Pepeketua - New Zealand native frogs

Pepeketua - New Zealand native frogs

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Overview
Using this Resource
Connecting to the Curriculum
Marking Student Responses
Working with Students
Further Resources
This task is about using information about native frogs to think about possible threats to their survival.

Question

Here is some information that scientists have observed about frog lifecycles.
 
Frog life cycle
 
In New Zealand we have three species of frogs that have been introduced from other countries. These are the ones we are most likely to see.
These frogs are adapted to live part of their lives in water. They lay large numbers of eggs in water. Tadpoles hatch from the eggs and live totally in water, breathing through gills like a fish. They gradually develop lungs and legs, and then are able to spend time on land.
From the list below, which adaptations are advantages for frogs' survival? (Choose one or more.)

    • Tadpoles cannot survive out of water.

    • Many eggs are produced so the population can cope with more being lost to predators.

    • Tadpoles can live in a dry climate providing the water they live in doesn't dry up.

    • Tadpoles and eggs are a food source for other things living in the water.

Archey's frog with eggs
In New Zealand we also have four species of native frogs.  One thing that is different about them from most other frogs is their unusual life cycle.

Question

The table below shows some differences between New Zealand’s native frogs and most other frogs.

NZ native frogs     Most other frogs
Live in cool damp forests Live near water
Lay eggs in damp places under rocks and logs  Lay eggs in water
Lay a small number of quite large eggs with a big yolk Lay many small eggs
Develop in the egg until they have reached the froglet stage Hatch out of the egg as a tadpole
Froglets are looked after by their parents Parents do not look after eggs or tadpoles
Froglets have lungs to breathe oxygen from the air Tadpoles have gills to breathe oxygen from the water

Which of the following adaptations help native frogs survive? (Choose as many as are advantages.)

    • Parents protect eggs and young froglets from predators.

    • They do not require a pond or stream to go through their life cycle.

    • There are fewer eggs.

    • The young are more developed than other frogs when they hatch.

Question 1Change answer

Climate change is one type of change that affects an environment and what lives there.
If the forests where the native frogs live became much drier, why might laying their eggs under rocks and logs no longer be useful for their survival?  

Question

If scientists had to move native frogs to another place, what conditions would they most likely choose? (Choose the best one.)

    • Warm, windy and dry

    • Cold and frosty

    • Rainy, misty and cool

    • By a pond, river or stream.

Explain your answer.

Question

The Department of Conservation has only so much money to spend on saving endangered plants and animals. People have different ideas about what is important to save. Gathering different viewpoints can be a good starting point for a discussion.
This question is about how you feel about saving New Zealand's endangered frogs. 
How would you feel if native frogs became extinct?
Choose one from the following list that is closest to your feelings.

    • I would be concerned that we might end up with too many insects if there were no pepeketua to eat them.

    • I would be sad that something unique to the world had disappeared.

    • They have been on Earth a lot longer than humans so have more right to be here than we have.

    • I don't really care what happens to them.

    • I don't think frogs are important enough to worry about.

    • I think there are more important things to spend money on than frogs.

    • I would worry that the environments where the frogs live would get out of balance if frogs disappeared.

    • I would be upset because I think all things have got the right to be on Earth.

Task administration: 

Māori have 3 names for frogs – pepeke, peketua and pepeketua. These are applied to any frog in New Zealand.

Two resources about native frogs were developed together. The other, Archey's frog, is about the role of skin in respiration and hydration.

Copyright: 
Image: P.Bishop, www.nzfrogs.org
Level:
5
Curriculum info: 
Science, Understanding about science, Living World
Keywords: 
ecology, adaptation, conservation, frogs, native frogs, kaitiakitanga
Description of task: 
Task: Decide the advantages for survival of both introduced and native frogs' life cycles, explain how climate change could impact on native frogs, and identify level of interest in survival of native frogs. Assessment focus: using information about adaptations.
Curriculum Links: 
Science capabilities
The capabilities focus is brought about by the conversations you have and the questions you ask.  
 
Capability: Use evidence
This resource provides opportunities to discuss the evidence needed to support an explanation.
Science capability: Use evidence (TKI)
 
