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Modern Biology. Holt, Rinehart and Winston, 1999

Matter and Energy Transformations: Instructional Analysis

I: Providing a Sense of Purpose

Conveying unit purpose

Rating = Poor
The material meets no indicators.

Indicator 1: Not met
The unit and chapter openings do not provide a problem, question, or representation (or otherwise identified purpose) for the students. Unit openers begin with a two-page collage of five or so photos, a list of the chapters, and a quotation. Chapters begin with a photo, a list of sections within the chapter, and a Focus Concept section. Unit and chapter titles indicate what will be covered in that portion of the material: for example, Unit 1: Biological Principles; Chapter 6: Photosynthesis; Chapter 7: Cellular Respiration; and Chapter 22: Ecosystems and the Biosphere. Lists of section titles and objectives also describe content. For example, section titles listed for Chapter 7: Cellular Respiration include 7-1 Glycolysis and Fermentation and 7-2 Aerobic Respiration (p. 126s). Objectives listed for this chapter include, “Define cellular respiration” and “Describe the major events in glycolysis” (p. 127s). However, these lists offer no statement of purpose. In some cases, the Focus Concept provides a suggestion for how the chapter should be read. For example, the Focus Concept for Chapter 7: Cellular Respiration says, “As you read, note the similarities and differences between the biochemical pathways described in this chapter and those you studied in the chapter on photosynthesis” (p. 126s). However, such advice serves more to inform students of what content they may expect to find in the chapter than to explain why it is important for them to know this content. In one case a Focus Concept did hint at purpose: the Focus Concept for Chapter 2: Chemistry says, “As you read, become aware of how a basic knowledge of chemistry will help you understand and explain biological processes” (p. 30s). However, this advice is not typical of the material and far from a strong declaration that the purpose of the chapter is to help students learn basic chemistry in order to be able to explain biological processes.

Indicator 2: Not met
Since no unit or chapter purposes are provided for the students, no purposes can be considered for comprehensibility.

Indicator 3: Not met
Again, since no unit or chapter purposes are provided for the students, no purposes can be considered for interest and motivation.

Indicator 4: Not met
Since no unit or chapter purposes are provided for the students, students cannot be asked to think about such purposes.

Indicator 5: Not met
Since no unit or chapter purposes are provided for the students, lessons cannot be consistent with them.

Indicator 6: Not met
Since no unit or chapter purposes are provided for the students, the material cannot return to them.

Conveying lesson/activity purpose

Rating = Poor
The material mostly meets indicator 1 but does not meet the other four indicators.

Indicator 1: Mostly met
The material consistently presents a purpose for the chapter readings in lists of objectives that appear at the beginning of each section. For example, the objectives for Section 6-1: Capturing the Energy in Light include “Explain how the structure of the chloroplast relates to its function” and “Describe the role of chlorophylls and other pigments in photosynthesis” (p. 111s).

Lists of objectives also convey the purposes of the investigations that appear at the end of each chapter. For example, the investigation at the end of chapter 22 on Constructing and Comparing Ecosystems has two objectives: “Observe the interaction of organisms in a closed ecosystem” and “Compare this ecosystem with others observed in nature” (p. 438s).

However, purposes for teacher demonstrations are suggested only occasionally. In Chapter 7: Cellular Respiration, for example, no purpose is given for the following activities: Engage Students (p. 127t); Reteaching Activity (p. 128t); Demonstration (p. 130t); Engage Students (p. 133t); Demonstration (p. 134t); Reteaching Activity (p. 135t); and Inclusion Activity (p. 136t). In Teaching Strategy: Observing Fermentation, a purpose is suggested: “Have groups of 3–6 students examine how the rate of fermentation varies with the type of substrate” (p. 129t). However, the teacher is not told to convey the purpose of this activity to students.

Indicator 2: Not met
The activity purposes presented are unlikely to be comprehensible to students because they often include terms with which the students are not yet familiar. For example, the objectives for Section 6-1: Capturing the Energy of Light include the terms “chlorophylls,” “pigments,” “electron transport,” “photosynthesis,” and “light reactions” (p. 111s). Similarly, the objectives for the laboratory investigation on comparison of ecosystems includes the term “closed ecosystem,” which students may not understand (p. 438s).

Indicator 3: Not met
The material does not encourage students to think about the purpose of an activity.

Indicator 4: Not met
The material does not convey or prompt teachers to convey to students how the activity relates to the unit purpose.

Indicator 5: Not met
The material does not engage students in thinking about what they have learned so far and what they need to learn next.

Justifying lesson/activity sequence

Rating = Fair
The material somewhat meets the first indicator but does not meet the second.

Indicator 1: Somewhat met
In the treatment of this topic, the text first presents transformation of matter and energy in summary form at the organism level in Chapter 1: The Science of Life (p. 10s), moves to the cellular/chemical level in Chapter 6: Photosynthesis and Chapter 7: Cellular Respiration, and to the ecosystem level in Chapter 22: Ecosystems and the Biosphere. This sequence is logical in that the text begins at the level with which students are most familiar (the organism level) and then moves to the less familiar levels.

Sometimes the sequence of subsections within a chapter seems logical. For example, Chapter 22: Ecosystems and the Biosphere, Section 22-3: Terrestrial Ecosystems, after a description of the seven major biomes, presents the ecosystems generally in order from the drier biomes to the wetter biomes, although this order is not entirely consistent. This organization may help students remember the biomes and their characteristics.

