Teaching activity - Food webs
This resource for level 5 students illustrates how to gather and interpret data using photographs of various feeding relationships.
About this resource
This resource illustrates how richly detailed photographs can be adapted to provide opportunities for students to strengthen the capability of gathering and interpreting data in the context of science.
Teaching activity: Food webs
Mātauranga Māori
Mātauranga Māori recognises that Māori have a close association with te ngahere – the forest – and are keen observers of forest interactions. Such observation and the systematic collection of data is a cornerstone of science research. The article, Insects and forest ecosystems from the Science Learning Hub, shares University of Auckland Associate Professor Jacqueline Beggs' (Ngāti Awa) involvement in native forest restoration.
Learning focus
Students explore how evidence can be built by making inferences based on close observations.
Learning activity
University of Canterbury: Science Outreach Resources
"Food webs" was developed by the University of Canterbury Science Outreach initiative. It includes a set of vivid photographs selected to illustrate various feeding relationships on Rangatira Island. The supporting notes for NZC level 5 focus on building conceptual understandings of food webs.
The photographs provide opportunities for students to differentiate between observation and inference in scientists’ investigations.
- Show the students the photograph of several weta on the carcass of a dead bird.
- In small groups, ask the students to describe what they can see.
In this initial activity discourage students from making inferences – just get them to describe what they can see.
- Now ask the students what they think is happening in this photograph, and why they think that.
- Prompt the students to elaborate on their answers, backing up their ideas with evidence. (This could be what they can see in the photo or prior knowledge.)
When answering this question, students are making meaning based on their observations. (They are making inferences based on what they see, in combination with what they already know.)
- Ask the students how they could check if their inferences are correct. Then discuss how scientists confirm their ideas about feeding relationships, when these are based on their initial observations in an ecosystem.
- Now select one of the other photographs and display this. (Skink, snipe, black robin, or kakariki could be used for this purpose.) Give the students the information summary for the animal displayed. Ask them to confirm:
- Which parts of the information, if any, can be confirmed by observing the photograph.
- Which parts might be supported by further observation and what sort of data would need to be gathered. For example, watching animal in the act of feeding.
- What indirect observations could be used to make inferences about what has been eaten. For example, analysis of faeces.
Evidence in science is carefully constructed from observations (direct and indirect) of the natural physical world. Scientists put effort into ensuring they have robust data (i.e., that their observations are accurate). This effort is not usually described when the focus is on the products of scientists’ thinking; students need encouragement and support to pay attention to the meaning-making behind knowledge claims.
Developing an appreciation of the many ways that data might be gathered and interpreted in science supports students to become scientifically literate, that is, to participate as critical, informed, and responsible citizens in a society in which science plays a significant role. This is the purpose of science in The 2007 New Zealand Curriculum.
What are we looking for?
When you ask, “What do you see?” do students limit their answers to things that are observable?
Can they differentiate between what is directly observable and what they already know?
Can they differentiate between the observations they make and the inferences they draw from these?
Can they describe specific investigative processes that might be used to check if inferences are supported by evidence?
This activity could be a prelude to the construction of a food web as suggested in the resource. Students could follow this up by using any other example of a food web to unpack the nature of the investigative activity (observations and inferences) on which it would be based. The aim is to have them understand that scientific models such as food webs are always careful, evidence-based constructions. They never arrive “ready-made” although that is how students typically encounter them in books and on websites.
The Science Learning Hub Pokapū Akoranga Pūtaiao has some useful marine food web resources to extend students understanding:
Any clear, detailed photographs of interactions in the living world could be used to encourage and practise the skills of close observation and to differentiate between observation and inference.
The Science Learning Hub Pokapū Akoranga Pūtaiao has a student activity about the Maud Island frog called Observation: Learning to see.
The capability 4 resource, Bioaccumulation interactive, has a related focus on other types of models as evidence-based constructions.
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