Demonstration—an effective technique
in teaching biology1
M. A. Maun and Teresa Winnitoy2
ABSTRACT
The demonstration is a teaching technique
which provides a synthesis between formal lecture sessions and personalized systems of instruction. It provides a valuable complement to
lectures providing the opportunity for personal
contact between students and professor and
among students themselves. The active participation by the students in the learning process makes
it an effective teaching technique.
Additional index words: Display, Peer interaction.
D
URING the last decade the number of students in
the biology programs in Canadian universities and
colleges has increased. Enrollment of 500 or more students in each of the first and second year core courses is
not uncommon. Due to this increase teachers have been
using, with varying degrees of success, several new innovations and communication devices like television,
computers; audio-tutorials, and group discussions. The
most important change has been a deviation from the
conventional lecture sessions to a personalized or grouporiented, self-help learning system. Dowdeswell (1971)
pointed out that these innovations in teaching style are
based on the realization that a higher priority should be
given to the needs of a student rather than to "the attitudes and notions of the teacher". Both lectures and
personalized system of instruction have merits and
weaknesses.
The basic theme of the personalized system of instruction is that a student is given more responsibility for
learning. Postlethwait et al. (1969) and Postlethwait
(1978) pointed out that a new concept can only be
learned by the learner. A teacher can provide guidance,
facilities, motivation, and an environment conducive to
learning, but cannot make a student learn a concept.
According to Keller (1968) a personalized system of instruction (P.S.I.) entails a course which is divided into
1
Contribution from the Biology Core Program, University of Western2 Ontario, London, Ontario, Canada N6A 5B7.
Associate professor and teaching assistant, respectively.
units, each of which outlines the specific objectives and
fine details of that concept. A student is allowed to proceed through the units at his own speed and can discuss
and clarify any questions with a tutor. Protopapas
(1974) provided evidence of the effectiveness and acceptability of P.S.I, by students. He pointed out, however, that some students may find it hard to pace themselves and may not work well independently, especially
extroverts whose internal motivation is low (Dowdeswell, 1977).
Lectures are valuable in awakening critical attitudes
and in providing the latest advances in research not yet
printed in textbooks (Powell, 1969). Lectures also provide the most efficient use of staff time, with a high rate
of information transfer from professor to students. The
lecturer, however, has been condemned by many educators for the lack of participation and personal contact
with group members.
The course, "Biology of Populations," has 500 students with two lecture sections of 250 students each
(Table 1). It runs for a full academic session (September
to May) and a student receives three course credits.
Table 1. A comparison between the three methods of
teaching; conventional, personalized system of
instruction (P.S.I.), and the demonstration
method used in "Biology of Populations'^
P.S.I.
Conventional
Demonstration
Lectures
Tapes
(multiple sections)
Section A
Section B
Section A
Section B
Labs
Tutorials
Audio-visual Labs
Labs (26 per
academic session;
Sept. to April)
Labs (12 per
academic session)
Demonstrations (12
per academic
session)
Field Trips (two
field trips to examine
local flora and
fauna)
t Calendar Description: Biol. 201. Biology of Populations. (A mandatory
course in year two of B.Sc. in Biology). The distribution, genetics and evolution of populations and their growth, regulation, and interactions with other
populations and their environment (2 lectures, 3 laboratory hours per week).
Pre-requisite: One introductory course in biology. Co-requisite: One course
in mathematics.
MAUN AND WINNITOY: DEMONSTRATION-TEACHING
There are 52, I-hour lecture sessions for each of the A
and B sections (a lecture is repeated) and 26, 3-hour lab
sessions per year. In lecture sections of 250 students
there is a lack of communication between instructors
and students. Exchange of ideas and answering of questions and arguments e:‘ highly inconvenient because of
an indifferent attitude Jf a large majority.
