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Documentary Lens Lesson Plan for Emergence of a Dragonfly
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Documentary Lens Lesson Plan for
Emergence of a Dragonfly
by William Scott
S.J. Willis Continuing School, Greater Victoria School Board, SD #61, BC
Curriculum Connections
Emergence of a Dragonfly shows a time-lapse view of the final moult of an aquatic nymph as it
transforms itself into an adult dragonfly. This metamorphosis, a process that in real time might
take a couple of hours, is shown over a five-and-a-half-minute time period in the film. This silent
film without commentary is an extreme form of observational documentary. It is introduced by a
very brief on-screen introductory text. The running time is six minutes.
This lesson has been designed for the science curriculum in British Columbia. Along with
tying in many of the general skills and processes of science such as observing, inferring or
hypothesizing common to all levels, this film has curriculum links to Grades 2, 4, and 7 in Life
Science, Science 10 in genetics, and Biology 11 for arthropods. Although these materials have
been designed for the Grade 7 science curriculum, the nature of the film allows for teacher
adaptation to other grades and subjects.
Related units of study: Science Processes; Body Systems: Reproduction, Growth and Change;
and Ecosystems.
Lesson Objectives
Working in groups, students observe, analyze, and interact with a film on the incomplete
metamorphosis of a dragonfly. Students will use qualitative and quantitative observations to
describe the growth and development of a dragonfly using concepts of ratio and proportion.
Examining the class results involves data analysis.
Through small group work, class discussion, readings and Internet research, students will
explore dragonfly biology based on questions that arise from their own observations and interests.
Outcomes and Expectations
Students will:
 describe the growth and changes in the development of an organism (Life Science: Body
Systems - Reproduction, Growth and Change)
 determine measures of central tendency for a set of data: mean (mode & median ) and range
(Statistics and Probability in Data Analysis)
 use text and electronic media features, including indices, tables of contents and keyword
searches, to locate specific information (Comprehend and Respond: Strategies and Skills)
 locate and interpret details in print and non-print media to gather information and build
understanding (Comprehension)
© 2005 National Film Board of Canada
Documentary Lens Lesson Plan for Emergence of a Dragonfly
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Resources
 The AES Bug Club for Young Entomologists http://www.ex.ac.uk/bugclub/
 A Beginner's Guide to Dragonflies (A detailed article of six pages with adult dragonfly and
damselfly diagrams) http://powell.colgate.edu/wda/Beginners_Guide.htm
 Biokids: Dragonflies (Excellent readability containing background information and pictures)
http://www.biokids.umich.edu/critters/information/Anisoptera.html
 Biology of Dragonflies and Damselflies http://uci.net/~pondhawk/odonata/odonata.html
 Diagrams of Dragonfly Nymphs (from Buglopedia)
www.bugsurvey.nsw.gov.au/html/popups/bpedia_08_tol_dr-ny-a.html
 Dragonflies and Damselflies http://insectzoo.msstate.edu/Students/odonata.html
 Dragonflies of the Family Aeshnidae in British Columbia: Biological Notes and Field Key,
Based on Specimens in the Royal British Columbia Museum Collection
http://www.royalbcmuseum.bc.ca/nh_papers/aeshnareport/aeshnarep.html
 Introduction to Insects (on-line diagrams of dragonfly’s incomplete metamorphosis can be
found at Gary A. Dunn’s useful site) http://members.aol.com/YESedu/introbug.html
 Buglopedia (from the New South Wales Department of Natural Resources)
http://www.bugsurvey.nsw.gov.au/
 Background on documentaries available in the “Behind the Camera” article at the
Documentary Lens Web site.
Materials Required
Supplies per class: one rubber or latex glove (small size to fit student volunteer’s hand snuggly);
scissors; chalkboard protractor and large ruler; chart paper and felt pens.
Supplies per student pair or triad: a calculator; pencil and pen; protractors and small plastic
rulers (if students are working at a number of computer stations); and 20 cm string or a long pipe
cleaner (not really essential items).
