Biology Concepts and Connections 5th Edition Chapter 7 Worksheet Answers

Suggested Citation:"Chapter 6: Activities for Teaching About Evolution and the Nature of Science." National Academy of Sciences. 1998. Teaching About Evolution and the Nature of Science. Washington, DC: The National Academies Press. doi: 10.17226/5787.

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Activities for Teaching About Evolution and the Nature of Science

Prior chapters in this volume answer the what and why questions of teaching about evolution and the nature of science. As every educator knows, such discussions only set a stage. The actual play occurs when science teachers act on the basic content and well-reasoned arguments for inclusion of evolution and the nature of science in school science programs.

This chapter goes beyond discussions of content and rationales. It presents, as examples of investigative teaching exercises, eight activities that science teachers can use as they begin developing students' understandings and abilities of evolution and the nature of science. The following descriptions briefly introduce each activity.

Activity 1: Introducing Inquiry and the Nature of Science

This activity introduces basic procedures involved in inquiry and concepts describing the nature of science. In the first portion of the activity the teacher uses a numbered cube to involve students in asking a question—what is on the unseen bottom of the cube?—and the students propose an explanation based on their observations. Then the teacher presents the students with a second cube and asks them to use the available evidence to propose an explanation for what is on the bottom of this cube. Finally, students design a cube that they exchange and use for an evaluation. This activity provides students with opportunities to learn the abilities and understandings aligned with science as inquiry and the nature of science as described in the National Science Education Standards.¹ Designed for grades 5 through 12, the activity requires a total of four class periods to complete. Lower grade levels might only complete the first cube and the evaluation where students design a problem based on the cube activity.

Activity 2: The Formulation of Explanations: An Invitation to Inquiry on Natural Selection

This activity uses the concept of natural selection to introduce the idea of formulating and testing a scientific hypothesis. Through a focused discussion approach, the teacher provides information and allows students time to think, interact with peers, and propose explanations for observations described by the teacher. The teacher then provides more information, and the students continue their discussion based on the new information. This activity will help students in grades 5 through 8 develop abilities related to scientific inquiry and formulate understandings about the nature of science.

Activity 3: Investigating Natural Selection

In this activity, the students investigate one mechanism for evolution through a simulation that models the principles of natural selection and helps answer the question: How might biological change have occurred and been reinforced over time? The activity is designed for grades 9 through 12 and requires three class periods.

Activity 4: Investigating Common Descent: Formulating Explanations and Models

In this activity, students formulate explanations and models that simulate structural and biochemical

data as they investigate the misconception that humans evolved from apes. The investigations require two 45-minute periods. They are designed for use in grades 9 through 12.

Activity 5: Proposing Explanations for Fossil Footprints

In this investigation, students observe and interpret "fossil footprint" evidence. From the evidence, they are asked to construct defensible hypotheses or explanations for events that took place in the geologic past. Estimated time requirements for this activity: two class periods. This activity is designed for grades 5 through 8.

Activity 6: Understanding Earth's Changes Over Time

Comparing the magnitude of geologic time to spans of time within a person's own lifetime is difficult for many students. In this activity, students use a long paper strip and a reasonable scale to represent visually all of geologic time, including significant events in the development of life on earth as well as recent human events. The investigation requires two class periods and is appropriate for grades 5 through 12.

Activity 7: Proposing the Theory of Biological Evolution: Historical Perspective

This activity uses historical perspectives and the theme of evolution to introduce students to the nature of science. The teacher has students read short excerpts of original statements on evolution from Jean Lamarck, Charles Darwin, and Alfred Russel Wallace. These activities are intended as either supplements to other investigations or core activities. Designed for grades 9 through 12, the activities should be used as part of three class periods.

Activity 8: Connecting Population Growth and Biological Evolution

In this activity, students develop a model of the mathematical nature of population growth. The investigation provides an excellent opportunity for consideration of population growth of plant and animal species and the relationship to mechanisms promoting natural selection. This activity will require two class periods and is appropriate for grades 5 through 12.

The activities in this chapter do not represent a curriculum. They are directed, instead, toward other purposes.

First, they present examples of standards-based instructional materials. In this case, the level of organization is an activity—one to five days of lessons—and not a larger level of organization such as a unit of several weeks, a semester, or a year. Also, these exercises generally do not use biological materials, such as fruit flies, or computer simulations. The use of these instructional materials in the curriculum greatly expands the range of possible investigations.

