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Coastal and marine studies in Australia: a workshop manual for teachers

Griffith University and the Department of the Environment, Sport and Territories, 1997
ISBN 0 868 57872 X

Module 5

Investigating Coastal and Marine Environments Through Science

INTRODUCTION

The importance of both content and process is emphasised in almost all curriculum documents, syllabi and statements in science education. However, many teaching and learning resources tend to focus on content with few resources available with up-to-date information on the process of science. The 1980s and 1990s have seen changes in the processes of science used to investigate coastal and marine environments. Here the emphasis has been on how the processes of science can provide answers and make predictions to understand and manage our coastal and marine environments. This module provides teachers with information and skills on the processes of science used to investigate coastal and marine environments and their relevance to teaching practice.

In order to do this, participants will analyse the "Working Scientifically" strand in the science profile from the nationally-developed curriculum. They will also analyse science processes in other syllabus documents and the relationship between curriculum frameworks and current practices for investigating coastal and marine environments. It provides an introduction to some of the methods used in science to support generalisations for the patterns they see in coastal and marine environments. It also provides participants with the skills to be able to implement these strategies in their classrooms and in the field. In summary, this workshop seeks to challenge participants to appreciate the relevance of scientific methods for their teaching practice and to help teachers develop skills to implement these strategies.

OBJECTIVES

The objectives of this workshop are:

WORKSHOP OUTLINE

There are six activities in this workshop:

  1. Introduction
    This is an icebreaker activity. The purpose of this activity is to exchange ideas on how the participants use science to investigate coastal and marine environments and relate this to the "Working Scientifically" strand of the Statements and Profiles for science in nationally-developed curriculum documents. The investigation of coastal and marine environments in the field is emphasised.
  2. Observing, Collecting Data and Generalising
    This activity outlines common methods used in schools to investigate coastal and marine environments. It is introduced by a mini-lecture and then participants are asked to classify some science activities which are used to investigate coastal and marine environment.
  3. Generalisations and Evidence
    This mini-lecture provides participants with an overview of scientific methods and the standards of evidence scientists presently accept as valid when investigating coastal and marine environments.
  4. Barnacles in Mangrove Forests: An Example
    This mini-lecture illustrates the processes of modern science using a mangrove environment as an example.
  5. Design your own Field Trip: The Real Distribution of Mangrove Oysters
    This activity provides an overview of how to implement such strategies and how to develop a field excursion based on them.
  6. Conclusion: Where to Now with Science?
    This activity provides participants with an opportunity to comment on the use of science for investigating coastal and marine environments, its relationship with curriculum documents and with classroom practice. It also discusses the limitations of scientific processes.

MATERIALS REQUIRED

A. Provided

Overhead Transparencies
OHT 1: Observing, Collecting Data and Generalising
OHT 2: Generalisations and the Evidence 1
OHT 3: A Model for Scientific Investigations
OHT 4: Generalisations and the Evidence 2
OHT 5: Why are there More Barnacles on the Seaward Side of Trees?
OHT 6: A Simple Generalisation
OHT 7: An Alternative Generalisation
OHT 8: Benefits of "Working Scientifically"


 

Resources
Resource 1: "Working Scientifically"
Resource 2A: Investigating Plankton from the Mangroves
Resource 2B: Change and the Mangroves
Resource 2C: Field Excursion to the Mangroves - Junior Secondary
Resource 2D: Investigating Common Barnacles in the Mangroves
Resource 3A: "Working Scientifically"
Resource 3B: ACT Science Curriculum Framework
Resource 4A: The Real Distributions of Mangrove Oysters
Resource 4B: Design Your own Field Trip


 

Readings
Reading 1: Observing, Collecting Data and Generalising
Reading 2: Generalisations and the Evidence
Reading 3: Barnacles in Mangrove Forests: An Example
Reading 4: A Field Trip: An Example

B. To be obtained

Activity 1: Several sheets of chart paper, thick pens and OHT pens.


REFERENCES

Edwards, P., Watts, M. and West, A. (1993) Making the Difference: Science, Technology and the Environment, WWF, Surrey.

