Sustain the chain
View Sequence overviewStudents will:
- observe and discuss a video on invasive species.
- model the effect of an introduced or invasive species on the environment.
- model the effect of removing a food source from within a habitat.
Students will represent their understanding as they:
- represent their ideas on interactions between organisms.
- discuss how introduced animals can affect the survival of other organisms.
In this lesson, assessment is formative.
Feedback might focus on:
- Have students identified the links or feeding relationships in the different food chains?
- Are they able to describe the impact of introduced plants and animals in a habitat?
- Are students reasoning and justification based on evidence they have collected?
Whole class
Class science journal (digital or hard-copy)
Materials to create a word wall
Sticky notes
Cards and spinner prepared from the Changing habitats Resource sheet. Laminating the cards prior to use means they can be reused. Alternative pictures or food chains appropriate to your local environment can be used.
The video Crazy Yellow Ants (3:47 min)
Optional: the video Calligrapha Beetle Business (2:34 min)
Each student
Individual science journal (digital or hard-copy)
Lesson
The Inquire phase allows students to cycle progressively and with increasing complexity through the key science ideas related to the core concepts. Each Inquire cycle is divided into three teaching and learning routines that allow students to systematically build their knowledge and skills in science and incorporate this into their current understanding of the world.
When designing a teaching sequence, it is important to consider the knowledge and skills that students will need in the final Act phase. Consider what the students already know and identify the steps that need to be taken to reach the level required. How could you facilitate students’ understanding at each step? What investigations could be designed to build the skills at each step?
Read more about using the LIA FrameworkRe-orient
Discuss the context that is being used for this teaching sequence, from the point of view of how the students will be changing the habitat of the bushland/school garden.
The Inquire phase allows students to cycle progressively and with increasing complexity through the key science ideas related to the core concepts. Each Inquire cycle is divided into three teaching and learning routines that allow students to systematically build their knowledge and skills in science and incorporate this into their current understanding of the world.
When designing a teaching sequence, it is important to consider the knowledge and skills that students will need in the final Act phase. Consider what the students already know and identify the steps that need to be taken to reach the level required. How could you facilitate students’ understanding at each step? What investigations could be designed to build the skills at each step?
Read more about using the LIA FrameworkIdentifying and constructing questions is the creative driver of the inquiry process. It allows students to explore what they know and how they know it. During the Inquire phase of the LIA Framework, the Question routine allows for past activities to be reviewed and to set the scene for the investigation that students will undertake. The use of effective questioning techniques can influence students’ view and interpretation of upcoming content, open them to exploration and link to their current interests and science capital.
When designing a teaching sequence, it is important to spend some time considering the mindset of students at the start of each Inquire phase. What do you want students to be thinking about, what do they already know and what is the best way for them to approach the task? What might tap into their curiosity?
Read more about using the LIA FrameworkHuman impact
Pose the question: How do we affect a habitat?
Refer to a student question (if one has been asked) as a jumping off point for the following investigation about habitats. If students haven’t asked this question themselves, add it to the list of class questions and discuss that answering this question will be the centre of today’s investigation.
Brainstorm things that happen that affect the plants and animals in a food chain. Write each idea on a sticky note.
Discuss the difference between natural events (bushfires, floods) and human impacts (extending farmlands, clearing land for housing and roads, spraying crops, farming animals as food).
Organise the ideas on the sticky-notes into these categories
Pose the question: Does spraying/killing insects that eat a human-food crop just affect the targeted insects, or are other things affected too?
The Inquire phase allows students to cycle progressively and with increasing complexity through the key science ideas related to the core concepts. Each Inquire cycle is divided into three teaching and learning routines that allow students to systematically build their knowledge and skills in science and incorporate this into their current understanding of the world.
When designing a teaching sequence, it is important to consider the knowledge and skills that students will need in the final Act phase. Consider what the students already know and identify the steps that need to be taken to reach the level required. How could you facilitate students’ understanding at each step? What investigations could be designed to build the skills at each step?
Read more about using the LIA FrameworkThe Investigate routine provides students with an opportunity to explore the key ideas of science, to plan and conduct an investigation, and to gather and record data. The investigations are designed to systematically develop content knowledge and skills through increasingly complex processes of structured inquiry, guided inquiry and open inquiry approaches. Students are encouraged to process data to identify trends and patterns and link them to the real-world context of the teaching sequence.
When designing a teaching sequence, consider the diagnostic assessment (Launch phase) that identified the alternative conceptions that students held. Are there activities that challenge these ideas and provide openings for discussion? What content knowledge and skills do students need to be able to complete the final (Act phase) task? How could you systematically build these through the investigation routines? Are there opportunities to build students’ understanding and skills in the science inquiry processes through the successive investigations?
Read more about using the LIA FrameworkHabitat pyramid
Using the cards from the Changing habitats Resource sheet, provide:
- approximately 60% of students with a grass card.