This drawback of the conventional method prompted
us to develop a system which would provide a compromise between the conventional method and P.S.I. In
this system we retained the formal lecture sessions as in
the conventional method but replaced 12 of the laboratory sessions with 12 sessions which we have named
“Demonstration” (Table 1). A “Demonstration” is a
self-teach approach in which the instructor plays a supporting role.
DESCRl PTlON
Each demonstration presents material on a specific
topic being discussed in lecture, e.g. adaptation, competition, world population growth, agricultural
productivity, etc. Each topic is presented through a
series of interrelated displays (about 9 to 14 in each
demonstration) which include specific examples from
books or research articles published in journals. Each
topic receives thorough coverage and brings together the
latest information relevant to the topic. Each objective
is described, illustrated, and evidence is presented in the
form of tables or graphs (Table 2).
TECHNIQUE
81
neath each display case a desk top (30 cm wide) supported by storage cabinets provides space at which a student can study and write notes. The room has space for
about 30 students. Displays are set up at eye level for
either a sitting or standing student (Fig. 1). For a round
table discussion tables are set up in the center of the
demonstration room.
Contents of a Display
Each display consists of a visual presentation through
the use of charts, tables, illustrations, and live or dried
material (Fig. 2). Some organisms such as fish, small
rodents, birds, and plants are ideal for use as live displays to illustrate principles such as organismal diversity, ecological isolation, covergence, competitive exclusion, etc. Students are provided with a written outline
that explains the main points of the display (Box 1). The
data presented are a synthesis of results from one or
more research articles. Often the research article is
simplified to make it more easily understandable for a
student. Scientific jargon is clarified and only salient
points from tables and graphs are presented. The
written explanation of a display consists of one or two
questions which allows a student to think critically.
Some displays in a demonstration may be supplemented
Demonstration Room
The demonstrations are set up in a room designed
specifically for this purpose (Fig. 1). Display cases have
been installed along three walls of the room and a blackboard and screen are located on the fourth wall. BeTable 2. The objectives, and headings of displays in a
demonstration on “Adaptation in 0rganisms”t
Particulars
Description
Objectives
To show a) adaptive value of some external characters of animals
and plants, and b) variation among different individuals of a
species in one area.
Patterns for survival-shows cryptic coloration, warning coloration, Batesian mimicry, Mullerian mimicry, frightening coloration, and confusion syndrome.
Adaptation to physical environment; roadrunner (Geococcyx
californianus).
Cryptic coloration and patterns; peppered moth (Biston
Film
Display I .
Display 2.
Display 3.
Display 4.
Display 5 .
Display 6.
Display 7.
Display 8.
Display 9.
betularia).
Energetics or crypsis? Eastern gray squirrel (Sciurus
carolinensis).
Warning coloration; monarch butterfly (Danausplexippus).
False warning coloration; viceroy butterfly (Limenitis archippus).
Geographic variation of an adaptation; viceroy butterfly and
queen butterfly (Donas gilippus).
Mimicry in plants; Orchids and hymenopteran insects.
Mimicry of vertebrate eyes; peacock butterfly (Inachis io).
Sexual dimorphism and sec recognition; common flicker
(Colaptus auratus).
t This demonstration was written by Dr. D. M. Scott, professor, Dep. of Zoology who gives lectures in “Biology of Populations”.
Fig. 1. A general view of the demonstration room. Display cases are installed along the three walls of the
room. Blackboard and a movie screen are on the
fourth wall (not seen in the picture).
JOURNAL OF AGRONOMIC EDUCATION
82
by computerizedinstruction, slides, and films pertaining to the topic. Simple computer programs such as
humanpopulation growth, diversity, and stability of
populations are available. The course has three computer terminals. The instructor provides information on
howto run a programand students take turns to see, for
example, growth of populations with different intrinsic
growthrates. Slides are illustrated by slide synchs and
narrated with tapes madeby the instructor lecturing in
the course.
ternate weeks. The teacher-student ratio is 1:30 and a
student meets with the instructor once every 2 weeks for
3 hours for the whole academicsession.
