RNCSE 21 (1–2)

Reports of the National Center for Science Education
Volume: 
21
Issue: 
1–2
Year: 
2001
Date: 
January–April
Articles available online are listed below.

No "Kansas" in Arkansas

Reports of the National Center for Science Education
Title: 
No "Kansas" in Arkansas
Author(s): 
Art Hobson
Volume: 
21
Issue: 
1–2
Year: 
2001
Date: 
January–April
Page(s): 
6
This version might differ slightly from the print publication.
A small group of scientists has prevented another "Kansas" from happening in Arkansas. In 1999, anti-evolutionists quietly proposed that all references to "evolution" be removed from the Arkansas science education standards, and that "theories" be substituted for "theory" in the standards’ phrase "scientific theory of the development of living things". The clear intent of these "small" changes was to remove evolution from the state standards and to encourage the teaching of creationism as an alternative to evolution. If unopposed, these changes would probably have been inserted into the state science standards.

An interdisciplinary evolution discussion group at the University of Arkansas in Fayetteville learned of these proposed changes through statewide contacts with other groups interested in evolution education. To oppose the proposed changes, the group drew up a petition that supported the Department of Education's efforts to strengthen science education while protesting that the substitution of "theories" for "theory" would undermine this goal.

Ninety-one of the 95 faculty members of the natural and physical science departments signed the petition, including all 42 members of the Departments of Anthropology and Biological Sciences. The petition campaign was purposely carried out without newspaper coverage or other publicity, because it appeared that a strong petition could by itself have defeated the anti-evolution efforts and that publicity and political activity might have been counterproductive.

The petition’s effect was decisive. The Department of Education removed the proposed changes from the science standards. In fact, the petition’s demonstration of strong support for good science encouraged the state to propose new, pro-evolution changes in the state standards. Some of these changes deal with scientific methodology. For example, an explanation of "theory" was added:
[The term] scientific theory is not used, as people often use the word theory, to mean a hunch or a guess. A scientific theory is held with a high degree of confidence and is supported by enough evidence to make its abandonment unlikely. As new evidence is found, a theory may be modified but only with compelling evidence, verification and peer review.
Other changes deal explicitly with evolution. For example, the revised text reads:

[Students will] understand that all living things contain similar genetic material that evolves because of gene mutation, natural selection, and change in environments. Species change through time, and new life forms evolve.
The lesson here is that each state needs at least one organized pro-evolution group that maintains good lines of communication with departments of education, boards of education, and state and local legislators. [Ed: NCSE maintains links to several pro-evolution organizations in most states. These include science-teaching organizations, scientific research societies, civil-liberties groups, religious organizations, and more. Just call, write, or e-mail NCSE, or check out our web site www.ncseweb.org. ]

About the Author(s): 
Art Hobson
Professor Emeritus of Physics
University of Arkansas
Fayetteville AR 72701
ahobson@uark.edu

The Goal of Evolution Instruction: Belief or Literacy?

Reports of the National Center for Science Education
Title: 
The Goal of Evolution Instruction: Belief or Literacy?
Author(s): 
Robert A Cooper
Volume: 
21
Issue: 
1–2
Year: 
2001
Date: 
January–April
Page(s): 
14–18
This version might differ slightly from the print publication.

In the inaugural issue of RNCSE, Alters (1997) proposed that the goal of evolution education should be to teach students to believe in evolution. He argued that educators have resisted teaching evolution with the goal of student belief on the basis of five misconceptions. These are (Alters 1997: 16):

  1. "belief" means little more than personal convictions — no empirical evidence;
  2. "belief" is never a goal in public education;
  3. evolution has little empirical evidence;
  4. belief cannot be assessed, therefore it does not belong as an educational goal;
  5. teaching evolution with belief as a goal is tantamount to proselytizing students
Although he offers sound arguments to refute misconceptions (2) and (4), Alters's analyses of misconceptions (1), (3), and (5) need further examination. The issues regarding the teaching of evolution in public schools with diverse populations are much more complex. We must avoid the temptation to teach evolution in a didactic, authoritarian manner regardless of the nature of the student population and their prior beliefs — an approach that would be detrimental to the goal of scientific literacy for all (American Association for the Advancement of Science 1990). It is time to revisit these issues and explore them in the context of current efforts in science education reform and what we know about how students learn. A thorough analysis of the situation with an eye toward making instructional recommendations must take into account what we have learned from research into students' pre-instructional beliefs and worldviews.

Use of the word "belief"

In his discussion of the first misconception, Alters contended that the words "believe" and "accept" are essentially synonymous and are used interchangeably by both scientists and Protestant ministers. He also acknowledged that the word "believe" is more often associated with nonscientific uses in the vernacular but dismissed this distinction as unimportant. However, the distinction between the words "believe" and "accept" should not be merely dismissed as semantics in the context of teaching about evolution.

The choice of words teachers use when discussing evolutionary theories and the evidence that supports them may be crucial to the students' interpretation of the teacher's instructional intent. The use of the word "belief" often carries with it connotations of acceptance based only on faith or personal opinion. When the subject of evolution is raised, students frequently ask teachers whether they believe in evolution or not. A teacher who simply responds in the affirmative may inadvertently convey an inaccurate view of evolution and the nature of science. Whether intended or not, students may have the impression that the teacher is proselytizing for evolution. It is essential that students understand that acceptance of beliefs in science, unlike in religion, is based upon reliable empirical evidence and sound arguments. The use of the word "believe" by scientists and Protestant ministers may convey vastly different messages depending on the context in which these words are used, and students must be made aware of this distinction.

As Alters correctly pointed out, "What is of importance is on which data and arguments one bases a particular belief or acceptance" (1997: 15). Yet teachers cannot and should not dismiss the different interpretations students may have of the words "believe" and "accept". Consequently, teachers should avoid the careless use of the word "believe" when teaching about evolution and be certain that students are aware that a scientist's "belief" in evolution stems from the examination of, and the acceptance of, the empirical evidence and arguments supporting evolutionary theory. Smith endorses this view when he wrote:
Although the distinction between believing and accepting may be a subtle one for many, it is crucial to understanding the nature of science; moreover, drawing carefully the distinction between belief (or faith) in the absence of objective evidence and acceptance that is based on evidence provides an excellent opportunity for helping students understand what science is (1994: 595).

Evolution has little empirical evidence

Another misconception addressed by Alters is that theories of evolution are supported by little or no empirical evidence. Alters contended that the lack-of-evidence "misconception is generally held by non-biology majors who simply have not been introduced to the voluminous amount of data that support evolution, and/or do not themselves believe evolution occurred" (1997: 16). He echoed the view common to professional scientists that this situation could be remedied simply by teaching evolution as fact.

In fact, this misconception is much more widespread and complex than most of us imagine, and the suggestion that teachers simply teach evolution as fact is unlikely to remedy the situation. The misconception that there is little evidence to support evolution is typically at the root of arguments for equal time for creationism in the classroom, and the wide appeal of such arguments is apparent in the results of a recent Gallup poll, which found that 68% of Americans advocate the teaching of creationism along with evolution in public schools (Gallup News Service 2001). Significant percentages of the American population also prefer the biblical account of creation to evolution, suggesting that religious beliefs are frequently at the root of the lack-of-evidence claims. The situation is clearly much more complex than the fact that students simply have not been exposed to the evidence. Instructional recommendations for dealing with evolution in such a climate must go further than simply recommending that evolution be taught as fact.

There are essentially three problems that arise from such an approach. First, in many instances, science teachers who see evolution as conflicting with their religious beliefs may not present evolution accurately, if they present it at all. Even if the teacher's religious beliefs are not an issue, many science teachers simply have a poor understanding of the factual basis of evolutionary theory (Eve and Dunn 1990; Osif 1997) and many others apparently avoid evolution or de-emphasize it because they fear potential conflict (Scharmann 1993). Some of the problem may be in the scant instruction in evolution that teachers-in-training receive, so they know or understand the subject poorly themselves. Practicing teachers may also need periodic updates on the mass of new scientific discoveries and information that validate evolution.

Second, even when teachers understand evolution and teach it well, students frequently hold misconceptions about evolution that employ teleological and Lamarckian concepts (Jensen and Finley 1997). There is ample evidence in the science education and cognitive psychology literature that pre-instructional beliefs like these are remarkably resistant to change. For instruction to be successful, it must go beyond simply teaching evolution as fact (Chinn and Brewer 1993). Good evolution instruction must engage students in inquiry and provide activities that tend to promote conceptual change (Jensen and Finley 1995; Nickels and others 1996).

Finally, evolutionary theories intersect with deeply held beliefs that constitute students' worldviews (Cobern 1991). Implying that simple exposure to the evidence for evolution will result in conceptual change in students assumes that all students already accept the basic assumptions of a scientifically compatible worldview. On the contrary, students come to class with a wide variety of worldviews — many that are inconsistent with the basic assumptions of a scientifically compatible one. Despite the fact that evolution receives support from a wealth of data in many different disciplines, the evidence for evolution is not the issue for these students. Because of their worldviews, they simply do not believe evolutionary explanations, and since they do not consider evolutionary accounts believable, their interpretation of instructional goals will differ from that of the teacher. Their perception will likely be that a teacher who presents evolution in a didactic, authoritarian manner is proselytizing for evolution.

Taking these differences in worldview into account, Cobern argues that "The acquisition of a scientific viewpoint is not at heart an epistemological issue, nor is it a simple matter of conceptual change" (1991: 179). Thus, establishing an instructional environment for these students that is conducive to learning requires an approach that is akin to "foreign relations" (Hills 1989: 183; Cobern 1995).

Teaching evolution as fact is proselytizing

It is possible that teachers are prevented from teaching students to believe in evolution because of a concern that teachers who teach evolution as fact are proselytizing. Alters argued, "Teachers are not proselytizing students when they attempt to change students' belief from 'arsenic is healthy to ingest' to 'arsenic is dangerous to ingest.' Likewise, teachers are not proselytizing when they attempt to have students believe in the scientific fact of evolution" (1997: 16). Indeed, the US Court of Appeals in Florey v Sioux Falls School District (1980) ruled, in effect, that while the fact of evolution may offend some students and parents, the offense is unintended and unavoidable.

This approach may address the legal and constitutional issues, but it avoids educational issues for students whose worldviews are incompatible with science. A didactic and authoritarian approach has little chance of achieving the goal of student belief. Besides alienating students, the teacher's example is likely to foster misconceptions both about evolution and the nature of science. Cobern similarly criticizes this approach:
The challenge here is disbelief — many students simply do not believe evolutionary accounts of origins. By neglecting this legitimate student concern, the teacher tacitly takes an authoritarian and dogmatic stance with the result that the beliefs of many students, if not most, remain unchanged. Moreover, students also resist conceptual change, and hence their understanding of evolution remains inadequate (1994: 585).
When a teacher presupposes that all students will accept from the outset the assumptions underlying a scientifically compatible worldview, those assumptions become part of what has been referred to as the "hidden curriculum". Kilbourn argues that such an approach circumvents student choice since their awareness that there are other ways to view the world can be blocked. He contended that "such teaching is a morally questionable practice" (1980: 42). In any event, it is highly probable that such an approach will serve only to foster misunderstanding of evolution and nature of science.

