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Asia-Pacific Forum on Science Learning and Teaching, Volume 16, Issue 1, Article 7 (Jun., 2015) |
In the new biology textbook that was examined in line with the purpose of this research many metaphors, anthropomorphic terms or expressions, and biomimetics to be interpreted as analogies were encountered. The following language was taken into account while deciding whether a comparison in the textbook was an analogy:
(1) Metaphors were not evaluated as analogies. Examples included: “Water is life” (p. 41); “Glucose is decomposed into smaller building stones by means of a serial enzyme” (p. 65); and “Forests are the lungs of our world” (p. 195).
(2) Anthropomorphic terms or expressions were not evaluated as analogies. Examples included: “…cells in our body are not capable of leaving the environment that they do not like” (p. 44); “…Archaebacteria are grouped as hot lovers, salt lovers and metal producers… the best temperature is 65–85 centigrade degrees for the archaebacteria which like hot environments” (p. 131); “Ants are examples of social groups. There are individuals with special duties such as “worker” and “soldier” ants within these groups” (p. 158); and “Organisms which are environment workers …” (p. 164).
(3) Biomimetics were not evaluated as analogies. For example: “The outer appearance or internal structure of living things contribute to the economy as models in the production of many materials. Likewise, dragonflies were used in the construction of helicopters, polar bears were used in the construction of heat keeper clothes, spider webs were used in the construction of durable biological materials, and bats were used in the construction of radars” (p. 239).
(4) In some comparisons, analogue and target concepts were within the same domain of biology. Such comparisons were not evaluated as analogies. Examples included: “…vertebrates are another group that harmonize well with extraordinary living conditions like insects…” (p. 158); “…some of protists produce their own food like plants …” (p. 136); and “…latest molecular works show that mushrooms resemble animals rather than plants” (p. 140).
As it can be seen from the above examples, the origin of analogies and anthropomorphic expressions is metaphors. However, all metaphors are not analogies. Analogies and metaphors are close teaching tools in terms of meaning. For both analogies and metaphors describe interesting similes and comparisons. The difference between them is hidden in the process of comparison. In analogies, similar attributes of analogue and target concepts are brought to the forefront and an explicit comparison is made. In contrast, in metaphors interesting but nonconcurrent attributes of analogue and target fields are brought to the forefront and an implicit comparison is made. In fact, metaphors clearly have imitating or exaggerating expressions and they are mostly used in literary texts (Duit, 1991).
Based on the similarity condition of the target concept with the analogue, mainly two types of analogies are mentioned. They are same domain analogies and different domain analogies. As it can be seen in the above examples, analogue or target concepts in the same domain analogies are found in the same biological domain. Such analogies are not preferred so much because they can lead to misconceptions in students. In different domain analogies, on the other hand, analogue and target are found in different domains. In this research, the comparisons that are made between a biological target concept and an analogue concept from daily life were evaluated as analogies. For example, “a cell can resemble a pasta factory in terms of its structure and functions” (p. 94). Such analogies were based on the comparison between two different domains. The analogue domain was associated with daily life (pasta factory) and the target domain was associated with a biological concept (cell). Different domain analogies were evaluated as a pedagogic teaching tool in many research studies (Curtis and Reigeluth, 1984; Duit, 1991; Orgill and Bodner, 2006; Thiele et al., 1995). Different domain analogies were emphasized to be effective in student understanding of unfamiliar target concepts.