However, this material also includes less logical sequencing. For example, chapter 22 presents the flow of energy before it presents the cycling of matter. Yet the cycling of matter is more concrete and more familiar to students and easier to grasp than the flow of energy. Also, although chemistry and biochemistry topics are introduced in chapters 2 and 3, this information is not related to ecosystems in chapter 22.

Indicator 2: Not met
The material does not provide a rationale for its sequence of topics, chapters, or lessons.

The pages on Planning your Curriculum (pages 46T–47T) and the Planning Guide pages that precede each chapter (see, for example, pages 109A–109B) list the content to be presented and the order in which it is presented. However, no rationale for the sequence of topics is offered.

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II: Taking Account of Student Ideas

Attending to prerequisite knowledge and skills

Rating = Poor
The material somewhat meets indicator 4 but does not meet the other four indicators.

Indicator 1: Not met
The material does not alert the teacher to specific prerequisite ideas or skills needed for understanding key ideas about matter and energy transformations.

Indicator 2: Not met
The material does not alert teachers to the specific ideas for which the prerequisites are needed.

Indicator 3: Not met
The material does not alert students to the prerequisite ideas or experiences that are being assumed.

Indicator 4: Somewhat met
The material states three out of eight prerequisite ideas and provides some support for one of the three. The prerequisite idea “[As in physical systems] Energy can only change from one form into another” appears in the introduction to Energy: “The amount of energy in the universe remains the same over time, but energy can change in form constantly” (p. 35s). The text states this prerequisite again and gives an example in physical systems:

Energy can occur in various forms, and one form of energy can be converted to another form. In a light bulb’s filament, electrical energy is converted to radiant energy (light) and thermal energy (heat).

p. 35s

Then the text notes the forms of energy involved in biological systems, including free energy, and gives an example of an energy transformation in a living system:

As energy flows through a single organism, it may be converted from one form to another. For example, if you ate breakfast this morning, your body is at work now changing the chemical energy found in food into thermal and mechanical energy, among other things.

p. 35s

The text presents the prerequisite idea that “Carbon and hydrogen are common elements of living matter” in the context of discussing the composition of matter: “In fact, more than 90 percent of the mass of all kinds of living things is composed of combinations of just four elements: oxygen, O, carbon, C, hydrogen, H, and nitrogen, N” (p. 31s).

The text also presents the prerequisite idea that “Food provides the molecules that serve as...building materials for [humans]” (though not for “all organisms”):

All of the different foods in the world contain at least one of six basic ingredients: carbohydrates, proteins, lipids, vitamins, minerals, and water....Four of these nutrients—carbohydrates, proteins, fats, and vitamins—are organic compounds because they contain the elements carbon, hydrogen, and oxygen.

p. 977s

Proteins are the major structural and functional material of body cells. Proteins from food help the body to grow and to repair tissues. Proteins consist of long chains of amino acids. The human body uses about 20 kinds of amino acids to construct the proteins it needs.

p. 978s

However, the following prerequisite ideas are not even mentioned:

No matter how substances within a closed system interact with one another, or how they combine or break apart, the total mass of the system remains the same. The idea of atoms explains the conservation of matter: If the number of atoms stays the same no matter how they are rearranged, then their total mass stays the same.

Arrangements of atoms have chemical energy.

An especially important kind of reaction between substances involves combination of oxygen with something else—as in burning or rusting.

Different amounts of energy are associated with different configurations of atoms and molecules. Some changes of configuration require an input of energy whereas others release energy.

Most of what goes on in the universe...involves some form of energy being transformed into another. Energy in the form of heat is almost always one of the products of an energy transformation.

See map “Matter and Energy Transformations:
What the Reviewers Looked For”

Indicator 5: Not met
The material makes only one connection between prerequisite and key ideas. The material relates the prerequisite idea “[As in physical systems] Energy can only change from one form into another” to the idea that “[humans] get energy [from] their food, releasing some of the energy as heat” (part of Idea c₂).

Energy can occur in various forms, and one form of energy can be converted to another form. In a light bulb’s filament, electrical energy is converted to radiant energy (light) and thermal energy (heat).

p. 35s

As energy flows through a single organism, it may be converted from one form to another. For example, if you ate breakfast this morning, your body is at work now changing the chemical energy found in food into thermal and mechanical energy, among other things.

p. 35s

However, the text does not relate the prerequisite idea that “food provides the molecules that serve as...building materials for [humans]” (though not for “all organisms”) to the synthesis of food molecules by plants (Idea a₁) or the subsequent breakdown or reassembly of those food molecules (Idea b₁), even though key Ideas a₁ and b₁ are treated. And the only connection between the prerequisite idea and the idea that “Other organisms...get energy...by oxidizing [the sugar molecules] (part of Idea c₂) relies on students’ understanding of the term “aerobic respiration”:

Carbohydrates are broken down in aerobic respiration to provide most of the body’s energy. Although proteins and fats also supply energy, the body most easily uses the energy provided by carbohydrates. Carbohydrates contain sugars that are quickly converted into the usable energy ATP, while proteins and fats must go through many chemical processes before the body can obtain energy from them.

p. 977s

The text does not relate the other prerequisite it presents or any other prerequisites to the key ideas.

Alerting teachers to commonly held student ideas

Rating = Poor
The material meets no indicators.

Indicator 1: Not met
Only one instance was found in which the material alerts the teacher to a commonly held idea that has appeared in a scholarly publication. The teacher’s guide says that “Many students think that because plants perform photosynthesis, plant cells do not have mitochondria. It is important for students to understand that plants also carry out cellular respiration, a process that requires mitochondria” (p. 76t). This relates to part of a misconception identified by Driver, Squires, Rushworth, and Wood-Robinson: “Students may think that plants do not respire, or that they respire only in the dark” (1994, p. 34).

