.

Instructions for classroom demonstration -

Each group needs to present their scenario to the class by:
- Gathering as many volunteers as there are species in their food web, and inviting them to stand in a circle
- Giving each volunteer a species card
- Nominating a group leader to lead the demonstration and read out the scenario
Give a ball of string to the species at the base of the food web. The ball of string needs to then be passed to any species in the food web that relies on the original species, and should then be passed onto any species dependent on those species, and so on until all volunteers are holding the string.
The group leader needs to then read out the scenario to the class once through so that everyone understands what this scenario is about. They can then focus on how the food web is affected by this scenario; species immediately affected by the impact of climate change must sit down. These are now dead and must remain sitting down. Any species that are affected by this species dying must now also sit down, and so on until all species that could sit down have sat down.

Step 4. Once each group has shared their scenario, engage students in a discussion around this activity. Consider the following questions in your discussion:

What happens to the web when one species suffers a decline in numbers?
Which types of species were most affected (e.g. producers, consumers, predators etc.)? Why do you think this is? Which ones were least affected and why?
Imagining that this was a one-off event, what do you think would happen to this ecosystem in the long term?
What about if this change happened annually – do you think this ecosystem could adapt? Why or why not?

Conclude the lesson by explaining that not all impacts are negative (an increase in some species may benefit humans, for example). There will be winners and losers with climate change, but for the most part, impacts will be negative and have flow-on effects.

Reflection

Invite students to work independently to answer the following questions:

In what ways were the ideas presented in this lesson connected to what you already knew?
How was your thinking pushed or extended in new directions during this lesson?
What is still challenging for you about the ideas looked at in this lesson?
What questions do you now have about the ideas presented in this lesson?

Teacher Reflection

Note: Cool Australia and Earthwatch have also partnered to create citizen science units of work for maths and geography. To further enhance students' learning, consider teaming up with teachers in these complementary faculties to run a cross-curricular project on phenology and citizen science.

Citizen Science - Food Webs and Climate Change

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