Evolution and the nature of science

The failure of many students to understand and accept the fact of evolution is often a consequence of the naïve views they hold of the nature of science, which may be largely a result of the way science is presented in textbooks and in classroom discourse (Toumey 1996; McComas 1998). Many students believe that the business of science is to discover knowledge using a special method that leads to fundamental, unchanging truths that must be accepted with certainty by the scientific community (McComas 1998). In the public eye, the prestige and authority of science buttress scientific conclusions "because science is widely believed to transcend the social forces that obviously shape other human institutions, such as politics or religion. Science is believed to be, in a word, 'objective'" (Toumey 1996: 6).

According to this naïve view, the key to the unique success of science at producing true knowledge is "The Scientific Method", which, on the standard account, involves formulating hypotheses, making predictions, and then going into the laboratory to perform the crucial experiment (Gould 1980). In this parody of scientific methods, if a hypothesis passes the test set up by the crucial experiment, that is, if it is confirmed by direct observation, then it is "proven" and it is considered a fact or a law and it is true for all time.

In contrast, the work of many evolutionary biologists involves the reconstruction of the past. The methods they use do not conform to the standard view of "The Scientific Method". Although they cannot replay the past in order to experiment on and make direct observations of the events, there are methods for reconstructing the past history of life on earth (Cooper in press). The methods and patterns of reasoning resemble those that forensic scientists use to reconstruct a crime scene. Just as forensic scientists can reach conclusions that are reliable enough to convict a suspect of a crime, evolutionary biologists can establish reliable knowledge of the earth's past. Unfortunately, since most nonscientists, largely as a result of their science education in school, place a high priority on direct observation of events that occur during controlled experiments, they question the validity of the historical reconstruction of the past on the grounds that no one was there to see it happen. These critics frequently contend, for example, that since no one actually saw humans evolve from their ancestors, this conclusion may not be true, and, therefore, it is acceptable to believe whatever one wants about human origins.

Because evolutionary biologists employ different approaches to problem solving, "creation scientists" (Morris 1974) and, more recently, proponents of "Intelligent Design" (Johnson 1991) have attempted to characterize evolutionary biology as a philosophy of naturalism rather than a science. Both groups claim that creationism and evolution can be placed on an equal footing with regard to empirical support; therefore, a balanced and fair treatment should give equal time to both sides of the issue.

To a public that misunderstands science, arguments for equal time in the curriculum seem entirely fair and democratic. Any approach to evolution education based chiefly on a claim to scientific authority puts teachers in a weak position to defend against equal time arguments (Cooper 1996) and will lend credence to the misrepresentation of evolution as a philosophy of naturalism. Teachers need to avoid authoritarian instructional approaches that disguise the processes that generate scientific knowledge and give the appearance that they are proselytizing. Such didactic and authoritarian approaches to instruction tend only to reinforce misunderstandings of science.

The only way to confront misunderstandings of evolution and the nature of science is to help students achieve a better understanding of the inquiry methods actually employed by scientists. The NRC's National Science Education Standards characterized scientific inquiry as the "diverse ways in which scientists study the natural world and propose explanations based on the evidence derived from their work" (NRC 1996: 23, emphasis added), clearly rejecting the myth of the Scientific Method. Students' understanding of scientific inquiry must also include methods of historical reconstruction. Gould (1986) argues that historical sciences such as evolutionary biology require a different, though no less rigorous, method in order to reconstruct history. In Gould's view, the elucidation of this historical method was one of Darwin's greatest achievements. In addition to establishing the fact that all life was related by common descent and providing a mechanism for evolution, Darwin also freed the discipline from metaphysical speculation and put it on a firm, empirical base. By first teaching students about scientific methods and the nature of scientific knowledge, biology teachers can provide a framework that will enable students to appreciate evolution as the powerful and unifying theoretical perspective that it is.

Approaches to evolution instruction

How should teachers approach the topic of evolution? Clearly, if we are going to teach students successfully about evolution and have them recognize and accept it as a well-supported scientific theory, then we need to address the widely-held misconceptions students harbor about evolution and the nature of science. One suggestion is to assess students' prior beliefs and modes of thought as a first step in any unit on evolution (Bishop and Anderson 1986, 1990; Nelson 1989; Scharmann 1993; Cobern 1994; Smith 1994; Jensen and Finley 1997). Among these, Cobern (1991, 1994) provides the most thorough treatment of worldview considerations and the potential difficulties that may arise when instruction conflicts with worldview. He cautions that the approach to teaching about evolution should not be scientistic — that is, teachers should avoid adopting a view that the scope of scientific authority is unlimited and beyond reproach (Duschl 1988: 52) or that "science provides the one reliable source of objective knowledge" (Cobern 1994: 585). Cobern recommends beginning instruction in evolution with a classroom dialogue that is informed with the knowledge of the cultural history of Darwinism.

Smith (1994) contends that any classroom discussion that precedes the teaching of evolution, and thus sets the stage for an understanding of evolution as science, should deal with the nature of science and how it differs from religion and other disciplines. He concluded that "evolution instruction is challenging because it is both conceptually difficult and because it may not fit with students' worldviews, histories, and perceptions. Successful instructional planning must take all of these facets into consideration" (Smith 1994: 596).

Clough (1994) agrees with Cobern (1994) and Smith (1994) that potential student concerns about conflicts between science and religion should also be addressed prior to the introduction of evolution in the classroom. He also recommends that teachers (1) distinguish theories of evolution from theories of the origin of life from its inorganic precursors — separate and distinct theories that are frequently conflated by students and the general public; (2) help students to understand the distinction between the use of the word "theory" in science and its use in the vernacular; (3) adopt an instrumentalist perspective with regard to belief in evolution, using the historical example of the use of this approach by Copernicus for heliocentrism and for Kekule in his study of atoms. Finally, and perhaps most important, Clough stressed (4) the need for teachers to respect students' beliefs. If students perceive a lack of such respect from their teachers, it will serve to engender hostility toward science and evolution.

Jensen and Finley (1997) used a historically-rich curriculum and paired-problem-solving to achieve some success in eliminating misconceptions about evolution and the nature of science. They identified three pre-Darwinian theories that were used to make sense of the biological world early in the 19th century. They labeled these teleology, Lamarckian evolution, and natural theology. Because many student misconceptions of evolution are consistent with one of these pre-Darwinian theories, Jensen and Finley reasoned that if they brought these pre-Darwinian theories to the students' attention and then pointed out their flaws, they would be more successful in promoting the development of a Darwinian point of view among students. They reported improved student understanding of evolution using their approach. In addition, they observed an increased use of Darwinian ideas by students and a decreased use of non-Darwinian ideas.

The approaches recommended in these articles enable biology teachers to expose students' prior beliefs and set up conditions that may allow students to examine and contrast those beliefs with currently accepted scientific views. These papers represent only a small sample of the recommendations and activities for teaching about evolution that are available in the literature.

Conclusion

Alters's intent that all students both understand evolution and believe it to be the best explanation for life's unity and diversity is a noble one. After all, he argued that we teach other theories, such as the Copernican theory of the solar system, with the intent that students will both understand and believe them. However, the strategies we adopt must employ recommendations based on an understanding of the complex issues resulting from students' pre-instructional beliefs and diverse worldviews. An authoritarian approach will only serve to polarize religion and science in the minds of students, and foster close-mindedness and resistance from many who will then be ignorant of the historical background and the empirical evidence that have led biologists to the evolutionary point of view.

While we may adopt universal belief as our goal, we must also recognize that, given the diversity of worldviews we find in the typical classroom, the goal may be an unrealizable one. In particular, fundamentalist Christians who insist on a literal reading of Genesis may never find sufficient grounds for a reconciliation of their religious beliefs and evolution (Ruse 2001). The most important issue at stake here, however, is not whether students ultimately accept or reject evolution, but that students develop an accurate understanding of the nature of science and the scientific process, resulting in the improvement in scientific literacy. An education that promotes intellectual maturity and reflective judgment (King and Kitchener 1994) must enable all students to understand and appreciate all perspectives, including the scientific one. Instruction designed to achieve this goal must be informed by the metaphor of teaching science as "foreign affairs" (Hills 1989; Cobern 1995). Even if students ultimately choose to reject an evolutionary view of the world, the ability to "see" from that perspective may promote greater tolerance and understanding as well as greater intellectual maturity. Whether students choose to accept (believe) evolution or not, they must come to understand what science is and understand that evolution is a powerful scientific theory that provides a unifying framework for biology.

Since science — and evolution in particular — is judged not to conflict with the basic tenets of many religions organizations and denominations (Matsumura 1995), most students will find that they can retain their religious beliefs while developing a sound understanding of evolution. Many students may even come to accept (believe) that the evolutionary point of view is the best account of the evidence that we have.

References

American Association for the Advancement of Science. Science for all Americans. New York: Oxford University Press, 1990.

Alters B. Should student belief of evolution be a goal? Reports of the National Center for Science Education 1997 Jan–Feb; 17 (1): 15–6.

Bishop BA, Anderson CW. Evolution by Natural Selection: A Teaching Module. East Lansing (MI): The Institute for Research on Teaching, Michigan State University, 1986.

Bishop BA, Anderson CW. Student conceptions of natural selection and its role in evolution. Journal of Research in Science Teaching 1990; 27: 415–27.

Chinn CA, Brewer WF. The role of anomalous data in knowledge acquisition: A theoretical framework and implications for science education. Review of Educational Research 1993; 63 (1): 1–49.

Clough MP. Diminishing students' resistance to biological evolution. The American Biology Teacher 1994; 56: 409–15.

Cobern WW. World View Theory and Science Education Research, NARST Monograph nr 3. Manhattan (KS): National Association for Research in Science Teaching, 1991.

Cobern WW. Point: Belief, understanding, and the teaching of evolution. Journal of Research in Science Teaching 1994; 31 (5): 583–90.

Cobern WW. Science education as an exercise in foreign affairs. Science & Education 1995; 4 (3): 287–302.

Cooper RA. Should creationism be part of evolution statement? [letter to the editor]. The American Biology Teacher 1996; 58 (3): 133–4.

Cooper RA. Scientific knowledge of the past is possible: Confronting myths about evolution and the nature of science. The American Biology Teacher, in press.

Duschl RA. Abandoning the scientistic legacy of science education. Science Education 1988; 72 (1): 51–62.

Eve RA, Dunn D. Psychic powers, astrology & creationism in the classroom? The American Biology Teacher 1990; 52: 10–21.

