A systemic functional analysis of multisemiotic biology texts 5

CHAPTER FIVE MULTIMODAL CONSTRUCTION OF BIOLOGICAL KNOWLEDGE In this chapter I present the results of the analysis of the visual selections and how the visual text relates to and interacts with the linguistic text. By visual text I refer to the semiotic resources deployed in the print media biology textbook that depend on the transmission and reflection of light on a treated surface (rather than the transmission of sound in the air) to make meaning, including the typographical features of the writing system of the English language. However, the focus of this chapter is on the visual displays such as schematic drawings, tables, statistical graphs and micrographs. This chapter takes as points of departure the discussion of the frameworks for the analysis of the visual display and seeks to illustrate how meanings are made in the texts using a variety of resources. Thus it complements in a significant measure what is presented in Chapter Four, which is the analysis of meanings made through the linguistic semiotic code. It will be seen that biologists not rely on language alone to make meaning and that visual displays are an important resource for meaning-making. In what follows I discuss the page layout and colour schemes of the texts (Section 5.1), present the frequencies of the categories of visual displays that occur in the texts (Section 5.2) and then analyze one visual display of each main category (Section 5.3). I conclude this chapter with a brief summary (Section 5.4). 190 5.1 Page Layout and Colour Schemes in the Texts Before conducting detailed analysis of selected visual displays in the texts we need to consider three issues that affect not only any one visual display but also almost all meaning-making in the texts, issues that enable and constrain meaning-making in the first place. First, how big is the page and how is it designed in a way that provides a textual space where meanings are made? Second, how is colour deployed to make meaning? And thirdly how is the reader expected to move his or her attention from one semiotic mode to another in a multisemiotic text, and within one semiotic from one part to another? Since the last issue, i.e. the reading path, has been dealt with in Section 3.2.3 above, I discuss the first two questions below. First, a page is a textual as well as a physical unit. At first glance, a page is a physical object on the surface of which words and pictures are printed: we can touch it, turn it and tear it from the book. Physically speaking, then, the pages of all three texts adopt a size close to the standard A-4 size paper, measuring about 10.8 × 8.3 inches. The selection of such a size can be seen as a response to the increasing number of visual images in the texts, as well as to the size of the school bag, the desk and the hand of a university student in his or her late teens. A bigger book makes it easy to arrange the images and the words and a pocket size edition of these biology texts would be hard to imagine. The page size is among the first factors affecting the page design. At the same time, a page is also a small-scale multimodal meaning-making unit (Baldry 2000b: 41-42): it has internal design, page layout, that organizes its various textual elements. Kress and van Leeuwen (1996: 183) approached this issue in terms of the systems of INFORMATION VALUE, SALIENCE and FRAMING (see Section 3.1.2.2 above). What is equally fundamental is the column grid of the page. 191 In Texts and 2, a normal page with the exception of end-of-chapter “Essential Concepts” pages and “Questions” pages, which are in double column, and “Key Terms”, which are listed in four-column tables in Text 1, and end-of-chapter “Summary”, “Exercises” and text boxes, which are in double column, and “Key words”, which are listed in three columns in Text 2, is split into main text (the body) and text margin (see Figures 1.1 and 1.2 above for sample pages). Physically speaking, the width of the margin is around half of the body of the text, that is, twothirds of the left-right page is devoted to the body of the text and one-third to the margin (see Figure 5.1). There is a gutter of approximately cm to set apart the body and the margin. body Figure 5.1 Demarcation of the page in Texts and The demarcation of main text and text margin is intended to serve a purpose in the texts. The major running text appears only in the body of the page, while the caption text, visual display and in-chapter questions (in Text 1) are printed in the text margin. That is, the text margin provides a place where questions are asked about what has been talked about in the body of the text or explanatory texts (caption) are provided for the visual display in the body of the text. From this we see that the page has one part that is the chief information provider and another part that serves a subordinate role: as a question, explanation or facilitator of the main text1. The page layout of Text is different. Except for the large visual displays such as Figure 23.30 that extend from the left to the right of the page, the page contains two 192 equal columns, with a gutter of about 1cm to separate the two portions (see Figure 1.3 for a sample page). Another aspect of the page as a textual unit is that the main text and the figures they refer to are laid out with a page or a two-page spread as a unit. As S. Gibbs, the managing editor of ECB (personal communication, February 8, 2001), notes, In “laying out” book pages we always try to ensure that figures are in close proximity to