- approximately 25% of students with an insect (cicada) card.
- approximately 10% of students with a rosella card.
- approximately 5% of students with a falcon card.
In a class of 30, this would be approximately 18 grass cards, 8 insect cards, 3 rosella cards and 1 falcon card.
- Arrange the students in a habitat pyramid.
- Students holding grass cards should sit in a row on the floor.
- Students holding cicada cards should kneel in a row behind the grass holders. They put their hands on the shoulders of two ‘grasses’.
- Students holding a rosella card should sit on chairs in a row behind the cicada holders. They put their hands on the shoulders of two ‘cicadas’.
- The students holding a falcon card should stand behind the rosella holders. They put their hands on the shoulders of two ‘rosellas’.
Discuss how students are representing the flow of energy in a food chain.
- What does each consumer need access to?
- A food source.
- If there is not enough food for the consumer, what might happen to it?
- It might need to leave the area for another one, it might not be healthy enough to reproduce, or it might die.
- Explain that we've created a model of a closed system. A closed system is contained and no other plants or animals can come into the area. Is this what would happen in real-life usually?
- No. Many animal environments interact with each other, and other living things come in and out of it.
- Where might we see a closed system in real-life?
- Islands, because land and living things are surrounded by the ocean—although birds can still fly between islands and animals can travel on refuse rafts. Fish tanks, ant farms or terrariums are closed systems, as they are contained in one space, and often sealed so other things can't enter.
Optional: Discuss when and why scientists use models, their benefits and their limitations. See the Scientific models professional learning embedded in this step for more details.
Using the spinner from Changing habitats Resource sheet, spin to determine the change in the habitat.
Model the impact of the change in the number of organisms in the habitat pyramid, based on where the spinner lands.
| Grasses | A bushfire (a natural event) has destroyed some grass. A student holding a grass card is removed from the habitat pyramid. As a consequence the cicada that needs that grass is also removed. This may affect the students holding rosella and falcon cards. |
| Cicadas | Insect repellent is sprayed on a cicada. Remove a student holding a cicada card. As a consequence the rosella that needs that cicada is also out. This may then affect falcon cards. This also means that less grass is eaten. Provide a new grass card to a student and add them to the habitat pyramid. |
| Eastern Rosellas | A rosella eats a snail that has been poisoned by snail bait, and dies from secondary poisoning. Remove a student holding a rosella card, and a falcon card holder if affected. This means that fewer cicadas are eaten. Provide a new cicada card to the habitat pyramid. |
| Falcons | Someone decides to practice their hunting skills on larger birds. Remove a student holding a falcon card. This means that less rosellas are eaten. Provide a new rosella card to the habitat pyramid. |
Repeat this process up to 5 times. During the Question routine at the beginning of the lesson, students identified possible natural events and human impacts on food chains. Use these suggestions to model the impact on the grass-cicada-eastern rosella-falcon food chain.
After giving students time to discuss with a partner, ask them to make a claim about the changes that happen in ecosystems. Encourage them to use evidence from the model they've just experienced and reasoning to support the claims they make. The QCER approach can support this.
Some examples might include:
- If there are not enough grasses and plants to eat, then insects will die, and when the insects die, the things that eat them die too. We saw this in the Changing habitats model, when things in the pyramid started to die as the grasses started to die.
- When there are no predators in the habitat, the smaller animals don't have anything to eat them, and they reproduce a lot, and need more food. We saw this in the Changing habitats model, when the falcon was removed, and more rosellas came and ate all the cicadas.
Pose the question: What would happen if another animal, such as a fox, was introduced to the habitat pyramid?
Suggest that the fox is a better hunter than the other animals so they can ‘steal’ the food from other animals. Model this in the habitat pyramid for five spinner rounds, with the fox selecting one Eastern Rosella and one Cicada each round.
Reset the habitat pyramid and introduce a rabbit that needs to eat two lots of grass each round (removing them from the game). Model the impact in the habitat pyramid for 5-10 rounds of the spinner.
- What happened when the fox/rabbit was introduced?
- Which organisms were directly affected by the fox/rabbit?
- Which organisms were affected indirectly (not eaten by them, but affected anyway)?
- Why were these organisms affected?
- How are each of the organisms in the food chain important to the other organisms?
Students draw the food chain in the habitat pyramid in their science journal, and describe the impact of introducing rabbits into the habitat pyramid including the impact on each of the grass, cicadas, rosellas and falcon.
Question, Claim, Evidence, Reasoning (QCER)
In science, arguments that make claims are supported by evidence.
In science, arguments that make claims are supported by evidence. Sophisticated arguments follow the QCER process:
- Q What question are you trying to answer?
- For example ‘What invasive species is of the greatest concern to Australia?’
- C The claim.