Gallup News Service. Public favorable to creationism: But prefers it be taught along with evolution. 2001 Feb; Available from . Last accessed September 28, 2001.

Gould SJ. Senseless signs of history. In: Gould SJ. The Panda's Thumb. New York: WW Norton, 1980. p 27–34.

Gould SJ. Evolution and the triumph of homology, or why history matters. American Scientist 1986; 74: 60–9.

Hills GLC. Students' "untutored" beliefs about natural phenomena: Primitive science or commonsense? Science Education 1989; 73: 155–86.

Jensen MS, Finley FN. Teaching evolution using historical arguments in a conceptual change strategy. Science Education 1995; 79 (2): 147–66.

Jensen MS, Finley FN. Teaching evolution using a historically rich curriculum & paired problem solving instructional strategy. The American Biology Teacher 1997; 59 (4): 208–12.

Johnson PE. Darwin on Trial. Washington (DC): Regnery Gateway, 1991.

Kilbourn B. World views and science teaching. In: Munby H, Orpwood G, Russell T, eds. Seeing Curriculum in a New Light: Essays from Science Education. Toronto: OISE Press/The Ontario Institute for Studies in Education, 1980. p 34–43.

King PM, Kitchener KS. Developing Reflective Judgment: Understanding and Promoting Intellectual Growth and Critical Thinking in Adolescents and Adults. San Francisco (CA): Jossey-Bass, 1994.

Matsumura M, ed. Voices for Evolution, 2d ed. Berkeley (CA): National Center for Science Education, 1995.

McComas WF. The principal elements of the nature of science: Dispelling the myths. In: McComas WF, ed. The Nature of Science in Science Education: Rationales and Strategies. Dordrecht (NL): Kluwer Academic Publishers; 1998. p 53–70.

Morris HM. The Troubled Waters of Evolution. San Diego CA: Creation-Life Publishers, 1974.

National Research Council [NRC]. National Science Education Standards. Washington (DC): National Academy Press, 1996.

Nelson CE. Skewered on the unicorn's horn: The illusion of tragic tradeoff between content and critical thinking in the teaching of science. In: Crow LW. ed. Enhancing Critical Thinking in the Sciences. Washington (DC): Society for College Science Teaching, 1989. p 17–27.

Nickels MK, Nelson CE, Beard J. Better biology teaching by emphasizing evolution & the nature of science. The American Biology Teacher 1996; 58 (6): 332–6.

Osif BA. Evolution and religious beliefs: A survey of Pennsylvania high school teachers. The American Biology Teacher 1997; 59: 552–6.

Ruse M. Can a Darwinian be a Christian?: The Relationship Between Science and Religion. Cambridge (UK): Cambridge University Press, 2001.

Scharmann LC. Teaching evolution: Designing successful instruction. The American Biology Teacher 1993; 55 (8): 481–6.

Smith MU. Counterpoint: Belief, understanding, and the teaching of evolution. Journal of Research in Science Teaching 1994; 31 (5): 591–7.

Toumey CP. Conjuring Science: Scientific Symbols and Cultural Meanings in American Life. New Brunswick (NJ): Rutgers University Press, 1996.

About the Author(s): 
Robert A Cooper
Pennsbury High School
705 Hood Boulevard
Fairless Hills PA 19030
rac7@erols.com

Teaching Evolution: Do State Science Standards Matter?

Reports of the National Center for Science Education
Title: 
Teaching Evolution: Do State Science Standards Matter?
Author(s): 
Randy Moore
Volume: 
21
Issue: 
1–2
Year: 
2001
Date: 
January–April
Page(s): 
19–21
This version might differ slightly from the print publication.
Lerner's (2000) much-publicized evaluation of states' standards for teaching evolution and their impact on science teaching produced a variety of responses among educators. Many scientists were encouraged by the fact that 31 states have satisfactory or better standards, whereas other educators were dismayed that 19 states have standards that are less than satisfactory. Indeed, although the average grade for all 50 states was a passable C, more states received failing grades (F and F-) than were rated excellent (see Figure 1). Ten of the states receiving grades of D or worse do not use the word evolution in their educational guidelines, and one (Maine) uses the word evolution once.

State standards for teaching evolution are important, for they are presumably the basis for what teachers teach and students learn, and thereby establish the foundation for states' desired educational outcomes. However, a more important factor that influences the quality of evolution education is not discussed in Lerner's report — namely, the evolution-related attitudes and actions of biology teachers. How do states' standards for teaching evolution relate to the acceptance or rejection of evolution by biology teachers?

Table 1 summarizes how the quality of states' standards for teaching evolution relate to the evolution-related attitudes of biology teachers. In states having low standards for teaching evolution (for example, grades of D, F, or F-, such as in Illinois, Kentucky, Ohio, Georgia, and Kansas), relatively large percentages of biology teachers believe that creationism should be taught in science classes in public schools. In some of these states, significant percentages of biology teachers actually teach creationism in their classes, despite the fact that the US Supreme Court's decision in Edwards v Aguillard established that it is unconstitutional (Moore 2000). The presence of low standards for teaching evolution also correlates with biology teachers' lack of emphasis on evolution (for example, Tennessee and Oklahoma) and anti-science policies such as the presence of anti-evolution disclaimers in biology textbooks (as in Alabama). As Lerner (2000) noted, although low standards for teaching evolution are concentrated in the Bible Belt, they also occur elsewhere (for example, Ohio and Illinois).

Figure 1 States having satisfactory standards for teaching evolution are not much different. For example, in Louisiana (see Aguillard 1999, Moore 1999c, and references therein) where standards are "satisfactory", over 40% of biology teachers believe that creationism is or may be scientifically valid, and they either do or want to teach creationism in their classes (see Table 1). Nearly another quarter of biology teachers avoid or play down the topic, and many of the state's biology teachers do not recall hearing the word evolution in their college biology courses. Furthermore, the Louisiana Committee for Science Standards treats evolution as it does witchcraft, the occult, and other fringe ideas that are banned from the state's exit exams.

In Texas, another state having "satisfactory" standards for teaching evolution, evolution receives inadequate coverage in at least half of all biology courses (Shankar 1990; Shankar and Skoog 1993). Thus, the presence of "satisfactory" guidelines for teaching evolution does not mean that large percentages of biology teachers do not endorse (and sometimes teach) creationism in their courses. What about states that have "good" (for example, Minnesota and South Dakota) or "excellent" or "very good" (for example, Indiana and Pennsylvania) standards for teaching evolution? Although these states have the nation's highest standards for teaching evolution, relatively large percentages of their biology teachers believe that creationism should be included in science classes, spend little time teaching evolution, and question the scientific validity of evolution (Weld and McNew 1999; Rutledge and Warden 2000).

Do Standards Matter?


Although standards for teaching science have been touted as being important for the reform of science education, the studies summarized in Table 1 show that standards often mean little in biology classrooms. Indeed, prior research shows that relatively large percentages of biology teachers throughout the United States continue to endorse creationism, question evolution, and even teach creationism in their courses, regardless of their state's standards for evolution education (see Table 1 and references therein). As Don Aguillard has noted, creationism is alive and well in biology classrooms (Moore 1999c).



Evolution-related instruction is influenced by educational standards and a variety of other factors such as textbooks, the curriculum, and tests. However, the most important factor in student learning is the teacher. Throughout the United States, many biology teachers avoid (or do a poor job of) teaching evolution, endorse creationism, or, in some cases, teach creationism. One important consequence of such behavior by teachers is that the biology education of "over a quarter — and perhaps as many as half — of the nation's high school students is shaped by creationist influence — in spite of the overwhelming opposition of the nation's scientific, educational, intellectual, and media establishments" (Eve and Harrold 1991).

The endorsement of creationism by relatively large percentages of biology teachers is not a new phenomenon. For example, more than 60 years ago biologist Oscar Riddle (1941) reported the popularity of creationism among biology teachers and noted that fewer than half of high school biology teachers taught evolution. Almost two decades later Herman Muller (1959) again observed the popularity of creationism among biology teachers and noted that biology teaching was dominated by "antiquated religious traditions".

When the National Association of Biology Teachers (NABT) established its "Fund for Freedom in Science Teaching" in the 1970s to combat the anti-science campaigns of creationists, many members of NABT were outraged. According to Nelkin (1982: 158), "letters poured into" NABT's national office decrying "vicious scientific attacks on the creationists" and attempts to "promote atheism and agnosticism in the schools". To accommodate its many creationist members, NABT sponsored a well-attended session about creationism at its annual meeting and published several articles promoting creationism in its journal, The American Biology Teacher (for example, Gish 1970, 1973; Moore 1973; also see Nelkin 1982). Today, many biology teachers continue to proclaim their endorsement of creationism and rejection of evolution (Harp 1999; Scanlon and Uy 1999; Wolfson 1999; Moore 1999a, 2000).

Standards are not altogether useless in the fight for evolution education. Standards for teaching evolution can provide important support for biology teachers facing protests from creationist students, parents, and administrators who want creationism to be taught (or evolution not to be taught) in biology classes. In addition to state standards, numerous science education organizations (for example, the American Association for the Advancement of Science [1989], the National Association of Biology Teachers [1997], the National Academy of Sciences [1998], the National Research Council [1985], and the National Science Teachers Association [1997]) have issued standards and policy statements urging biology teachers to make evolution a central theme in their classes.

However, states' and science education organizations' standards for teaching evolution have not changed the fact that evolution is often taught poorly — or not at all — in biology classes. As a result, the public (including our former students) overwhelmingly endorses creationism over evolution (for example, Gallup and Newport 1991; Moore 2000; Greenwood and North 1999; Sonderstrom 2000; Finn and Kanstoroom 2000). Throughout the country, large percentages of biology teachers have ignored these standards. If we are to do a better job of teaching evolution — and if our students (future citizens, taxpayers, and political leaders) are going to learn it better — we must do more than establish standards that are ignored.

References



Affannato FE. A Survey of Biology Teachers' Opinions about the Teaching of Evolutionary Theory and/or the Creation Model in the United States in Public and Private Schools. Unpublished PhD dissertation. Ames (IA): University of Iowa, 1986.

Aguillard D. Evolution education in Louisiana public schools: A decade following Edwards v Aguillard. The American Biology Teacher 1999; 61 (3): 182–8.

Aldrich KJ. Teachers' attitudes toward evolution and creationism in Kansas biology classrooms, 1991. Kansas Biology Teacher 1991; 8 (1): 20–1.

American Association for the Advancement of Science. Project 2061: Science for All Americans. Washington (DC): American Association for the Advancement of Science, 1989.

Buckner EM. Professional and Political Socialization: High School Science Teacher Attitudes on Curriculum Decisions, in the Context of the "Scientific" Creationism Campaign. PhD dissertation, Georgia State University. Ann Arbor, MI: University Microfilms International, 1983.