A total of 25 analogies were found in the new biology textbook. Each analogy was examined independently by the researcher and two biology lecturers with an original agreement of 91.5% for the 183 classifications (8 criteria x 25 analogies). The remaining 17 classifications (8.5% of 200) were agreed upon following consensus discussions. Seventeen analogies on average were used in previous biology textbooks and 9.7 analogies on average were used in previous science textbooks in Turkey (Calik and Kaya, 2012; Dikmenli, 2010). Based on these results, it was determined that the use of analogies increased in the new biology textbook when compared to the biology textbooks that were prepared based on the previous curriculum. Curtis and Reigeluth (1984) determined that 8.3 analogies on average in science textbooks, Thiele and Treagust (1994) determined 9.3 analogies on average in secondary school chemistry textbooks, Thiele et al. (1995) determined 43.5 analogies on average in secondary school biology textbooks, Newton (2003) determined 2.6 analogies on average in science textbooks, and Orgill and Bodner (2006) determined 19.75 analogies on average in college biochemistry textbooks. This supports the results that more analogies are used in biology textbooks when compared to science and chemistry textbooks (Calik and Kaya 2012; Thiele et al., 1995).
Analogies were classified in four groups, namely macroscopic, microscopic, sub-microscopic, and symbolic in terms of the level of target concept. Biological concepts that can be directly observed or perceived by means of sense organs were evaluated within the macroscopic level; for example, organism and puzzle analogy (Figure 1).
Figure 1. “Organisms are constituted by many parts which complete each other just like a puzzle…” (p. 38)
Biological concepts that can only be observed or perceived by means of microscopic tools were handled at the microscopic level. For example, “…in the electron microscope, there were hydrophobia viruses in the shape of a bullet inside the blood cells in the nerve tissue of an animal …” (p. 167).
Target concepts that cannot be directly observed like atoms and molecules but explained through models were at the sub-microscopic level. For example, “Enzyme molecules function just like the scissors and sewing machine of a tailor. That is to say, genes are cut by enzymes, and genes cut are tied by enzymes” (p. 67).
The target concepts that can be explained through biological formula or symbols such as genetic code were at the symbolic level. For example, “…if the information inside the DNA of a person was written in size 10 font on single line A4 paper, it would be like a 46 volume encyclopaedia each of which consists of nearly 23,000 pages” (p. 72).
In the new biology textbook, analogies were determined to be used for the target concepts mostly at the microscopic (28%) level and sub-microscopic level (28%), and then the macroscopic (24%) and symbolic (20%) level (Table 1). The microscopic and sub-microscopic nature of the target concepts such as viruses, bacteria, molecular structure of the cell membrane, enzyme molecule, DNA molecule, DNA fingerprint, and genetic information presented the role of the use of analogy in biology textbooks because these concepts can be either observed by means of microscopic tools or represented by means of instructional tools such as model and analogy, etc. In this regard, it was seen that most of the analogies in the biology textbook were used for biological concepts that are difficult to understand. Orgill and Bodner (2006) noted that analogies in college biochemistry textbooks were instead used for difficult target concepts such as energy, DNA and ATP. Dikmenli (2010), in contrast, showed that analogies in previous biology textbooks were generally used for biological concepts in relation to the structure and functions of the cell and nucleic acids. From this aspect, the findings of the present research promoted the results of previous studies. Chemistry consists of complicated and abstract matters. Therefore, chemistry teachers usually address concepts in three levels, namely microscopic, sub-microscopic, and symbolic (Johnstone, 1991; Treagust, Chittleborough and Mamiala, 2003). In this research, the microscopic level was added to these three levels by the very nature of biology because most of the biological concepts could only be observed by means of tools such as the light and electron microscope.