- For example ‘I think the feral cat is the greatest concern to Australia.’
- E The evidence.
- For example ‘The feral cat is widespread throughout Australia. It has a large variety of prey (stomach contents can include small mammals, birds, reptiles, amphibians, fish, and insects) and very few predators (humans and wild dogs). It can breed in any season, and can survive with limited access to water.’
- R The reasoning.
- Saying how the evidence supports the claim. For example ‘The widespread distribution of feral cats all over Australia, the types of prey and the small number of predators means that feral cats have a huge impact on food chains as they prey on birds, insects and small mammals. The flow-on effect of this to secondary and tertiary consumers in the food chain as their prey disappears.
In science, arguments that make claims are supported by evidence. Sophisticated arguments follow the QCER process:
- Q What question are you trying to answer?
- For example ‘What invasive species is of the greatest concern to Australia?’
- C The claim.
- For example ‘I think the feral cat is the greatest concern to Australia.’
- E The evidence.
- For example ‘The feral cat is widespread throughout Australia. It has a large variety of prey (stomach contents can include small mammals, birds, reptiles, amphibians, fish, and insects) and very few predators (humans and wild dogs). It can breed in any season, and can survive with limited access to water.’
- R The reasoning.
- Saying how the evidence supports the claim. For example ‘The widespread distribution of feral cats all over Australia, the types of prey and the small number of predators means that feral cats have a huge impact on food chains as they prey on birds, insects and small mammals. The flow-on effect of this to secondary and tertiary consumers in the food chain as their prey disappears.
Invasive species
An invasive species is one which has been introduced to an ecosystem by humans and has a negative impact on its surroundings.
An invasive species is one which has been introduced to an ecosystem by humans—either accidentally or deliberately—that has a negative impact on its surroundings. This impact might include damage to other living things, such as:
- that caused by lantana, which is a poisonous weed.
- interference with agriculture, for example, foxes attacking sheep.
- damage to biodiversity, for example, eating seabird eggs.
- or damage to personal resources, for example, camels knocking over fences.
A feral animal is an animal species that has reverted to the wild from domestication. The mere keeping of a species in captivity does not imply domestication, so the term should never be used to refer to wild, non-domesticated species. Rabbits would be classed as feral by this definition.
If a species is introduced it will not necessarily survive in Australia. It must have features that are suitable to the climate and environment. For example, a polar bear would be unlikely to survive in Darwin because its thick hair and blubber would cause it to overheat. However, camels have survived being introduced to Australia because their features are suitable for a hot desert environment.
Many introduced species have survived in Australia, such as the cane toad, European carp, Indian Myna birds and the blackberry. These species, and others, have thrived in Australia. Some introduced species can cause substantial environmental damage and have an associated economic cost. Various strategies to reduce their numbers have been researched and trialled, with some methods having greater success than others. For example, several methods have been employed in attempts to reduce the numbers of rabbits in Australia, including demolishing the burrows, fumigating the burrows and releasing targeted viruses. Each method is effective for killing individuals but rabbits reproduce so quickly that often numbers are quickly replenished.
An invasive species is one which has been introduced to an ecosystem by humans—either accidentally or deliberately—that has a negative impact on its surroundings. This impact might include damage to other living things, such as:
- that caused by lantana, which is a poisonous weed.
- interference with agriculture, for example, foxes attacking sheep.
- damage to biodiversity, for example, eating seabird eggs.
- or damage to personal resources, for example, camels knocking over fences.
A feral animal is an animal species that has reverted to the wild from domestication. The mere keeping of a species in captivity does not imply domestication, so the term should never be used to refer to wild, non-domesticated species. Rabbits would be classed as feral by this definition.
If a species is introduced it will not necessarily survive in Australia. It must have features that are suitable to the climate and environment. For example, a polar bear would be unlikely to survive in Darwin because its thick hair and blubber would cause it to overheat. However, camels have survived being introduced to Australia because their features are suitable for a hot desert environment.
Many introduced species have survived in Australia, such as the cane toad, European carp, Indian Myna birds and the blackberry. These species, and others, have thrived in Australia. Some introduced species can cause substantial environmental damage and have an associated economic cost. Various strategies to reduce their numbers have been researched and trialled, with some methods having greater success than others. For example, several methods have been employed in attempts to reduce the numbers of rabbits in Australia, including demolishing the burrows, fumigating the burrows and releasing targeted viruses. Each method is effective for killing individuals but rabbits reproduce so quickly that often numbers are quickly replenished.
Scientific models
Scientists use models to represent and visualise complex ideas.
Scientists use models to represent and visualise complex ideas. Models can help bring these ideas into focus, leading to more questions and better explanations. Models are also used to communicate ideas to others. They can be evaluated and refined over time. In this sequence, students use role-play as a physical model to refine their understanding of the role of different organisms in a habitat.