Activities for Emergence of a Dragonfly
Introductory Activity
Activating Prior Knowledge
Have students dedicate a page for their notes to the introductory activities. Write the following on
the overhead or the board:
Just when the
caterpillar thought
the world was over
it became a butterfly. (Anonymous)
Ask the class to define “metamorphosis.” Review the concept together. Have the students
make a list of changes that humans go through. The word meta is Greek for change of, and
morphosis means form. In terms of insects, metamorphosis is a transition from one form to
another, into an adult. Butterflies and their kin go through four stages of complete
metamorphosis, transforming from egg to larva to pupa to adult. In incomplete metamorphosis,
insects like dragonflies or damselflies change from egg to larval form (nymph) to adult, a threestage life cycle.
Have students speculate about the importance of metamorphosis in our culture. You might
want to mention a few current or ancient examples. For example, dragonflies in various Native
© 2005 National Film Board of Canada
Documentary Lens Lesson Plan for Emergence of a Dragonfly
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cultures symbolize swiftness or agility and they are often connected to water, spring, fertility
and/or renewal.
Brainstorm students’ current knowledge of dragonflies and their role in the ecosystem.
Dragonfly biology is an excellent topic to introduce the class to the study of insects (arthropods)
and/or pond ecosystems. Dragonflies belong to the insect order Odonata that also includes
damselflies. Odonata is Greek for “toothed jaws.”
On the board, draw a timeline or circle representing a dragonfly’s lifespan of 1-6 years. Have
students speculate as to how long each stage lasts and what the dragonfly might eat at each stage.
Have students review the dragonfly lifecycle, and emphasize the following points:
 After hatching from the egg, the larva or nymph, is aquatic. Eggs don’t overwinter; the larvae
do.
 The larva goes through a number of moults (usually 10-14).
 Wing buds get larger with each moult.
 Species vary in the length of time that they remain as larva, from 1-6 years.
 Adult dragonflies in Canada live 1 or 2 months; if they’re lucky they reproduce.
The following points should emerge either now or during subsequent research:
 The main predators of larvae are fish, frogs and diving ducks. Dragonfly larvae are
carnivorous, and they tend to prey on the larvae of smaller insects, fish spawn and tadpoles.
The larval stage can vary in duration from about 3 months to 4 or more years depending on
the species and growth conditions (latitude, altitude and amount of daylight).
 Adult dragonflies are often at the top of the pond food chain. They eat a large variety of
flying insects (mosquitoes, midges, flies, bees and other dragonflies). Their main predators
tend to be birds (red-winged blackbirds, purple martins, kites, kingbirds, moorhens or coots)
or predaceous insects (other dragonflies or giant robber flies).
Review the following key terms: invertebrates, insects and exoskeleton. Using handouts
and/or the overhead, review the main parts of insect anatomy, using diagrams of the larval
dragonfly and the adult dragonfly.
Developing Understanding and Skill Activity
Step 1
To simulate the dragonfly’s problem of shedding its larval shell, ask for a volunteer with a “thick
skin” to participate in a class demonstration. Ask the students for ideas as to why pulling
ourselves out of our skin might be a problem for us. (Our skin tends to flake off in tiny pieces; for
the most part, our skin layers are tightly bonded to each other.) What would we have to do before
pulling ourselves out of our skin?
Have the volunteer put a rubber glove on one hand and then have him or her take off the
glove without using a free hand, feet, or teeth. Students’ can provide suggestions. Once the
student has removed the glove, discuss the similarities and differences in this model to the
dragonfly’s problem.
© 2005 National Film Board of Canada
Documentary Lens Lesson Plan for Emergence of a Dragonfly
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Similarities: The rubber glove usually needs to be pressed against a substrate so that friction
helps pull the glove off the hand. In the same way, the larva tends to attach itself to a plant or
other substrate by means of its claw-like legs. It continues to grasp the substrate after the
dragonfly has emerged and left. Also the more tightly the glove or larval skin is attached to
the “body” inside, the harder it is to remove the outer layer.