However, many other commonly held student ideas, identified in the research literature, are not presented to the teacher in this material. These include the following ideas:

1. Students think that food is whatever nutrients organisms must take in if they are to grow and survive rather than those substances from which organisms derive the energy they need to grow and the material of which they are made (American Association for the Advancement of Science [AAAS], 1993, pp. 120, 342; Driver et al., 1994, p. 27).
2. Students think that food is a requirement for growth rather than a source of matter for growth (AAAS, 1993, p. 343; Driver et al., 1994, p. 60).
3. Students think that plants get their food from the environment (mainly from the soil) rather than manufacture it themselves (AAAS, 1993, p. 342; Driver et al., 1994, p. 30).
4. Students think that plants have multiple sources of food rather than that plants make food from water and carbon dioxide in the air, and that this is their only source of food (AAAS, 1993, p. 342; Driver et al., 1994, pp. 31, 60).
5. Students may think that organisms and materials in the environment are very different types of matter and are not transformable into each other (AAAS, 1993, p. 342).
6. Students may not believe that a plant’s mass may increase mainly due to the incorporation of matter from carbon dioxide (a gas) (Driver et al., 1994, pp. 32, 39).
7. Students tend to regard food that is eaten and used as a source of energy as belonging to a food chain, while the food that is incorporated into the body material of eaters is often seen as something different and is not recognized as the material that is the food at the next level (Driver et al., 1994, p. 35).
8. Students may think that dead organisms “rot away”; they do not realize that the matter from the dead organisms is converted into yet other materials (AAAS, 1993, p. 343).
9. Middle school students seem to know that some kind of cyclical process takes place in ecosystems. Some students see only chains of events and pay little attention to the matter involved in processes such as plant growth or animals eating plants. They think of the processes in terms of creating and destroying matter rather than in terms of transforming matter from one substance to another. Other students recognize one form of recycling through soil minerals but fail to incorporate water, oxygen, and carbon dioxide into matter cycles. Students may see no connection between the oxygen/carbon dioxide cycle and other processes involving the production, consumption, and use of food (AAAS, 1993, p. 343; Driver et al., 1994, p. 65).
10. Students may think that matter and energy are converted back and forth in everyday (non-nuclear) phenomena (Schneps & Sadler, 1988).

While the teacher’s guide includes a feature called Overcoming Misconceptions, this feature typically presents misconceptions not relevant to the key ideas (e.g., “Students often don’t recognize that atoms consist largely of empty space. If the nucleus of an atom were the size of a marble, the first energy level would be about 0.8km (0.5 mi) away” [p. 32t] or “Many people think that plants are green because they use green light in photosynthesis. In fact, plants absorb and use mainly red and blue light for photosynthesis...” [p. 113t]).

Indicator 2: Not met
Even the one commonly held idea that is mentioned is not adequately explained.

Assisting teachers in identifying their students’ ideas

Rating = Poor
The material provides some tasks that meet indicator 1 but not indicator 2 and the tasks are not sufficient. Indicator 3 is only minimally met and indicators 4 and 5 are not met.

Indicator 1: Met
The material provides some questions or tasks that could be used by teachers to identify student ideas, primarily through features called Understanding the Visual and Assessing Prior Knowledge. However, typically the questions and tasks provided only ask students to recall facts or define terms rather than to express in detail their understanding about the key ideas related to matter and energy transformations. For example, Chapter 6: Photosynthesis opens with a photograph of a cornfield. The Understanding the Visual feature tells the teacher to:

Ask students to study the photograph of the field of corn and to provide two reasons why photosynthetic organisms are vital for the survival of nearly all other living things. (Photosynthetic organisms capture the sun’s energy and store it in organic compounds, and they release molecular oxygen, which they and other living things use to harness the energy in those organic compounds.)

p. 110t

Assessing Prior Knowledge at the beginning of chapter 6 includes the direction, “Ask students to define the term carbohydrate and to tell what type of carbohydrate glucose is” (p. 110t).

Chapter 7: Cellular Respiration opens with a photograph of a panda eating bamboo shoots. In Understanding the Visual, the teacher is told to:

Have students examine the photograph. Ask them how animals, such as the one shown here, are either directly or indirectly dependent on plants for energy. (Plants capture energy from the sun and store it in carbohydrates. Animals acquire a portion of this energy by eating either the plants themselves or other animals that have eaten the plants.)

p. 126t

At the beginning of Chapter 22: Ecosystems and the Biosphere, Assessing Prior Knowledge tells the teacher, “Ask students how respiration relates to the carbon cycle. Review with them that the product of respiration is carbon dioxide, which is released in the atmosphere as a gas” (p. 415t).

Indicator 2: Not met
The questions and tasks provided are often unlikely to be comprehensible to students who have not studied the topic and who are not familiar with the scientific vocabulary. For example, the task posed at the opening of chapter 6, “Ask students to study the photograph of the field of corn and to provide two reasons why photosynthetic organisms are vital for the survival of nearly all other living things” (p. 110t), will be comprehensible only to someone who already knows what a photosynthetic organism is. Similarly, the question, “Ask students how respiration relates to the carbon cycle” (p. 414t), presented before the beginning of chapter 22 in which the carbon cycle is presented, will be incomprehensible to someone who has not yet studied the carbon cycle.