Harlen, W. and Elstgeest, J. (1992) UNESCO Sourcebook for Science in the Primary School: A Workshop Approach to Teacher Education, UNESCO, Paris.

Harlen, W., Macro, C., Schilling, M., Malvern, D. and Reed, K. (1990) Progress in Primary Science: Workshop Materials for Teacher Education, Routledge, New York.

Monk, M. and Dillon, J. (eds) (1995) Learning to Teach Science: Activities for Student Teachers and Mentors, The Falmer Press, London.

Pritchard, I. and Preuss, P. (1991) Data Handling Skills for Australian Science Students, Cambridge University Press, Melbourne.

Ross, P.M. (1995) Mangroves - a Resource, Environmental Trust Grant, Environmental Protection Authority, NSW.

Underwood, A.J. (1990) Experiments in Ecology and Management, their Logics, Functions and Interpretations, Australian Journal of Ecology, 15, pp. 365-389.

Underwood, A.J. (1991) The Logic of Ecological Experiments: A Case History from Studies on the Distribution of Macroalgae on Rocky Intertidal Shores, Journal of Marine Biological Association of the United Kingdom, 71, pp. 841-866.

Underwood, A.J. and Chapman, M.G. (1993) Seashores: A Beachcomber's Guide, New South Wales University Press, Sydney.

Underwood, A.J. and Chapman, M.G. (eds) (1995) Introduction to Coastal Habitats, Coastal Marine Ecology of Temperate Australia, University of New South Wales Press, Sydney, pp. 1-15.

Wellington, J. (ed.) (1989) Skills and Processes in Science Education: A Critical Analysis, Routledge, London.

ACTIVITIES

1. Introduction

The aim of this activity is for participants to reflect upon aspects of their current practices when teaching about coastal and marine environments in science and relate this to the "Working Scientifically" strand from the nationally-developed curriculum for science.

Note to facilitators: Facilitators may choose to use the scientific process sections of local syllabi instead of the national document in this activity if this is likely to be more helpful to participants.

Conduct a brainstorming exercise in which participants work as a whole group to develop a way of teaching about a particular coastal or marine topic in science. The rules of brainstorming include:

Note to facilitators: This activity could be conducted in small groups if there is a large number of participants attending or a variety of levels of teaching science in the whole group.


2. Observing, Collecting Data and Generalising

The aim of this activity is to provide an overview of some common methods used to investigate coastal and marine environments. It does this by providing a summary of a common method used in schools and then engages participants in the classification of some related activities using a mangrove environment as an example. The activity sets the scene to challenge participants to think about the validity of this method.

Debriefing


3. Generalisations and Evidence

The purpose of this mini- lecture is to focus on the four mangrove activities again and to consider: "Which activity 'best' supports the generalisations reached and which cannot?" It provides an overview on how the process of science seeks to support or reject generalisations. Reading 2 provides facilitators with background for this activity.

4. Barnacles in Mangrove Forests: An Example

This activity uses an example of barnacles in mangrove forests to illustrate the concepts developed in the last activity.


5. Designing a Field Trip

This activity uses data to allow participants to work through formulating their own hypotheses and null hypotheses. It then asks participants to design a field excursion based on this method.


6. Where to Now with Science?


OHT 1

OHT 1


OHT 2

Generalisations and the Evidence 1

1. Make more observations and collect more data

Problems?


2. Subject our generalisations to disproof

Advantages?


OHT 3

A Model for Scientific Investigations

OHT 3


OHT 4

Generalisations and the Evidence 2

Hypothesis

'Given a set of conditions an event is likely to occur'.

Null Hypothesis

'Given a set of conditions no event will occur'.

The null hypothesis is tested by an experiment.

If the null hypothesis is accepted by the results of the experiment (test) then the hypothesis is rejected and the generalisation must be wrong.


OHT 5

Why are There More Barnacles on the Seaward Side of Trees?: Possible Generalisations


OHT 6

A Simple Generalisation

OHT 6

OHT 7

An Alternative Generalisation

OHT 7


OHT 8

Benefits of "Working Scientifically"


Resource 1

Science - A Curriculum Profile for Australian Schools

Source: Department of Environment, Sport and Territories (1996) Coast and Marine Schools Project. Stage 1 - Part 4: Links with Curriculum, Final Report, Canberra, Table 4.A.1.