Differences: The dragonfly has to make a split in the outer skin first, and it doesn’t pull itself
out of its larval skin in the same manner. The rubber glove is more flexible than the larval
skin. Also the dragonfly must “puff” itself up after emerging so that it has room to grow.
Step 2
Have students examine a larval dragonfly diagram to predict where the adult might emerge. (See
Resources above)
Step 3
Explain to the class that they are going to be viewing the film twice. Ask students to jot down, in
point form, the two most interesting sequences/events they observe, and to give reasons for their
choices. Students should also list as many questions as they can think of regarding dragonfly
biology.
Questions can focus on anything researchable: from factors that affect larval/adult dragonfly
development to dragonfly senses and behaviour to dragonfly interactions in the ecosystem. Each
student should aim to generate a minimum of 12 questions, and then pick the three that they find
the most intriguing and record them. The questions should be phrased so they encourage detailed
answers rather than yes or no responses. For their most important questions, students should
predict or speculate about some possible answers.
For example, what factors determine when a dragonfly emerges or moults its exoskeleton?
Student predictions might include hormones, length of daylight, food eaten, and/or water
temperature. How does a larva or adult detect, catch, and eat its prey? Student predictions might
include sense of smell/vision, mouth parts, and clawed legs working together.
Finally, students are to give their overall impression of the film.
Step 4
Ask the class to think about how they could use the film to measure any growth of the dragonfly
as it emerges. The actual length of the dragonfly larva in the film is probably 2.5-4 cm. Suggest
that the magnified versions in the video are in the same proportions to the real larva.
Tell students to try to watch the film from two perspectives: as scientists and as documentary
filmmakers. As scientists, they will measure the lengths of various body parts to compare their
relative lengths in the larva and adult dragonfly. This type of measurement is often done in
seeking ways to distinguish different species from each other. On their diagram of the larva, they
are to locate the exact place it pulls itself out of its old exoskeleton.
As filmmakers, they will describe the sequences as extreme close-ups (ECU) of single body
parts, close-ups (CU) of two body regions, or full shots (FS) showing the entire dragonfly.
Step 5
Have students view the video a second time to complete their descriptions of the main action
occurring in each scene on the student video log sheet.
If you are using a VCR/monitor, stop the video after the following sequences: #4, #5, and #6
to allow students the time to complete the video log and to carry out the measurements required
© 2005 National Film Board of Canada
Documentary Lens Lesson Plan for Emergence of a Dragonfly
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to complete the relative size of body parts. Review # 4-6 with the class, so they feel comfortable
with the process.
Use the attached teacher program log as a guide for times/events. Return to scene 4 and have
a pair of volunteers make measurements from the classroom VCR monitor or have pairs of
students at a computer complete the measurements in teams. Each student should measure the
larva using a length of string or a pipe cleaner, and then use a ruler to determine the actual length
in centimetres. (Clear plastic rulers are harder to read if used by themselves. If students take their
measurements independently, they will be more likely to catch errors. In pencil, students should
complete the appropriate section of the relative size of body parts versus leaving the calculations
for a later time.)
Note
The Worksheet Video Log for this lesson includes suggested responses. You will likely want to
remove some or all of the suggested answers in the “Type of shot,” “Text on screen or scene
description and action in scene,” and “Questions about the biology of dragonflies that come to
mind as you watch the film.”
Step 6
If pairs of students have their own computer, they could continue the process and complete the
Worksheet Video Log. If you are using a VCR in front of the class, you might want to be more
selective and restrict the number of scenes you have students review (sequences 11-12, 17-20, 22,
and 24 would work well). Measurements of the adult dragonfly are required in scene 24 to
complete the relative size of body parts.
Post-Viewing Activity
“Have students work together in small groups to decide on their six most interesting questions
about dragonfly biology (collected from individual students’ lists of top three questions in Step 3
above). They are to write their questions on chart paper (if possible, post the chart paper around
the classroom). By random allocation, make different groups responsible for reporting back to the
class on each topic area.”