One task may be comprehensible to students who have not studied the topic. This is the task related to the photograph of the panda eating bamboo shoots: “Have students examine the photograph. Ask them how animals, such as the one shown here, are either directly or indirectly dependent on plants for energy” (p. 126t). A response to this task does not depend on knowledge of scientific vocabulary. However, one task is not enough to conclude that this indicator is met.

Indicator 3: Minimally met
The feature Assessing Prior Knowledge is identified in teacher material at the beginning of the text as serving the purpose of identifying students’ ideas: “Assessing Prior Knowledge helps you assess how much your students know—and what misconceptions they may have—before you begin teaching” (p. 40T). However, the questions provided for this feature are not likely to be helpful. In contrast, while a few of the questions provided in Understanding the Visual could be used to determine students’ ideas before instruction, this feature is not identified as serving the purpose of helping teachers to identify their students’ ideas. Rather, the teacher section at the beginning of the text states, “Understanding the Visual provides additional information about the opening photograph that can be used to begin discussing the chapter content” (p. 40T).

Indicator 4: Not met
The questions and tasks posed typically do not ask students to make predictions or give explanations of phenomena; instead they focus primarily on identifying students’ understanding of terms.

Indicator 5: Not met
No suggestions are made for how teachers can probe beneath students’ initial responses or how teachers may interpret student responses. Sometimes a single, correct answer is immediately presented to the teacher, as in the following example:

Have students examine the photograph. Ask them how animals, such as the one shown here, are either directly or indirectly dependent on plants for energy. (Plants capture energy from the sun and store it in carbohydrates. Animals acquire a portion of this energy by eating either the plants themselves or other animals that have eaten the plants.)

p. 126t

This suggests to the teacher that further exploration of student responses to the question is not needed, when, in fact, the scope of some misconceptions may be revealed only with extensive questioning of students’ original answers.

Addressing commonly held ideas

Rating = Poor
The material meets no indicators.

Indicator 1: Not met
The material does not explicitly address any commonly held student ideas.

Indicator 2: Not met
The material does not include any questions, tasks, or activities that are likely to help students progress from their initial ideas.

Indicator 3: Not met
The material does not include suggestions to teachers about how to take into account their own students’ ideas.

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III: Engaging Students with Relevant Phenomena

Providing variety of phenomena

Rating = Poor
Since the rating scheme depends on how many phenomena meet both of the indicators, the report for this criterion is organized to reflect the overall rating rather than each indicator judgment.

The material uses phenomena to support only one of the key ideas. For other key ideas, phenomena are not effectively linked with the key idea or are not provided at all.

For the key idea that “At each link in a food web, some energy is stored in newly made structures but much is dissipated into the environment as heat” (part of Idea d₂), the text describes three phenomena:

In a recent study of wolves and moose on Isle Royale, Michigan, ecologists found that only 1.3 percent of the total energy consumed by the moose on the island was transferred to the wolves through the wolves’ predation on the moose.

p. 418s

...consider what happens when a deer eats l,000 kcal of leaves. About 350 kcal are eliminated as urine, dung, and other wastes. Another 480 kcal are lost as heat. Only about 170 kcal are actually stored as organic matter, mostly as fat.

p. 419s

If you go on a safari in Kenya or Tanzania, for example, you will see about 1,000 zebras, gazelles, wildebeest, and other herbivores for every lion or leopard you see, and there are far more grasses, trees, and shrubs than there are herbivores.

p. 419s

These phenomena are effectively linked with the key idea in text that introduces the section where these phenomena are presented, Quantity of Energy Transfers:

Roughly 10 percent of the total energy consumed in one trophic level is incorporated into the organisms in the next level. The ability to maintain a constant body temperature, the ability to move, and a high reproductive rate are functions that require a lot of energy. The kinds of organisms that have those characteristics will transfer less energy to the next trophic level than organisms that do not....Finally, no transformation or transfer of energy is 100 percent efficient. Every time energy is transformed, such as during the reactions of metabolism, some energy is lost as heat.

pp. 418–419s

Otherwise, the phenomena that are offered are not explicitly related to key ideas and hence are unlikely to make them credible to students. For example, two phenomena are provided that could be used to support parts of the idea that “Plants make sugar molecules from carbon dioxide (in the air) and water” (Idea a₁). Photomicrographs of an open stoma and a closed stoma are presented with a caption explaining that, “When a stoma is open, water, carbon dioxide, and other gases can pass through it to enter or leave a plant” (p. 119s). Then a demonstration provides students with a look at actual stomata on several kinds of plants (p. 119t). These two experiences may convince students that there are structures through which substances like carbon dioxide and water can enter leaves, but no link is made with the key idea that, once these substances have entered the plant through the stomata, they are used in the plant’s production of sugar molecules. A third phenomenon related to the first part of this key idea is provided when students observe microscopic starch granules in a potato. The teacher is to “Explain that the organic compounds plants make through photosynthesis are stored mainly as starch” (p. 119t). The link with the key idea is tenuous, however, as text does not say that the “organic compounds” are sugars and that these are made from carbon dioxide and water.

The investigation Observing Cellular Respiration (pp. 142–143s), in which students observe that germinating seeds have a higher respiration rate than non-germinating seeds, might have been used to support the idea that “Plants break down the sugar molecules they have synthesized into carbon dioxide and water, use them as building materials, or store them for later use” (Idea b₁) and the idea that “Plants get energy to grow and function by oxidizing the sugar molecules” (part of Idea b₂) but was not connected to these ideas about matter and energy transformation. The inputs and outputs of cellular respiration are probed in the Background questions:

Question: When glucose is oxidized in aerobic respiration, what other substance is consumed and what substances are produced?

