AAAS Project 2061 Textbook Evaluations

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Biology: Visualizing Life. Holt, Rinehart and Winston, 1998

Cell Structure and Function: 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 openers do not provide a problem, question, representation (or otherwise identified purpose) for the students. Typically, units begin with a colorful two-page photograph, a list of the chapters included in the unit, and a few boxes of text. For unit one (pp. 2–3s), text boxes describe cystic fibrosis and the faulty gene that causes this disease. Another text box, called “Looking Ahead,” raises some questions and refers students to pages where the questions are treated:

• How could you find out if you are a carrier of a defective gene? See Science, Technology, and Society: DNA Profiling: Promise or Peril? pages 38–39.
• Where in a cell are instructions for making proteins? See A Closer Look: Eukaryotic Cell, page 53.
• Who helps scientists find answers to the mysteries of cell structure? See Career Opportunities: Science Technology, page 55.
• How do protein channels restrict the kind of particles that enter and exit a cell? See pages 69–71.

p. 3s

However, these questions deal with a very small number of topics covered in the unit and do not provide a purpose for the unit as a whole. Nor do these questions frame the chapters within the unit. The chapters also begin with a colorful one-page photograph and a list of the chapter sections. For example, Chapter 3: Cells, opens with a photograph of streptococcus bacteria (p. 40s). An Author’s Rationale, which appears below the picture, describes the contents of the chapter but does not provide the purpose for the chapter. Unfortunately, neither the teacher’s guide nor the student text presents a purpose for the chapter.

Indicator 2: Not met
Since there are no unit or chapter purposes clearly stated for the students, the question of comprehensibility cannot be addressed.

Indicator 3: Not met
Again, since there are no unit or chapter purposes clearly stated for the students, the question of whether students would be interested and motivated cannot be addressed.

Indicator 4: Not met
Again, since there are no unit or chapter purposes clearly stated for the students, the question of whether students are asked to think about such purposes cannot be addressed.

Indicator 5: Not met
Again, since there are no unit or chapter purposes clearly stated for the students, the question of whether lessons are consistent with a purpose cannot be addressed.

Indicator 6: Not met
Again, since there are no unit or chapter purposes clearly stated for the students, the question of whether the material returns to the stated purpose at the end of the unit cannot be addressed.

Conveying lesson/activity purpose

Rating = Poor
The material meets one out of the five indicators.

Indicator 1: Mostly met
The material consistently provides a purpose for readings and laboratory activities, but not for teacher demonstrations.

Readings. Two features can help to convey the purpose of readings to students:

• Introductory paragraphs, which are bolded and appear at the beginning of each reading section, sometimes convey a reason for why students should read a section. For example, at the beginning of Section 3-1: At the Boundary of the Cell, students read:

  Your body is composed of trillions of cells. As long as these cells work normally, you are generally unaware of them. However, abnormal cell behavior can bring about changes such as the uncontrolled growth of these cancer cells. If we are ever to find cures for this deadly disease and others, we must first look closely at cells to understand how they function.

  p. 41s

  However, this reading section focuses more narrowly on the cell membrane, the cell’s surface area, and the structure of water.

• Section objectives (e.g., “Define the function of a cell membrane,” “Explain why smaller cells function more efficiently than larger cells,” “Distinguish between polar and nonpolar molecules,” and “Compare the interaction of water molecules with each other and with lipid molecules” [p. 41s]) may also help to convey the purpose of each section to students. However, no suggestions are given for how to use these objectives, either on page 41t or in the front material for teachers.

Laboratory activities found in the back section of the text consistently provide a purpose in the teacher’s guide and a list of objectives, as well as either a Background or a Situation for the students. Situations provide real-life contexts for the laboratories, while Backgrounds provide useful information for the activities. An example of a laboratory activity in which the purpose is clearly provided is Exploration 3A: Observing Cells With a Microscope. In the Situation, students are told that they are part of a biological research team that is studying life in a polluted pond and that their job is to observe the organisms with a compound microscope, determine the size of their cells, and categorize them as prokaryotic or eukaryotic (p. 760s).

Teacher demonstrations. None of the demonstrations described in chapter 3 offers purposes. Typically, a demonstration begins with an instruction to the teacher, such as “[p]oint out that the cytoplasm is a colloid and not a solution” (p. 51t) or “[p]repare a wet-mount slide of Elodea” (p. 54t), but does not offer a purpose for the demonstration.