© 2005 National Film Board of Canada
Documentary Lens Lesson Plan for Emergence of a Dragonfly
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Worksheet Video Log for Emergence of a Dragonfly
Name ______________________________ Date _______________________
Sequence
number and time
Type of shot
(ECU, CU, FS)
Text or scene description and action
Questions about the biology of
dragonflies that come to mind as I
watched the film
#1
0:00 to 0:06
Text appears: “The National Film
Board of Canada presents A
FRAGMENT OF LIFE”
#2
0:06 TO 0:33
Title of film appears: “Emergence
of a Dragonfly” There are three
stages in the development of a
dragonfly: the egg, the nymph,
and the adult insect; this is called
simple or incomplete
metamorphosis.
If the larva is aquatic, how does
it move around, catch its prey,
get oxygen?
How and when does it prepare
for the transition to life on land?
What specific changes occur?
What controls the timing of the
change?
#3
0.33 to 0:50
In the change from the aquatic
nymph to the airborne adult, the
skin splits away along the back
and the dragonfly struggles out.
The film has no text from here on.
What changes occur in the
dragonflies skin to allow it to
moult like this?
DNA? Hormones?
#4
0.53 to 1.06
FS
Sideview from left-hand side of
larva. The larva is gripping a plant
stalk with its legs. The abdomen
of the nymph appears to flick
upwards in an arch 4 times. This
segment ends with an ECU of the
head thorax area of the larva
viewed from the left-hand side.
Is the flicking a method of
making sure the new adult is
totally separate from the old
larval skin or shell? Or is it a by
product of filming?
#5
1:06 to 1:20
CU
View shifts to another close-up of
the back (dorsal side of thorax)
and head. A split in the larval skin
occurs just above the wing buds
on the thorax.
What part of the adult will
emerge first?
#6
1:20 to 1:50
CU
From a slight sideways view the
split appears to be triangular and
widens. “Shoulders” (top of
thorax) of emergent adult are
visible.
What causes the larval skin to
break? Is the thorax swelling?
Are these segments shown in
real time?
#7
1:50 to 2:00
ECU
Focus on legs that appear crablike. The legs appear to be
pulsing slowly out.
Are the adult legs soft when
they emerge? Is the dragonfly
able to use them at all?
#8 and 9
2:00 to 2:13
CU side to
FS dorsal
Head and thorax from left side.
The adult shoulders are visibly
free, and the head is arching
Would the dragonfly be able to
see or respond to predators at
this point?
© 2005 National Film Board of Canada
Documentary Lens Lesson Plan for Emergence of a Dragonfly
Sequence
number and time
Type of shot
(ECU, CU, FS)
Text or scene description and action
Page 7
Questions about the biology of
dragonflies that come to mind as I
watched the film
forward. Left eye of the adult
becomes visible. Ends with dorsal
view with head completely free.
#10
2:13 to 2:22
ECU
Side view of the head. Mouth
parts are visible and moving, legs
emerging, head slowly moves
away from the larval shell to go
off-screen.
If this film is 6 minutes long and
the process takes over an hour,
what parts of the process did
the filmmaker cut?
#11
2:22 to 2:27
FS
Side view. Emerging adult looks
like a race car driver leaving his
car, legs moving slightly with one
leg almost free. (Note: what
appears to be white cord-like
tissue is not a leg.)
Is the dragonfly motionless for
most of the time that the director
films? Does it have to rest or
wait? Why?
#12
2:28 to 2:36
ECU
Side view of leg slowly emerging.
First pair becomes free.
What predators do dragonflies
have?
#13
2:36 to 2:48
CU
Top view. Upper body moves
backwards. Two front legs point
upwards as the second pair of
legs becomes free.
How many cameras did the
filmmaker have to use? Is this
film constructed from filming one
dragonfly or many different
dragonflies?