Second, these activities demonstrate how existing exercises can be recast to emphasize the importance of inquiry and the fundamental concepts of evolution. Each of these exercises was derived from already existing activities that were revised to reflect the National Science Education Standards. For each exercise, student outcomes drawn from the Standards are listed to focus attention on the concepts and abilities that students are meant to develop.

Third, the activities demonstrate some, but not all, of the criteria for curricula to be described in Chapter 7. For example, several of the activities emphasize inquiry and the nature of science while others focus on concepts related to evolution. All activities use an instructional model, described in the next section, that increases coherence and enhances learning.

Finally, there remains a paucity of instructional materials for teaching evolution and the nature of science. Science teachers who recognize this need are encouraged to develop new materials and lessons to introduce the themes of evolution and the nature of science. (See http://www4.nas.edu/opus/evolve.nsf)

Developing Students' Understanding and Abilities: The Curriculum Perspective

For students to develop an understanding of evolution and the nature of science requires many years and a variety of educational experiences.

Teachers cannot rely on single lessons, chapters, or biology and earth science courses for students to integrate the ideas presented in this document into their own understanding. In early grades (K–4) students might learn the fundamental concepts associated with "characteristics of organisms," "life cycles," and "organisms and environments." In middle grades they learn more about ''reproduction and heredity" and "diversity and adaptation of organisms." Such learning experiences, as described in the National Science Education Standards, set a firm foundation for the study of biological evolution in grades 9–12.

The slow and steady development of concepts such as evolution and related ideas such as natural selection and common descent requires careful consideration of the overall structure and sequence of learning experiences. Although this chapter does not propose a curriculum or a curriculum framework, current efforts by Project 2061 of the American Association for the Advancement of Science (AAAS) demonstrate the interrelated nature of students' understanding of science concepts and emphasize the importance of well-designed curricula at several levels of organization (for example, activities, units, and school science programs). The figure on the next page presents the "Growth-of-Understanding Map for Evolution and Natural Selection" based on Benchmarks for Science Literacy.²

Developing Student Understanding and Abilities: The Instructional Perspective

The activities in the chapter incorporate an instructional model, summarized in the accompanying box, that includes five steps: engagement, exploration, explanation, elaboration, and evaluation. Just as scientific investigations originate with a question that engages a scientist, so too must students engage in the activities of learning. The activities therefore begin with a strategic question that gets students thinking about the content of the lesson.

Once engaged, students need time to explore ideas before concepts begin to make sense. In this exploration phase, students try their ideas, ask questions, and look for possible answers to questions. Students use inquiry strategies; they try to

An Instructional Model

ENGAGE This phase of the instructional model initiates the learning task. The activity should (1) make connections between past and present learning experiences and (2) anticipate activities and focus students' thinking on the learning outcomes of current activities. Students should become mentally engaged in the concept, process, or skill to be explored.

EXPLORE This phase of the teaching model provides students with a common base of experiences within which they identify and develop current concepts, processes, and skills. During this phase,xxxxx students actively explore their environment or manipulate materials.

EXPLAIN This phase of the instructional model focuses students' attention on a particular aspect of their engagement and exploration experiences and provides opportunities for them to develop explanations and hypotheses. This phase also provides opportunities for teachers to introduce a formal label or definition for a concept, process, skill, or behavior.

ELABORATE This phase of the teaching model challenges and extends students' conceptual understanding and allows further opportunity for students to test hypotheses and practice desired skills and behaviors. Through new experiences, the students develop a deeper and broader understanding, acquire more information, and develop and refine skills.

EVALUATE This phase of the teaching model encourages students to assess their understanding and abilities and provides opportunities for teachers to evaluate student progress toward achieving the educational objectives.

relate their ideas to those of other students and to what scientists already know about evolution.

In the third step, students can propose answers and develop hypotheses. Also in this step, the teacher explains what scientists know about the questions. This is the step when teachers should make the major concepts explicit and clear to the students.

Educators understand that informing students about a concept does not necessarily result in their immediate comprehension and understanding of the idea. These activities therefore provide a step referred to as elaboration in which students have opportunities to apply their ideas in new and slightly different situations.