Indicator 2: Not met
The section objectives often include technical vocabulary—for example, “lipid molecules” (p. 41s), “phosopholipids” and “lipid bilayer” (p. 46s), “prokaryotic” and “eukaryotic” (p. 50s)—that may not be comprehensible to students who have not already studied the topic. The tasks described in the Backgrounds and Situations in the laboratories in the back section of the text also sometimes include terminology that may not be comprehensible to students who have not already studied the topic—for example, “dialysis” (p. 762s).

Indicator 3: Not met
Students are not asked to think about the purpose of the readings, demonstrations, or laboratory activities.

Indicator 4: Not met
The material does not convey or prompt teachers to convey how the activities are related to a unit or chapter purpose.

Indicator 5: Not met
None of the purposes provided in introductory paragraphs, section objectives, teacher demonstrations, or laboratory activities in the back section of the book engages students in thinking about what they have learned so far and what they need to learn/do next.

Justifying lesson/activity sequence

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

Indicator 1: Somewhat met
The sections within the main chapter covering the key ideas about cell structure and function appear to be logically sequenced. The chapter sections for Chapter 3: Cells include 3-1: At the Boundary of the Cell, 3-2: Membrane Architecture, and 3-3: Inside the Cell. This sequence starts at the membrane and works toward the inner structures.

However the presentation of information within some sections seems less logical. For example, Section 3-1: At the Boundary of the Cell begins with a brief introduction to the cell and the cell membrane. The next section focuses on factors that limit the size of the cell (p. 42s), which is followed by a presentation on the structure of water and its interaction with oil (pp. 43–45s). Overall, this section seems to be a hodgepodge of topics instead of a carefully planned or logical sequence of topics.

Indicator 2: Not met
The material does not convey a rationale for the sequence of the chapters or the topics within the chapters. Although the opening of each chapter includes a section called Author’s Rationale, this section does not provide a rationale for the sequence. It merely explains what topics are included in the chapter. For example, the Author’s Rationale for chapter 3 says the following:

This chapter is critical for understanding important biological concepts in the rest of the text. It describes the architecture of the cell membrane and the characteristics that have made cells so successful. Surface-area-to-volume ratio is presented in detail because it is a useful concept that helps students understand cell size limitations in this chapter, as well as cell and tissue arrangements for specialized functions described in later chapters. The organizing role of water is present here in the context of its most important function, rather than in isolation in a discussion of chemistry.…

p. 40t

The reason for the sequence of lessons in the chapter is not presented.

There is one effort to justify the order of topics: the Author’s Rationale for chapter 2 says, “Since most life-defining characteristics are determined at the molecular level, some basic chemistry is introduced here. This information provides the framework needed to understand cellular processes in Chapters 3–5” (p. 22t). However, with only one example, this indicator cannot be considered to be even partially met.

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II: Taking Account of Student Ideas

Attending to prerequisite knowledge and skills

Rating = Poor
The material minimally meets one indicator.

Indicator 1: Not met
The material does not alert teachers to specific prerequisite ideas or skills. At the beginning of each chapter, there is a feature on the student page called Review. This feature lists topics that students should review before continuing into the chapter. For example, the Review section for chapter 3 lists the following topics:

• cells (Section 1-3)
• characteristics of living things (Section 2-1)
• electrons, covalent bonding (Section 2-2)
• lipids, proteins (Section 2-3)

p. 40s

However, only topics are listed. Specific prerequisite ideas are not noted in these sections, and without more guidance it is unlikely that students will know exactly what parts of those listed sections should be reviewed.

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 prerequisite ideas or experiences that are being assumed.

Indicator 4: Minimally met
The material mentions some prerequisite ideas or parts of prerequisite ideas but does not address them adequately. In the context of introducing the major themes in biology, the text presents the prerequisite idea that “Within cells, many of the basic functions of organisms—such as extracting energy from food and getting rid of waste—are carried out. The way in which cells function is similar in all living organisms” [5C(6-8)/3]. The text notes that “The complex chemical processes that occur within cells are much the same in all organisms, and all cells have the same basic structure” (p. 16s). This prerequisite idea is presented again in Chapter 3: Cells: “Like all living things, cells perform basic functions of life. Cells use energy, cells maintain homeostasis, and cells reproduce” (p. 52s). Even though this passage also provides three functions that cells and organisms alike perform, the examples given are abstractions (e.g., use energy, maintain homeostasis) instead of specific instances of life functions.