where they are discussed in the text. This means that the reader is not distracted by having to turn pages in order to find the relevant figure. The second issue that affects meaning making in the texts is concerned with the use of colour, or the colour scheme, i.e. the principled selection of a number of colours out of “systems of colour” (Kress and van Leeuwen 2002: 366). Human vision, and therefore visual semiosis, depends on, or is realized through colour. Without light or colour we not see anything. The essential issue is the colour scheme of the textbook, black and white or full colour. Texts and are full colour while Text is largely black and white. In Table 3.2 “Functions and systems in schematic drawing” above, I identify “colour” as a semiotic resource operating across all three metafunctions. First, in a schematic drawing, colour can be used to represent the original colour of the natural world, for example, the green to represent the colour of the leaves. Thus colour may function as an experiential resource. In this respect, the colour in the drawing shows directly this aspect of the original object to a very high fidelity with or without the aid of natural language. Colour can also be used to represent abstract entities, such as the blue of the uniform to signal that the wearer is a policeman or policewoman. Second, where the colour in the drawing is added, extraneous of the original object, the colour may serve to engage the viewer. Thibault (2001: 317) notes that “[full] colour is 193 usually the unmarked choice in modern science textbooks for school pupils” and that “the reasons are mainly interpersonal” (2001: 317). The textbook authors / publishers engage and interact with the student readers by inviting them to experience the colourful (though not necessarily faithful) materiality of the subject matter. Reading textbooks thus becomes a sensory, physiological experience, as well as an intellectual one. Thirdly, colour in the drawings may also serve to link the visual elements, “to provide cohesion and coherence” (Kress and van Leeuwen 2001: 58). In Texts and 2, for instance, green, coupled with larger font size and initial capitals, is used to signal the headings and in Text boxed essays are shaded with light green. Citing the example of the use of colour in maps, Tufte (1990: 81; original emphasis) summarizes “the fundamental uses of color in information design” as follows: “to label (color as noun), to measure (color as quantity), to represent or imitate reality (color as representation), and to enliven or decorate (color as beauty)”. Kress and van Leeuwen (2002: 350) further argue that because colour has been culturally shaped to construct all three metafunctions, it may be considered as “a semiotic mode in its own right, along with language, image, music, etc”. 5.2 Categories of Visual Displays in the Texts The types of visual displays that are selected in the texts and the frequency of each type are summarized in Table 5.1. As seen here, the three texts show considerable variation in the types and frequencies of visual display. For instance, structural formulas of molecules2 and equations of reactions occur in Text only. A structural formula describes how the various atoms in a molecule are bonded together and an 194 Text Text Text Types Number % Number % Number % Schematic drawing 18 54.6 -- 48 61.5 Photograph 13 39.4 -- 24 30.8 Table 3.0 -- 7.7 Statistical graph 3.0 -- Equation 15 -- Structural formula of molecule many -- Total 33 100 -- -- 78 100 Table 5.1 Types of visual display equation describes what reactants participate in the reaction under certain circumstances and what products result. They are thus well suited for the biochemistry text. In Texts and 3, on the other hand, schematic drawings are most frequent, followed by micrographs, i.e. photographs taken through a microscope. The three texts also differ in the extent of integration between the linguistic text and images. Whereas in Texts and the visual images are separated from the linguistic texts but are referred to in the latter, for example by “(see Figure 17-6)” (in Text 1), in Text the structural formulas and equations are very often integrated with the linguistic text so that no separate title or caption is felt necessary for the formulas 195 and equations: they have in these cases become part of the running text. In Text 2, only when the formulas and equations become extremely complex they occupy a separate section on the page (e.g. Figure 10.1 of Text 2). In addition, the schematic drawings and the micrographs in Texts and occur in two forms, either alone or in “split-screen” format, that is, one or more micrographs are juxtaposed with their simplified schematic drawings, side by side within one figure or occasionally in two adjacent figures. But as will be seen in the analysis of Figure 17-10 in Text below, the micrograph and its schematic drawing counterpart in a splitscreen format are not equivalent. Whereas the former is believed to be a trace of nature, the latter is a pedagogic reconstruction of the trace. Overall, it seems that the schematic drawings are intended to contribute more to the construction of biological knowledge in the textbooks than the micrographs, which serve merely as the “guarantee” of the reality (Bastide 1990: 213) and “a guarantee of objectivity” (Barthes 1977: 44). These guarantees form one of the bases for the claims made in the linguistic and visual (i.e. schematic drawing) text. It also seems to follow that the drawings need to be studied carefully while a glance is sufficient for the micrographs. On the other hand, the distributional features of the visual displays described above, like those of the verbal text that they accompany, are realizations of particular contextual configurations; the distribution and the types of visual displays may well differ if other texts are analyzed. 