Capability: Engage with science
This resource provides opportunities to discuss real life contexts and consider actions/issues that can be taken to solve problems.
Science capabilities: 
Engage with science, Use evidence
Answers/responses: 
Question What to look for
Select advantages for frog survival
Both of:
  • Many eggs are produced so the population can cope with more being lost to predators.
  • Tadpoles can live in a dry climate providing the water they live in doesn't dry up.
Advantages of native frogs' life cycles
All of the adaptations described could be advantageous. However, each also involves some disadvantages (refer to Working with Students).
Explain why laying eggs under rocks and logs will no longer be useful if conditions become drier.
Explanation should relate to lack of damp places for laying eggs/ development of eggs.
If scientists had to move native frogs to another place, what conditions would they most likely choose? 
Explain your answer
Rainy, misty and cool
Explanation should relate to conditions required for survival.
(Do not accept They will die/ They will not survive.)
How would you feel if native frogs became extinct?
Accept any answer.
Look for responses that suggest students have:
  • an understanding that native frogs play a role in a part of New Zealand's ecosystems
  •  a realistic understanding of the magnitude of that role
  • an interest in the context.
Diagnostic and formative information: 
Adaptations
Assessment purpose: Can students make inferences related to described adaptations?
Research suggests that students can describe adaptations, but have more difficulty with explaining how the adaptations help particular species survive. The way this task was scaffolded appeared to help students make those connections.
  • About half the trial students corrrectly selected the two advantages of a frog's life cycle.
  • Over 60%  selected three advantages of the native frogs' life cycle.
  • About half were able to explain why laying eggs under rocks and logs might no longer be an advantage if the environment became dryer.
There will not be damp places to lay eggs.
If the climate becomes quite dry it is likely for there to be no damp places to lay the eggs.
If the forest is dry then the ground will be dry as well, so they won't be able to put them in a damp place.
Next Steps
Nature of Science: Understanding about science (Science Capability: Engage with science)
Part of understanding the concept of adaptation is the awareness that gaining an advantage is generally a delicate balacing of advantages and disadvantages. Native frogs' adaptation of laying fewer but bigger eggs is an example of this.
 
Advantages of laying fewer but bigger eggs Disadvantages of laying fewer but bigger eggs
A small number of eggs means parents can look after them
Less energy is required to produce fewer eggs 
A bigger yolk sustains the developing embryo longer, resulting in a more mature froglet
Eggs need parental care
More energy is required to tend to the eggs
Cannot afford to lose as many to predators
This more general area of capability is about how students (and scientists) think more provisionally about science ideas rather than in black and white/ right or wrong terms. 
  • Assign different statements from the table comparing native frogs with other frogs to small groups. Ask students to work together to infer the advantages and disadvantages of the particular adaptation. Encourage students to think of how the advantages and disadvantages might play out. What might the frogs have to sacrifice in order to be suited to a particular environment?
  • Archey's frog looks at a different frog adaptation. Trials suggest it is a more challenging assessment.
 
Explanations
Assessment purpose: Can students use evidence to support ideas?
Explaining is an important part of science. Explanations should make clear links between the question, evidence available, and, usually, knowledge of the particular context.
There were two explanations required in this task.
  1. See above
  2. About 75% correctly identified the types of conditions required if scientists wanted to shift native frogs to a different place. Most who did this correctly were able to give an explanation for why this was important. 
So the air is humid enough for them to survive
Native frogs like moist conditions so rainy, misty and cool is the best suit.
The air would be very humid and they can live without a pond or river as long as there is humidity.
Plenty of moisture and no high temperatures to dry out the frog's skin.
 
Fewer students made a clear link to the frogs' adaptations.
This will keep its skin moist so it can breathe.
The frogs like to lay their eggs under cool and damp rocks and logs and already live in more misty places as it keeps their skin damp.
​
Most students did not structure their responses well, using part sentences, minimal punctuation, and minimal use of conjunctions to signify cause or condition.
 
Next Steps
Nature of Science: Understanding about science. (Science Capability: Use evidence)
Critique with students some examples. Ask:
  • What evidence is being used to support the expl?
  • What science knowledge is referred to?
  • Have they used conjunctions to link evidence and proposition?
  • How could this explanation be improved?
Attitude towards conserving native frogs.
Most students showed some concern for the challenges for New Zealand frogs.
Statement Number of responses (n47)
I would be concerned that we might end up with too many insects if there were no pepeketua to eat them. 5
I would be sad that something unique to the world had disappeared. 9
They have been on Earth a lot longer than humans so have more right to be here than we have. 2
I don't really care what happens to them. 0
I don't think frogs are important enough to worry about. 2
I think there are more important things to spend money on than frogs. 1
I would worry that the environments would get out of balance if frogs disappeared. 10
I would be upset because I think all things have got the right to be on Earth. 6
No response 4
 
Eight students gave multiple answers. These were not included in the individual totals.
 
Next Steps
Nature of Science: Participating and Contributing (Science Capability: Engage with science)
​For students to be involved in science in the real world, they need to be ready, willing and able to bring together their theoretical knowledge and practical concerns.. Not all are interested in the same contexts - this question provides some indication of how interested your class is in this context. 
  • To unpack the idea that people come from different perspectives, a selection of opposite statements could be given to small teams to debate particular viewpoints. Encourage students to use evidence to back up their viewpoint.
  • Alternatively, students could take the perspective of different people (e.g, forest owners, DOC management, Forest and Bird, city dwellers, local iwi, etc.) and debate the pros and cons of conservation measures.
The Science Learning Hub includes resources on native frogs.
http://www.nzfrogs.org/ is a website about native frogs, including research and conservation.
 
For teacher support for structuring explanations  go to Thinking about how language works.

The following Level 5 ARB resources are about adaptations: