Science

Year 9

Unit 6

Lesson: Exploring ecosystems — Understanding the flow through an ecosystem (2 and 3 of 6)

150 minutes

Content descriptions

Science Understandings

Biological sciences

• Ecosystems consist of communities of interdependent organisms and abiotic components of the environment: matter and energy flow through these systems

Communicating

• Communicate scientific ideas and information for a particular purpose, including constructing evidence-based arguments and using appropriate scientific language, conventions and representations

General capabilities

Literacy

Students will:

• use and develop an understanding of science language specific to this lesson. This will include:

• technical vocabulary and everyday language used in science contexts (e.g. energy, feeding relationships, producers, consumers)

• procedural vocabulary (e.g. analyse, discuss, reflect)

• visual representations (e.g. food webs, flowcharts)

Critical and creative thinking

Students will:

• generate and evaluate ideas about ecosystems

• solve problems related to ecosystem dynamics and populations.

Personal and social competence

Students will:

• make responsible decisions

• work effectively in teams

• follow procedures and work safely.

Lesson objectives

Students will:

• understand inputs and outputs of an ecosystem

• examine the movement of matter and energy through an ecosystem.

Evidence of learning

Can the student:

• describe inputs and outputs of an ecosystem?

• explain how energy and matter move through an ecosystem?

• Identify plankton species within an ecosystem

Resources

Plankton Powerpoint

Plankton net, microscope, ID charts

Learning area specific language (metalanguage)

inputs, outputs, food webs, producers, consumers, energy, matter, flow, factors, photosynthesis, cellular respiration, competition, predation, mutualism, commensalism

The Australian Curriculum: Science includes a glossary of definitions of language specific to the science learning area. (Select Download.)

Definitions of science terms are also available from the C2C: Science glossary.

Misunderstandings and alternative conceptions

Students may demonstrate the following misunderstandings or alternative conceptions:

Students may think that all the energy from the sun is converted into useable energy for consumption. Explain that most of the sunlight that shines onto an ecosystem will not be utilised by just corals.

Students may think that all the energy consumed by an organism is passed onto the organism that consumes it. Explain to students that much of the energy that is consumed by an organism will be used to maintain the bodily processes required for life.

Students may think that respiration only occurs in animals. Explain to students that respiration can also occur in corals.

Students may think that communities and ecosystems stand alone and are closed. Explain to students that ecosystems and communities are open systems and so factors will continuously flow into and out of the system.

Teaching and learning sequence

Opening the lesson

Teaching strategy used

Interactive teaching: Whole-class Discussion

Discuss and record the factors that move into and out of the ecosystem (refer to biotic and abiotic conditions discussed previously in the unit).

Introduce and define the terms ‘inputs’ and ‘outputs’.

Focus questions:

What biotic and abiotic things could move into and out of the reef ecosystem?

What is meant by the term ‘flow’?

What is meant by the term ‘factors’?

What similarities do you see between the inputs and outputs?

What could remain within the ecosystem?

Remind students that ecosystems are open systems, meaning that biotic and abiotic factors are free to flow into and out of the system.

Body of lesson

Teaching strategies used

Direct teaching: Explicit teaching

and

Indirect Teaching: Inductive teaching

Explain to students that these factors influence how the ecosystem functions.

Focus questions:

How does sunlight influence an ecosystem?

How does current influence an ecosystem?

How does an animal influence an ecosystem?

What parts of the ecosystem rely on the inputs discussed?

What are the sources of energy and nutrients for coral in an ecosystem?

What are the sources of energy and nutrients for animals in an ecosystem?

Explain to students that the interrelationships between the abiotic and biotic factors of the environment facilitate the movement of matter and energy through a system.

Plankton Trawl Powerpoint

Introduce Plankton to the students and work through powerpoint.

Plankton are Producers and First Order Consumers.

Plankton need sunlight as well as coral to ensure growth for life. This energy isn’t passed on in the food chain but required for the plankton to grow.

Plankton can determine the health of a reef ecosystem.

Stop at Slide 14

Food webs and food chains help to explain part of this movement.

Revise with students the hierarchical structure of organisms and how each level acquires essential nutrients and energy for survival and what it contributes to the environment during life and in death.

Focus questions:

What is at the bottom of this food chain?

How does human input affect this food chain?

What would happen if Phytoplankton are missing from an ecosystem?

Can chemicals accumulate in the food chain?

Are plankton an important part of human survival?

Indirect Teaching: Inductive teaching

and

Interactive teaching: Whole-class Discussion

Explain to students that the sun is the source of all energy for ecosystems. Without it, all the components of an ecosystem will collapse. Energy is transferred and transformed as it flows through an ecosystem.

Discuss the process of photosynthesis with the class

Focus questions:

Name some organisms that utilise photosynthesis in the ocean?

Explain what role these organisms play in an ecosystem?

Can producers utilise all the energy available from the sun?

What are some of the factors that could limit the amount of sunlight a producer could receive within a reef system?

How does this energy get to the other organisms of the ecosystem?

How does this process affect the amount of energy that is passed up the feeding chain?

Indirect Teaching: Inductive teaching

Focus questions:

How did the energy available to the higher order feeders change?

How could this explain population numbers?

Which organisms will the waste be utilised by?

How could the availability of energy relate to the number of feeding levels within a food web?

Why is there more biodiversity at the Equator than in the higher latitudes?

Explain to students that species within an ecosystem interact in a range of ways. Such interactions are not just related to the flow of energy but also for a range of resources that exist within the system, and are essential for the species survival and longevity.

Interactive teaching: Whole Class Discussion

Focus questions:

What kind of resources may be needed to ensure a species survives?

What would happen to population numbers if multiple species were competing for the same resources?

Do all interactions between species result in one being disadvantaged?

Explain to students that such interactions can effect populations and thus the flow of matter and energy through a system, as a result of the shift in the food webs and species numbers.

Closing the lesson

Teaching strategy used

Interactive teaching: Whole-class Discussion

Dry Lab

Discuss the inputs and outputs that were discussed at the start of the lesson and how these can influence the nature of an ecosystem in relation to availability of energy and matter.

Focus questions:

What would occur if the availability of a particular resource was limited?

How would population numbers of a particular species change?

What abiotic factors could effect species populations?

What biotic factors could effect the distribution of nutrients?