Strand: Working Scientifically

Level

Planning investigations

Conducting investigations

Processing data

1
1.13
Lists, without support, what is known about familiar situations and suggests questions for investigation.
Plan investigations.
1.14
Carries out instructions and procedures involving a small number of steps. Carry out procedures involving a small number of steps.
1.15
Talks about observation and suggests possible interpretations. Process data.
2
2.13
Formulates questions to guide observation and investigations of familiar situations.
List questions that can guide investigations of marine environments.
2.14
Conducts simple tests and describes observations.
Conduct tests and describe observations of a marine environment.
2.15
Identifies patterns and grouping in information to draw conclusions Draw conclusions on a marine investigation.
3
3.13
Suggests ways of doing investigations, giving consideration to fairness.
Identify different ways of doing marine investigations.
3.14
Organises and uses equipment to gather and present information. Organise equipment and presentation of information.
3.15
Argues conclusions on the basis of collected information and personal experience.
Argue conclusions.
4
4.13
Identifies factors to be considered in investigations, controls which may be needed and ways of achieving control.
Identify factors involved in marine investigation.
4.14
Collects and records information as accurately as equipment permits and investigation purposes require.
Collect and record information accurately.
4.15
Draws conclusions linked to the information gathered and the purposes of the investigation.
Organise data so as to draw conclusions related to the original aims.
5
5.13
Selects an appropriate pathway for an investigation, given its purposes and the resources available.
Identify ways for carrying out a marine investigation and compare the resources required for each.
5.14
Uses instruments and techniques to provide accurate and reliable results. Conduct investigations which require correct use of instruments and techniques, in order to achieve accuracy and reliability.
5.15
Selects ways to present information that clarifies pattern an assists in making generalisations. Organise experimental data.
6
6.13
Plans procedures to investigate hypotheses and predictions for situations involving few variables.
6.14
Selects instruments and techniques to collect useful quantitative and qualitative information. Utilise quantitative and qualitative information during marine investigations.
6.15
Uses information as a stimulus for further investigations or analysis. Identify limitations in model used.
7
7.13
Identifies advantages and limitations of controlled experiments and describes alternatives.
Identify advantages and limitations of controlled experiments and describe alternatives.
7.14
Takes account of the limitations of techniques and instruments and their influence on the accuracy and reliability of an investigation. Discuss the limitations of techniques and instruments when reporting results.
7.15
Identifies the limitations of particular forms of information and analysis
Identify limitations in model used.
8
8.13
Identifies and considers ethical implications of investigative procedures.
Discuss the need for investigations and their ethical implications.
8.14
Assesses dangers in particular procedures and equipment, taking responsibility for their safe and accurate use. Identify dangers with certain procedures.
8.15
Demonstrates rigour in handling of data.
Discuss issues involved with handling data.
Strand: Working Scientifically