In terms of the analogical relationship between analogue and target concepts, it was determined that mostly functional (40%), and then structural-functional (32%) and structural (28%) analogies were found (Table 1). Most of the functional analogies were used for complicated and abstract biological concepts and they were interesting. In one of them, the function of the enzyme molecule was explained by comparing it to the function of scissors and a sewing machine (p. 67). In one of the structural-functional analogies, the cell concept was explained in details by comparing it to a pasta factory in terms of structure and function (p. 94). A structural analogy that was used in the textbook was formed by the following expressions. A “DNA molecule is made of a double nucleotide chain and it resembles tower stairs in terms of structure. The two edges of the stairs are made of phosphate and sugars, and the steps are made of bases” (p. 71). While functional analogies were higher in number in the new biology textbook in terms of the analogical relationship between the analogue and target concepts, structural analogies were higher in number in previous biology textbooks (Dikmenli, 2010). When we suppose that functional or structural-functional analogies are more effective in teaching (Duit, 1991; Thiele and Treagust, 1994), it is desired to use functional analogies mostly in the new biology textbook. In a structural analogy, students should be aware that analogue and target concepts only share structural attributes. Otherwise, students can also transfer function and behaviour attributes from the analogue to the target. In such a case, students can develop misconceptions (Orgill and Bodner, 2006). According to previous research, functional analogies were used mostly in science, chemistry, biology, and biochemistry textbooks (Curtis and Reigeluth, 1984; Thiele and Treagust, 1994; Thiele et al., 1995; Orgill and Bodner, 2006).
In terms of presentation format, it was determined that 19 analogies in the book (76%) were presented in the verbal format while six analogies (24%) were presented in the pictorial-verbal format (Table 1). In one of the analogies that were presented in the pictorial-verbal format, cell concept was explained by comparing it to a pasta factory (p. 94). In this analogy, which is structured in detail, the cell membrane resembled a factory wall, the pores in the cell membrane to security officers, cytoplasm to a factory garden, ribosome to production machinery, Golgi apparatus to the packaging unit of the factory, mitochondria to an energy plant, and core to the management centre of the factory. This analogy in the book was promoted through images of the analogue and target (Figure 2, p. 94).
Figure 2. An example of Pictorial-verbal analogy used in the new biology textbook (p. 94).
In this analogy, written text was promoted through an image of the analogue and thus the cell topic became an interesting and permanent one for the students. In most of the verbal analogies that were used in the textbooks, analogical expressions were promoted through microscopic and sub-microscopic images and diagrams of the target concept. Dikmenli (2010) determined that pictorial-verbal analogies were used much less (42%) in previous biology textbooks. The spread of pictorial-verbal analogies in the new biology textbook was a positive development for students because pictorial-verbal analogies facilitate remembering and increase the permanency of knowledge. It is known that images are remembered more than sentences. Bean, Searles, Singer and Cowen (1990) concluded that an analogy that is presented in pictorial-verbal format was more effective in understanding the structure and functions of the cell when compared to an analogy which is presented in verbal format.
Table 1. Categorization and number of analogies in the ninth grade biology textbook.
Category
Number of Analogies
25
%
Level of Target Concept
Macroscopic
6
24
Microscopic
7
28
Sub-Microscopic
7
28
Symbolic
5
20
Analogical Relationship
Structural
7
28
Functional
10
40
Structural-Functional
8
32
Presentation Format
Verbal
19
76
Pictorial-Verbal
6
24
The level of abstraction
Concrete-Concrete
4
16
Abstract-Abstract
2
8
Concrete-Abstract
19
76
Position
Advance Organizer
6
24
Embedded Activator
17
68
Post-Synthesizer
2
8
Level of Enrichment
Simple
13
52
Enriched
7
28
Extended
5
20
Pre-topic Orientation
Analogue Explanation
3
12
Strategy Identification
1
4
Both
4
16
None
17
68
Limitations
Existing
4
16
None
21
84
In terms of the level of abstraction of the analogue and target concepts, it was found that 16% of the analogies in the biology textbook were concrete-concrete, 8% were abstract-abstract and 76% were concrete-abstract (Table 1). The most significant role of the analogies was to concretize the abstract concepts. Students cannot directly observe abstract concepts in the classroom environment but they can envisage them thanks to instructional tools such as model and analogy. It was determined that mostly concrete-abstract analogies were used in the biology textbook. For example, “Cell resembles a small chemistry factory…thousands of reactions occur per second in this factory…” (p. 63). In this analogy, the biological events that occur in a cell were explained by comparing them to the events that occur in a small chemistry factory. Previous research also presented similar results (Dikmenli, 2010; Orgill and Bodner, 2006; Thiele et al., 1995). Unlike these research studies, Newton (2003) claimed that concrete-concrete type analogies were used more frequently in elementary school science textbooks that were prepared for students in the age group of 7–11. In elementary education, the students in younger classes are at the phase of concrete processes based on their cognitive development phases. These students could not understand abstract concepts and their relations well. These students cannot perceive abstract relations in analogies, either. Therefore, the analogies, which are established in these classrooms, had to be at a superficial and concrete level.
