science activity six: save our conkers · science activity six: save our conkers © stemnet 2012 |...

© STEMNET 2012 | pagE 1 of 10Endorsed by the Society of Biology

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Sponsored by AstraZeneca Science Teaching Trust.

SciENcE acTiviTy Six: SavE our coNkErScaN you DiScovEr WHaT’S HappENiNg To our coNkEr TrEES? WiLL THEy BE ok?

01 introduction 5-15 minutes02 practical activity ~40 minutes03 plenary 15-20 minutesIt would be useful to give the school some information about yourself in advance of the session. You may be able to bring photographs, equipment or other means to illustrate your work. The session should help students to recognise that the science they do in school relates to science in the real world, scientists are real people, and that they could be scientists too.Throughout the session, try to refer to your own personal experience as a scientist as much as possible.This activity is seasonal. But it does allow students the opportunity to investigate real live organisms and a contemporary issue. It is best carried out from early June to August, but should be successful right up to early October. As chestnut trees are deciduous, material is not available after the leaves have fallen.During the practical work you will be able to walk round and talk to students to gain an idea of what level you will need to adopt for the discussion and plenary.

DELivEry

Students investigate the organisms found in horse chestnut leaves infected by leaf miner moths.The students record their observations before being given identification guidance and further background information to consider.

Introduce yourself as a professional scientist.Explain, using examples from your own experience, that:

Scientists collect data and make sense of it. ●

They learn how things work through observation and experiment. They try to explain ●observations and test their explanations through experiments. When they have a good explanation they can use it to solve problems.

iNTroDucTioN01

SciENcE acTiviTy Six: SavE our coNkErS

© STEMNET 2012 | pagE 2 of 10

The taskBackground infoYou could use the following information, or you may have your own ideas that relate more directly to your own work and expertise.Have you noticed how autumn seems to be coming early for conker trees? Whitish patches develop on the leaves in the spring and by late summer these patches turn brown as these parts of the leaves die. Sometimes whole trees turn brown long before the leaves should be ready to be shed in the autumn. What is causing this to happen? Is it going to affect our conkers? Is there any way that this disease can be controlled?Getting startedHow can we use science to investigate a problem to understand what is causing it and consider potential solutions?In this activity you are going to work as scientists to try to find out what is happening to conker trees and discover the cause of what is happening. You will investigate damaged leaves and see if you can work out what is going on.Are we going to lose our conkers? Can you work as scientists to find out?You will collect data – working accurately and recording your observations as precisely as you can.Explain to the students that they will be working in pairs and briefly run through Procedure 1, emphasising any safety precautions and pointing out any other important information. For example, they will need to try to gather as much information as they can and record their observations as accurately as they can, before forming conclusions based on the evidence they have obtained.You will need to make sense of your data - use your scientific knowledge to try to explain what is happening.Observe how the students progress with Procedure 1. If time allows, briefly discuss their findings and then introduce and run through Procedure 2. If time is short, you can still select questions from Procedure 2 to discuss in the plenary.

What you will needDiscuss this with the teacher and/or technician at the school. You may wish to take some of your own materials. Make sure that everything will be available on the day.For each student

Student Instruction Sheet (may be printed separately, or you may wish to modify this ●to suit your own circumstances)

pracTicaL acTiviTy02



For each pair of studentsPlastic ziplock bags (approx A4) containing chestnut leaves infected by leaf miner ●moths, collected 2 weeks in advance between July and September*Hand lenses or magnifying glasses ●

Microscope lamp ●

Petri dish with lid ●

Scalpel or cocktail stick ●

White tile ●

*Moths, wasps and pupae may still be found into early October, but larvae become increasingly difficult to find as autumn progresses. To obtain specimens of moths and wasps to show students, leaves can be sealed into a large plastic bag a few days in advance. Look for trees with leaves low enough to harvest easily, or use a long handled pruner.

To project images and videosComputer linked to internet and data projector. (Illustrations downloaded from the ●web would be useful - see Discussion. You may wish to construct a short PowerPoint presentation.)

Health and safetyAll activities have been trialled and tested by 4science (www.4science.org.uk) and every reasonable effort made to ensure that the activities are safe when conducted as instructed.However, a full risk assessment should be carried out before any practical work is undertaken. The supervising teacher should be able to advise on this and any local requirements, such as procedures recommended by Local Authorities or safety advisers used by the institution.4science assume no responsibility for any damage or injury caused or sustained while carrying out these activities to the full extent permitted by law.For this practical you may wish to discuss with the teacher issues such as the safe handling of sharp objects.Students must be supervised at all times during practical work by a teacher (and/or responsible adult).