#14
2:48 to 3:00
ECU
Side view of second pair of legs
being freed. (Note: what appears
to be white cord-like tissue is not
a leg.)
The emerging dragonfly seems
very flexible. Does the
exoskeleton harden quickly or
slowly?
#15
3:00 to 3:12
FS
View of the emerging adult
arched backwards and
downwards away from the larval
shell. The right leg of the final
third pair of legs is freed.
What scientific experiments
have been done to understand
the hidden processes we are
seeing?
#16
3:12 to 3:19
ECU
Close-up of head and first pair of
legs. Mouth parts moving
Do dragonflies have antennae?
What are they used for?
#17
3:19 to 3:24
FS
The adult abdomen has been
freed significantly, as compared
to sequence #15. Note the
relative size and length of the
wing buds.
#18
3:25 to 3:40
CU to FS
A close-up of the abdomen and
the third leg switches to a side
view. In a contortionist move, the
upper body and legs flip towards
the larval shell. The front legs
appear to grasp the head region
of the larval shell; the second and
third pair grasp the abdomen and
substrate respectively.
Do all dragonflies do this the
first time? Do some have to try
several times?
What would happen if the
dragonfly was prevented from
performing this motion? Would it
still be able to remove itself?
#19
ECU
Side view of the head of the
Is it possible to develop and
© 2005 National Film Board of Canada
Documentary Lens Lesson Plan for Emergence of a Dragonfly
Sequence
number and time
Type of shot
(ECU, CU, FS)
3:40 to 3:49
Text or scene description and action
young adult with two pairs of legs
attached to the head region of the
larval shell. The third pair are on
the substrate. The abdomen
appears to get pulled out of the
larval shell in pulses as the adult
pushes its body forward against
the resistance of its legs.
Page 8
Questions about the biology of
dragonflies that come to mind as I
watched the film
raise millions of dragonflies as
mosquito control devices?
It seems like the dragonfly is
using a significant amount of
effort. It must still be a fairly tight
squeeze.
#20
3:49 to 3:55
FS
Side view of the adult as the last
part of the abdomen is pulled free
and extended downwards.
#21
3:55 to 4:08
CU to ECU
A head and thorax side view
switches to a dorsal or top view of
the lower thorax , showing the
wing buds.
#22
4:08 to 4:29
CU
A sideview close-up of the lower
thorax, wing buds, top of the
abdomen is intercut with a CU of
the head. The main action is the
time lapse growth of the wings
with the abdomen appearing to
‘pulse.’ Count the number of
segments in the abdomen.
If this whole process takes an
hour or two, how do the wings
expand so rapidly? Are the wing
cells growing rapidly? Are they
being inflated with blood or air?
How could you test these
hypotheses? Do dragonflies
sting their prey?
#23
4:29 to 4:44
ECU to CU
Extreme close-up of the lower
thorax at the point of wing bud
attachment switches to a CU from
the side with abdomen extending.
Is there any relationship
between dragonfly length and
weight or between either of
these and final wing length?
#24
4:44 to 5:01
FS to CU to
ECU
Sideview of the entire body with
abdomen and wings appearing to
‘pulse.’ In the ECU of the wings,
veins in the wing are readily seen.
Parts of the wings don’t look
expanded and resemble crinkled
cellophane.
Is this a male or a female?
Could we tell if this is a female
or a male at this point? What
physical traits are used to
identify dragonfly species? How
do the wings complete their
development?
#25
5:01 to 5:08
FS
Sideview of the entire body
How long does it take for the
dragonfly to be able to fly? What
speed do they fly at compared
to honey bees or birds? Do
dragonflies with longer wings fly
faster? What factors determine
how fast an insect flies?
#26
5:08 to 5:26
FS
Dragonfly on a bulrush. Wings
which were together on its back
are now extending horizontally.
Wings obviously beating
independently.
Do maturing dragonflies change
colour? How accurate are their
various senses and which are
most important?
© 2005 National Film Board of Canada