5.3 Textual Analysis of Some Figures In this section3 I analyze a schematic drawing (Section 5.3.1), a micrograph (Section 5.3.2), a split-screen format of a drawing and a micrograph (Section 5.3.3), a statistical 196 graph (Section 5.3.4), a scientific table (Section 5.3.5), and the structural formula of a molecule (Section 5.3.6). The analyses are presented in decreasing detail so that only the prominent and new features are discussed in the latter analyses. 5.3.1 A Schematic Drawing: Figure 17-3 of Text Figure 17-3 (ECB: 549), together with the relevant verbal text, is reproduced in Figure 5.2. The reader is formally introduced to Figure 17-3 when he or she reads the following clause: These two processes together constitute the M phase of the cell cycle (Figure 17-3). However, he or she may not wait until being instructed to view Figure 17-3. Since Figure 17-3 is a full-colour drawing, a picture more attractive than the largely black and white verbal text, a reader’s attention is more likely to be drawn to the drawing than to the written description. Thus one plausible reading session may be that a reader, at some point in his or her reading, turns his or her attention to the figure, and then back to the verbal text for careful study and then back to the figure again, following a back-and-forth type of reading path, as explained above. The reading path within Figure 17-3 is marked in Figure 5.2 by the blue italicised Roman letters A to G. As is clear from Figure 5.2, the reading path is not linear, from left to right, from top to bottom, but is determined Ideationally by what is in focus in the running text (the M phase of the cell cycle), and Interpersonally by the visual means of directing the reader’s attention (for example, the bright yellow 197 Figure 5.2 Reading path for Figure 17-3 198 Shading and Capitalization of MITOSIS and CYTOKINESIS and light green Shading of M phase and the large square bracket embracing MITOSIS and CYTOKINESIS). This is, in verbal and common parlance, equivalent to saying “Hey, look at what is highlighted first!” Indeed, in this part of the reading, Steps C and D are all an experienced reader needs to attend to. The highlighting devices such as arrows are equivalent to a lecturer’s cursor in an actual classroom, where he or she, while talking to the students, points to relevant parts of the figures. Although in viewing Figure 17-3 one’s gaze, especially that of a novice, may work from Step G down to Step D due to the Interpersonal impact of the downward-pointing arrows and the reading habit of a normal reader, it is nonetheless arguable that the reading path suggested above is most economical for the experienced reader, that is, one that has followed the textual explication up to this point. At the rank of Work, Interpersonally, this figure thus employs an array of visual means to emphasize various parts of the cell structure and stages of cell division. Ideationally, the figure is designed to tell a story about what happens in a cell cycle, in particular the M phase of the cell cycle. The Ideational meanings include: (a) material processes realized by changes in the shapes at different stages, the arrows and the nominal groups in the linguistic text, (b) intensive identifying processes realized by the labels, leaders and the pictorial elements, and, in the absence of leaders by the labels, the spatial proximity between the pictorial element and the labels, and the pictorial elements, and (c) possessive identifying relational process realized by the labels, the square bracket, the pictorial elements and the linguistic text. The overriding experiential content seems to be concerned with material processes, although the intensive and possessive relational processes contribute significantly to the construction of biological knowledge. And Textually, the drawing is not isolated from 199 description of the physical features the drawing visualizes a classification, a theoretical construct. Lynch (1990) has discussed the transformational practices from micrographs to schematic drawings and notes that although they have something in common (that is, the micrographs are the source material and the drawings derive from them), they may be about different things. A photograph provides “the unique, situationally specific, perspectival, instantaneous, and particular aspects of the thing under examination while the diagram brings into relief the essential, synthetic, constant, veridical and universally present aspects of the thing ‘itself’” (1990: 163). Having made the first departure from the photochemical “fidelity”, the drawing (in particular Lynch’s “models”) may travel further in adding “theoretical information which cannot be found in any single micrographic representation” (1990: 168). This is apparently what happens in the drawing-micrograph pair in Figure 17-10. The micrograph comes first while the drawing derives from it. It is true that the drawing shows what are also visible and recognizable in the micrograph, for instance the mitotic spindle and the chromosomes, but it shows more cell components and does so more clearly than the micrograph. Furthermore, the drawing attempts a theoretical categorization, which is not possible in the blurred micrograph. 