If a student feels he knowsthe concept well enough
and could use his time more efficiently elsewhere, he
Table 3. Scheduleof lab anddemonstration
sessions
(16 sectionsof 30 studentseach)during
5.day workweek
Operation
Lab]"
The demonstration room is open from 8:30 to 5:30
p.m. Mondayto Thursday. Students are free to come
any time, but the instructors are present from 8:30 to
11:30 a.m. and 2:30 to 5:30 p.m. each day. The course
includes formal lectures, demonstrations, and labs.
Demonstrationsare alternated weekly with labs (Table
3). Students cometo the demonstration and labs in al-
Morning
Afternoon
8:30-11:30 a.m.
2:30-5:30 p.m.
Demonstration]"
Lab1"
Demonstration].
S-10
S-9
S-2
Monday
S-I
S-4
S- 12
S- 11
Tuesday
S-3
S-14
S-13
S-6
Wednesday
S-5
S- 16
S- 15
S-8
Thursday
S-7
Changeof a lab or demonstration.
Friday
Preparatorymeetingsof instructors for discussion of a lab or
demonstration.
Students attending a lab this weekwill go to the demonstrationsnext weekand
vice-versa.
DISPLAY 1
Ae
B o Energyinputs,outputsandenergy
efficiency(kilocalo~ies)
incorn
productlc~.
INCREASES
IN
PRODUCTIVITY
OF
SELECTED
FARMPRODUCTS
1935--1967
Particulars
t 945
1970
Labor
Machinery
FueJ
Nitrogen
Phosphorus
Potassium
Seeds
for planting
Irrigation
InseCticides
Herbicides
Drying
Electricity
Transportation
12,500
160,000
543,400
56,000
1 O,150
5,000
30,464
42,000
0
0
4,000
32,000
20,000
4,900
420~00
797,000
896,000
44,950
60,000
59,136
76/300
11,000
11,000
120,000
310,000
70,000
Totalinputs
935,514
2,879,986
3,046.400
7,257,600
INPUTS
OUTPUTS
Cornyield
ENERGY
EFFICIENCY
Output/Input
~Kcal)
Adapted
fromPimental
et a/ (1975).
FROM; U.S.D- A YEARBOOK.
1970.
Fig. 2. A displayonfarmproductivityandenergycrisis.
3.26
2.52
MAUN AND WINNITOY: DEMONSTRATION-TEACHING
need not attend the demonstration. In the demonstration room students proceed at their own pace, repeating
a display which illustrates a difficult concept as often as
necessary. If a student’s concentration is poor, he can
take a break, leave, or return the next day. Since it is his
own time, it is to his advantage to use it well.
If a student is unable to answer a question, he usually
discusses it with peers or the instructor. About one-half
hour before the end of a demonstration period (11:OO
a.m. or 5:OO p.m.), the instructor brings the students together and asks questions about any difficulties encountered in the displays and provides answers to questions in the handout. Students are tested on the material
in the demonstrations with written examinations.
T o ensure uniformity of instruction, a preparatory
meeting of all instructors is held. Each display is reviewed and every question is discussed thoroughly.
Strengths of Demonstrations
a. Teacher-Student Contact. A student comes in
direct contact with an instructor and is able to clarify
points missed in lectures (see student response in Table
4). Acquaintance with the students helps the instructor
tailor the course to individual needs, giving additional
instruction to slower students and leading advanced students to further inquiry (Fig. 3).
b. Peer Interaction. Students learn from discussions
with their friends and classmates (Table 4). Generally
two to four students work together. Frequently, a teacher explains a concept to one student, and that student
explains it to others. There are three main benefits: the
instructor is freed of repetitive explanations, allowing
more time for other problems; the student learns the
concept more thoroughly because he is teaching it; and
TECHNIQUE
83
other students learn more quickly because of the peer
relationship (Farley and Moore, 1975).
c. Development of Skills and Background Knowledge. Students obtain practice in the interpretation and
critical evaluation of data, especially the reading of
graphs and tables (Table 4). They become familiar with
biological and statistical terminology. An effort is made
in the demonstration to improve the student’s knowledge of natural history-examples used consist of a
wide variety of native flora and fauna (Table 4).
d. Student Choice. Based on 204 responses, a high
proportion of students (85%) said that the demonstrations were useful (Table 4). In the survey, we asked the
Table 4. The response of students to the effectiveness
of demonstration as a teaching technique
Student response?