Level

Evaluating Findings

Using Science

Acting Responsibility

1
1.16
Relates observations and interpretations to other situations.
Evaluate findings.
1.17
Identifies ways science is used in daily life.
1.18
Collaborates with others in the care of living things.
2
2.16
Cooperatively suggests possible improvements to investigations in the light of findings.
Cooperatively evaluate marine investigations.
2.17
Describes the ways people in the community use science.
Describe ways people in the marine field use science
2.18
Explains ways that applications of science protect people.
3
3.16
Evaluates the fairness of a test designed and carried out.
Evaluates the fairness of a marine investigation.
3.17
Compares ways of solving problems and finding explanations.
Identify ways of solving problems and finding explanations
3.18
Identifies ways science is used responsibly in the community.
Identify ways science is used responsibly in a marine environment.
4
4.16
Reviews the extent to which conclusions are reasonable answers to the questions asked.
Compare conclusions with the original aims of marine investigations.
4.17
Describes techniques used to extend the senses. Identify techniques used in exploring the oceans and other marine environments.
4.18
Identifies the information needed to make decisions about an application of science. Determine the information required to make a judgement about an application of science.
5
5.16
Identifies and considers factors that influence and confidence in a conclusions.
Critically evaluate experimental findings and conclusions.
5.17
Identifies factors that influence people's perceptions of science. Investigate factors which influence people's understanding of marine science.
5.18
Proposes and compares options when making decisions or taking action.
Achieve alternative solutions to a problem
6
6.16
Assesses conclusions in relation to other evidence and sources.
Compare experimental findings and conclusions.
6.17
Reports on factors that have made possible or limited the work of particular scientists. Assess the achievement of marine scientists and the contexts which they worked.
6.18
Analyses costs and benefits of alternative scientific choices about a community problem. Analyse costs and benefits of alternative scientific choices about a community problem.
7
7.16
Discuss the limitations of conclusions.
Identify limitations of conclusions.
7.17
Analyses the influence certain scientists have had on the ways we think about the world.
Analyse the influence marine scientists have had on our thoughts about the world.
7.18
Reports on actions taken by scientists over concerns about responsible applications of science.
Assess the involvement marine scientists have in environmental issues.
8
8.16
Evaluates the implications of investigation for other people and the environment and considers ethical questions.
Discuss social implications of investigations.
8.17
Analyses the interactions between scientific developments and the beliefs and values of society. Analyse the interactions between scientific developments and beliefs and values of society.
8.18
Identifies and reports on the information need to make a responsible decision about a scientific endeavour. Identify and report on the information required to make a decision about marine endeavour.


Resource 2A

Investigating Plankton from the Mangroves

Source: Adapted from Seaweek: Exploring the Deep Sea, Seaweek Secondary School Kit, Levels 6-7, Marine Education Society of Australasia, Inc., Brisbane, 1997.


Plankton are producers and lower order consumers in the carbon cycle. A plankton trawl can be carried out from a jetty inside a mangrove forest at dusk. Once collected they should be transferred to seawater in a tank and can be observed using a dissecting microscope.

Activities


Resource 2B

Change and the Mangroves

Source: Adapted from Ross, P.M. (1995) Mangroves: A Resource, Environmental Protection Authority, Sydney.
Background Information

Mangroves are fragile and lots of human activities could seriously threaten them. Now that you have done some reading about the mangroves you have been sent out to check the state of the mangroves at different places along the Australian coast. Try and think about some reasons for what you see.

Location 1

You walk through the mangrove forest and onto the mudflat and you only see one or two crabs. It is winter.


Cause:


Effect on the environment:


Should anything be done to help the situation? What?

Location 2

You observe that many mangrove trees have lost their leaves. It is summer time and the roots of the mangrove trees look healthy.


Cause:


Effect on the environment:


Should anything be done to help the situation? What?

Location 3

You record that the whole of the area past the mangrove trees has an enormous amount of algae. It is February.


Cause:


Effect on the environment:


Should anything be done to help the situation? What?


Resource 2C

An Extract of a Field Excursion to the Mangroves - Junior Secondary Source: Adapted from Ross, P.M. (1995) Mangroves: A Resource, Environmental Protection Authority, Sydney.

Saltmarsh

  1. Draw the red plant which is found in this area.

  2. Some of the snails are found underneath these plants.

  3. How do they feel? (smooth, bumpy etc.)

The Mangrove Forest

  1. Draw a leaf of the main mangrove tree in the area. Find out from an identification book the name of this tree.

  2. Lick the leaf. How does it taste?

  3. Name some of these plants and animals.

  4. Run a transect, from the land to the sea run a transect and every 10 m put down the 1 m quadrat and count the animals and plants under the quadrat.

  5. Measure the air and soil temperature at each quadrat.

  6. Fill in table below.

Back at School

  1. Graph your results (number of organisms and temperature).

  2. Did the animals or plants change in number throughout the forest?

  3. Where were the animals in greatest abundance?

  4. Think of some reasons for this and write them down.

Organism/ Temperature

Quadrat 1

Quadrat 2

Quadrat 3

Quadrat 4

Quadrat 5

           
           
           


Resource 2D

Investigating Common Barnacles in the Mangroves

Source: Adapted from Ross, P.M. (1995) Mangroves: A Resource, Environmental Protection Authority, Sydney.