Eglin PG. Creationism versus Evolution: A Study of the Opinions of Georgia Science Teachers. PhD dissertation, Georgia State University, 1983.

Ellis WE. Creationism in Kentucky: The response of high school biology teachers. In RW Hanson, ed. Science and Creation. New York: Macmillan, 1986. p 72–91.

Eve R, Harrold F. The Creationist Movement in Modern America. Boston: Twayne, 1991.

Finn CE, Kanstoroom M. Foreword. In: Lerner LS. Good Science, Bad Science: Teaching Evolution in the States. Washington (DC): Thomas B Fordham Foundation, 2000.

Gallup GH Jr, Newport F. Belief in paranormal phenomena among adult Americans. Skeptical Inquirer 1991; 2: 137–47.

Gish D. A challenge to neo-Darwinism. The American Biology Teacher 1970; 32: 495–6.

Gish D. Creation, evolution, and the historical evidence. The American Biology Teacher 1973; 35: 132–40.

Greenwood MRC, North KK. Science through the looking glass: Winning the battles but losing the war? Science 1999; 286: 2071–9.

Harp L. School guide drops word "evolution." Louisville Courier-Journal 1999 Oct 5; A1, A5.

Hessler E. Two "e" words: Ecology and evolution. Minnesota Science Teachers Association Newsletter 2000 Winter; 37 (2): 6.

Lerner LS. Good Science, Bad Science: Teaching Evolution in the States. Washington (DC): The Thomas B Fordham Foundation, 2000. (Also available at .)

Moore JN. Evolution, creationism, and the scientific method. The American Biology Teacher 1973; 35: 23–6.

Moore R. Creationism in the United States. VIII. The lingering threat. The American Biology Teacher 1999a; 61: 330–40.

Moore R. Science at Scopes' school today. Journal of College Science Teaching 1999b; 28: 229–30.

Moore R. The courage and convictions of Don Aguillard. The American Biology Teacher 1999c; 61 (3): 166–74.

Moore R. In the Light of Evolution: Science Education on Trial. Reston (VA): National Association of Biology Teachers, 2000.

Muller HJ. One hundred years without Darwinism are enough. The Humanist 1959; 19: 139.

National Academy of Sciences. Teaching About Evolution and the Nature of Science. Washington (DC): National Academy Press, 1998.

National Association of Biology Teachers. 1997. Position statement on the teaching of evolution. NABT News and Views 1997 Jun: 4–5.

National Research Council. Mathematics, Science and Technology Education: A Research Agenda. Washington (DC): National Academy Press, 1985.

National Science Teachers Association. An NSTA position statement on the teaching of evolution. Journal of College Science Teaching 1997; 27 (1): 7–8.

Nelkin D. The Creation Controversy: Science or Scripture in the Schools? New York: WW Norton, 1982.

Nickels MK, Drummond BA. Creation/ evolution: Results of a survey conducted at the 1983 ISTA convention. Creation/ Evolution Newsletter 1985; 5 (6): 2–15.

Petto AJ. Creeping creationism in Pennsylvania's science education standards. Reports of the National Center for Science Education 2000; 20 (4): 13–4.\

Riddle O. Preliminary impressions and facts from a questionnaire on secondary school biology. The American Biology Teacher 1941; 3: 151–9.

Rutledge ML, Mitchell MA. High school biology teachers' knowledge structure, acceptance, and teaching of evolution. The American Biology Teacher, in press.

Rutledge ML, Warden WA. Evolutionary theory, the nature of science and high school biology teachers: Critical relationships. The American Biology Teacher 2000; 62 (1): 23–31.

Scanlon L, Uy GL. Private and church schools' approaches vary widely. Louisville Courier-Journal 1999 Jul 4; A10.

Shankar G. Factors Influencing the Teaching of Evolution and Creationism in Texas Public High School Biology Classes. Doctoral dissertation, Texas Tech University, 1989. Dissertation Abstracts International 1990; 51 (03): 733A.

Shankar G, Skoog GD. Emphasis given evolution and creationism by Texas high school biology teachers. Science Education 1993; 77 (2), 221–33.

Sonderstrom M. Australopithecus or Adam's rib? McGill News 2000; 80 (1): 16–20.

Tatina R. South Dakota high school biology teachers and the teaching of evolution and creationism. The American Biology Teacher 1989; 51 (5): 275–80.

Weld J, McNew JC. Attitudes toward evolution. The Science Teacher 1999; 66 (9): 27–31.

Wolfson, A. "Monkey Trial" town embraces creationism more fervently today. The Louisville Courier-Journal 1999 Oct 4; A1, A6.

Zimmerman M. The evolution-creation controversy: Opinions of Ohio high school biology teachers. Ohio Journal of Science 1987a; 87: 115–25.

Zimmerman M. Ohio school boards presidents' views on the evolution-creation controversy. Newsletter of the Ohio Center for Science Education 1987b Oct.

Zimmerman M. Ohio school boards presidents' views on the evolution-creation controversy. Newsletter of the Ohio Center for Science Education 1988 Jan.

About the Author(s): 
Randy Moore
Professor of Biology
Editor, The American Biology Teacher
374 Appleby Hall — General College
University of Minnesota
128 Pleasant Street SE
Minneapolis MN 55455-0434

The American Scientific Affiliation and the Evangelical Response to Evolution

Reports of the National Center for Science Education
Title: 
The American Scientific Affiliation and the Evangelical Response to Evolution
Author(s): 
Keith B Miller
Volume: 
21
Issue: 
1–2
Year: 
2001
Date: 
January–April
Page(s): 
22, 27–29
This version might differ slightly from the print publication.
The American Scientific Affiliation (ASA) is an association of Christians interested in the interaction and integration of their faith with the scientific disciplines. The ASA was founded in 1941 by scientists of evangelical Christian faith who were concerned about the growing influence of scientific materialism and who desired to present science in a theistic context. (Read a discussion of the early history of the ASA in The Creationists by Ronald Numbers [Berkeley: University of California Press, 1992].) Today, it is an organization that, with another affiliated society, the Canadian Scientific & Christian Affiliation, has about 2000 members. Together they publish the journal Perspectives on Science and Christian Faith. Members have at least a bachelor's degree in a scientific or engineering field or in the history or philosophy of science. As an organization, the ASA takes no official position on specific scientific questions. All members assent to the following doctrinal statement:
We accept the divine inspiration, trustworthiness and authority of the Bible in matters of faith and conduct. We confess the Triune God affirmed in the Nicene and Apostles' creeds, which we accept as brief, faithful statements of Christian doctrine based upon Scripture. We believe that in creating and preserving the universe, God has endowed it with contingent order and intelligibility, the basis of scientific investigation. We recognize our responsibility, as stewards of God's creation, to use science and technology for the good of humanity and the whole world.

Members of the ASA represent a wide range of disciplines and bring their expertise to bear on a wide range of issues - including such critically important ones as biomedical and environmental ethics. However, issues surrounding evolution, both scientific and theological, have featured prominently in discussions among ASA members since the organization's inception. Articles on these topics are also commonly presented in the pages of the ASA's journal.

In 1997, a subcommittee of the ASA appointed a "Commission on Creation" to draft a general statement on creation that would reflect points of agreement among those representing a wide spectrum of views. ASA members holding the various perspectives on creation were appointed to the commission, and the resulting "General Statement on Creation" was unanimously approved by them. In addition, several more specific statements were drafted to represent the diversity of views in the ASA. These are labeled Young-Earth View, Old-Earth View, Theistic-Evolution View, and Intelligent-Design View (see the text of the General Statement on Creation and the views of specific working groups at http://www.asa3.org/ASA/topics/Evolution/commission_on_creation.html#CommissiononCreation. Additional statements representing these specific views were written by proponents of the respective positions and appear with the general statement. It is important to emphasize that the general statement is simply a product of the work of the commission, and it does not exhaustively represent all the views present within the ASA or within the larger Christian community.

As a member of the commission that drafted the statement, I offer here a few reflections on its value, and on its context within the larger popular controversy over evolution.

To begin, my own position is that there is no inherent conflict between evolutionary theory and a Christian faith with a high view of Scripture. By evolution, I mean the theory that all living things on earth are descended from a common ancestor through a continuous chain of cause-and-effect processes. I believe that there are no necessary breaks or gaps in causal explanations. That is, all transitions in the history of life are potentially explicable in terms of "natural" cause-and-effect processes. This theory is no mere guess or hunch, but an extremely well-supported explanation of the observed record of organic change. It has great explanatory power in drawing together an incredibly wide range of data from many disciplines in an explanatory framework. It has been very effective in generating fruitful and testable hypotheses that have driven new discoveries and advanced our scientific understanding of the universe.

I also fully and unhesitatingly accept the doctrine of creation: God is the creator of all things, and nothing would exist without God's continually willing it to be. God is intimately and actively involved in all natural processes. Every natural process is as much an act of a personal creator as any miracle. The best term I know for this view of God's creative activity is "continuous creation". Furthermore, I believe that knowing God through creation is an act of faith and cannot be a conclusion obtained through scientific investigation. However, scientific observation provides no proof of the existence of a creator God; indeed it cannot. Nor does scientific description, however complete, provide any argument against a creator. Since God acts through process, evolution and the theology of creation are perfectly compatible. In fact, I see them as mutually reinforcing. An evolutionary understanding of creation illuminates our theological understanding, and theology places our scientific discoveries in a more comprehensive context and provides necessary moral guidance in the scientific endeavor.

Much of the controversy over evolution and creation seems to rest firmly on the widely held view that evolution and Christianity are in necessary and irreconcilable conflict. However, this conflict view has been thoroughly discredited by both theological and historical scholarship. Christian theologians representing many theological traditions (including evangelicals) have long recognized that a faithful reading of Scripture does not demand a young earth, nor does it prohibit God's use of evolutionary mechanisms to accomplish His creative will. Many evangelical Christians in Darwin's time found no inherent conflict between evolutionary theory and Scripture. In fact, several of the authors of the Fundamentals (the set of volumes that gave us the term "fundamentalist") accepted some form of evolutionary theory. Even BB Warfield, a theologian who argued forcefully for Biblical inerrancy, accepted the validity of evolution as a scientific description of origins. The principal advocates of evolutionary theory in America included Asa Gray, George Frederick Wright, and James Dana - all committed Christians.

This is of course not to deny that a number of Christian theologians and scientists both past and present have had significant objections to certain aspects of evolutionary theory. Charles Hodge, a respected and influential theologian at Princeton in the early 1800s, is an example of a highly competent scholar who saw Darwinian evolution as incompatible with the Christian faith. Scholarly theological critiques of evolution such as his, however, provide no basis whatsoever for propounding a "warfare" metaphor for the relationship of evolution and the Christian faith. The history of the evangelical Christian response to evolution is detailed in a number of excellent scholarly books. These include The Post-Darwinian Controversies by James R Moore (Cambridge [UK]: Cambridge University Press, 1979), Darwin's Forgotten Defenders by David N Livingstone (Grand Rapids [MI]: Wm B Eerdmans Publishers, 1987), and Evangelicals and Science in Historical Perspective, edited by David N Livingstone, DG Hart, and Mark A Noll (Oxford: Oxford University Press, 1999).

I believe that one of the most important contributions of the "Statement on Creation" is to combat the tired portrait of evangelical Christians as being driven by their acceptance of the truth of the Bible to oppose the theory of evolution - if not the whole of the modern scientific enterprise. The reality is that there is a very wide spectrum of views, which the ASA statement reflects. Furthermore, people often assume that acceptance of evolutionary theory is a function of the "liberalness" of one's theology. On the contrary, as James R Moore observed, in the late 1800s Darwinism was "accepted in substance only by those whose theology was distinctly orthodox" and rejected by those with more liberal theologies (see the preface of The Post-Darwinian Controversies).

There is an extensive scholarly record on the philosophical and theological implications of evolutionary theory by Christian scholars. The fruits of these efforts need to be more widely known and discussed. There is a desperate need for the heated conflict that has surrounded the issue of evolution to cool down. The evolution/creation "warfare" view has effectively inhibited productive popular dialogue on important theological and scientific issues - it is now time to finally lay it to rest!

About the Author(s): 

Keith B Miller
Department of Geology
Kansas State University
Manhattan KS 66506
kbmill@ksu.edu

The Children's Crusade for Creation

Reports of the National Center for Science Education
Title: 
The Children's Crusade for Creation
Author(s): 
Steve Randak
Volume: 
21
Issue: 
1–2
Year: 
2001
Date: 
January–April
Page(s): 
27–28
This version might differ slightly from the print publication.

[Reprinted with permission by the National Association of Biology Teachers from The American Biology Teacher 2001; 63 (4).]

The nightmare of every biology teacher happened at our school. Creationists petitioned the school board to have creation science added to the biology curriculum. The outcome was mixed.

WHY US?

Why did it happen at Jefferson High School, Lafayette, Indiana, in the shadow of Purdue University? It seems reasonable to assume that if you are not teaching evolution, you greatly reduce your chances of a confrontation. As you increase both the time spent on evolution and the effectiveness of your instruction, the risk of creationist intervention should logically increase.

After an introductory unit on the nature of science, we teach one semester of ecology and one semester of evolution, with genetics and the cell included in evolution. John Moore's deductions of evolution are the skeleton upon which we build the second semester's study (Moore 1993). In addition to teaching the big ideas in biology, we spend considerable time teaching life skills with goal setting, group learning, student choice, and oral testing. We use several tools that increase the chance that the 80% of the time spent in labs will result in critical thinking skills development.

Because the class is team-taught, student-centered, and constructivist, students tend to enjoy it and they learn (Randak 2000). These factors work together to create an environment that stress students with creationist beliefs. To relieve that stress, we teach a comprehensive 5-week introductory unit on the nature of science. It includes not only the scientific method but a condensed history of science and a consideration of how science is distinguished from nonscience. The commitment to developing a deeper understanding of the nature of science comes, in part, from our involvement with a NSF-sponsored ENSI program (ENSI 2000). The ENSI philosophy assumes that if students develop an understanding of what science is and how to distinguish science from nonscience, they will have fewer problems when confronted with evolution (Nickels 1996). In the past it worked. This time it did not, and we wondered why.

STUDENT-DRIVEN CREATIONISM

Contrary to our expectations, the entire initiative to add creationism to the curriculum was student-driven; no adult took an obvious role. We know from talking with students that one of our chemistry teachers offered a great deal of support for the creationist view. In the past, he had spent the first several weeks of school preaching the creationist dogma; he appeared to have stopped because of administrative pressure, but he recently started preaching in his classroom again. The inspiration from this one adult may have been the reason this creationist action happened or it may truly have been a student-initiated response to our effective teaching of evolution. Our superintendent holds this latter opinion. He feels that creationist parents and students are upset because we teach evolution effectively.

THE CRUSADE

The school's Christian Club served as the springboard for the initiative. These students organized and obtained hundreds of student signatures and dozens of faculty signatures on a petition requesting that "creation science" be added to the biology curriculum. We found that even among faculty the claim "It is only fair that both sides be presented" was very compelling (even 2 of our 16 science staff signed the petition). The chemistry teacher's signature was missing.

Most of the students and adults that signed the petition do not understand that science has little to do with the playground idea of fairness — that science is a competition of ideas where ideas are accepted on the strength of the supporting evidence. We spent considerable time refuting the scientific claims for creationist arguments both with individual students and in small groups.

However, we quickly discovered that our rejection of the science in "creation science" caused students supporting that position to take our criticism as an attack on their religious beliefs. To quote one student, "It is bad enough that you teach the earth is old; you should not be able to attack my evidence that the earth is young." When these students felt their faith was under siege, they often reverted to nonscientific accusations, such as "evolution is a religion" or "it is only a theory". To a teacher, it is humbling to see students in the midst of gaining critical thinking skills revert to such tactics.

One positive outcome was that the engagement energized all our students. We had more interest in the study of evolution and higher grades in that part of the course than ever before — even though this class had not performed as well as previous classes on the other parts of the course.

THE OUTCOME

What is most encouraging about this story is the way our school corporation responded. The superintendent immediately expressed his support for our curriculum and kept us informed of his actions, while the biology staff mutually decided to maintain a low profile in the media. The superintendent educated the school board about the nature of science and the law and, with the help of the science department head, convinced the one wavering board member. The students were respectfully treated by the administration and the school board. At its public meeting, under the glare of local and national television lights, the school board was told politely that the curriculum would not be altered. It all seemed to work in the way a science educator would hope. But there are lingering issues that we see as a mixed outcome.

THE WARNING

When things calmed down and I had some free time, I called Eugenie Scott at NCSE. I was curious to know how our experience fit into the larger picture. What she told me was a shock. I assumed that student-led crusades for "creation science" were common. They are not. I assumed that school boards and superintendents often do the right thing. They do not. I was told that our resolution was the ideal, not the norm, and at that moment I experienced more concern than any time during the many months of controversy.

Children crusading for creation science or "intelligent design" in the name of fair play is a compelling idea to an unaware public. If the tactic is used successfully in school districts less ideal than ours, it will surely meet with success — and science education will suffer.

[Ed: In the spring of 2001, Joe Baker, a high-school student at Pennridge High School in Perkasie, Pennsylvania, also petitioned the school board in his district to include creationism in the science curriculum. The request was not granted, and Baker graduated in May, after nearly a year of student-centered activism to oppose evolution in the curriculum.]

REFERENCES


ENSI [Evolution and Nature of Science Institute] 2000. http://www.indiana.edu/~ensiweb/. Last accessed September 18, 2001.

Moore JA. Science As A Way of Knowing. Cambridge (MA): Harvard University Press, 1993.

Nickels MK, Nelson CE, Beard J. Better biology teaching by emphasizing evolution & the nature of science. The American Biology Teacher 1996; 58 (6): 332­6.

Randak SH. Biology. 2000. http://www.lsc. k12.in.us/ttb/BioHome.html. Last accessed September 18, 2001.

About the Author(s): 
Steve Randak
Jefferson High School
1801 South 18th Street
Lafayette IN 47905
srandak@nlci.com

Steve Randak teaches biology at Jefferson High in Lafayette, Indiana. In his 33-year career, he has received Indiana's Outstanding Biology Teaching Award and the Presidential Award for Excellence in Science Teaching.

Defining Evolution

Reports of the National Center for Science Education
Title: 
Defining Evolution
Author(s): 
John Wilkins
Volume: 
21
Issue: 
1–2
Year: 
2001
Date: 
January–April
Page(s): 
29–37
This version might differ slightly from the print publication.

INTRODUCTION

When we try to explain evolution to those who do not know much about it, one of the problems we have is the definition of what counts as evolution. In part, this is because some of the definitions found in the scientific literature, including textbooks and popularizations of evolutionary theory, use technical terms that do not seem to convey to the public that evolution explains the diversity of living forms. In part, it is also because the popular idea of evolution as it is found in dictionaries, science fiction, and philosophical potboilers is a holdover of concepts that have long been abandoned in the biological sciences, if not in theology or in the "science" of popular media.

It is important to understand these various definitions relative to each other and to show that accepting evolution as defined in the sciences does not commit one to accepting another form, as proposed by theology or philosophy. In particular it is important to realize that, contrary to many nonscientific uses of the term, evolution is neither a progressive process — modern theory does not make it inevitable that the latest is the best — nor can we expect to be able to predict the "next step" in evolution.

To understand the current meaning of the word "evolution", it is useful to take a journey through history and trace the various meanings of the word "evolution" as the modern view takes form.

THE HISTORY OF "EVOLUTION"

Evolution before Darwin

Initially, the Latin word evolutio meant the unrolling of a scroll. This gives the flavor of the inevitable recitation of a story or message. The story is already written, and all that is required is to "read off" the message in an orderly fashion from beginning to end. "Evolution" was therefore a natural term for the early developmental biologists, such as the Dutch entomologist Jan Schwammerdam in 1669 and Charles Bonnet in the 1740s, to apply to the development of an embryo (Richards 1992a, 1992b; Mayr 1982). This appears to be the first recorded use of the term in a biological context.

Early evolutionists, like Jean Baptiste de Lamarck and Erasmus Darwin (Charles's grandfather), believed that species also changed in such a predetermined fashion (by ascending the Ladder of Nature, called the scala naturae). The term "evolution" was applied to the transmutation of one species to another in the early years of the 19th century, by Lamarck's disciple Etienne Geoffroy Saint-Hilaire and Geoffroy's student, embryologist Etienne Serres, to describe such views. Charles Lyell, in the influential second volume of his Principles of Geology (1833), which Darwin received during the voyage of the Beagle and which prepared him to formulate an evolutionary view, attacked Lamarck and Geoffroy on transmutation, and borrowed the term "evolution" from Serres to describe their views. By 1833, then, when Lyell's work was published, it had become common usage to equate "evolution" with the transmutation of species.

So evolution originally referred to the supposed series of changes that a species was predetermined to undergo, in the same way that an embryo is preprogrammed to develop. Such views persisted into the first half of the 20th century, despite Darwin's theory, which asserts no such predetermined series or stages. These views are called orthogenetic ("straight line") theories of evolution (Mayr 1982) and are in great disfavor today. All that persists of that original meaning is that species change over time. However, the use of "evolution" in its original sense is still common in astronomy to describe the sequence of stellar development (Gould 2000).