Finally, how well do students understand the concepts, or how successful are they at applying the desired skills? These are the questions to be answered during the evaluation phase. Ideally, evaluations are more than tests. Students should have opportunities to see if their ideas can be applied in new situations and to compare their understanding with scientific explanations of the same phenomena.

Activity 1
Introducing Inquiry and the Nature of Science

This activity introduces basic procedures involved in inquiry and concepts describing the nature of science. In the first portion of the activity the teacher uses a numbered cube to involve students in asking a question—what is on the bottom?— and the students propose an explanation based on their observations. Then the teacher presents the students with a second cube and asks them to use the available evidence to propose an explanation for what is on the bottom of this cube. Finally, students design a cube that they exchange and use for an evaluation. This activity provides students with opportunities to learn the abilities and understandings aligned with science as inquiry and the nature of science as described in the National Science Education Standards. Designed for grades 5 through 12, the activity requires a total of four class periods to complete. Lower grade levels might only complete the first cube and the evaluation where students design a problem based on the cube activity.

Standards-Based Outcomes

This activity provides all students with opportunities to develop abilities of scientific inquiry as described in the National Science Education Standards. Specifically, it enables them to:

identify questions that can be answered through scientific investigations,
design and conduct a scientific investigation,
use appropriate tools and techniques to gather, analyze, and interpret data,
develop descriptions, explanations, predictions, and models using evidence,
think critically and logically to make relationship between evidence and explanations,
recognize and analyze alternative explanations and predictions, and
communicate scientific procedures and explanations.

This activity also provides all students opportunities to develop understanding about inquiry and the nature of science as described in the National Science Education Standards. Specifically, it introduces the following concepts:

Different kinds of questions suggest different kinds of scientific investigations.
Current scientific knowledge and understanding guide scientific investigations.
Technology used to gather data enhances accuracy and allows scientists to analyze and quantify results of investigations.
Scientific explanations emphasize evidence, have logically consistent arguments, and use scientific principles, models, and theories.
Science distinguishes itself from other ways of knowing and from other bodies of knowledge through the use of empirical standards, logical arguments, and skepticism, as scientists strive for the best possible explanations about the natural world.

Science Background for Teachers

The pursuit of scientific explanations often begins with a question about a natural phenomenon. Science is a way of developing answers, or improving explanations, for observations or events in the natural world. The scientific question can emerge from a child's curiosity about where the dinosaurs went or why the sky is blue. Or the question can extend scientists' inquiries into the process of extinction or the chemistry of ozone depletion.

Once the question is asked, a process of scientific inquiry begins, and there eventually may be an answer or a proposed explanation. Critical aspects of science include curiosity and the freedom to pursue that curiosity. Other attitudes and habits of mind that characterize scientific inquiry and the activities of scientists include intelligence, honesty, skepticism, tolerance for ambiguity, openness to

new knowledge, and the willingness to share knowledge publicly.

Scientific inquiry includes systematic approaches to observing, collecting information, identifying significant variables, formulating and testing hypotheses, and taking precise, accurate, and reliable measurements. Understanding and designing experiments are also part of the inquiry process.

Scientific explanations are more than the results of collecting and organizing data. Scientists also engage in important processes such as constructing laws, elaborating models, and developing hypotheses based on data. These processes extend, clarify, and unite the observations and data and, very importantly, develop deeper and broader explanations. Examples include the taxonomy of organisms, the periodic table of the elements, and theories of common descent and natural selection.

One characteristic of science is that many explanations continually change. Two types of changes occur in scientific explanations: new explanations are developed, and old explanations are modified.

Just because someone asks a question about an object, organism, or event in nature does not necessarily mean that person is pursuing a scientific explanation. Among the conditions that must be met to make explanations scientific are the following:

Scientific explanations are based on empirical observations or experiments. The appeal to authority as a valid explanation does not meet the requirements of science. Observations are based on sense experiences or on an extension of the senses through technology.
Scientific explanations are made public. Scientists make presentations at scientific meetings or publish in professional journals, making knowledge public and available to other scientists.
Scientific explanations are tentative. Explanations can and do change. There are no scientific truths in an absolute sense.
Scientific explanations are historical. Past explanations are the basis for contemporary explanations, and those, in turn, are the basis for future explanations.
Scientific explanations are probabilistic. The statistical view of nature is evident implicitly or explicitly when stating scientific predictions of phenomena or explaining the likelihood of events in actual situations.
Scientific explanations assume cause-effect relationships. Much of science is directed toward determining causal relationships and developing explanations for interactions and linkages between objects, organisms, and events. Distinctions among causality, correlation, coincidence, and contingency separate science from pseudoscience.
Scientific explanations are limited. Scientific explanations sometimes are limited by technology, for example, the resolving power of microscopes and telescopes. New technologies can result in new fields of inquiry or extend current areas of study. The interactions between technology and advances in molecular biology and the role of technology in planetary explorations serve as examples.