Background Information

If you enter a mangrove forest and look at the barnacles on the bark of the trees, it seems that they are more common on the bark of trees which are closest to the sea than on trees which are closest to the land. Barnacles have parts of their life cycle which swim in the water feeding on phytoplankton. These stages are known as larvae. The last stage is called a cyprid. It has a specific function to return to the forest and find a place on a mangrove tree on which to stick. Samples were taken of the water column by using a plankton net. Data was collected on how many cyprids were in the water column. The results were graphed. What generalisations can you make?

Water samples between zones


Resource 3A

Analysing Science Activities

  1. Read and discuss the four activities in Resource 2A-2D and tick which science processes are used in the activities.

  2. Working Scientifically

    Activity A

    Activity B

    Activity C

    Activity D

    Observation        
    Data Collection        
    Data Analysis        
    Generalisation        
  3. Analyse the four activities again by ticking the appropriate boxes in the table.

  4. Working Scientifically

    Activity A

    Activity B

    Activity C

    Activity D

    Quantitative data used        
    Qualitative data used        
    No data used        
    Generalisation supported by data        
    Generalisation not supported by data        
  5. Which of the four activities 'best supports' the generalisation reached? Why?


Resource 3B

"Working Scientifically"

Source: Adapted from Australian Education Council (1994) Science: A Curriculum Profile for Australian Schools, Curriculum Corporation, Carlton, Victoria; and Science Curriculum Framework, Australian Capital Territory, Canberra.

Science - A Curriculum Profile for Australian Schools

Strand: "Working Scientifically"

6.13

Plans procedures to investigate hypotheses and predictions for situations

6.16

Assesses conclusions in relation to other evidence and sources

6.18

Analyses cost and benefits of alternative scientific choices

7.15

Identifies the limitations of particular forms of information and analysis

Science Curriculum Framework - Australian Capital Territory

Strand: "Working Scientifically, Investigating, Using Science, Acting Responsibly"

Upper primary

(Junior) High School

(Senior High School) Post Compulsory


Resource 3C

ACT Science Curriculum Framework

Source: Macquarie Research Ltd (1996) Coast and Marine Schools Project. Stage 1 - Part 4: Links with Curriculum, Final Report, Macquarie University, Table 4.A.13.

Strand: Working Scientifically

Band

Outcomes

Investigating: Using Science: Acting Responsibly
Early Years of Schooling Coastal and marine issues can be used to:
  • express own ideas about the marine world
  • reflect on own ideas
  • make guesses
  • make observations and measurements with and/or without equipment
  • carry out own investigations
  • classify, record information
  • develop prediction, hypothesising and fair testing skills
  • know name and properties of some objects
  • act responsibly in the care of marine environments
  • identify ways science is used in daily life
  • present findings in a variety of ways.
Lower Primary
  • express own ideas about the marine world
  • reflect on own ideas
  • make guesses
  • plan and carry out investigations
  • make predictions and hypothesise
  • make observations and measurements with and/or without equipment
  • locate, classify and record information
  • organise and communicate findings in a variety of ways
  • formulate ideas
  • discuss limitations of investigations
  • build a vocabulary of scientific terms
  • describe the ways indigenous people use science.
Upper Primary
  • find out about everyday phenomena
  • investigate the use of science in a community
  • explore environmental impact of a scientific application
  • publish and present findings
  • consider scientific elements which affect the marine environment
  • discuss how science can improve quality of life in marine environment
  • recognise contributions to science by scientists using a variety of resources
  • formulate questions to increase scientific understanding
  • choose, classify and record information
  • make predictions, hypotheses and inferences
  • recognise controlled variables, logical reasoning and fairness
  • use simple measuring devices.
High School Coastal and marine issues can be used to:
  • make precise measurements
  • investigate, seek information, test hypothesis and make predictions
  • design, carry out, report on and evaluate investigations involving dependent and independent variable
  • use sampling and statistical techniques
  • design equipment
  • record findings using scientific and mathematical conventions
  • present structured reports work in groups
  • discuss scientific information from environmental, religious, social, legal and economic viewpoints
  • discuss advantages and disadvantages of scientific advances communicate to a range of people in many forms
  • reflect on own knowledge
  • discuss work of professional scientists.
Post Compulsory
  • carry out investigations individually and in a group
  • make hypotheses
  • design and carry out controlled scientific investigations
  • present findings in a variety of ways and to a range of audiences
  • use direct and indirect methods to investigate relationships
  • give detailed evaluations to investigation
  • discuss relationships between results and predictions
  • examine a wide range of views
  • make conclusions
  • synthesise information from a range of sources
  • test the objectivity, reliability, internal consistency and validity of scientific explanation
  • evaluate scientists' works
  • examine the practical implications of findings from a wide variety of view points.