DiscussionThe website encouraging students to collect and send data to the scientists investigating the moth can be found at: www.ourweboflife.org.uk. This contains many useful illustrations.

pLENary03



The Forestry Commission website has information, along with the British leaf miners and UK Moths websites.Hold a class discussion to consider the answers to questions in Procedure 2.Two short videos are available to aid or conclude the discussion, or students may watch these later in their own time:(i) www.ourweboflife.org.uk – Michael Pocock explains how he is using schoolchildren to help investigate the effects of the predatory wasps on the alien moth (55 seconds).(ii) A good summary can be found at http://www.youtube.com/watch?v=_GyAa2VjWdg (2minutes 20 seconds).

Explanations

procedure 1What can you see? Write notes on your observations. Describe as accurately as you can what you can see. Make drawings if necessary.Students should be able to see larvae and observe movement in the larvae inside the leaf mines. Backlighting shows that the larvae have eaten leaf tissue to form the mines. Damage to the cells and tissues eventually causes them to die resulting in the browning.

Describe what you find.Larvae can be removed from the mines and can be seen to be caterpillar-like.

Again describe your observations as accurately as you can.Tiny moths and wasps may be found. Shapes, colours and numbers can be described or drawn.

Suggest what is happening in the leaf. What kind of damage is there and what may have caused it? What relationships between organisms could exist here?The larvae appear to be feeding inside the leaf creating the mines. There may be stab holes caused by the beaks of birds attempting to feed on the larvae. The wasps are parasitic and lay their eggs in the larvae.

procedure 2What do you think an alien species is?Alien species are introduced from another country, they did not naturally occur in the new country.

Suggest how the moth has been able to spread so rapidly.It can fly! This is assisted by winds. Adult moths and larvae in infested leaves may be spread by cars, lorries and trains. Transportation by vehicles would account for the sudden appearance of the moth miles from known areas of infestation – like its first appearance in the UK in Wimbledon.



Why is the leaf miner likely to reduce the size and number of conkers, even though it does not kill the trees?The tree needs food made by photosynthesis in the leaves. Damage to leaves and early leaf loss will reduce the amount of food available for tree growth and for making conkers.

How can you recognise that the moths and wasps are insects?Suggestions may include 6 legs (3 pairs), exoskeleton (hard outer body) with jointed limbs, head, thorax and abdomen, 2 pairs of wings.

How might the wasps help to control the alien leaf-miner moths?Eggs are laid in the moth larvae and wasp larvae hatch out and slowly eat their insides away leaving vital organs until last, finally killing them.

Suggest possible methods of control.Perhaps the most likely suggestion is the use of insecticides. These have been shown to be effective, but they are difficult to apply safely and effectively, especially to large trees. They are also expensive.Removal and composting or burning of fallen leaves kills the overwintering pupae and reduces moth numbers in the following spring.It is also possible that the parasitic wasps may bring the moth under control – this would be an example of biological control of a pest species. See: http://www.forestry.gov.uk/fr/INFD-6Q3DPF

Note: All websites cited in this resource were valid at October 2012

Students may visit the websites at www.ourweboflife.org.uk or www.conkertreescience,org.uk which contain more information and links to investigations which they can read about or take part in. Data collection includes the possible use of an app.Students could watch the videos http://www.conkertreescience.org.uk/ and http://www.youtube.com/watch?v=_GyAa2VjWdg

foLLoW up



There is an opportunity for curriculum links to be made. You may like to discuss with the supervising teacher whether they would like specific examples to be used or any issues to be raised.

Science: programme of Study for key Stage 3ks3

key concepts

1.1 Scientific thinkinga. using scientific ideas and models to explain phenomena and developing them creatively to generate and test theories.b. critically analysing and evaluating evidence from observations and experiments.

1.2 Applications and implications of sciencea. exploring how the creative application of scientific ideas can bring about technological developments and consequent changes in the way people think and behave.

key processes

2.1 Practical and enquiry skillsa. use a range of scientific methods and techniques to develop and test ideas and explanations.b. assess risk and work safely in the laboratory, field and workplace.c. plan and carry out practical and investigative activities, both individually and in groups.