Another prerequisite, that “Atoms may stick together in well-defined molecules or may be packed together in large arrays” [4D(6-8)/1] is mentioned briefly. In the context of presenting basic chemistry, the text explains that “[a] molecule is a group of atoms held together by covalent bonds” (p. 28s). However, the text continues by discussing covalent bonding—information that is unnecessary at this point.

It is also noteworthy that while the text shows diagrams of molecules (such as water on pp. 28s and 44s, glycerol on p. 31s, and phosopholipids on p. 46s), the prerequisite idea that “The configuration of atoms in a molecule determines the molecule’s properties. Shapes are particularly important in how large molecules interact with others” [4D(9-12)/8] is mentioned only in the context of proteins:

A protein’s function is determined by its particular three-dimensional shape, as illustrated in Figure 2-11. What determines a protein’s shape? Its amino acid sequence determines its shape.

p. 32s

Yet, this prerequisite idea is not stated as a general idea with applications to other molecules.

Other important prerequisite ideas are not addressed in the material:

• Various organs and tissues function to serve the needs of all cells for food, air, and waste removal. [5C(6-8)/2]
• The rate of reactions among atoms and molecules depends on how often they encounter one another, which is affected by the concentration, pressure, and temperature of the reacting materials. [4D(9-12)/9]

Indicator 5: Not met
Adequate connections are not made between key ideas and their prerequisites. In chapter 3, three sidebar notes called Connection: Chapter 2 direct the teacher to review concepts from chapter 2, such as covalent bond formation (p. 44t), the structure of amino acids (p. 49t), and characteristics of life (p. 54t). For example:

Review covalent bond formation, emphasizing that atoms share electron. Use a molecular model kit to build a water molecule, or draw its structure on the board. Ask students how many atoms are present (3) and how many covalent bonds are present (2).

p. 44t

However, this only directs the teacher to refer to the initial place where covalent bonds are presented, not to the related key idea.

Alerting teachers to commonly held student ideas

Rating = Not rated
For the topic of cell structure and function, materials were not rated on this criterion because no research base outlines commonly held student ideas.

Assisting teachers in identifying their students’ ideas

Rating = Poor
The material provides one task that minimally meets indicators 1, 2, and 3.

Indicator 1: Minimally met
This material begins each chapter with a section in the teacher’s guide called Determining Prior Knowledge. Only one question in these sections is somewhat related to the key ideas and may help teachers find out what their students think before they begin instruction. The teacher is to ask students to “draw a generalized cell and label any parts they can remember from previous course work” (p. 40t). But most questions either do not focus on the key ideas or ask students to recall information from the previous chapter, instead of asking for their own ideas about what they are about to study. For example:

Inflate several balloons with different amounts of air. Have students identify the surface area and volume of each balloon. See if they can identify which measurement increases more rapidly as a balloon is inflated.

p. 40t

Ask students to name and describe the functions of the three major types of cell-membrane proteins discussed in Chapter 3.

p. 62t

Indicator 2: Minimally met
The cell-drawing task is likely to be comprehensible to students. However, it is not likely to provide teachers with information about their students’ own ideas related to the key ideas or to reveal any misconceptions that the students may have.

Indicator 3: Minimally met
The questions/tasks given in Determining Prior Knowledge are identified as serving the purpose of identifying students’ ideas. In the teacher’s section at the front of the book, the teacher reads that this feature “helps you assess how much your students know—and what misconceptions they may have—before you begin teaching” (p. T42). However, only one question was related to the key ideas for cell structure and function.

Indicator 4: Not met
The questions/tasks provided in the material do not ask students to make predictions or give explanations.

Indicator 5: Not met
The material offers no suggestions for how teachers can probe beneath students’ initial responses to questions. For example, the teacher’s guide does not tell the teacher to listen for his or her students’ responses, use ample wait time, or avoid correcting students’ ideas at this time. Without these warnings, it is unlikely that the questions provided will fully elicit student ideas.