Resource 4 A

The Real Distributions of Mangrove Oysters

Background Information

The Sydney rock oyster, Saccostrea commercialis, live on the trunks of the grey mangrove, Avicennia marina. It was observed that there were more oysters on the trees at the front of the mangrove forest and fewer on trees at the near the back of the mangrove forest. They were counted in these two areas of the mangrove forest. The quadrat size was 50x50 cm. Write down the hypothesis and null hypothesis that the collected data were intended to test.

Hypothesis

Null Hypothesis

Results

Oysters on Trees in a Mangrove Forest

Seaward Zone

Landward Zone

Quadrat No.

Site A

Site B

Quadrat No.

Site A

Site B

1 42 64 1 1 3
2 161 17 2 7 1
3 79 66 3 1 8

4

17 68 4 11 1

5

22 28 5 4 7
  1. Calculate the average number of oysters in each zone.

  2. Plot on a graph the average number (y-axis) versus the zones (x-axis).

  3. Write a sentence describing the results.

  4. Was the null hypothesis supported or rejected? Why?

  5. Was your generalisation supported or rejected? Why?

  6. Suggest 3 additional generalisations which include the factors which could be causing this pattern.

Resource 4 B

Design Your Own Field Trip

The aim of this activity is for you to design your own field trip to investigate coastal and marine environments using the scientific process discussed so far.

Issues you need to consider:


Reading 1

Observing, Collecting Data and Generalising

The start of investigating any coastal and marine environment is by observing. There are many ways we can observe. For most observations we use our senses. We can visit the environment in which the organism lives and observe it. We can collect the organisms if they are too tiny to see with our eyes and observe them using a microscope. We could make up lots of questions from these observations. If we are interested in the investigations which have been done on an organism, we can make a search of a CD ROM data base and find references to articles on this organism. We can then go to these articles and read about where the organism lives. We can also talk to our friends and to scientists and ask them about the observations we have made.

Through this process of observation (reading, talking, drawing, writing) we may have discarded some of our questions (because they have answers) and now have other questions (which do not have answers). We might have questions about how an organism lives in a coastal and marine environment. We may have questions about how people use the coast or how they affect the coastal and marine environment. Whatever our question, before we come to an answer we will probably go through two more steps - generalising (our answer) and data collecting.

Already we probably have some general statements in mind which summarise our observations and questions. So how will we give support to our generalisation? What type of evidence is needed so we can convince other people of the answer to the question we have?

One of the most common forms of evidence is to provide people with data. But, just as there are different ways to observe, there are also different ways to collect data. There are two main types of data we can collect, qualitative and quantitative. Examples of qualitative data collection include making more observations or looking at the same pattern in a number of places. This type of evidence, however, has problems. The disadvantage is that we are dependent on the person collecting the qualitative data to be objective and have no bias. It is rare, if not impossible, to have no biases when collecting data because we are humans and have an emotional as well as a rational response to a problem. Thus qualitative data is difficult for marine scientists to accept as evidence.

The second way to support a generalisation is to collect quantitative data. The advantage of collecting quantitative data is that it provides an objective view. The disadvantage is that our data are limited to that moment in time and that place we measured. The collection of quantitative data can also depend on the skills of the observer to set up a fair sampling design. Sampling normally involves the use of a tool (eg. quadrat, percentage cover) to save time. Thus, although the collection of quantitative data has problems it is more likely to be believed and thought of as valid by marine scientists.

