There is a content match, mostly at the level of substances (rather than molecules). More than 20 instances were noted that relate to this key idea, mainly in course 3. The chapter in course 3 on organic chemistry (chapter 10) describes the molecular composition of carbohydrates, proteins, and lipids, and indicates that proteins serve as building material, whereas carbohydrates and lipids are energy stores. However, subsequent chapters treat the idea that food is building material in terms of substances, rather than molecules. Course 3, Chapter 11: Fueling the Body states the idea explicitly (pp. 339t, 352t, 361s) and describes the uses of food for energy (pp. 346–347s), for providing building materials “to effectively repair wounds, such as scrapes, cuts, or broken bones,” and for growth and development (p. 350s). Examples of food serving as energy or building materials are given (in cows, birds, humans, elephants, and lions). Course 2 includes a demonstration of a peanut burning to show that food can serve as a source of stored energy (Chapter 19: How Cells Do Their Jobs, p. 613s).

There is a partial content match. The following presentation of Idea c₂ shows which parts of the idea are treated (in bold) and what alternative vocabulary, if any, is used (in brackets): Plants [Cells] break down the sugars they have synthesized back into simpler substances—carbon dioxide and water—and assemble sugars into the plants’ body structures, including some energy stores. Course 1 states a less sophisticated version of this idea in the context of describing plant processes:

Let’s look at what happens to the products formed during photosynthesis. Some of the sugars formed are used by the plant for its own life processes, such as growth. Some sugar is stored. When you eat carrots or potatoes, you are eating stored food. [Chapter 10: Plant Life, p. 336s]

Students are expected to repeat this statement in responding to questions (e.g., p. 336st, Check your Understanding, item 2).

Course 2 presents components of this idea in the account of cellular respiration (chapter 19, p. 595st) but does not tie them together. Alongside a diagram of a mitochondrion in a human cell (p. 595st, Figure 19–8), the inputs and outputs of cellular respiration are shown. Adjacent text describes the process of respiration in humans and then implies that plants also respire; but the focus is on energy transformation:

But what about plants? Plants don’t feel warm. Do plants carry out respiration? In the following activity, you can prove to yourself that plants carry out respiration, and that this process converts one form of energy to another. [p. 595s]

Two pages later, the text notes that cells respire, and it gives the waste products of respiration but does not make the connection to plants:

Cells, like most factories, produce waste. The waste products of respiration are water and carbon dioxide. They are released from your body when you are exhaling. Nearly all organisms give off carbon dioxide as a result of respiration. [p. 597s]

There is a content match. The idea appears mainly in text; it is introduced in the context of photosynthesis (course 1, chapter 10) and ecosystems (course 1, chapter 11), presented as an example of a reaction that uses energy (course 2, Chapter 18: Chemical Reactions), and then portrayed as a part of the story of cells and energy (course 2, chapter 19). In course 1, a simpler version of this key idea is given—that plants use light energy to make food. After using the reaction as an example of an endothermic reaction, the more sophisticated version of the idea is presented:

Green plants convert light energy from the sun into sugars through the process of photosynthesis. The sugar produced contains a form of chemical energy. This same chemical energy is passed on to you through the food chain. [course 2, p. 594s]

The text asserts the key life science ideas without developing an evidence-based argument to support them. Further, it does not provide examples of phenomena that could be explained by these ideas. For example, the heat generated by a compost pile (or fermenting grape juice) could be used to make plausible the idea that living things release heat while breaking down their food (Idea d₃). Although activities involving growing yeast and compost piles are mentioned, neither is offered as evidence to support any idea, nor is evidence offered for the assertion that plants use carbon dioxide and water to make sugars (Idea c₁).

This set of key life science ideas tells a story of matter and energy transfer and transformation that spans several levels of biologic organization—ecosystems, organisms, cells, and possibly molecules. Links between the life and physical sciences are particularly important, as, for example, in linking the transformation of matter and energy in physical systems (where it may be easier to keep track of the beginning and ending products of matter and energy).

Science Interactions is an integrated program in that it distributes the Earth, life, and physical sciences over three grades (rather than including the content of a single discipline in each grade). As stated in the introductory material, “[T]he series helps you teach some of the basic concepts from physical science early on. This, in turn, makes it easier for your students to understand other concepts in life and Earth science” (p. 11T). The program also attempts to make numerous connections among the sciences and between science and technology. This organization has implications for the coherence of the presentation of the key life science ideas.

The table below shows how the key life science ideas are distributed over the three courses. Nearly all of the ideas are treated in multiple chapters and often in multiple courses. This makes it possible for students to encounter these ideas in a variety of contexts. (It should be noted that this table was prepared by the reviewers. The material itself does not alert teachers to how the ideas are distributed.)

Course, Chapter, Chapter Name	Key Life Science Idea
	a	b	c1	c2	c3	c4	d1	d2	d3	e
1.8 Viruses and Simple Organisms						X
1.9 Animal Life		X			X
1.10 Plant Life		X	X	X			X
1.11 Ecology		X				X	X			X
2.16 Breathing									X
2.17 Basic Units of Life									X
2.18 Chemical Reactions			X				X		X
2.19 How Cells Do Their Jobs	X			X	X		X	X	X	X
3.10 Organic Chemistry	X
3.11 Fueling the Body	X				X

In the course materials, however, little attempt is made to relate the ideas to one another or to ideas in physical science. For example, no attempt is made to connect energy transformations in cells, organisms, and ecosystems. The idea that energy flows through ecosystems (Idea e) is restated in the chapter that deals with cellular respiration but not connected to the idea that energy transformations in ecosystems result from energy transformations in millions and millions of cells. Similarly, little effort is made to associate energy transformations in living systems with those in physical systems. Even though an earlier chapter shows that heat energy can be transformed into mechanical energy (course 2, Chapter 13: Energy Resources, pp. 392–394s), no effort is made to connect this to the energy transformations in cells.