5.3.4 A Statistical Graph: Figure Q17-1 of Text Figure Q 17-1 (ECB: 550) is a statistical graph which appears in Question 17-1. Here the students are expected to solve the problem by reference to information from the main text and the verbal section of the question and the graph. The Question including 223 the graph is reproduced in Figure 5.5. The discussion below briefly deals with the reading path, the Ideational meaning of the graph and how the graph contributes to the problem-solving required to answer the question5. Question 17-1 Cells from a growing population were stained with a dye that becomes fluorescent when it binds to DNA, so that the amount of fluorescence is directly proportional to the amount of DNA in each cell. To measure the amount of DNA in each cell, the cells were then passed through a fluorescence-activated cell sorter (FACS), an instrument that registers the level of fluorescence in individual cells. The number of cells with a given DNA content were plotted on a graph, as shown in Figure Q17-1. Indicate on the graph where you would expect to find cells that are in the following stages: G1, S, G2, and mitosis. Which is the longest phase of the cell cycle in this population of cells? Figure Q17-1 Figure 5.5 Reproduction of Figure Q17-1 224 The expected reading path for this multimodal composite involves a shuttling between the verbal and the visual codes: from the main text to the Question (including the graph), then to the “problem” part of the Question and relevant main text, and finally to the graph again. Within the graph, after locating the orientations of the graph and identifying what the horizontal x-axis and the vertical y-axis refer to, the reader would survey the green-shaded curve which is supposed to carry the New. At this stage the reader may have to mark the graph to solve the problem. Ideationally, at the rank of Graph, the graph shows visually the Result (or part of the Result) of an experiment, the frequency distribution of cells with different DNA contents in a population of growing cells. The x values refer to the DNA content per cell, as the label indicates, and the y values the number of cells with a given DNA content. In other words, cells in the population are divided into various types according to the amount of DNA the cell contains: the type of cells on the right of the x-axis contains more DNA than a type on the left. The value in the y-axis records the number or frequency of occurrence of each type of cells in the population. A higher point on the graph means that the number of cells of a particular type is greater. Thus Ideationally the graph is a visual equivalent to a group of linguistic relational processes through its Curvature. In addition, this graph shows the “conceptual relations, and not actual data” (Lemke 1998a: 102). For instance, we are not told how many cells there are in the population, the exact number of cells with different DNA contents, nor how much DNA each cell contains, as there is no indication of the unit of measurement on either x- or y- axis. We are provided with the theoretical relation between the two variables: the type of cell defined by its DNA content and its frequency of occurrence in the population. 225 It is worth noting that this Ideational meaning resides uniquely in a graph and that it cannot be expressed as effectively by a verbal text or a mathematical equation. For Figure Q17-1 visually expresses the general abstract pattern, or spatializes the quantitative relationship. It is a document with visual impact, one that enables the viewer or reader to “take in” the pattern at a glance. However well a verbal clause or clause complex or a mathematical equation may express the trend or relationship, a graph always does so with a strong visual impact. I would also like to note that just as the move from concrete data recording to the abstract relationship between the values of two variables may involve grammatical metaphor, the visualization of the abstract relationships may involve semiotic metaphor as formulated by O’Halloran (1999a; 2003). By semiotic metaphor, O’Halloran (2003: 357) refers to the phenomenon in which “when a functional element is reconstrued using another semiotic code” there may occur “a shift in the function and the grammatical class of [the] element, or the introduction of new functional elements”. The formulation of semiotic metaphors involved in the movements between natural language, mathematical symbolism and visual display is crucial for the ultimate solution to mathematical problems, as demonstrated by O’Halloran (1999a; 1999b; 2003). Here I analyse the movements between the verbal text and the visual text in Figure Q 17-1, which involves instances of semiotic metaphor. “The number of cells with a given DNA content” in the verbal section of Question 17-1 functions as one participant, the Goal, with “The number of cells” as the Head and “with a given DNA content” as the embedded Postmodifier (Halliday 1994: 191-192). Experientially the “cells” functions as the Thing and “with a given DNA content” the Qualifier. But the elements “The number of cells” and “with a given DNA content” not mean only 226 within language; they are also to mean intersemiotically, that is, in relation to the visual text. In other words, the Head and Postmodifier composite in the linguistic text is transformed into two separate participants in the visual text, the two variables represented by the x-axis and the y-axis perpendicular to each other. This shift from one linguistic participant to two visual participants of equal status may be considered an example of “parallel