Addressing commonly held ideas

Rating = Not rated
For the topic of cell structure and function, materials were not rated on this criterion because no research base outlines commonly held student 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.

This material provides very few phenomena to support the key ideas related to the cell structure and function topic. For the idea that the cell membrane controls what enters and exits the cell (Idea a), the teacher’s notes explain that faulty channel proteins cause cystic fibrosis by impairing the transport of chloride ions, causing them to accumulate outside the cell in a thick mucus (p. 48t). This example shows that when the cell membrane is impaired, it does not serve as an adequate control for what can enter and exit the cell and thus has dire consequences for the cell and the organism. In a demonstration, students observe how Elodea cells react to being placed in a 5% salt solution (p. 54t). However, this demonstration is not explained in terms of the role of the cell membrane in the observed shrinking of the cell and some of its organelles.

For the idea that cells have specialized parts for the different functions they perform (Idea b), the text mentions that the number of mitochondria in a cell depends on the particular function and needs of the cell and that muscle cells can contain thousands of mitochondria while mature red blood cells have none (p. 52s). Similarly, a corresponding teacher’s note explains that a liver cell has about 2,500 mitochondria and that “[t]his high number of mitochondria reflects the many jobs the liver cell performs and the high level of energy it requires” (p. 52t). No other phenomena are provided for the other cell structure and function key ideas.

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. Given that so few phenomena were provided and the two that were provided and linked to the key ideas were brief text statements, there is essentially nothing to be judged for vividness.

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IV: Developing and Using Scientific Ideas

Introducing terms meaningfully

Rating = Poor
Both indicators are minimally met.

Indicator 1: Minimally met
The material attempts to link some of the technical terms presented to relevant experiences. For example, a few organelles are compared to the “cell’s laborers.” For example, the endoplasmic reticulum is compared to a highway system and the Golgi apparatus is compared to a packaging and distribution center (p. 52s) and to a post office (p. 53s). Similarly, the cell membrane is compared to a submarine’s hull (p. 41s). Mostly, however, technical terms such as “ribosomes,” “cytoplasm,” and “cytosol” (pp. 50–51s) are introduced without enough elaboration to be understandable to students.

Indicator 2: Minimally met
Many of the technical terms presented, such as “hydrogen bond” (pp. 44–45s), “phospholipid,” “lipid bilayer,” “channel protein,” “receptor protein,” “marker protein,” (pp. 46–49s), “eukaryotes,” “prokaryotes,” “cytoplasm,” and “cytosol” (pp. 50–51s) are beyond what is needed for intelligible conversation about the key ideas. Furthermore, a teacher’s note encourages the teacher to point out “desmosomes” and “zymogen granules” in the human pancreatic cells on a videodisc (p. 51t). Some technical terms are included in the student text without being bolded, such as “nuclear envelope” and “nuclear pores” (p. 52s). However, it should be noted that this curriculum material does not include some of the technical terms often associated with this set of key ideas, such as nucleolus, chromoplasts, cristae, peripheral proteins, integral proteins, thylakoid, grana, and lumen.

Representing ideas effectively

Rating = Poor
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 has hardly any representations that are accurate, comprehensible, and explicitly linked to the real thing being represented. Thus, little support is provided to clarify the key ideas for students.

Most diagrams and figures provided in the relevant chapters for the key ideas about cell structure and function do not target these key ideas. For example, many diagrams and figures (e.g., Figure 3-12 on p. 51s and Figure 3-13 on p. 54s) show only the structure of cell organelles and thus do not help to clarify the idea that cells have specialized structures for specific functions (Idea b). Other diagrams and figures provide information that is beyond this set of key ideas. For example, representations for the idea that the cell membrane controls what can enter and exit the cell (Idea a) typically focus on the membrane architecture (Figures 3-7 to 3-11 on pp. 46–49s), rather than the control of the cell membrane.