So, we have made observations, asked questions and generalised an answer. We have then collected data. Did we ever predict what the answer would be before collecting data? Are there steps we can add to this flow chart? The answer to this is 'yes'. Indeed, we probably predicted the outcome before we collected the data. This step sometimes is not done consciously nor do we often state our prediction clearly. We also probably did the observations and question sections many times before making a generalisation.


Reading 2

Generalisations and the Evidence

Source: Adapted from Underwood, A.J. and Chapman, M.G. (1995) Introduction to Coastal Habitats in A.J. Underwood and M.G. Chapman (eds) Coastal Marine Ecology of Temperate Australia, University of New South Wales Press, Sydney, pp.1-15. Reproduced with permission of the University of New South Wales Press.


The good thing about Resources 2A, 2B, 2C and 2D is that they can be used as a method of observation. This is an important part of "Working Scientifically". The end point, however, of Resources 2A, 2B, and 2C are that the generalisations made cannot be supported or rejected . Only in Resource 2D was the generalisation supported with data. Yet the problem with Resource 2D was that it seemed to collect data before asking a question or predicting what the outcome may be. Most data collection takes place because there has been an outcome predicted.

The first steps in investigating coastal and marine environments are to observe and make generalisations. We also can have more than one generalisation to explain the same observations. These generalisations are just that; they may be true or they may not. There needs to be some sequence which will provide evidence for some generalisations and not others.

How to do this, thus becomes the question.

There are two ways we could proceed. First, we could just go out and make more observations (qualitative). With this method, however, we may be tempted to accept or reject our generalisations based on whether our new observations are consistent with our generalisation. This is not regarded as a satisfactory way to proceed because the test becomes the opinion or guess of the individual. Also it is not possible to make all the observations in all areas of an environment at all times. Every observation possible would be necessary to prove a generalisation. We could, however, try and subject our generalisation to a test. This test is often called an experiment.

Deciding which procedure to use as a valid test of a generalisation has been a popular debate since the early 1980s with scientists who investigate coastal and marine environments. It has also started to become an issue in curriculum documents (Resources 3B and 3C). Previous to the debate in the scientific community, a large number of the studies done in coastal and marine environments were qualitative, based on 'natural history', and provided subjective generalisations for the patterns which were observed. This method was problematic for marine scientists, because they believe that the aim of science is to predict what will happen given a new set of conditions. When you say that, given a new set of conditions something is likely to occur, this is called a prediction or hypothesis. To do this requires quantitative data.

A discussion of logic ensued in the scientific community and resulted in the conclusion that generalisations are hard to prove, but easy to disprove. If generalisations can withstand disproof, then we have the evidence which is required to support them. The method which is agreed on by modern science is to subject observations and generalisations to the possibility of being disproven by quantitative data. Thus the null hypothesis became the focus of the test or experiment.

Let's however think about whether it is possible to disprove the following predictions:

The second prediction is easy to disprove; the first much more difficult. The second prediction needs to be tested once to find whether there is a difference or not. A prediction which includes a statement that 'no difference' or 'no event' will occur is called a null hypothesis. The null hypothesis is tested by an experiment. If we reject a null hypothesis which says there will be no difference (because of the results of the experiment), then there must be a difference. The event predicted by the hypothesis must occur and the generalisation is supported. If the null hypothesis is accepted by the test and results of the experiment then the hypothesis is rejected and the generalisation must be wrong.


Reading 3

Barnacles in Mangrove Forests: An Example

Source: Adapted from Ross, P.M. (1995) Mangroves: A Resource, Environmental Protection Authority, Sydney.


Imagine that you are entering a mangrove forest and are interested in the barnacles which live on bark of the trunk of the tree. For example, we may observe that there are more barnacles on the bark of the trees in the seaward than in the landward zone of a mangrove forest. We may also observe that in the landward zone, there is more light and there are fewer grazing snails than in the seaward zone. The landward zone is also further from the sea during low tide. A number of different generalisations could explain the pattern we have observed.