semiotic metaphor” (O’Halloran 1999a: 348) in that the two participants in the second semiotic derive from the Goal in the first. This movement from the linguistic to the visual code permits, however, the exploitation of the meaning potential of the visual semiotic. Once this shift has taken place, it is possible to represent the relationship between the number of cells and the amount of DNA content per cell in terms of the height of the points or lines in the coordinate system and to make visual comparisons and even hypothesize some mathematical relationship between the two variables6. The precise shape of the curve in the visual text did not exist in the linguistic text and thus may be considered as a case of “divergent semiotic metaphor” (O’Halloran 1999a: 348) because a new participant is introduced with the movement from the language to the visual image. In this case the divergent semiotic metaphor (the curve) occurs as a consequence of the parallel semiotic metaphor (the introduction of two participants). As will be clear shortly, the solution of the problem depends to a large extent on how much sense the student can make of the two instances of semiotic metaphor together with the information contained in the main text. In what follows I discuss two questions: (i) how the Question and the graph relate to the main text? and (ii) how the main text and Question (including the graph) contribute to the solution of the problem? 227 (i) The Relationship between the Question, the Graph and the Main Text The relevant main text reads: During S phase (S = synthesis), the cell replicates its nuclear DNA, … S phase is flanked by two phases where the cell continues to grow. The G1 phase (G = gap) is the interval between the completion of M phase and the beginning of S phase (DNA synthesis). The G2 phase is the interval between the end of S phase and the beginning of M phase (Figure 17-4). (ECB: 550) This means that if a cell in G1 phase has 2n units of DNA content, then by the end of S phase (“replicates its nuclear DNA”), it has doubled the amount of nuclear DNA content and in the G2 and M phases, it has 4n units of DNA content. That is, the amount of DNA per cell in G2 and mitosis is twice the amount in G1 and S phase is in the transition from 2n to 4n units. Then how Question 17-1 and the graph relate to such information contained in the main text? The main text reveals the general facts, the “laws” in biology, the conclusion, and / or the theory, which scientists arrive at from numerous experiments (as can be seen in the use of simple present tense in the quotation above). Question 17-1 (including the graph), on the other hand, reports just one experiment, complete with Method and Results of an experimental report (the verb tense in some of the first few clauses in the Question is the simple past, for example, “were stained” and “were then passed”). That is, the main text presents the conclusion and the Question presents one of the experiments leading to such a general conclusion. Question 17-1 is not, however, a real experimental report, but rather it is a textbook question. In a real experimental report, the conclusion is presented in the final part while in the textbook question the conclusion is the point of departure and the student is expected to apply this general rule to solve a practical problem. 228 (ii) The Contribution of the Main Text, Question Text (including the Graph) in Solving the Problem There are two parts to the Question. The first part reads: “Indicate on the graph where you would expect to find cells that are in the following stages: G1, S, G2, and mitosis.” To answer this question, the student must understand the change in the amount of DNA content at different stages of the cell cycle. That is, he or she must understand the relevant part of the main text quoted above. Then in relation to the question he or she must also know how to interpret the x-axis and know that at point b (the point on the x-axis corresponding to Peak B, not shown in the reproduction in Figure 5.5) the amount of DNA per cell is twice that at point a (the point on the x-axis corresponding to Peak A, again not shown in Figure 5.5), and that Peak B is therefore the place where one would expect to find cells in G2 and mitosis phases (chromosomes replicated, doubled) and Peak A the place to find cells in G1 phase (chromosomes not yet replicated). Here the ability to deduce b = 2a on the x-axis is crucial to the solution of the problem. To know where to find the cells that are in the S phase, the student must again understand the relevant main text. He or she must also be able to translate such main text information into the line segment ab on the x-axis and know that cells that are in the S phase can be found between Peaks A and B. The second sub-question reads: “Which is the longest phase of the cell cycle in this population of cells?” To answer this question, the student needs to interpret the divergent semiotic metaphor, that is, he or she needs to know how to interpret the frequency graph. That is, Peak A is the highest, indicating that the number of cells with this DNA content, i.e. cells at G1 phase, is the largest. This further suggests that 229 G1 is the longest phase of the cell cycle, assuming that the cells were selected on a random basis. 