Two analogies are provided in the relevant chapters for the key ideas about cell structure and function. Of the two provided, neither are well-developed or ask the students to critique or analyze the analogies. One analogy compares the cell membrane to a submarine’s hull (p. 41s) and the other analogy compares the organelles to laborers. This is mentioned in a section titled “Organelles: A Cell’s Laborers” (p. 52s) while three examples of laborers follow on the next page (i.e., that the Golgi apparatus is like a post office, the mitochondria are the powerhouse, and the endoplasmic reticulum is a highway) (p. 53s). However, these analogies are not sufficiently developed nor are students asked to think about or critique their limitations or usefulness. Other suggestions in the teacher’s notes ask the students to come up with analogies for the cell membrane (pp. 47t and 49t). Two modeling activities are suggested for the cell membrane, neither of which is particularly useful for clarifying the role of the cell membrane in controlling what can enter and exit the cell (Idea a). The first modeling activity uses dialysis tubing to represent the cell membrane (p. 41t). However, this demonstration represents the cell membrane as passive and not controlling what can enter and exit the cell. Furthermore, students are not asked to discuss this activity in terms of this key idea nor are they asked to critique the limitations of the model. The other modeling activity, in which students design the membrane from marshmallows, jelly beans, and toothpicks (p. 48t), focuses on the membrane architecture instead of on the function of the cell membrane as Idea a does.

Demonstrating use of knowledge

Rating = Poor
The material meets no indicators, since it does not demonstrate how the key ideas related to cell structure and function can be used to explain phenomena or solve problems.

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 provides very few opportunities for students to practice using the key ideas related to cell structure and function. For the idea that the cell membrane controls what can enter and exit the cell (Idea a), students are asked “In what ways is a cell membrane similar to and different from the hull of a submarine?” (p. 60s, question 4) and “How would a cell be affected if the cell membrane were completely solid and watertight?” (p. 60s, question 5). For the idea that cells have specialized parts for specific functions (Idea b), students are asked:

Name five organelles found in cells, and describe how each organelle enables the cell to display the properties of life as they are described in Chapter 2.

p. 60s, question 17

How do chloroplasts and mitochondria function in the capture and release of energy within the cell?

p. 61s, question 19

A scientist decides to remove one particular kind of organelle from a eukaryotic cell to see if the cell can survive without it. The scientist chooses to remove all mitochondria from the cell. The cell subsequently dies. Explain the probable reason.

p. 61s, question 22

Although the last question provides a somewhat novel context to think about the role of mitochondria in the cell, the rest of the practice questions ask for students to recall information from the text. Other key ideas are not practiced.

Only one of the few practice tasks provided is novel. In no case is there a sequence of questions or tasks in which complexity is progressively increased. No guided practice with feedback is provided.

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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
The material does not routinely encourage students to express their ideas. Only two tasks were identified that might elicit students’ own ideas. Both focus on the same key idea (Idea a) and both are nearly the same task. These tasks appear in the teacher’s notes in Section 3-2: Membrane Architecture:

Ask students to list analogies that illustrate the cell membrane’s ability to control which substances enter and exit the cell. (Analogies may include a toll gate, an airport security gate, a stadium gate, and a fence gate.)

p. 47t

Have students select an object visible from outside of their house that could serve as a model for either the lipid bilayer or a protein of a cell membrane. Have them defend their analogy. (Examples might include a wall as the lipid bilayer, a door or window as a channel protein, a TV antenna or satellite dish as a receptor, or a nameplate as a marker protein.)

p. 49t

Section Review and Chapter Review questions, which provide the correct answer, were not considered. The focus on correct answers suggests that the questions are not really designed to elicit students’ own ideas.

Indicator 2: Not met
The two examples of having students develop analogies for the cell membrane (pp. 47t and 49t) do not allow students to represent their ideas. And only in one instance were they asked to defend their analogy. This is not sufficient for having students clarify or justify their own ideas.

Indicator 3: Not met
Opportunities are not provided for each student to express ideas. Even in the two examples noted above it is not clear that each student will express his or her ideas.

Indicator 4: Not met
The material does not give specific suggestions to help the teacher provide explicit feedback to students, nor does the text provide such feedback.

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

Guiding student interpretation and reasoning

Rating = Poor
One indicator is somewhat met.

Indicator 1: Somewhat met
The material includes specific questions at the end of each text section in a feature called Section Review. This feature provides questions about the content of that section. Two such questions (and answers) were found that are relevant to the key ideas:

Question: What is the function of a cell membrane?

Suggested Response: The cell membrane controls which substances enter and exit the cell.

p. 45st, question 1

Question: How have organelles enabled eukaryotic cells to become successful?