In terms of the position of the analogue relevant to the target, mostly embedded activator (68%), and then advance organizer (24%) and post-synthesiser (8%) type analogies were used in the new biology textbook (Table 1). Previous studies also presented similar results (Dikmenli, 2010; Curtis and Reigeluth, 1984; Orgill and Bodner, 2006; Thiele and Treagust, 1994). Specifically, Newton (2003) determined that all analogies in science textbooks that were prepared for students at the age group of 7–11 were embedded activator. The analogies in the embedded activator type were more convenient for students in the younger age group because advance organizer or post-synthesiser type analogies required experience and preliminary knowledge for students.
In terms of the level of enrichment of analogy, mostly simple (52%), and then enriched (28%) and extended (20%) analogies were used in the biology textbook (Table 1). Simple analogies were commonly used in both current and previous biology textbooks (Dikmenli, 2010). However, research studies noted some disadvantages of simple analogies. In simple analogies, the students had to establish the relationship between the analogue and target domain themselves. Therefore, frequent use of simple analogies could lead students to develop misconceptions (Thiele et al., 1995). Glynn and Takahaski (1998) claim that analogies should be enriched or extended as suitable for the purpose. Elaborate analogies facilitated students learning the target concept and increased their interest in the topic (Paris and Glynn, 2004).
In terms of pre-topic orientation, 12% of the analogies used in the biology textbook only involved analogue explanation, 4% only involved strategy identification, while 16% involved both analogue explanation and strategy identification. Sixty-eight per cent of the analogies involved neither analogue explanation nor strategy identification (Table 1). Approximately similar results were seen in elementary and middle school science, chemistry, and biology textbooks (Curtis and Reigeluth, 1984; Dikmenli, 2010; Thiele and Treagust, 1994). In order to establish a correct analogical transfer between the analogue and target field, the basic attributes of the analogue that is used in the analogy should be explained. Curtis ve Reigeluth (1984) claims that analogue explanation is highly significant when the analogue is unknown, complicated or unfamiliar for the learner. Analogue explanation aims to guarantee that the students focus on suitable qualifications in the analogical transfer (Thiele and Treagust, 1994). Furthermore, students should be aware of the fact that the comparison made between the analogue and target field is an analogy (strategy identification). Otherwise, the reader can transfer unwanted relationships and this can lead to misconceptions. Although there are similar aspects between the analogue and target fields in an analogy, students should be shown that these similarities never completely overlap with each other. In case of failure to do this, the analogue concept could sometimes replace the target concept.
In terms of the limitations of analogy, limitations were emphasized in 16% of the analogies that were used in the biology textbook, and the limitations of analogies were not pointed out in 84% of them (Table 1). An example that marked the limitations of analogy was as follows: “Cell resembles a small chemistry factory…thousands of reactions occur per second in this factory…. It should be known that a cell is not a place where thousands of enzymes work randomly. The reactions in the cell occur in order. And, the intracellular environment is a different laboratory where different events occur…” (p. 63). Approximately similar rates were also seen in chemistry and biology textbooks (Dikmenli, 2010; Thiele and Treagust, 1994). In order to prevent misconceptions that can originate from analogies (Brown and Clement, 1989; Clement, 1993; Coll and Treagust, 2001; Kao, 2007), it was necessary to mention the breaking points, which might lead to misconceptions in the analogies used in the textbooks or the attributes that are not shared between the analogue and target.