Suggested Response: O₂ is consumed; CO₂ and H₂O are produced.

pp. 142s and 143t, Background, question 1

Question: Write the balanced equation for the complete oxidation of glucose in aerobic respiration.

Suggested Response: C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + energy

pp. 142s and 143t, Background, question 2

However, these questions are not related to students’ subsequent observations. Furthermore, students are not told that the starch in the seed is a stored food source that is broken down by the germinating seedling to use as building material and energy for the growing plant. This investigation is a missed opportunity to develop explicitly this key idea about matter transformation.

A demonstration in which students observe that yeast cells produce carbon dioxide as they metabolize sugar (p. 12t) could be used to support the key idea that, “Other organisms break down the stored sugars or the body structures of the plants they eat (or animals they eat) into simpler substances, reassemble them into their own body structures, including some energy stores” (Idea c₁). The teacher is told to “Tell students that...the yeast cells are using the sugar in a metabolic pathway called cellular respiration. As a result, carbon dioxide gas is produced” (p. 12t). This statement by the teacher might provide a link with the first part of the key idea. However, it is unlikely to do so because it occurs so early in the text that students have little cognitive context in which to fit either the experience or the idea. Furthermore, the teacher’s statement to the students includes technical terms like “metabolic pathway” and “cellular respiration,” with which students have had no experience and which they will probably not understand.

For the remaining four key ideas about the transformation of matter and energy no phenomena at all are provided.

Providing vivid experiences

Rating = Poor
Since the rating scheme depends on how many phenomena meet all of the indicators, the report for this criterion is organized to reflect the overall rating rather than each indicator judgment.

The material meets no indicators. None of the firsthand experiences are adequately connected to the key ideas about matter and energy transformations. While the phenomena that are connected to key Idea d₂ might be vicarious for students (see above for phenomena described in text on pages 418–419s), these are not sufficient for the set of key ideas.

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IV: Developing and Using Scientific Ideas

Introducing terms meaningfully

Rating = Poor
The material meets no indicators.

Indicator 1: Not met
The material does not link technical terms to relevant student experiences. New terms are usually defined in the text, but the definitions are not reinforced with student experiences. Sometimes a representation is also provided, but the representations are usually little more than graphic depictions of the narration, which is not a relevant experience for students. In a few instances, examples are provided for new terms. For example, a specific food chain (grass, a meadow mouse, a snake, and a hawk), is provided when the term “food chain” is introduced (p. 417s).

Indicator 2: Not met
This material does not restrict the use of technical terms to those needed to communicate intelligibly about the key biology ideas. The text includes many terms that are unnecessary, such as “chlorophyll a,” “chlorophyll b,” “accessory pigment,” “carotenoids,” “photosystem I,” “photosystem II,” “electrons,” “primary electron acceptor,” “electron transport chain,” “NADP⁺,” “NADPH,” “redox reactions,” “chemiosmosis,” “fermentation,” “pyruvic acid,” “PGAL,” “NAD⁺,” “lactic acid fermentation,” “alcohol fermentation,” “thylakoids,” “stroma,” “granum,” and “biogeochemical.”

Representing ideas effectively

Rating = Fair
Since the rating scheme depends on how many representations meet all of the indicators, the report for this criterion is organized to reflect the overall rating rather than each indicator judgment.

The material includes only a few representations that meet all three indicators (comprehensible, accurate, and explicitly linked to the real thing). These representations can help make some ideas comprehensible but not others.

For the idea that “Other organisms break down the consumed body structures to sugars and get energy...[from the sugar molecules]” (part of Idea c₂) the text provides a photograph of a panda eating bamboo shoots and relates it to this key idea in the caption of the photograph and accompanying notes to the teacher:

Like other heterotrophs, the giant panda...obtains organic compounds by consuming other organisms. Biochemical pathways within the panda’s cells transfer energy from those compounds to ATP.

p. 126s

(Plants capture energy from the sun and store it in carbohydrates. Animals acquire a portion of this energy by eating either the plants themselves or other animals that have eaten the plants.) Tell students that the focus of this chapter is the process by which organisms convert some of the energy in carbohydrates into a form they can use to drive cellular activities.

p. 126t

The text also uses a representation to clarify the idea that “At each link in a food web, some energy is stored in newly made structures but much is dissipated into the environment as heat. Continual input of energy from sunlight keeps the process going” (Idea d₂). The text includes a diagram representing the decrease in available energy at each trophic level and relates the diagram to the key idea in the accompanying text:

Roughly 10 percent of the total energy consumed in one trophic level is incorporated into the organisms in the next level. The ability to maintain a constant body temperature, the ability to move, and a high reproductive rate are functions that require a lot of energy. The kinds of organisms that have those characteristics will transfer less energy to the next trophic level than organisms that do not....Finally, no transformation or transfer of energy is 100 percent efficient. Every time energy is transformed, such as during the reactions of metabolism, some energy is lost as heat.

pp. 418–419s

And the text includes a diagram of the nitrogen cycle (p. 422s) that may help clarify the idea that “The chemical elements that make up the molecules of living things pass repeatedly through food webs and the environment, and are combined and recombined in different ways” (Idea d₁). The diagram shows formulas and models of three different nitrogen-containing compounds; the accompanying text explains that since plants can only use one of the compounds, they depend on other organisms to “transform nitrogen gas into a usable form” (p. 423s). However, a diagram of the carbon cycle (p. 421s) does not clarify the idea. While the diagram portrays molecules of carbon dioxide, it does not show carbon to be present in any other combination in the organisms shown.