Science cannot answer all questions. Some questions are simply beyond the parameters of science. Many questions involving the meaning of life, ethics, and theology are examples of questions that science cannot answer. Refer to the National Science Education Standards for Science as Inquiry (pages 145-148 for grades 5-8 and pages 175-176 for grades 9-12), History and Nature of Science Standards (pages 170-171 for grades 5-8 and pages 200-204 for grades 9-12), and Unifying Concepts and Processes (pages 116-118). Chapter 3 of this document also contains a discussion of the nature of science.

Materials and Equipment

1 cube for each group of four students (black-line masters are provided).

(Note: you may wish to complete the first portion of the activity as a demonstration for the class. If so, construct one large cube using a cardboard box. The sides should have the same numbers and markings as the black-line master.)
10 small probes such as tongue depressors or pencils.
10 small pocket mirrors.

Instructional Strategy

Engage Begin by asking the class to tell you what they know about how scientists do their work. How would they describe a scientific investigation? Get students thinking about the process of scientific

inquiry and the nature of science. This is also an opportunity for you to assess their current understanding of science. Accept student answers and record key ideas on the overhead or chalkboard.

Explore (The first cube activity can be done as a demonstration if you construct a large cube and place it in the center of the room.) First, have the students form groups of three or four. Place the cubes in the center of the table where the students are working. The students should not touch, turn, lift, or open the cube. Tell the students they have to identify a question associated with the cube. Allow the students to state their questions. Likely questions include:

What is in the cube?
What is on the bottom of the cube?
What number is on the bottom?

You should direct students to the general question, what is on the bottom of the cube? Tell the students that they will have to answer the question by proposing an explanation, and that they will have to convince you and other students that their answer is based on evidence. (Evidence refers to observations the group can make about the visible sides of the cube.) Allow the students time to explore the cube and to develop answers to their question. Some observations or statements of fact that the students may make include:

The cube has six sides.
The cube has five exposed sides.
The numbers and dots are black.
The exposed sides have numbers 1, 3, 4, 5, and 6.
The opposite sides add up to seven.
The even-numbered sides are shaded.
The odd-numbered sides are white.

Ask the students to use their observations (the data) to propose an answer to the question: What is on the bottom of the cube? The student groups should be able to make a statement such as: We conclude there is a 2 on the bottom. Students should present their reasoning for this conclusion. For example, they might base their conclusion on the observation that the exposed sides are 1, 3, 4, 5, and 6, and because 2 is missing from the sequence, they conclude it is on the bottom.

Use this opportunity to have the students develop the idea that combining two different but logically related observations creates a stronger explanation. For example, 2 is missing in the sequence (that is, 1, _, 3, 4, 5, 6) and that opposite sides add up to 7 (that is, 1–6; 3–4; _–5) and because 5 is on top, and 5 and 2 equal 7, 2 could be on the bottom.

If done as a demonstration, you might put the cube away without showing the bottom or allowing students to dismantle it. Explain that scientists often are uncertain about their proposed answers, and often have no way of knowing the absolute answer to a scientific question. Examples such as the exact ages of stars and the reasons for the extinction of prehistoric organisms will support the point.

Explain Begin the class period with an explanation of how the activity simulates scientific inquiry and provides a model for science. Structure the discussion so students make the connections between their experiences with the cube and the key points (understandings) you wish to develop.

Key points from the Standards include the following:

Science originates in questions about the world.
Science uses observations to construct explanations (answers to the questions). The more observations you had that supported your proposed explanation, the stronger your explanation, even if you could not confirm the answer by examining the bottom of the cube.
Scientists make their explanations public through presentations at professional meetings and journals.
Scientists present their explanations and critique the explanations proposed by other scientists.

The activity does not explicitly describe "the scientific method." The students had to work to answer the question and probably did it in a less than systematic way. Identifiable elements of a method—such as observation, data, and hypotheses—were clear but not applied systematically. You can use the experiences to point out and clarify scientific uses of terms such as observation, hypotheses, and data.