There are more barnacles on the trees in the seaward than the landward zone because

  1. There are fewer barnacles in the landward zone

  2. It is hotter there

  3. There is more light there

  4. There are more grazing snails there

If we knew something about the current literature and life history of these organisms (see Resource 2 D), we might also include another generalisation. Barnacles have a stage in their life known as a larvae and these swim around in the water column eventually returning to the mangrove forest. This larval stage attaches itself onto a tree trunk. Thus, another generalisation can be added to the list:

  1. There are more barnacles in the seaward than in the landward zone because more larvae are in the water column in the seaward zone than in the landward zone. How can we support some generalisations and not others? We have a number of generalisations for the patterns we have observed of barnacles in mangrove forests? So one by one they need to be subjected to a test.

Test 1

Generalisation: There are more barnacles on the trees in the seaward than the landward zone (an observation) because there were fewer barnacles observed in the landward zone (the reason).

This is the first generalisation which requires testing on a field trip. This is necessary because it may be that the observer is suffering from a delusion and the observations do not represent reality.

Prediction/Hypothesis: If the seaward and landward zone were sampled, there will be more barnacles in the seaward and fewer in the landward zone.

Null Hypothesis: There will be no difference in the number of barnacles in the seaward and landward zone.

The test or experiment: Sample the number of barnacles in the seaward zone and landward zone in a number of places at a number of times. The aim here is to make this test as fair as possible. This was done in a mangrove forest in Sydney.

Results: The average number of barnacles in the seaward zone was 70.3 per 6.25 sq. cm., compared to 20.5 per 6.25 sq. cm. in the landward zone.

Thus the null hypothesis can be rejected and support given to the generalisation.

Tests 2-4

Now we have support for our initial generalisation we can do the same things for each generalisation (ii).- (iv).

Test 5

From Resource 2D, the generalisation (v) was that there are more barnacles in the seaward than in the landward zone (observation) because more larvae are in the water column in the seaward zone than in the landward zone (reason).

Hypothesis: If the water column was sampled, there will be more larvae in the seaward and fewer in the landward zone.

Null hypothesis: There will be no difference in the number of larvae in the seaward and landward zone.

Test/Experiment: This was done by sampling the water column in the two areas and counting the number of larvae.

Results: In September 1991 in the Seaward zone there were 80 larvae per cubic meter of water, but only seven larvae per cubic meter of water in the Landward zone.

Conclusion: Reject the null hypothesis and accept the generalisation.


Reading 4

A Sample Field Trip for Secondary Students

Source: Adapted from Ross, P.M. (1995) Mangroves: A Resource, Environmental Protection Authority, Sydney.

A. At the field trip

  1. Identification of plants and animals: Walk through the mangrove forest and identify some common plants and animals from the saltmarsh to the seagrass. Think about the patterns the organisms are distributed in and the factors which might be affecting them (temperature, wave action, predation etc). Also, think about how you might measure the density of one of these animals or plants and the factors affecting them.
  2. Meet in small groups in the saltmarsh.
    • Describe the pattern of the organisms which you have observed.
    • What factors might be affecting it? (You now have a generalisation)
    • Write down your hypothesis from the generalisation I predict that if
    • Write down your null hypothesis from the generalisation There will be no difference
    • Discuss with your group and the teacher your generalisation and how you might test it.
  3. Do the test. Record your data in a table, similar to the one below.

B. After the field trip, in the classroom

  1. Graph your data and the factors which you measured.
  2. Describe the density of your organism from the saltmarsh to the seagrass.
  3. Describe the characteristic(s) of the environment that may influence the density of your organism.
  4. Was the distribution of the organism you measured the same throughout the zones? Was your null hypothesis supported or rejected?
  5. If the null hypothesis was rejected does this support your generalisation?
  6. If the null hypothesis was accepted does this reject your generalisation?
Replicate No. 1 2 3 4 5 6 7 8 9 10 Factors
Zones                      
Seagrass                      
Mangrove, Forest                      
Seaward zone                      
Middle zone                      
Landward zone                      
Saltmarsh