Darwin's view of evolution

Before Darwin, transmutation of species generally meant that a species as a whole changed into a more complex species through some (unspecified) process. Darwin intended no such meaning when he introduced evolutionary theory in On the Origin of Species (1859). First, he realized that change was not necessarily a process of increasing complexity or perfection. Second, he proposed a specific mechanism that explained why new species were different in appearance and behavior — natural selection. Third, and most important, Darwin saw that the origin of a new species did not involve an entire species' undergoing change. He saw that the origination of a new species might occur in only a part of the parental species — in a subpopulation. The remaining populations of the original species could remain unchanged.

Species to Darwin were just permanent varieties. The species he had studied in the wild, and those he read about in the work of others, and most of all his alternately loved and hated barnacles (he spent 9 years cataloguing modern and fossil barnacles before publishing the Origin), all exhibited variation, including what were then called "races", or subspecies. This is the meaning of "races" in the subtitle of the Origin ("The preservation of favoured races in the struggle for life") — varieties within a species.

The fact that speciation occurred in subpopulations implied that species shared common ancestry with others that had split off from the same or related parental stock. So Darwin concluded that there was an "insensible series" of varieties — or what we would speak of today as genetic variants — from geographic differences to fully distinct but interfertile varieties or races, to distinct and mutually infertile species. This conclusion is not generally accepted today. The contemporary view is that species arise not from genetically distinct races, but from local and isolated populations that may initially be much the same genetically as the main populations of a species.

However, Darwin did not use the word "evolution" in the first edition of the Origin (although he used "evolving" in the sense of "unfolding" in the final paragraph). Only later, in the Descent of Man (1871; see Gould 2000), was Darwin forced to adopt the term "evolution", partly because it was in common use, and also because his associate Herbert Spencer had used the term two years before Darwin went public on evolution. The fact that the ideas he outlined are often included in the general understanding of "evolution" causes some confusion, which can be alleviated by carefully distinguishing among the components of Darwin's theory.

The main components of Darwin's theory are
  1. that species change (transmutation: Darwin's preferred term was "descent with modification");
  2. that related species are descended from a common ancestor (common descent);
  3. that the main mechanism by which species become distinct from one another is natural selection; and
  4. that species arise geographically near to their ancestor (biogeography).
His theory had several other components, some of which are now rejected (his model of inheritance is the main one), but they are minor components of his evolutionary theory and can be ignored here (Wilkins 1998).

In the book that effectively crystallized the Modern Synthesis of genetics and Darwinism, Ronald Fisher began by saying
Natural Selection is not Evolution. Yet, ever since the two words have been in common use, the theory of Natural Selection has been employed as a convenient abbreviation for the theory of Evolution by means of Natural Selection, put forward by Darwin and Wallace (Fisher 1930: xi).
Fisher may be historically inexact, but there is a solid point here: natural selection is what many people mean by "evolution". This impression is reinforced by the writings of such luminaries as Richard Dawkins, who makes selection the core of his view of evolution.

But natural selection is also the mechanism by which species do not change. Selection only forces change if a population is not well-suited to competing for resources or overcoming risks in its local environment. If a species is well-adapted, then selection will inhibit change; this is called balancing selection. Thus, we have to distinguish between the mechanism that is sometimes an agent for change from the process of change itself (see Figure 1).

Figure 1

Before Darwin, the prevailing view was that species are types. A type was both a means of identifying and classifying an organism and also a force that caused it to exhibit certain physical characteristics. The type made that organism what it was. Organisms that varied too far from the type were "monsters", degradations of the type (for example, a French biologist contemporary of Linnaeus, Georges Buffon, thought that evolution was a degradation of a number of created types; Lovejoy 1959). Entire species were called monsters, because they were too far removed from the central type of a family or genus of organisms. Such central types were called the archetype by Richard Owen.

Darwin imagined the archetype as an actual historical ancestor — that the variation present in an ancestral population could be the basis for descendant populations both to share important identifying characteristics and to differ significantly in some ways from the ancestor. Furthermore, he saw that neither the archetype nor the type of a single species exerted any influence on the subsequent history of a lineage. For Darwin, types were just the most common form of a species or genus. The type might remain stable, or it might change. In modern terms, we would say that the type is just the mode of the distribution of species' characters. What causes the type to remain stable or to change is another matter. Whether the type changes or remains stable, the cause might be selection or some other process, such as random drift.

Evolution after the discovery of the gene

Modern definitions of evolution are based on the fact that all organisms living in breeding populations are generally quite similar, but no two individuals are exactly alike. They have differences due to their heredity, their upbringing, and their life histories. Some of these differences are of evolutionary significance: all of them involve their genes in some way; their dispositions to grow in particular ways, their ability to react to and make use of their environments, and even their abilities to deal with disease and injuries are genetically influenced, but not necessarily determined. Selection acts at base on genetic differences among organisms, not on an individual gene. Moreover, these differences have to occur in populations by virtue of the normal processes of genetic recombination in reproduction.

Darwin's theory was extended by the so-called "biometrics" movement (which is the foundation of both statistics and population genetics) and melded together with Mendelian genetics beginning about 1920. This culminated in the Modern Synthesis (henceforth, the Synthesis) forged in the works of Fisher, Theodosius Dobzhansky, Ernst Mayr, JBS Haldane, Sewall Wright, and Julian Huxley between 1930 and 1942. For the architects of the Synthesis, it was natural to use the powerful set of theoretical and analytic techniques of genetics to define evolution (see references and discussion in Bowler 1984). Thus, Huxley, summarizing the views developed by Dobzhansky and others in the development of the Synthesis wrote:
Mendelism is now seen as an essential part of the theory of evolution. Mendelian analysis does not merely explain the distributive hereditary mechanism: it also, together with selection, explains the progressive mechanism of evolution (1942: 26)
and
[W]hat evolves is the gene-complex; and it can do so in a series of small if irregular steps, so finely graded as to constitute a continuous ramp (1942: 68).
The "allele-frequency" definition of evolution has survived to become the "standard" definition in textbooks and discussions about the nature of evolution. Here is a more-or-less random collection of quotations from various sources to illustrate how different views have developed based on this initial insight.
Biological evolution ... is change in the properties of populations of organisms that transcend the lifetime of a single individual. The ontogeny of an individual is not considered evolution; individual organisms do not evolve. The changes in populations that are considered evolutionary are those that are inheritable via the genetic material from one generation to the next. Biological evolution may be slight or substantial; it embraces everything from slight changes in the proportion of different alleles within a population (such as those determining blood types) to the successive alterations that led from the earliest proto-organism to snails, bees, giraffes, and dandelions (Futuyma 1986: 7).
[E]volution can be precisely defined as any change in the frequency of alleles within a gene pool from one generation to the next (Curtis and Barnes 1989: 974).
The fundamental evolutionary event is a change in the frequency of genes and chromosome configurations in a population (Wilson 1992: 75).
On the simplest perspective of all, biological evolution is analyzed initially as changes in allelic frequencies at a single locus. More complicated phenomena must be explained by means of combinations of these minimal units (Hull 1992: 185).
Natural selection deals with frequency changes brought about by differences in ecology among heritable phenotypes; evolution includes this as well as random effects and the origin of these variants (Endler 1992: 221).
Since evolution may be defined as cumulative change in the genetic makeup of a population resulting in increased adaptation to the environment, the fundamental process in evolution is change in allele frequency (Hartl 1988: 69).
Organic ... evolution, or biological evolution, is a change over time of the proportions of individual organisms differing genetically in one or more traits; such changes transpire by the origin and subsequent alteration of the frequencies of alleles or genotypes from generation to generation within populations, by the alterations of the proportions of genetically differentiated populations of a species, or by changes in the numbers of species with different characteristics, thereby altering the frequency of one or more traits within a higher taxon (Futuyma 1986: 551).
Notice that some say that observable change in the frequencies of alleles is sufficient to define evolution, while others, such as Futuyma, think it necessary to go into more detail. For the purpose at hand, the dispute is unimportant.

A more important controversy, however, is between the proponents of the allele-frequency definition and those who reject it altogether as too narrow:
I pointed out more than a decade ago (1977) that the reductionist explanation, so widely adopted in recent decades — evolution is a change in gene frequencies in populations — is not only not explanatory, but is in fact misleading. Far more revealing is the definition: "Evolution is change in the adaptation and in the diversity of populations of organisms" (Mayr 1988: 162).
Evolution may be defined as any net directional change or any cumulative change in the characteristics of organisms or populations over many generations — in other words, descent with modification... It explicitly includes the origin as well as the spread of alleles, variants, trait values, or character states. Evolution may occur as a result of natural selection, genetic drift, or both; the minimum requirements are those for either process. Natural selection does not necessarily give rise to evolution, and the same is true for genetic drift (Endler 1986: 5).
Population geneticists use a different definition of evolution: a change in allele frequencies among generations. This meaning is quite different from the original; it now includes random as well as directional changes ..., but it does not require the origin of new forms. It is roughly equivalent to microevolution (subspecific evolution; macroevolution involves major trends, or trans-specific evolution...). Unfortunately, the use of the population genetics definition often results in an overemphasis on changes in allele frequencies and an underemphasis on (or no consideration of) the origin of the different alleles and their properties. Both are important in evolution.... An additional problem is that, for quantitative genetic traits, the frequencies of alleles at many contributing loci can change while the overall mean and variance of the trait remain roughly constant (Endler 1986: 7-8).
And even those who stress the genetic character of evolution sometimes take a broader view:
Evolution is a directional and essentially irreversible process occurring in time, which in its course gives rise to an increase of variety and an increasingly high level of organization in its products (Julian Huxley cited in Newman 1956: 278).
These examples illustrate that there is a wide range of approaches to defining evolution and that "experts" disagree over what to emphasize in their definitions. Some think that genes are a very good place to start, while others insist that important concepts about evolution are not captured in allele-frequency definitions. However, when it comes down to the nature of the evolutionary process, much of this is a matter of semantics — what to spell out and what to leave implicit. Despite the superficial differences in these descriptions, the apparent disagreements do not usually entail differences of opinion about what happened in the course of evolution, at least not in broad outline.

ISSUES IN EVOLUTION

Macroevolution

Creationists, and anti-evolutionists in general, frequently claim that macroevolution is not deducible from the allele-frequency definition of evolution. They very often claim that there are barriers to changing beyond the "kind" (an ill-defined term with no fixed meaning, which seems roughly equivalent to "species") — although such change has been observed many times as new species have been observed to evolve from old ones. This is the lowest level of macroevolution, as we will see in a moment.

Some anti-evolutionists even allow for evolution of one species into another, but deny that the emergence of "major" groups, such as families or orders in the Linnaean hierarchy, can be the result of microevolutionary change. Often, this concession to microevolution is made only to accommodate the species diversity we see today from the necessarily restricted variation among the original "kinds" that are supposed to serve as the founding populations at the Creation or that were carried on the Ark.