Suggested Response: Organelles function as specialized compartments, making a eukaryotic cell much more efficient than a prokaryotic cell.

p. 58st, question 2

Both of these questions require students only to recall information from the text.

Only two questions focusing on a key idea were noted, one in a teacher demonstration and one in a laboratory investigation. Both the activities and the questions are similar. The teacher is to demonstrate the selective permeability of dialysis tubing and then ask students to “describe their observations and hypothesize what is happening in the beaker” (p. 41t). The expected answer is that the “dialysis tubing acts like a cell membrane, allowing substances like iodine to pass through” (p. 41t). Similarly, after investigating dialysis tubing in a laboratory experiment, students are asked “Why can dialysis tubing be used as a model for the cell membrane?” (p. 763s). The suggested response is that “It is selectively permeable, like cell membranes” (p. 763t).

Indicator 2: Not met
None of the questions in the Section Reviews, demonstrations, or laboratory activities has helpful characteristics such as framing important issues, helping students make connections between their own ideas and the presented scientific ideas, or anticipating student misconceptions.

Indicator 3: Not met
None of the Section Reviews, demonstrations, or laboratory activities involves scaffolded sequences of questions, which could guide students from phenomena or their own ideas about phenomena to the scientific ideas. Instead, individual questions focus on a particular area.

Encouraging students to think about what they have learned

Rating = Poor
The material meets no indicators.

Indicator 1: Not met
The material does not give students an opportunity to revise their initial ideas based upon what they have learned.

Indicator 2: Not met
The material does not engage students in monitoring how their ideas have changed at one or a few points in the unit.

Indicator 3: Not met
The material does not engage students in monitoring how their ideas have changed periodically in the unit.

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VI: Assessing Progress

To assess students’ understanding of concepts at the end-of-instruction, Biology: Visualizing Life provides chapter tests in two formats in a separate Chapter Tests booklet. Test A items are all multiple-choice while Test B includes both multiple-choice and short response items. In addition, the material includes an Alternative Assessment task for each chapter (in the teacher’s guide) and a generic Portfolio Assessment that has students construct a concept map from each chapter (p. T39). All these assessment options are listed at the beginning of each chapter (e.g., p. 75B and p. 251B) and, for the first two criteria, were examined for chapters 3 and 4—the chapters that treat the key ideas on cell structure and function most extensively. The material also includes a test generator to assist teachers in assembling tests; however, since most items that are relevant to the key ideas are included in the chapter tests, the bank generator was not examined.

Aligning assessment to goals

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

The material provides very few items that meet indicators 1 and 2. Some questions target the idea that the cell membrane controls what can enter and exit the cell (Idea a), such as:

The structure that regulates what enters and leaves the cell is called

1. the nucleus.
2. the cell wall.
3. the nuclear membrane.
4. the cell membrane.

pp. 13 and 218, Chapter Test A: Chapter 3, item 1

The cell membrane

1. encloses the contents of a cell.
2. allows material to enter and leave the cell.
3. has a lipid bilayer forming its framework.
4. All of the above are true.

pp. 16 and 218, Chapter Test B: Chapter 3, item 5

Some questions go beyond this idea and focus on the membrane structure, such as:

In a cell membrane, there are protein channels that allow certain molecules to pass through the membrane.

pp. 17 and 218, Chapter Test B: Chapter 3, item 20

A few questions focus on the idea that cells have specialized structures for specific functions (Idea b), such as:

A particularly active muscle cell might contain large numbers of

1. chromosomes.
2. vacuoles.
3. mitochondria.
4. walls.

pp. 14 and 218, Chapter Test A, Chapter 3, item 17

However, most of the questions for Idea b focus on having the students recall the technical terms associated with the cellular function, and hence, require information beyond the key idea. For example:

The organelles that make sugar in plants are

1. the chloroplasts.
2. the mitochondria.
3. the Golgi bodies .
4. None of the above is true.

pp. 14 and 218, Chapter Test A: Chapter 3, item 18

Proteins are made in cells on the

1. mitochondria.
2. ribosomes.
3. nucleus.
4. cell membrane.

pp. 14 and 218, Chapter Test A: Chapter 3, item 16

One question is incorrect:

How are chloroplasts like mitochondria?