For the remainder of the second class period you should introduce the "story" of an actual scientific discovery. Historic examples such as Charles Darwin would be ideal. You could also assign students to prepare brief reports that they present.

Elaborate The main purpose of the second cube is to extend the concepts and skills introduced in the earlier activities and to introduce the role of prediction, experiment, and the use of technology in scientific inquiry. The problem is the same as the first cube: What is on the bottom of the cube? Divide the class into groups of three and instruct them to make observations and propose an answer about the bottom of the cube. Student groups should record their factual statements about the second cube. Let students identify and organize their observations. If the students are becoming too frustrated, provide helpful suggestions. Essential data from the cube include the following (see black-line master):

Names and numbers are in black.
Exposed sides have either a male or female name.
Opposing sides have a male name on one side and a female name on the other.
Names on opposite sides begin with the same letters.
The number in the upper-right corner of each side corresponds to the number of letters in the name on that side.
The number in the lower-left corner of each side corresponds to the number of the first letter that the names on opposite sides have in common.
The number of letters in the names on the five exposed sides progresses from three (Rob) to seven (Roberta).

Four names, all female, could be on the bottom of the cube: Fran, Frances, Francene, and Francine. Because there are no data to show the exact name, groups might have different hypotheses. Tell the student groups that scientists use patterns in data to make predictions and then design an experiment to assess the accuracy of their prediction. This process also produces new data.

Tell groups to use their observations (the data) to make a prediction of the number in the upper-right corner of the bottom. The predictions will most likely be 4, 7, or 8. Have the team decide which corner of the bottom they wish to inspect and why they wish to inspect it. The students might find it difficult to determine which corner they should inspect. Let them struggle with this and even make a mistake—this is part of science! Have one student obtain a utensil, such as a tweezers, probe, or tongue depressor, and a mirror. The student may lift the designated corner less than one inch and use the mirror to look under the corner. This simulates the use of technology in a scientific investigation. The groups should describe the data they gained by the "experiment." Note that the students used technology to expand their observations and understanding about the cube, even if they did not identify the corner that revealed the most productive evidence.

If students observe the corner with the most productive information, they will discover an 8 on the bottom. This observation will confirm or refute the students' working hypotheses. Francine or Francene are the two possible names on the bottom. The students propose their answer to the question and design another experiment to answer the question. Put the cube away without revealing the bottom. Have each of the student groups present brief reports on their investigation.

Evaluate The final cube is an evaluation. There are two parts to the evaluation. First, in groups of three, students must create a cube that will be used as the evaluation exercise for other groups. After a class period to develop a cube, the student groups should exchange cubes. The groups should address the same question: What is on the bottom of the cube? They should follow the same rules—for example, they cannot pick up the cube. The groups should prepare a written report on the cube developed by their peers. (You may have the students present oral reports using the same format.) The report should include the following:

title,
the question they pursued,
observation—data,
experiment—new data,

proposed answer and supporting data,
a diagram of the bottom of the cube, and
suggested additional experiments.

Due to the multiple sources of data (information), this cube may be difficult for students. It may take more than one class period, and you may have to provide resources or help with some information.

Remember that this activity is an evaluation. You may give some helpful hints, especially for information, but since the evaluation is for inquiry and the nature of science you should limit the information you provide on those topics.

Student groups should complete and hand in their reports. If student groups cannot agree, you may wish to make provisions for individual or "minority reports." You may wish to have groups present oral reports (a scientific conference). You have two opportunities to evaluate students on this activity: you can evaluate their understanding of inquiry and the nature of science as they design a cube, and you can assess their abilities and understandings as they figure out the unknown cube.

Activity 2
The Formulation of Explanations: An Invitation to Inquiry on Natural Selection

This activity uses the concept of natural selection to introduce the idea of formulating and testing scientific hypotheses. Through a focused discussion approach, the teacher provides information and allows students time to think, interact with peers, and propose explanations for observations described by the teacher. The teacher then provides more information, and the students continue their discussion based on the new information. This activity will help students in grades 5 through 8 develop several abilities related to scientific inquiry and formulate understandings about the nature of science as presented in the National Science Education Standards. This activity is adapted with permission from BSCS: Biology Teachers' Handbook.³