Even among scientists, the term "macroevolution" is a vague concept. Many authors think that there is a qualitative difference between adaptive evolution and the origins of higher taxa or forms. In the original formulation, Y'uri'i Filipchenko (in 1927) used the term to mean origination of a novel species by splitting from an ancestral species — what we now call speciation or cladogenesis. Today it is more widely used to mean "large-scale" change, such as the evolution of novel "body-plans", "grades" of ecological niche specialization, or "key innovations".



Those who prefer the allele-frequency definition of evolution argue that every such novelty began as minor variations on a theme in the origination of a slightly different species and that large- scale changes are the result of continued evolution of this kind over large periods of time. Often they think that evolution is always gradual (anagenetic) and that evolutionary trees (phylogenies) are just the additive sum of these gradual changes. Nobody denies either cladogenesis or anagenesis these days, but there is a fair bit of debate over the right mix (see Figure 2).

Varieties of evolution

Let us now look at the surviving meanings of evolution in order of increasing exactness, along with the names of some of the scientists with whom the ideas are associated (Bowler 1983, 1984; Mayr 1982; Mayr and Provine 1980; Ruse 1979/1999; see Figure 3).



I take the broadest definition of biological evolution to be:
  • Transmutation (descent with modification): This is the notion that new species emerge from existing species and that all existing species are the product of change in older ones. Early transmutationists: Lamarck, Erasmus Darwin (Charles's grandfather), Saint-Hilaire, Robert Chambers (author of the Vestiges of Creation, first published in 1844), and Charles Darwin. This view was common by the 1830s, and Darwin did not invent the idea.
A slightly narrower conception of evolution:
  • Common ancestry: Related species have changed from a common ancestor species; that is, the reason that species are similar and are related in classification is because they have evolved from a shared ancestral species. This is also called phylogenetic change, or more simply, phylogeny. In a limited way, both Lamarck and Erasmus Darwin proposed common ancestry, but the first complete account was propounded by Charles Darwin.
Narrower still:
  • Biogeographic distribution: Related species arise as geographic neighbors; this is the view that no new species arises except in close contact with its most related species. This view was proposed by Alfred Wallace and Charles Darwin. Of course, the fact that new species arise as biogeographic neighbors is explained by common ancestry, but Wallace formulated this model before the common ancestry model was published.
Evolutionary theory also has some strictly Darwinian elements:
  • The struggle for existence: More individuals will be born than the environment can support, so not all organisms survive to reproduce. Darwin derived this idea from Lyell, Thomas Malthus, and Alphonse de Candolle.
  • Variation among individuals: All organisms generate offspring that are slightly different from each other, so there is variety within all populations. This is one of Darwin's original contributions to biology, although he was influenced by de Candolle.
  • Natural selection: The local environment is more favorable to organisms with a particular variety or combination of traits within a species. Those so favored survive longer and reproduce more, resulting in that variety's becoming more common in subsequent generations than other varieties in the species. Darwin was not the first to recognize natural selection, but he was the first to use it as a mechanism of evolution.
  • Sexual selection: In sexually reproducing species, mate choice sustains display traits — the sex that needs to compete for mates will show variations in the characteristics associated with this competition. Darwin is the sole author of this mechanism of evolutionary change.
The Neo-Darwinian elements are:
  • Random mutation, or blind variation: Changes arise in genes at random, without respect to the survival needs of organisms and species.
  • Weismannism: Information from the somatic cells of the body is not inherited. This principle was proposed by August Weismann in 1882. The molecular genetic equivalent, due to Crick and Watson, is the Central Dogma of genetics: information is not passed from proteins to nucleotides (DNA or RNA).
The synthetic elements are:
  • Drift: Many changes occur that are not selected for, due to sampling accidents in population. Models of drift were sketched in the 19th century by Darwin, George Romanes, and Moritz Wagner, but they came into their own with the advent of the Synthesis. There are different (and not necessarily incompatible) models of drift. One is genetic drift (after Sewall Wright). This includes genetic neutralism, which involves selectively neutral mutations becoming fixed in a population (after Mootoo Kimura). This includes "founder effect" models of speciation, formulated by Mayr and Hampton Carson.
  • Canalization: Developmental processes are robust and resist change Models of canalization were proposed by Conrad Waddington and Ivan Ivanovich Schmalhausen). This notion is also sometimes called the "developmental constraints" model of evolution (see Schlichting and Pigliucci 1998).
  • Mendelian genetics: Heredity is the passing on of discrete units of genetic material, which recombine in certain ways and frequencies, and which are either dominant or recessive. As the name implies, Mendelian genetics derive from the work of Gregor Mendel, as "rediscovered" by Correns, De Vries, and Tschermak in 1900 (Stern and Sherwood 1966). Mendelian genetics was incorporated into the synthesis by Fisher and Haldane.
Postsynthetic elements include, but are not restricted to:
  • Rate variability: Evolution occurs at many different rates, from the instantaneous to the gradual, all of which are gradual and continuous at some scale. For example, GG Simpson (1944), Mayr (1942), and more recently, Niles Eldredge and Stephen Jay Gould (1972) in their famous punctuated equilibria model, examine how the pace of evolutionary change can vary under different circumstances.
  • Process structuralism: Some changes are biased by their structural relations and form. The foundation of process structuralism was laid by D'Arcy Thompson (1917) and recently revived by Brian Goodwin (1994), and others. Complex structures and systems are not free to vary independent of their relationships with other components of the complex.

The long inferential chain

It is very hard to work out the implications of the effects of processes of local variation on large-scale ones. If gene frequency changes in local populations are the foundation for all evolution, it still may not be evident that a new species will arise, that there will be some trends in evolution, or that the patterns of life at any one time will reflect a process of speciation and retention of novelties in large groups.

In part, this is because the chain of inference from population-level genetics to macroevolution is a very long one. Even if genes determined everything about species, we would not be able to generalize and elaborate these facts with any clarity or detail. We are limited in our ability to take all these things into account and lack the time and skills to work it all out fully. Reconciling the conservative character of genetic transmission with the tremendous potential for evolutionary change that is inherent in the genetic variation among individuals is particularly hard for those who lack a full appreciation of the way genes recombine and affect the development of organisms. This is especially true of secondary and post-secondary students and the general populace.

The allele-frequency definition, if adequate, would leave us unsatisfied that evolution really had been explained. Geneticists have observed in small scale a general resistance of the molecular components of the genome to change from the "norm" or "wild type". For this reason, if any biologist were to be anti-evolutionist, it would typically be one who works at the molecular level, such as a molecular geneticist or biochemist.

Allele frequencies change due to environmental factors acting on the population, to the relationships of mating within and between populations, and to sheer chance effects. To be able to predict accurately what will happen to a population in the future, one would need to have a full list of all the external influences on the population, along with knowledge of the size and structure of the population itself, including the mating behavior of the organisms within the population. Moreover, as Gould has emphasized (Gould 1989, 1996), contingency plays a large part in evolution, so that even if we had all this information, we could at best provide probabilities that specific outcomes might occur. The important thing to recognize is that we must consider the phenomenon of evolution simultaneously at many levels — the ecological, climatological, geological and developmental, as well as genetic.

Progress, or a lack of it

Since Lamarck, the view that evolution is progressive has been a recurring theme in biological writing. Even before Darwin published the Origin, his friend Herbert Spencer wrote that there was a general law of the "homogenous to the heterogeneous" — that is, life and the universe in general inevitably became more complex. Although some think differently (Ruse 1996), I believe that Darwin came to a contrary conclusion: that evolution had no direction or inevitability. Sometimes it seems that directionality does occur, but often this pattern is due to our own predilection for noticing only the emergence of large, obvious taxa, as when we refer to the "Age of the Reptiles" or "Age of the Mammals".

Many people believe that evolution necessarily leads to complexity or specialized forms of life. Most organisms, however, are single-celled, and yet their adaptations to specific environments and predation are anything but "simple". Multicellular life is not the goal of evolution: indeed, it is a statistical blip in the overall diversity of living things. Of course, any increase over nothing is an increase, so it is obvious there has been some innovation in the course of evolution on any scale one cares to measure, but whether it progresses is the subject of massive debate (Nitecki 1988).

One form of progress that is generally accepted by most commentators is the "arms race" or "escalation" form of evolution, where two or more species coevolve as they attempt to get the edge over their predators or prey (Vermeij 1987). This is also called the "Red Queen" effect, from the character by that name in Through the Looking Glass who has to run as hard as she can just to stay in one place (Van Valen 1976).

However, the common misunderstanding is that there is a "next step" in evolution (usually, human evolution). This is our old friend the developmental sense of evolution, the scala naturae. Although popular with science fiction screenwriters, it has no scientific basis. It may be that if there is a next species that evolves from humans, it will be a herbivorous and apelike animal that survives just fine in post-apocalyptic conditions. Brains, for example, take a lot of energy to maintain. Brains bigger than ours may turn out to be a liability, not an asset.

WHAT EVOLUTION INCLUDES

To summarize, we can see that the concepts expressed by the word "evolution" have themselves evolved. There is change, there is phylogeny (the multiplication and extinction of lineages), there is selection and drift (the dynamics of reproducing populations), and there is the genetic and biological basis that underlies all these changes — all these (and more) have fallen under the rubric "evolution". Eli Minkoff (1983: 575) consolidated the contemporary understanding this way:

Evolution
  • Originally, a synonym for ontogeny....
  • According to Lamarck and his contemporaries, the unfolding of (evolutionary) potentials as each species ascends the scala naturae.
  • From 1809 on, the transformation of one species into another; phyletic evolution.
  • According to many geneticists..., changes in the gene frequencies of populations.
  • Anagenesis plus cladogenesis. Phylogeny and the changes in gene frequencies that produce phylogenetic change.
In the nearly two decades since the publication of Minkoff's book, there have been many exciting developments in evolutionary research. Models of evolutionary change based on our emerging understanding of developmental and regulatory genes, transposons, somatic hypermutation, endosymbiosis, and other previously unrecognized mechanisms for producing and maintaining biological variation present exciting new opportunities for evolutionary biology. Although the precise role and contribution of each of these mechanisms to the pattern of evolutionary change is still unfolding, it is certain that they will add to a fuller understanding of evolution as well as a new definition of evolution that incorporates these mechanisms.

Acknowledgments

I am especially indebted to Don Lindsay, Joseph Boxhorn, Dave Woetzel and Larry Moran for many of the definition quotes and discussion, and to Dr Moran for the quote at the head of this article and his FAQ article at the Talk.Origins Archive. Joe Boxhorn provided the text of a Talk.Origins debate he had with Chris Colby on this topic that was very useful, and Mark Isaak and Wesley Elsberry also helped. Finally, I must thank Ivar Ylvisaker for excellent ideas for the structure of the article.

References

Bowler PJ. Evolution: The History of an Idea. Berkeley: University of California Press, 1984.