It is important to understand that models also have limitations, and we must think critically about these. Models are approximations and are often simplified to make them easier to understand. They can be missing important details. The adequacy of a model (i.e. what it shows, what it doesn’t show, what affordances it provides) should be examined and discussed to determine whether it is ‘good enough’ for its current purpose.
In this case, students are role-playing organisms in an ecosystem, but the ecosystem has been simplified to contain only four organisms. However, the benefits of being able to visualise the interactions between these organisms is ‘good enough’ to be helpful for students’ developing understanding.
Scientists use models to represent and visualise complex ideas. Models can help bring these ideas into focus, leading to more questions and better explanations. Models are also used to communicate ideas to others. They can be evaluated and refined over time. In this sequence, students use role-play as a physical model to refine their understanding of the role of different organisms in a habitat.
It is important to understand that models also have limitations, and we must think critically about these. Models are approximations and are often simplified to make them easier to understand. They can be missing important details. The adequacy of a model (i.e. what it shows, what it doesn’t show, what affordances it provides) should be examined and discussed to determine whether it is ‘good enough’ for its current purpose.
In this case, students are role-playing organisms in an ecosystem, but the ecosystem has been simplified to contain only four organisms. However, the benefits of being able to visualise the interactions between these organisms is ‘good enough’ to be helpful for students’ developing understanding.
The Inquire phase allows students to cycle progressively and with increasing complexity through the key science ideas related to the core concepts. Each Inquire cycle is divided into three teaching and learning routines that allow students to systematically build their knowledge and skills in science and incorporate this into their current understanding of the world.
When designing a teaching sequence, it is important to consider the knowledge and skills that students will need in the final Act phase. Consider what the students already know and identify the steps that need to be taken to reach the level required. How could you facilitate students’ understanding at each step? What investigations could be designed to build the skills at each step?
Read more about using the LIA FrameworkFollowing an investigation, the Integrate routine provides time and space for data to be evaluated and insights to be synthesized. It reveals new insights, consolidates and refines representations, generalises context and broadens students’ perspectives. It allows student thinking to become visible and opens formative feedback opportunities. It may also lead to further questions being asked, allowing the Inquire phase to start again.
When designing a teaching sequence, consider the diagnostic assessment that was undertaken during the Launch phase. Consider if alternative conceptions could be used as a jumping off point to discussions. How could students represent their learning in a way that would support formative feedback opportunities? Could small summative assessment occur at different stages in the teaching sequence?
Read more about using the LIA FrameworkCrazy yellow ants
Watch and discuss the video Crazy Yellow Ants (3:47 min).
- Crazy Yellow Ants and Red Fire Ants were called invasive. What does this mean?
- Do you think ants are an important part of our food chain? Why?
- What impact do you think 'introduced' ants would have on our native ants?
- Crazy Yellow Ants spray acid on other insects and small birds. Red Fire ants kill by many stings. How would this affect our habitat pyramid?
- Direct affect: kill Cicada and maybe Eastern Rosella. Indirect affect: kill all animals further up the food chain.
- How did scientists use a computer game to model how the native ants could stop the invasive ants?
- How is our habitat pyramid like the computer model?
- Both showed how the number of organisms decreased when there was a fight over food. Both were a closed system – with no other invaders or humans coming in.
- How is it different?
- Habitat pyramid did not have moving organisms and did not show other factors like shelter and water.
- How are humans trying to help the habitat?
- Using biosecurity to stop invasive animals coming in, reporting suspicious ants when you find them.
Optional: Watch and discuss the video Calligrapha Beetle Business (2:34 min).
- Does the sida weed come from Australia?
- Does this mean it is like the Crazy Yellow Ants, an invasive organism? What does this mean?
- Invasive is another word for introduced.
- Why is an invasive plant like sida weed a problem for farmers?
- It stops other plants from growing and cows can’t eat it.
- Is sida weed a producer or consumer? What evidence do you have to support your claim?
- Producer: it does not eat other organisms and is green so it uses light energy from the sun.
- Is the beetle a produce or consumer? What evidence do you have to support your claim?
- Consumer: it eats the sida weed.
- If the beetles were not used, farmers would have to use weed killing chemicals to spray the weeds. Why are the beetles better than the weed killing chemicals?
- Chemicals may kill other insects. This affects other organisms in the food chain.
- Why is the Calligrapha Beetle good for the habitat?
- It does not eat anything else and therefore does not affect other producers or food chains.
- How does Jack and Kelly help control the invasive sida weeds?
Reflect on the lesson
You might:
- re-examine the intended learning goals for the lesson and consider how they were achieved.
- update the word wall with the terms ‘introduced’ and ‘invasive’.
- update the TWLH chart by inviting students to add what they have learned (L) and the evidence/observations that show how (H) they now know that.
- discuss any questions that have not been answered by this teaching sequence.