5.3.5 A Scientific Table: Table 23.2 of Text In Table 5.1 above we see that tables are often deployed in the biology texts, particularly in Text 3. Drawing upon previous work on scientific tables (e.g. Baldry 2000b: 47-49; Lemke 1998a: 96-101; Thibault 2001: 294-300) and upon Table 3.3 “Functions and systems for numerical tables” above, I now briefly analyse Table 23.2 of Text (Taylor et al 1997: 790) in an attempt to illustrate the textual principles at work in a scientific table. The six tables in Text serve two related functions. They firstly provide information about a group of related items, as in Table 23.4 where the base sequences of the triplet code and the amino acids for which they code are arranged in a manner that facilitates a reader’s retrieval of the required piece of information. That is, given the triplet code the reader can easily find the amino acid it codes for and vice versa. In addition to the provision of information, a table may facilitate comparison between a number of items according to some criteria. This function arises from the special spatial arrangement of Given and New so that News appear on a specific portion of the table to make it easier for the reader to compare the items in focus, as explained in Section 3.2.2.2. Table 23.2 belongs to the latter type. Table 23.2 is reproduced in Figure 5.6. 230 Table 23.2 Comparison of mitosis and meiosis I. Mitosis Meiosis Prophase Homologous chromosomes remain separate No formation of chiasmata No crossing over Homologous chromosomes pair up Chiasmata form Crossing over may occur Metaphase Pairs of chromatids line up on the equator of the spindle Pairs of chromosomes line up on the equator Anaphase Centromeres divide Chromatids separate Separating chromatids identical Centromeres not divide Whole chromosomes separate Separating chromosomes and their chromatids may not be identical due to crossing over Telophase Same number of chromosomes present in daughter cells as parent cells Both homologous chromosomes present in daughter cells if diploid Half the number of chromosomes present in daughter cells Only one of each pair of homologous chromosomes present in daughter cells Occurrence May occur in haploid, diploid or polyploid cells Occurs during the formation of somatic (body) cells and some spores. Also occurs during the formation of gametes in plants Only occurs in diploid or polyploidy cells Occurs during formation of gametes or spores Figure 5.6 A scientific table 231 In terms of page layout, Table 23.2 is located at the bottom of the page, quite far from where it is introduced in the main text. Besides, the table occupies the whole of the left-right span of the page, thus breaking the double-column format for a normal page. Having discussed mitosis in Section 23.3 and meiosis in the first two subsections of Section 23.4, the textbook authors included a comparison between the two in the last subsection, 23.4.3 “Comparison of mitosis and meiosis”. This short subsection, which is made up of clauses, does little more than referring the reader to Table 23.2: “Therefore mitosis and meiosis I only are compared in table [sic] 23.2”. That is, the comparison itself is carried out not by the linguistic text in the body of the text, but by a table. It follows that the student reader is assumed or required to be able to know the grammar of the scientific table. At the rank of Table, Table 23.2 is organized horizontally along the types of nuclear division, either mitosis or meiosis and vertically along items to be compared, i.e. the stages of cell division and occurrence. In other words, mitosis and meiosis are compared in terms of what happens in each in prophase, metaphase, anaphase and telophase and in terms of their occurrence. As explained in Section 3.2.2.2, the tabular form creates a grid where GivenNew and experiential roles are mapped onto each other. In cases where the original linguistic text has already had a clear textual structure, the Table assigns HyperThemes and Hyper-News and even Macro-Themes and Macro-News (Martin 1992: 456; Martin and Rose 2003; Section 2.2.3 above), giving rise to a possible succession of “little waves”, “bigger waves” and “tidal waves and beyond” (Martin and Rose 2003). Following Thibault (2001: 299), Table 23.2 can be seen to display such a wave-like multi-layered patterning. Reading from top to bottom, the column heads 232 “Mitosis” and “Meiosis” (in italics in the original) function as the Hyper-Themes for the items listed beneath them, which serve as Hyper-News. The former are the point of departure of this multimodal composite while the latter develop the Hyper-Themes or provide detailed information about them, and hence are the major Point of the composite. This, in Martin and Rose’s (2003) terms, can be considered “bigger waves”. “Little waves” form within each of the clauses in the Cells of the table, for example, “Homologous chromosomes # remain separate”, which has its own ThemeRheme and Given-New structures. Taking into consideration the stubs, i.e. the items to compare in the table and reading from left to right, we find that the stubs also function as Hyper-Themes for the pairs of clauses on the right in the Cells. For example, the stub “Prophase” acts as the Hyper-Theme for the two groups of clauses listed under “Mitosis” and “Meiosis”. Putting the vertical and horizontal perspectives together gives us the key to the textual organization of the table. The comparison between mitosis and meiosis for each item is realized horizontally, i.e. by the News of each horizontal pair of clauses; for instance, for the item “Prophase”, the New to contrast the New “remain separate” in the clause just quoted is “pair up” in “Homologous chromosomes # pair up” to its right. The presentation of these comparisons proceeds vertically. This bidirectional working of the Theme and New structures in a table can be illustrated in Figure 5.7. 