Items in questionnaire
Demonstrations were useful
Learned to interpret a table or graph
Peer interaction
Got to know one instructor well
Clarification of points missed in lectures
Positive Negative Knew it already
85
69
78.5
82
76
15
31
11.5
18
24
__
t A total of 204 student responses were obtained.
Box 1. Written description of graphs and tables
presented in Fig. 2
Displuy 1. Farm Productivity and Energy Crises
Increases in productivity of selected farm products from 1935 to 1967
are shown in Fig. 2A.
Q1. What do you conclude from the graphs in Fig. 2A?
Answer. Several fold increase in total production of agricultural commodities.
The increase in total production resulted from an increase in output
per unit area. For instance, from 1945 to 1970 mean corn yields increased
from 34 bushels (1 bushel = 25.4 kg) per acre ( I acre = 0.405 ha) to 81
bushels per acre or 5,079.1 kg per ha (Pimental et al., 1975). This 2.4
fold increase in production per acre was due to 3.1 fold increase in
energy inputs. An itemized description of energy input for corn production and output is presented in Fig. 2B.
Q2. What do you conclude from Fig. 2B?
Answer. a) Labour input decreased more than 60%.
b) The energy used for machinery, fuel, fertilizers, drying,
electricity, and transportation has increased several fold.
c) Insecticides and herbicides were not used in 1945 but since
the last 20 years their use has been increasing rapidly.
The most radical change was observed in energy efficiency. The yield
in corn calories decreased from 3.26 per one fuel kilocalorie input in
1945 to a yield of 2.52 kilocalorie in 1970 (Fig. 2B).
4 3 . Why is there a reduction in energy efficiency from 1945 to 1970?
Answer. The law of diminishing returns.
Q4. How is the current energy crisis related to the production of corn?
Answer. Fossil fuels are directly or indirectly required for the items of
energy input listed in Fig. 28.
Fig. 3. A teacher discussing a concept with a student.
84
JOURNAL OF AGRONOMIC EDUCATION
students to choose one method: demonstrations, labs,
or tutorials. A majority (61 %) of the students wanted to
keep demonstrations, 14% recommended the replacing
demonstrations with labs, and 25% indicated that
demonstrations be changed to tutorials. Other comments in favor of demonstrations were: stimulates
participation, encouragement of personalized instruction, very interesting, visually appealing, large amount
of material covered well, can work at own speed, relevant examples shown, encourages thinking, and facilitates outside reading.
Weaknesses of Demonstrations
A small percentage of students (15%) indicated that
the demonstrations were not a useful technique.
Reasons given were; charts and graphs hard to understand, answers to questions not readily available, boring
material, instructor not enthusiastic, vague data, ambiguous questions, repetition of lecture material, not
enough guidance, and demonstrations covered too
much material.
SUMMARY
"Demonstration" is an effective technique which emphasizes interaction among students and teachers, and
students themselves. Students are induced to think,
reason, and argue their viewpoints. They also gain practical experience in interpretation of graphs and tables.
This technique combines all the tools of communication
emphasized by Postlethwait (1978). We use live or dead
plant and animal specimens. We provide the students
with a written description of the material presented in
graphs, photographs, and tables in a display. Demon-
strations are usually supplemented with films or slide
synchs with tapes pertaining to the topic and, above all,
we hold a round table discussion following each sesssion.
ACKNOWLEDGMENTS
We thank Miss Irene Krajnyk, teaching assistant, and Mrs. Teri
Cseh, technical assistant, for capable assistance.