Even with the above table, it is not possible to infer a logical sequence in the presentation of the key ideas. Although the claim is made in the introduction to the Teacher Wraparound Edition that “Science Interactions teaches concepts in a logical sequence from the concrete to the abstract” (p. 11T), this is not apparent from looking at the details of these specific key ideas. For example, Idea c₄ is the first idea presented: “Fungi help decompose dead organisms and recycle the materials of which these organisms were made” (course 1, Chapter 8: Viruses and Simple Organisms, p. 273s). Yet, it is not until later in course 1 that the text mentions what some of these materials are (in reviewing the main points of Chapter 11: Ecology, the text states: “Many materials, such as water, oxygen, carbon dioxide, and nitrogen, are constantly being recycled through the environment” [p. 374s]). Another concern is the delay in discussing what food is (Idea a) until late in course 2 and the beginning of course 3, after the processes of food-making and breaking down (Ideas c, d) have been presented.

While numerous connections are made in each chapter, many of them are so superficial that the net effect may leave both students and teachers overwhelmed. Indeed, the teacher’s introduction states that the program will help teachers “Connect one area of science to another. Relate science to technology, society, issues, hobbies, and careers. Show your students again and again how history, the arts, and literature can be part of science. And help your students discover the science behind things they see every day” (p. 11T). This may be the case, but it is not an approach that is likely to help students focus on an important set of ideas.

However, the inclusion of the photosynthesis reaction as an example of an endothermic reaction in course 2, Chapter 18: Chemical Reactions does not seem superficial. This is presented after students have observed a reaction in which heat is absorbed. One might ask why endothermic reactions are presented before exothermic reactions are (given that most students are probably more familiar with energy-yielding reactions) and why cellular respiration is not presented as an example of an energy-yielding reaction. Nonetheless, the inclusion of this life science example in a physical science chapter is not seen in materials often. (One also can wonder why the terms “endothermic” and “exothermic” are needed, but that issue is considered in the instructional analysis.)

The main chapters that treat the key life science ideas of matter and energy transformations (course 1, Chapter 10: Plant Life, and Chapter 11: Ecology; course 2, Chapter 19: How Cells Do Their Jobs; and course 3, Chapter 11: Fueling the Body) contain some content that goes beyond the level of sophistication of the key ideas. For example, course 1, Chapter 10 includes topics such as plant classification (pp. 316–321s) and plant reproduction (pp. 322–330s) that are outside the scope of science literacy as defined in Benchmarks for Science Literacy (American Association for the Advancement of Science, 1993) and National Science Education Standards (National Research Council, 1996). Even sections that treat key ideas on matter and energy transformations include investigations that are not related to the key ideas (e.g., chromatography of leaf pigments [pp. 332–333s] and opening and closing of stomata [pp. 334–335s]). Still other investigations focus on less sophisticated version of the key ideas, which students will likely have studied in earlier grades. For example, course 1 includes an investigation of what owls eat (chapter 11, pp. 354–355s) that focuses on what eats what rather than on the transformations of matter and energy that are involved. Although, overall, the content that exceeds the key ideas in these chapters is not excessive, it is interspersed with them; hence it may distract students from focusing on the key ideas.

The evaluation teams developed a summary assessment of the most common kinds of errors found in each of the three subject areas—physical science, Earth science, and life science. In this context, “errors” is taken to mean not only outright inaccuracies, but also those instances in which the material is very likely to lead to or support student misconceptions. Overall, inducement to misconstrue is the most serious problem of accuracy in the evaluated materials.

The teams’ collective findings, presented below, should be taken as having general applicability to all of the evaluated materials, not complete and specific applicability in toto to any one of them.

Identified errors occur most frequently in drawings and other diagrams. They take the form of representations that are likely to either give rise to or reinforce misconceptions commonly held by students. Following are life science examples of the kinds of misleading illustrative materials of most concern to the evaluation teams:

• Diagrams of energy pyramids that indicate decreases in energy (without indicating that the energy is given off as heat) can reinforce students’ misconception that energy is not conserved.

• Diagrams and explanations that show the reciprocal nature of respiration and photosynthesis can reinforce the misconception that only animals respire—and that plants do not. Furthermore, emphasizing the notion that these processes are reciprocal or balance one another fails to convey that the rate of photosynthesis is far more than that of respiration. Consequently, plants produce enough food (and oxygen) during photosynthesis both for their own needs and for the needs of other organisms.

• Diagrams of nutrient cycles in biological systems, such as the carbon-oxygen cycle or the nitrogen cycle, often misrepresent the transformation of matter—showing, for example, atoms of carbon in one form but not in others. By failing to show a particular element throughout the cycle, a text can reinforce the misconception that matter can disappear in one place and reappear in another, as opposed to simply changing forms.

The use of imprecise or inaccurate language is problematic in text and teacher materials, not solely in illustrations. In life science, one significant problem is that imprecise language in explanations of energy transformations can reinforce students’ common misconception that matter and energy can be interconverted in everyday chemical reactions. For example, presenting the overall equation for cellular respiration in which energy appears as a product without indicating where the energy was at the start can lead students to conclude that matter is converted to energy. Similarly, presenting the overall equation for photosynthesis in which energy appears only as a reactant can lead them to conclude that energy has been converted into matter.