Representations do not help to clarify other key ideas. Most representations that are related to the ideas include needless details that are likely to confuse rather than help students make sense of the ideas (e.g., comparison of fermentation and aerobic respiration, page 127s; ATP yield in glycolysis and Krebs cycle, page 137s). Even the equation for photosynthesis (p. 118s) could mislead students into thinking that energy is transformed into matter.

Demonstrating use of knowledge

Rating = Poor
The material meets no indicators.

Indicator 1: Not met
The material does not consistently demonstrate the use of key ideas or suggest how teachers could do so. In only one instance does the material demonstrate the use of a key idea: the text uses the idea that “At each link in a food web, some energy is stored in newly made structures but much is dissipated into the environment as heat” (part of Idea d₂) to explain why “ecosystems rarely contain more than a few trophic levels” and why the highest trophic levels support fewer individuals:

The low rate of energy transfer between trophic levels explains why ecosystems rarely contain more than a few trophic levels....If you go on a safari in Kenya or Tanzania, for example, you will see about 1,000 zebras, gazelles, wildebeest, and other herbivores for every lion or leopard you see, and there are far more grasses, trees, and shrubs than there are herbivores. Higher trophic levels contain less energy, and, as a consequence, they can support fewer individuals.

p. 419s

Indicator 2: Not met
The preceding example of demonstrating use of knowledge is step-by-step in that it deals with the proportion of lions to herbivores and the proportion of herbivores to plants. However, this single instance does not merit credit for this indicator.

Indicator 3: Not met
The single example is not explicitly identified as being a demonstration of the use of knowledge.

Indicator 4: Not met
There is no running commentary about the demonstration of the use of knowledge and the material does not provide criteria for judging the quality of the performance.

Providing practice

Rating = Poor
Since the rating scheme depends on how many practice tasks meet all of the indicators, the report for this criterion is organized to reflect the overall rating rather than each indicator judgment.

The material minimally meets one indicator (i.e., it meets the indicator for two of the nine key ideas) but does not meet any indicators across the set of key ideas.

The material provides two questions that give students a chance to practice using the ideas that “The chemical elements that make up the molecules of living things pass repeatedly through food webs and the environment, and are combined and recombined in different ways” (Idea d₁) and “At each link in a food web, some energy is stored in newly made structures but much is dissipated into the environment as heat” (part of Idea d₂).

Question: How does the transfer of energy in an ecosystem differ from the transfer of nutrients?

Suggested Response: Energy flows through an ecosystem, from producers to consumers, and some energy is continually being lost from the ecosystem. Nutrients cycle within an ecosystem and can be used again.

pp. 437s and 436t, question 20

Question: Nitrogen, water, and carbon are recycled and reused within an ecosystem, but energy is not. Explain why energy cannot be recycled.

Suggested Response: At each trophic level, energy is dissipated as heat, a form of energy organisms cannot use. Thus, energy is continually lost to the ecosystem.

pp. 437s and 436t, Critical Thinking, question 2

No opportunities are provided for practice of the other key ideas. Many of the questions provided at the end of the chapter for practice are beyond the scope of these key biology ideas and beyond what is needed for science literacy, such as “Explain how the Calvin cycle is an example of a biochemical pathway” (p. 122s, question 17). Other practice questions focus on middle school ideas, such as “Explain the difference between a herbivore, a carnivore, and an omnivore. Give an example of each type of organism” (p. 437s, question 16).

No novel tasks are provided. The answers to question 20 and question 2 described in the preceding text are given in text on pages 419–420s.

There is no increase in the complexity of tasks and there is no provision of guided practice with feedback or practice in which support is gradually decreased.

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V: Promoting Students’ Thinking about Phenomena, Experiences, and Knowledge

Encouraging students to explain their ideas

Rating = Poor
The material meets no indicators.

Indicator 1: Not met
No examples were found where the material encourages students to express their own ideas as they related to the key biology ideas. In some cases, tasks were suggested that are beyond the expected level of science literacy and that focus on a single, correct answer, rather than on discovering students’ own ideas. For example, a Reteaching Activity asks students to generate a sequential diagram of the reactions that make up photosynthesis. The teacher is told, “Their diagrams should begin with light absorption, include the light reactions (electron transport and chemiosmosis) and the Calvin cycle, and end with the production of organic compounds” (p. 120t).

Indicator 2: Not met
No examples were found where students were asked to clarify, justify, or represent their own ideas about the key science ideas related to the transformation of matter and energy.

Indicator 3: Not met
Since no opportunities for students’ explanation of their own ideas are given, whether each student is involved is not relevant.

Indicator 4: Not met
No suggestions are given to help the teacher provide explicit feedback to students.

Indicator 5: Not met
The material does not include suggestions on how to diagnose student errors, explanations about how these errors may be corrected, or recommendations for how students’ ideas may be further developed.

Guiding student interpretation and reasoning

Rating = Poor
The material somewhat meets indicator 1.

Indicator 1: Somewhat met
This material includes some specific and relevant questions about the readings and the laboratory activities. The reading sections are followed by Section Review questions. However, these questions offer very little help for students in interpreting and understanding the readings. Mostly the questions ask only for students to recall facts from the text, such as “How do autotrophs differ from heterotrophs in obtaining energy?” (p. 10s), “Define cellular respiration” (p. 131s), and “Why are autotrophs essential components of an ecosystem?” (p. 419s). The laboratory activities end with Analysis and Conclusion questions. However, few of the questions relate to the key ideas. For example, following an activity in which students measure the rate of respiration in germinating versus non-germinating seeds, the only question that is relevant to the topic of matter and energy transformations does not focus on the key idea:

Question: Which group of seeds had the higher average rate of respiration? What is the significance of this difference in terms of a seed’s ability to survive long periods?

