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Solving the dog death mystery Capability: Engage with science NoS achievement aims: Participating and contributing Contextual strands: Material world Level : 5

Science Learning Hub

This resource illustrates how a collection of Learning Hub resources could be adapted to build students’ capability to engage with science in the context of ethical issues related to a science investigation.   

Curriculum Aims and AOs

The Nature of Science strand


Achievement objectives relevant to this resource

Participating and contributing

Bring a scientific perspective to decisions and actions as appropriate.


Develop an understanding of socioscientific issues by gathering relevant scientific information in order to draw evidence-based conclusions and take action where appropriate.

Material World


Achievement objectives relevant to this resource

Chemistry and society

Make connections between the concepts of chemistry and their applications and show an understanding of the role chemistry plays in the world around them.


Link the properties of different groups of substances to the way they are used in society or occur in nature.

Learning focus

Students debate ethical issues associated with methods used in a life-threatening inquiry context.

Learning activity

The resource explores how scientists gathered and examined evidence to find out which toxins were killing dogs on two Auckland beaches. The sequence below draws the various resource pieces together to build towards this overall story:

First, a mouse bioassay process was used to isolate the toxin to a sample that was then identified as a specific species of sea slug. Next scientists measured the molecular mass of the toxin and matched it to the published register of known toxins to positively identify it as tetrodotoxin or TTX. They confirmed the presence of TTX in fresh samples of the sea slug, from these and other nearby beaches. Now they know that sea slugs can make and accumulate this toxin, only the molecular mass test will be needed to check if the sea slug is the cause of further instances of accidental poisoning. The bioassay step need not be used and hence mice will be spared.  

Begin by showing students the video:  Finding the dog killer. The video sketches the trail scientists used to urgently solve the problem of why dogs were dying on several beaches in Auckland.

Next students could explore the simple interactive model  What killed the dogs  and/or watch the video  Identifying the toxin . This step is intended to reinforce students’ awareness that quite different types of evidence may need to be sequentially accumulated as scientists ask and find answers to questions that arise as they progress through their investigation. There is also an opportunity to discuss why one team might need to “outsource” some steps to different groups of scientists with different expertise.

Adapting the resource

Scientists sometimes use controversial methods to obtain information quickly when the problem is life threatening. Clarify what is involved in bioassays by showing the next short video clip:  Mouse bioassays

Discuss when and why scientists might use this method, especially as they are trying to reduce the number of times they do so. Why was bioassay evidence needed in this case? 

Now have students read about the role of the National Poisons Centre.

If they click on the link to the related information about the  Grey side-gilled sea slug   they will see how what the scientists found out has been documented for anyone else to find, should the need arise. A discussion about this could help students appreciate how the findings from this one investigation can now contribute to society more generally.

Students could also discuss how systematic documentation of the poison, in combination with advanced techniques for chemical analysis, is helping to limit the need for further bioassays (assuming TTX proves to be the correct suspect in any future cases of accidental poisoning on beaches).   

What’s important here?

Supporting students to become scientifically literate, i.e., to participate as critical, informed, and responsible citizens in a society in which science plays a significant role is the purpose of science in NZC.

Scientifically literate citizens need to think about whether or not they consider research to be ethical and who benefits from any particular findings. Such concerns are particularly acute when benefits for some species [in this case, dogs and humans] are achieved at the expense of harm to other animals [in this case, mice]. This is an emotive issue and students need to appreciate that the issues are not clear cut, and that scientists are usually aware of their ethical obligations.

What are we looking for?

Can students respond thoughtfully to the argument that some more controversial evidence gathering methods are justifiable in life threatening contexts?

Can students explain how processes for systematically registering some types of scientific findings play an important role in helping society?

Opportunities to learn at different curriculum levels

For suggestions about adapting tasks in ways that allow students to show progress in engaging with science see  Progressions .

Exploring further

The capability 5 resource, The Gene Seekers, explores ethical issues in science from the perspective of involving human subjects, and explores implications when working in cross-cultural contexts.  

The Science Learning Hub has an ethical thinking toolkit  and suggestions for using it with students.

The relationship between scientific research and safety information/regulations is explored in the Assessment Resource Banks item  How safe are your sunglasses? .

Other resources for this capability

Yucky bugs (L1, 2, 3 & 4) Video from DOC website 

Staying Alive (L2) Connected 2, 2012

Hukanui Enviroschool (L2, 3 & 4) Connected 3, 2002

The Shell Collector (L2, 3 & 4) Connected 1, 2005

Rocky shore food web (L3 & 4) Assessment Resource Banks

Rapid response to the Rena (L3 & 4) Science Learning Hub

Tidal Communities: Interdependence and the Effects of Change (L3 & 4) Building Science Concepts, Book 22

Science Fairs (L3 & 4) No specific resource

The Gene Seekers (L5) Applications, 2001

What’s my carbon footprint? (L5) Genesis Energy resource

Biomagnets (L5 & 6) NCEA Level 1 assessment exemplars

Key words

Science Learning Hub, ethical issues, chemistry and society