233 Hyper-Theme Hyper-Theme Hyper-New Hyper-New Hyper-Theme Hyper-New {Theme-New Theme-New} Hyper-Theme Hyper-New {Theme-New Theme-New} Hyper-Theme … Hyper-New {Theme-New … Theme-New} Figure 5.7 The bi-directional wave in a table 5.3.6 A Structural Formula of Molecule: Figure 10.3 in Text Hoffmann (1993: 15) writes of contemporary chemistry that “[t]oday chemistry is the science of molecules and their transformations” and that “instead of substances, chemists think of molecules” (1993: 15). This molecular view of matter has greatly influenced contemporary biology (Section 3.2.1). To study life at the molecular level entails the question of how to construct and represent molecules. It follows that students of biology should learn the concept of bio-molecule and its visual “images”. The challenges this molecular view of life poses for the novice students are great. For instance, cells are small, too small for human vision, but bio-molecules cells are made of are even smaller, the sheer minute size of which poses a conceptual challenge for the new students. In addition, molecules and the atoms herein are threedimensional and dynamic. Biologically significant for the functioning of the molecule, this feature makes it difficult for the new students to know what the molecule looks like and how it is made up of the colliding atoms and electrons. 234 Fortunately chemists and chemistry educators have devised ways to represent the molecules. One of the most accessible ways to represent a molecule is through three-dimensional molecular models that students can manipulate either manually or through computer technology. Indeed, a lecturer in biochemistry will often show the class what a molecule, together with its constituent atoms, looks like through the commercial plastic molecular models. Printed textbooks, professional journals and lecturers in class, on the other hand, mostly prefer to have simplified two-dimensional structural formulas to represent the three-dimensional models, because the former can be sketched much more quickly than the latter. Between the “sketches” and the real models, there is considerable transformation and difference. A consensus has therefore had to form as to how to interpret and construct the two-dimensional geometrical representations. This set of conventions is what every chemistry major and biochemistry major needs to master. For a novice reader, Figure 10.3 of Text on page 307, which is reproduced in Figure 5.8, does not make much sense. But for a chemist, it describes the reaction where the open-chain D-glucose structure is converted into the cyclic hemiacetal structure. Three points are crucial to an understanding of the figure. First, how we interpret the open-chain structure (on the top left corner)? This is called the Fisherprojection (Blei and Odian 2000: 275); chemists have agreed to interpret the horizontal bonds as extending in front of the plane of the paper and the vertical bonds as extending behind the plane of the paper (2000: 275). Thus two-dimensional a “cross” as it is drawn, it is seen by chemists to represent a three-dimensional structure. Second, how we read the ring (either of the two structures on the bottom right corner)? The ring adopts the conventions of Haworth projections (2000: 308), 235 Figure 10.3 Hemiacetal formation in D-glucose. The oxygen of the OH at C5 of the acyclic structure becomes the oxygen in the hemiacetal ring, whereas the carbonyl oxygen becomes the OH at C1. Figure 5.8 A structural formula of molecule 236 whereby “the ring is perpendicular to the plane of the paper, and the groups attached to the carbons of the ring are parallel to the plane of the paper” (2000: 308). It apparently is a hexagon in geometry, but chemists and biochemical workers / researchers have used it to stand for three-dimensional molecules. Finally, how we interpret the colours used here? Colours superimposed on the atoms are used to distinguish those atoms that take part in the reaction. For instance, the blue OH in the open-chain structure is split into one blue O and one blue H, that is, the bond between the OH is broken and each of the atoms joins new partners. Without such colour coding, it might be difficult to tell which O and which H participate in the reaction, for there are so many of these atoms in many organic molecules. 5.4 Multimodal Meaning-making: Some Concluding Remarks This chapter has analysed the multimodal meaning-making in the biology texts. As may be clear from the above discussion, the visual images in the biology texts are not redundant with language in meaning-making; they extend and complement it. The words, on the other hand, specialize in a range of typological meanings and certain Interpersonal and Textual meanings and thus “anchor” and constrain the many possible meanings made in the visual (Barthes 1977: 38-41). One is dependent upon and cocontextualizes the other (Thibault 2000: 312). To understand the text, as in Figure 173 in Text or solve a problem, as in Question 17-1 in Text 1, the reader must be able to integrate the meanings made in the linguistic and the visual codes. My analysis has also shown that each type of visual display carries with it different sets of conventions of meaning-making, not only in the deployment and 237 interpretation of combinations of ink or paint (dots, lines, curves, etc.) but also in their relations to the verbal text. For example, how a scientific table is expected to be read is very different from a structural formula of a molecule, and again different from a micrograph. And