Suggested Response: The germinating seeds should have the higher rate of respiration. When a seed has a low rate of respiration, it uses its stored energy sources slowly, which allows the seed to survive for a long period of time.

p. 143st, question 4

Thus, this question misses the key idea that the germinating seeds are using the stored energy for their own growth and energy needs.

Indicator 2: Not met
None of the Section Review questions include helpful characteristics such as framing important ideas or helping students to make connections between their own ideas and the activity. And while some of the Analysis and Conclusion questions are intended to help students think about or organize their data, the questions do not focus on the key ideas.

Indicator 3: Not met
No scaffolded sequences of questions were provided.

Encouraging students to think about what they have learned

Rating = Poor
The material meets no indicators.

Indicator 1: Not met
No instances were found in which students were given an opportunity to revise their initial ideas.

Indicators 2 and 3: Not met
No instances were found in which students were asked to consider how their ideas have changed during instruction.

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VI: Assessing Progress

To assess students’ understanding of concepts at the end of instruction, Modern Biology recommends using the Modern Biology Chapter Tests and the Chapter Reviews (pp. 44T–45T). These components of Chapter 6: Photosynthesis, Chapter 7: Cellular Respiration, and Chapter 22: Ecosystems and the Biosphere—the chapters that treat the key ideas related to matter and energy transformations most extensively—were examined for the first two criteria.

Aligning assessment to goals

Rating = Poor
Since the rating scheme depends on how many assessment tasks meet both the indicators, the report for this criterion is organized to reflect the overall rating rather than each indicator judgment.

Modern Biology provides only two assessment items that align with any of the key ideas and the items assess only one key idea—the idea that “At each link in a food web, some energy...is dissipated into the environment” (part of Idea d₂). In one item, students are asked to describe and analyze three ecosystem pyramids, one of which is an energy pyramid (Chapter Tests, p. 88, question 30c). The answer given is explicit about the energy decrease at each trophic level: “There is a slightly greater transfer of energy with each change in trophic level, but only a very small amount of energy is transferred from the first to the second trophic level” (Chapter Tests, p. 222). In another item, students are asked “Why is so little of the energy from one trophic level transferred up to the next trophic level?” (Chapter Tests, p. 87, question 25) and the answer given is:

Some organisms die without being eaten by animals that belong to a higher trophic level, and thus energy from their bodies is not transferred to the next level. Some of the energy in an organism cannot be used by organisms at the next trophic level. Some of the energy in an organism at a higher trophic level is used for maintenance and cannot contribute to biomass.

Chapter Tests, p. 222

However, these items are not sufficient to assess this key idea.

Other items provided on the topic of matter and energy transformations do not focus on the key ideas. For example, students are asked to fill in a diagram of the nitrogen cycle and label the arrows (Chapter Tests, p. 87, question 27). The key idea that “The chemical elements that make up the molecules of living things pass repeatedly through food webs and the environment, and are combined and recombined in different ways” (Idea d₁) is neither necessary nor sufficient to answer the question. And while Idea d₁ might be necessary for the following questions, students would also need to know the meaning of the terms “biogeochemical cycle” and “abiotic”:

During a biogeochemical cycle, water, minerals, or carbon dioxide moves from the abiotic portion of the environment into living things and back again. (True/False)

Chapter Tests, pp. 85 and 222, question 10

Carbon moves from the biotic portion of its cycle into the abiotic portion during photosynthesis. (True/False)

Chapter Tests, pp. 85 and 222, question 11

Other items require only knowledge of terms rather than ideas about matter and energy transformation. For example, the item below requires only that students know that organisms that make their own food are called producers:

Organisms that obtain energy by making their own organic molecules are called

1. consumers
2. herbivores
3. producers
4. decomposers

Chapter Tests, pp. 86 and 222, question 14

And the following item emphasizes knowledge of the terms “photosynthesis,” “organic,” and “inorganic” rather than the idea that “Plants make sugar molecules from carbon dioxide (in the air) and water” (Idea a₁):

Question: During which process(es) in the carbon cycle is carbon converted from an inorganic form into an organic form?

Suggested Response: Carbon is converted from an inorganic form into an organic form during photosynthesis.

Chapter Tests, pp. 87 and 222, question 26

Testing for understanding

Rating = Poor
Since few assessment tasks were aligned to the key ideas, the report for this criterion is organized to reflect the overall rating rather that each indicator judgment.

Only two items test for understanding of the key ideas and this item only focuses on part of one idea. The two items described in the preceding text that focus on Idea d₂ focus on understanding it. The first item is novel. The second item is essentially the same as the Section Review question “Give two reasons for the low rate of energy transfer within ecosystems” (p. 419s). Furthermore, as noted, none of the other items focus on the key ideas, so no items test for understanding of them.

Using assessment to inform instruction

Rating = Poor
Since the material provides no tasks for this criterion, the report is organized to reflect the overall rating rather than each indicator judgment.

The material meets no indicators and does not claim to provide embedded assessments to inform instruction.

The material does not (a) use embedded assessment as a routine strategy, (b) assist the teacher in interpreting student responses to the end-of-chapter questions to diagnose what learning difficulties remain, or (c) provide specific suggestions to teachers about how to use the information from the end-of-chapter questions to make instructional decisions about what ideas need to be addressed by further activities.