2.2 Critical understanding of evidencea. obtain, record and analyse data from a wide range of primary and secondary sources, including ICT sources, and use their findings to provide evidence for scientific explanations.b. evaluate scientific evidence and working methods.

2.3 Communicationa. use appropriate methods, including ICT, to communicate scientific information and contribute to presentations and discussions about scientific issues.

range and content

3.3 Organisms, behaviour and healtha. life processes are supported by the organisation of cells into tissues, organs and body systems.d. all living things show variation, can be classified and are interdependent, interacting with each other and their environment.

curriculum opportunitiesa. research, experiment, discuss and develop arguments.b. pursue an independent enquiry into an aspect of science of personal interest.c. use real-life examples as a basis for finding out about science.e. experience science outside the school environment, including in the workplace, where possible.f. use creativity and innovation in science, and appreciate their importance in enterprise.i. prepare to specialise in a range of science subjects at key stage 4 and consider career opportunities both within science and in other areas that are provided by science qualifications.k. make links between science and other subjects and areas of the curriculum.

curricuLuM LiNkS>>



You will need to liaise closely with the teacher.Have you checked:

that all the necessary materials and resources, including worksheets, will be available? ●

the meeting arrangements at the school (for example: time, place, people’s names, ●contact numbers, parking)?the length of the session? ●

that risk assessments have been made and any appropriate safety measures are in place? ●

how your experiences as a working scientist can be related to the activity? ●

if and how any curriculum links should be made to the activity (this might also be ●related to your experience if you have provided the school with information about your work and interests)?what kind of follow up (if any) would be useful? ●

cHEckLiST>>


save our conkerscan you discover what’s happening to our conker trees? Will they be ok?


STuDENT SHEET pagE 1 of 3

what you need to do

procedure 1

Leaves have been collected from infected trees and kept in plastic bags. Collect a bag and record your observations. Use a magnifying glass or hand lens to help you.Note: The leaves were swept clear before being put into the bags, so anything in the bag has emerged from the leaf.

Take the leaf out and brush anything on the leaf surface or in the bag into a Petri dish. Replace the cover.

Observe the contents of the Petri dish. Again describe your observations as accurately as you can.

Use a scalpel or cocktail stick to cut open and peel back the leaf layers on a white tile and remove anything of interest. Describe what you find.

Hold the leaf in front of a lamp so that the light shines through from the back. What can you see? Write notes on your observations. Describe as accurately as you can what you can see. Make drawings if necessary.

Work with a partner to investigate leaf samples from infected trees. ●

See what you can discover in infected leaves. ●

Use some extra information to investigate what is happening. ●

You will be given some more information before carrying out the next stage of your investigation.




procedure 2

procedure 1

procedure 2

Look at the contents of your Petri dish. Use a hand lens or magnifying glass to identify if any of the following are present. Record the numbers of each of these that you find.

Horse chestnut leaf-miner moths: 5 mm long, metallic orangey brown with white stripes ●

Larvae: white or brown caterpillars ●

Pupae: dark brown without white stripes ●

Parasitic wasps: (not harmful to people!) 2- 3 mm long, shiny, dark coloured (sometimes ●have a light patch), unpatterned wings, narrow ‘waists’

Other insects: 2-5 mm long, never shiny, often pale brown or green in colour, wings may ●be missing or patterned, often have elongated or round bodies

The cause of the damage to the leaves is the Chestnut miner moth (Scientific name: Cameraria ohridella). This is an alien species.

The larvae of the moth mine inside the leaves of horse chestnut trees, and the damage can be dramatic. Up to 700 leaf mines can be found on a single leaf. Badly damaged leaves turn brown and fall early before normal leaf fall in the autumn.The moth has spread rapidly. It was first discovered in Macedonia in 1985. Since then it has spread across Europe to the UK where it was first found in Wimbledon in 2002. Up to 2006 severe damage was restricted to London and nearby counties. Now severe damage has occurred across South West England, through the Midlands, north of the Wash and to the borders of Wales and into southern Wales.

results and questions

What do you think an alien species is?

Suggest what is happening in the leaf. What kind of damage is there and what may have caused it? What relationships between organisms could exist here?




Suggest how the moth has been able to spread so rapidly.

How might the wasps help to control the alien leaf-miner moths?

How can you recognise that the moths and wasps are insects?

Why is the leaf miner likely to reduce the size and number of conkers, even though it does not kill the trees?

Suggest possible methods of control.

science activity six: save our conkers · science activity six: save our conkers © stemnet 2012 |...

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