1. They both can use energy from sunlight.
2. They look alike.
3. They both manufacture food and release energy.
4. They are both found in animal cells.

pp. 14 and 218, Chapter Test A: Chapter 3, item 19

The suggested answer is wrong. Mitochondria are not involved in the manufacturing of food and the chloroplast does not release energy.

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 than each indicator judgment.

None of the relevant assessment items described under the previous criterion requires application of key ideas. This is clearly insufficient to assess understanding of the set of key ideas.

Using assessment to inform instruction

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

Biology: Visualizing Life does not make any claims about assessing students throughout instruction to diagnose students’ remaining difficulties and to modify the instruction accordingly.

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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 elaborate on one or a few student text concepts (e.g., p. 46t, Health Connection) or briefly explain peripheral information (e.g., p. 52t, Matter of 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 for teachers to field potential student questions or difficulties (e.g., p. 45t, Answers to Section Review, answer 1; p. 66t, Answers to Section Review, answer 1). In addition, some answers are brief and require further explanation (e.g., pp. 760–761t, Analysis, answers 13 and 16). Some questions go unanswered (e.g., p. 40t, Determining Prior Knowledge).

The material provides minimal support in recommending resources for improving the teacher’s understanding of key ideas. The material lists resources available within supplemental program materials in introductory notes (pp. T26–T41) and in the “Lesson Resources” at the beginning of each chapter (e.g., pp. 61A–61Bt). 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 a few suggestions for how to encourage students’ questions and guide their search for answers. A few tasks ask students to generate questions and form responses (e.g., p. 59t, Alternative Assessment).

The material provides a few suggestions for how to respect and value students’ ideas. Some tasks explicitly elicit student ideas (e.g., p. 57t, Evaluating Viewpoints). In addition, teacher notes state that multiple student answers should be acceptable for some tasks (e.g., p. 64t, Inferring Relationships). Similarly, appendix notes about concept mapping state that students may see “different relationships between certain concepts” (p. 839s).

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. 75s, Chapter 4 Review, item 21; p. 763s, Analysis, item 15).

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. 5–15s). The material also discusses current issues in biology related to chapter content (pp. 38–39st, Science, Technology, and Society). In each Chapter Review, students are asked to read and respond to popular science articles (e.g., p. 61st, Discovering Through Reading, item 29). 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. However, a limited sense of desirable student-student interactions may be gained from procedural directions for laboratory and cooperative group activities (e.g., p. 42t, Demonstration; p. 46t, Active Reading).

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. 44s, 57s, 69s), but the number of photographs that include people throughout the material is 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 Career Opportunities, Multicultural Perspectives, and Historical Perspectives. Career Opportunities describe the careers of women or minority scientists, give information for students to learn more about the careers, and provide suggestions to the teacher for class discussions. For example, one Career Opportunities feature discusses the life and work experiences of technician Phyllis Stout (p. 55st). Multicultural Perspectives provide information about particular cultural groups related to the chapter content (e.g., p. 13t). Historical Perspectives sometimes describe the contributions of specific scientists, some of whom are women and minorities (e.g., p. 7t). 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 pair work (e.g., p. 46t, Active Reading), cooperative group activities (e.g., p. 53t, Visual Art Connection), laboratory investigations (e.g., pp. 760–761s), whole class discussions (e.g., p. 62t, Determining Prior Knowledge), essay questions (e.g., pp. 761s, 760t, Analysis, item 14), concept mapping (pp. 74s, 73t, Chapter 4 Review, item 3), modeling (e.g., p. 48t, Problem Solving), visual projects (e.g., p. 58t, Closure), research projects (e.g., p. 51t, World of Work), written reports (e.g., p. 71t, Life/Work Skills), and portfolio (e.g., p. 73t, Portfolio Assessment). 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 material includes a Reteaching feature (e.g., p. 72t) “for additional instruction in a major concept of the section” (p. T43), and supplemental program resources provide additional activities and resources for students (for a description, see pp. T34–T35).

The material provides some strategies to validate students’ relevant personal and social experiences with scientific ideas. Some text sections relate specific personal experiences students may have had to the presented scientific concepts (e.g., p. 41s). In addition, some features in teacher notes (e.g., p. 49t, Reteaching; p. 69t, Community Connection) 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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