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VII: Enhancing the Science Learning Environment

Providing teacher content support

Rating = Minimal support is provided.

The material provides minimal support in alerting teachers to how ideas have been simplified for students to comprehend and what the more sophisticated versions are. Content background notes usually briefly summarize the student text (e.g., p. 415t, Section Overview), briefly explain peripheral information (e.g., p. 116t, Quick Fact), or offer tidbits of questionable relevance (e.g., p. 133t, Quick Fact). Overall, the teacher content support is brief, localized, and fragmented.

The material does not usually provide sufficiently detailed answers to questions in the student book for teachers to understand and interpret various student responses. While most answers include expected scientific responses, little, if any, additional information is provided to help teachers field potential student questions or difficulties (e.g., p. 110t, Understanding the Visual; p. 131t, Answers to Section 7-1 Review, answer 1). In addition, some answers are brief and require further explanation (e.g., "Answers will vary" [p. 439t, Answers to Analysis and Conclusions, answer 1]).

The material provides minimal support in recommending resources for improving the teacher's understanding of key ideas. The material lists technology resources at the beginning of each chapter (e.g., "Photosynthesis by Logal Software. Available from WARD'S (item 74R5011-Mac, 74R5010-Windows)" [p. 109Bt]) and references for essays about current biology research (e.g., p. 357Bt, Trends in Biology; 447t, Further Readings). While these resources might help teachers improve their understanding of the key ideas, the lists lack annotations about what kind of specific information the resources provide.

Encouraging curiosity and questioning

Rating = Minimal support is provided.

The material provides no suggestions for how to encourage students' questions and guide their search for answers.

The material provides a few suggestions for how to respect and value students' ideas. Teacher notes state that multiple student answers should be acceptable for some questions (e.g., p. 439t, Answers to Analysis and Conclusions, answers 1–3, 6 and 8). In addition, students are sometimes asked to design experiments to extend particular laboratory investigations (e.g., p. 1001s, Further Inquiry).

The material provides a few suggestions for how to raise questions such as "How do we know? What is the evidence?" and "Are there alternative explanations or other ways of solving the problem that could be better?" However, it does not encourage students to pose such questions themselves. Specifically, the material includes a few tasks that ask students to provide evidence or reasons in their responses (e.g., p. 115t, Teaching Strategy; p. 437s, Short Answer, item 23).

The material provides a few suggestions for how to avoid dogmatism. The first chapter portrays the nature of science as a durable yet dynamic human enterprise in which all people can participate (e.g., pp. 14–20s). A feature in the student text, Literature & Life, presents excerpts from popular science books related to the chapter content (e.g., p. 430s). In addition, Research Notes in the student text (e.g., p. 447s) and teacher notes discuss recent research findings (e.g., p. 423t, Recent Research) and trends (e.g., p. 357Bt, Trends in Biology). However, the material also contributes to dogmatism by presenting most of the text in a static, authoritative manner with little reference to the work of particular, practicing scientists and expecting single, specific responses for most student tasks.

The material does not provide examples of classroom interactions (e.g., dialogue boxes, vignettes, or video clips) that illustrate appropriate ways to respond to student questions or ideas.

Supporting all students

Rating = Some support is provided.

The material generally avoids stereotypes or language that might be offensive to a particular group. For example, photographs and illustrations include a diverse cultural mix of students and adults (e.g., pp. 130s, 463s, 1000s), but the number of photographs that include people throughout the material are few.

The material provides some illustrations of the contributions of women and minorities to science and as role models. Most of the contributions of women and minority scientists, however, appear in separate sections entitled Great Discoveries and Cultural Connections. Great Discoveries provide essays, discussion questions and additional readings about the major contributions of a particular scientist, including women and minorities. For example, one Great Discoveries feature discusses the work of African American scientist, George Washington Carver, to improve agricultural practices in southern states (pp. 568–569st). Cultural Connections provide information about particular cultural groups related to the chapter content (e.g., p. 130t). All of these sections highlighting cultural contributions are interesting and informative, but some may not be seen by students as central to the material because they are presented in sidebars and teacher notes.

The material suggests multiple formats for students to express their ideas during instruction and assessment, including laboratory investigations (e.g., pp. 142–143s), whole class discussions (e.g., p. 983t, Engage Students), essay questions (e.g., p. 423st, Section 22-2 Review, item 6; Chapter Tests, p. 87, question 25), and research projects (e.g., p. 979t, Critical Thinking). However, the material does not usually provide a variety of alternatives for the same task in either instruction or assessment.

The material does not routinely include specific suggestions about how teachers can modify activities for students with special needs. However, the Teacher's Edition provides additional activities and resources for students of specific ability levels. Inclusion Activities (e.g., p. 422t) are designated as "alternative ways to teach the main concepts" (p. 41T). Reteaching Activities provide suggestions for reviewing the section concepts (e.g., p. 115t). Extensions (e.g., p. 141s) and Gifted Activities (e.g., p. 112t) provide opportunities for students to investigate topics beyond the textbook material. In addition, supplemental program resources provide further additional activities and resources for students (for a description, see pp. 34T–35T).

The material provides some strategies to validate students' relevant personal and social experiences with scientific ideas. Some tasks (e.g., p. 977t, Engage Students; p. 978t, Inclusion Activity) ask students about particular personal experiences they may have had or suggest specific experiences they could have. However, the material rarely encourages students to contribute relevant experiences of their own choice to the science classroom. Overall, support is brief and localized.

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