in terms of the intersemiotic relation, we may note that a schematic drawing, such as Figure 17-3 analysed above, spatializes the Ideational meanings made in the verbal text, while a statistical graph, such as Figure Q17-1, transforms a set of quantitative data into a visually perceptible object. Although many aspects of the interstratal relationship between the visual signifiers and their signifieds remain to be explored (Thibault 1997: 329-334), my analysis in the chapter has shown that the visual displays in disciplinary discourses as exemplified in the biology texts are important for meaning-making and that what they mean and how they mean it are not always self-evident or universal. It follows that just as we need to teach the students the linguistic resources of meaning making, we need also to teach them the visual resources of meaning making (Lemke 2000: 269), a topic which will be discussed in Chapter 6. 238 [...]... G-2 are made least prominent by means of smaller font Size, no-Shading and noCapitalization The leaders are also made insignificant by means of Length and 207 Weight Ideationally, they identify the major components of a cell, as if saying, for example, “This is the nucleus of the cell” I now conclude the analysis of Figure 17-3 with a discussion of the ideational complementarity of language and visual... three-dimensional metaphase plate, and the stage of development being pictured It also tells the reader the credits of this micrograph “(Courtesy of William Sullivan.)” 5. 3.3 Juxtaposition of a Micrograph and a Drawing: Figure 17-10 of Text 1 Figure 17-10 (ECB: 55 6) consists of two parts: Part (A) a schematic drawing on the top and Part (B) a micrograph at the bottom; this is a “split-screen” format In terms of. .. the page layout, the drawing and the micrograph are on the left in the main text portion, whereas the title and caption are in the text margin on the right At the rank of Work, Interpersonally, this figure employs an array of visual means to emphasize various parts of the mitotic spindle Ideationally, Part (A) of the figure is designed to show 2 15 (rather than simply verbalize) a classification of the... the caption and is placed in a specific position on the page The two parts of the figure are vertically positioned and share an imaginary vertical central line Parts (A) and (B) of the figure are each landscape oriented, designed to be viewed from left to right This vertical and horizontal flow of the visual text contributes to the Textual meaning of the text and facilitates the Ideational meaning,... “problem” part of the Question and relevant main text, and finally to the graph again Within the graph, after locating the orientations of the graph and identifying what the horizontal x-axis and the vertical y-axis refer to, the reader would survey the green-shaded curve which is supposed to carry the New At this stage the reader may have to mark the graph to solve the problem Ideationally, at the rank of. .. amount of DNA the cell contains: the type of cells on the right of the x-axis contains more DNA than a type on the left The value in the y-axis records the number or frequency of occurrence of each type of cells in the population A higher point on the graph means that the number of cells of a particular type is greater Thus Ideationally the graph is a visual equivalent to a group of linguistic relational... free from any Interpersonal meaning As for this title, the nominal group presents the Process of a cell dividing as a Thing, which is objective, absolute, visible and concrete 200 Such a high level of certainty about the state of affairs is attainable through nominal groups or grammatical metaphor in the form of nominalisation (Halliday 199 3a; 1998) In other words, distillation of phenomena into entity... Figure 5. 4 What follows is a selective analysis of the figure in terms of the Interpersonal (Modal) meaning, Ideational (Representational) meaning and Textual (Compositional) meaning Step A The Title for the Figure It is a nominal group, denoting a classification This classification, however, is not explicitly stated in the relevant main text, although two terms in the three-term classification do appear... words, what meets a reader’s eye in a schematic drawing is at least two steps away from what is really there: in terms of choice of colour and diagrammatic transformation Textually, several devices contribute to the organisation of the text For instance, Colour Cohesion and Contrast enable the viewer to recognize similarity and difference in the Ideational meaning and Interpersonal meaning: the colours... The two pairs of lines in the first circle in Step C are positioned diagonally relative to the vertical-horizontal frame of the drawing The red pair resembles the contour of a hill or sea wave, each of which is perceived as the trace of drastic movement or thrust resulting from the physical or geographical forces such as the gravitational pull The axis of the black pair is approximately 30° anticlockwise . such as schematic drawings, tables, statistical graphs and micrographs. This chapter takes as points of departure the discussion of the frameworks for the analysis of the visual display and. 5. 3 Textual Analysis of Some Figures In this section 3 I analyze a schematic drawing (Section 5. 3.1), a micrograph (Section 5. 3.2), a split-screen format of a drawing and a micrograph. level of certainty about the state of affairs is attainable through nominal groups or grammatical metaphor in the form of nominalisation (Halliday 199 3a; 1998). In other words, distillation of