Curtis H, Barnes NS. Biology, 5th ed. New York: Worth Publishers, 1989.

Darwin CR. On the Origin of Species by Means of Natural Selection. London: John Murray, 1859.

Darwin E. Zoonomia, or, The laws of Organic Life. 2d, corrected ed. London: Printed for J Johnson, 1796.

Dobzhansky, T. Genetics and the Origin of Species. New York: Columbia University Press, 1937.

Dobzhansky T. Changing man. Science 1967; 155: 409-15.

Eldredge N, Gould SJ. Punctuated equilibria: An alternative to phyletic gradualism. In: Schopf TJM, ed. Models In Paleobiology. San Francisco: Freeman Cooper, 1972. p 82-115.

Endler JA. Natural Selection in the Wild. Princeton: Princeton University Press, 1986.

Endler JA. Natural selection: Current usages. In: Keller E, Lloyd E, eds. Keywords in Evolutionary Biology. Cambridge (MA): Harvard University Press, 1992: 220-4.

Fisher RA. The Genetical Theory of Natural Selection. NY: Dover, 1958.

Futuyma DJ. Evolutionary Biology, 2nd ed. Sunderland (MA): Sinauer, 1986.

Goodwin BC. How The Leopard Changed its Spots: The Evolution of Complexity. New York: C Scribner's Sons, 1994.

Gould SJ. The Panda's Thumb: More Reflections in Natural History. Harmondsworth (UK): Penguin, 1980.

Gould SJ. Hen's Teeth and Horses' Toes. New York: WW Norton, 1983.

Gould SJ. Wonderful Life: The Burgess Shale and the Nature of History. New York: Norton, 1989.

Gould SJ. Full House: The Spread of Excellence from Plato to Darwin. New York: Harmony Books, 1996.

Gould SJ. What does the dreaded "E" word mean, anyway? Natural History, 2000 Feb: 109: (1): 32-44.

Hart DL. A Primer of Population Genetics. Sunderland (MA): Sinauer, 1988.

Hull DL. 1992. Individual. In: Keller E, Lloyd E, eds. Keywords in Evolutionary Biology. Cambridge (MA): Harvard University Press, 1992. p 180-7.

Huxley JS. Evolution: The Modern Synthesis. London: Allen & Unwin, 1942.

Lamarck JB de. Philosophie zoologique: Un exposition des considerations relatives à l'histoire naturelle des animaux. Paris: Dentu, 1809.

Lovejoy AO. Buffon and the problem of species. In: Glass B, Temkin O, Straus, WL Jr, eds. Forerunners of Darwin. Baltimore (MD): Johns Hopkins Press, 1959: 84-113.

Mayr E. Systematics and the Origin of Species from the Viewpoint of a Zoologist. New York: Columbia University Press, 1942.

Mayr E. The Growth of Biological Thought. Cambridge (MA): The Belknap Press of Harvard University Press, 1982.

Mayr E. Toward a New Philosophy of Biology. Cambridge (MA): The Belknap Press of Harvard University Press, 1988.

Mayr E, Provine WB, eds. The Evolutionary Synthesis: Perspectives of the Unification of Biology. Cambridge (MA): Harvard University Press, 1980.

Minkoff EC. Evolutionary Biology. Reading (MA): Addison-Wesley, 1983.

Newman JR. What is Science? Twelve Eminent Scientists and Philosophers Explain their Various Fields to the Layman. London: Gollancz, 1956.

Nitecki MH, ed. Evolutionary Progress. Chicago: University of Chicago Press, 1988.

Richards RJ. Evolution. In: Keller E, Lloyd E, eds. Keywords in Evolutionary Biology. Cambridge (MA): Harvard University Press, 1992a. p 95-105

Richards RJ. The Meaning of Evolution: The Morphological Construction and Ideological Construction of Darwin's Theory. Chicago: University of Chicago Press, 1992b.

Ruse M. Monad to Man: The Concept of Progress in Evolutionary Biology. Cambridge (MA): Harvard University Press, 1996.

Schlichting CD, Pigliucci M. Phenotypic Evolution: A Reaction Norm Perspective. Sunderland (MA): Sinauer Associates, 1998.

Simpson GG. Tempo and Mode in Evolution. New York: Columbia University Press, 1944 (1984).

Stern K, Sherwood E, eds. The Origins of Genetics, A Mendel Sourcebook. Eva Stern. translator. San Francisco: WH Freeman, 1966.

Stevens, PF. The Development of Biological Systematics: Antoine-Laurent de Jussieu, Nature, and the Natural System. New York, Columbia University Press, 1994.

Van Valen L. Ecological species, multispecies, and oaks. Taxon 25 (1976): 233-239.

Vermeij G. Evolution and Escalation. Princeton: Princeton University Press, 1987.

Weismann A. Studies in the Theory of Descent. Raphael Meldola, translator. New York: AMS Press, 1882.

Wilkins JS. Darwin's precursors and influences. Talk.Origins Archive http://www.talkorigins.org/faqs/darwin-precursors.html. 1998. Last accessed August 24, 2000.

Wilson EO. The Diversity of Life. London: Penguin, 1992.

The Big Tent and the Camel's Nose

Reports of the National Center for Science Education
Title: 
The Big Tent and the Camel's Nose
Author(s): 
Eugenie C. Scott, NCSE Executive Director
Volume: 
21
Issue: 
1–2
Year: 
2001
Date: 
January–April
Page(s): 
39–41
This version might differ slightly from the print publication.
Reprinted with changes in RNCSE 21:2, originally from
Metanexus: The Online Forum on Religion and Science
[In January 2001, "intelligent design" creationist William Dembski, author of The Design Inference, Intelligent Design: The Bridge Between Science and Theology, and the forthcoming No Free Lunch, posted an essay entitled “Is intelligent design testable?” on the Meta discussion board, an on-line forum devoted to discussion of science and religion (Dembski 2001a). In his essay, Dembski attributed to me the view that intelligent design is untestable, and then proceeded to argue — unconvincingly, to my mind — to the contrary. My response follows.]
William Dembski has responded to my January 18 Tom Jukes Memorial Lecture at UC Berkeley. Others are responding on Meta and elsewhere to the focus of his essay, whether natural selection is testable, and I shall not do so here. I should, however, comment on views attributed to me.

I was not really dealing with the testability of “intelligent design” (ID), though that is the impression one might get from Dembski’s essay. In this public lecture, I discussed both traditional “creation science” and neocreationism, and compared them. I talked about Behe’s irreducible complexity idea, and Dembski’s Design Inference, and illustrated the religious motivation for fighting evolution. I am not especially concerned with whether ID is testable. I look at the testability of ID the same way I look at the testability of traditional young-earth creationism (YEC): YEC can make empirically or logically or statistically testable statements (the earth was covered by a body of water, all living things are descended from creatures that came off a boat) but its foundational claim that everything came into being suddenly in its present form through the efforts of a supernatural creator is not a scientifically testable claim. I shall let theologians argue over whether special creationism is good theology, but invoking omnipotent supernatural causes puts one smack out of the realm of science, protestations of the validity of “theistic science” notwithstanding. One cannot use natural processes to hold constant the actions of supernatural forces; hence it is impossible to test (by naturalistic methodology) supernatural explanations (Scott 1998). Whether a supernatural force does or does not act is thus outside of what science can tell us.

Similarly, ID can make empirically or logically or statistically testable claims (certain structures are irreducibly complex; by using probability arguments like the “design filter” one can detect design) but the foundational claim that a supernatural “intelligence” is behind it all is not a scientifically testable statement. (And please, let us be grownups here: we are not talking about a disembodied, vague “intelligence” that might be material, we are talking about God, an intelligent agent who can do things that, according to ID, mortals and natural processes like natural selection cannot. Not for nothing does Dembski say that ID is the bridge between science and theology.)

In my talk, I was not deploring the untestability of ID per se but the fact that its proponents do not present testable models. I was referring to the fact that ID proponents do not present a model at all in the sense of saying what happened when. At least YEC presents a view of “what happens”: the universe appeared a few thousands of years ago, at one time, in its present form; living things are descended from specially created “kinds” from which they have not varied except in trivial ways; there was a universal flood that produced the modern geological features; and humans are specially created apart from all other forms. So what happened in the ID model?

I said (and have said repeatedly) that the message of ID is “evolution is bad science”, without providing an alternative view of the history of the universe. This is not trivial: in books by Phillip Johnson, as well as in Jonathan Wells’s new Icons of Evolution (2000), teachers are told that they should be teaching students about how evolution is a weak, unsubstantiated “theory in crisis”, to quote former anti-evolutionist Michael Denton.

The theories of astronomical, geological, and biological evolution attempt to explain evidence demonstrating that the universe has been around for a long time and has gradually unfolded from a different form to its present form. There are lots of details in there, about when and how things happened: when our galaxy formed, when other galaxies formed, when earth formed and out of what matter, when warthogs or whortleberries or liverworts came to resemble their present forms, and so on. Something happened, and we are trying to figure out what and trying to figure out the mechanisms that brought it about. ID tells us that evolution did not happen (what else is one supposed to take away from Icons of Evolution?) but it does not tell us what did.

Unless ID proponents can come up with an actual model of “what happened”, all they have is a sterile anti-evolutionism that adds little to YEC beyond the specific ideas of irreducible complexity and the design filter.

The reason ID proponents are so vague about an actual picture of what happened is that they strive to include YECs, progressive creationists (PCs), and theistic evolutionists (TEs) among their theorists and supporters (though the TE gang must feel rather uncomfortable, Dembski himself having proclaimed that “ID is no friend of theistic evolution” [Dembski 1995]). This is not just a big tent; it is one bulging with people who must be eyeing one another warily. Phil Johnson may want everyone just to be nice for the time being until evolution is vanquished, and then they can work out their disagreements, but if you think evolutionists squabble, wait until you see what happens when the ID folks have to sort out their differences.

As Ronald Numbers and Kelly Smith independently urged at last summer’s “Design and Its Critics” conference, if ID is going to attain any level of scholarly respectability, its proponents are going to have to distinguish their model from the discredited, unscientific YEC model, even if that means losing the support of biblical-literalist Christians (see RNCSE 2000 Jul/Aug; 20 [4]: 40–43 for Kelly Smith’s comments.) For aspiring scholarly movements, the enemy of my enemy is not my friend.

Given my odd line of work, I am concerned with practical issues such as what teachers are being told to do and what effect this will have on American education. As near as I can tell, teachers are being encouraged to teach students that evolution did not happen and, if it did, that natural selection is not the cause of it, and that in any event we have to leave room for the direct actions of a Creator, and all this is still called science. But to keep all the ID factions quiet, an actual picture of what happened, which is what evolution is trying to explain and what ID has to explain, is never mentioned.

What should teachers teach? Apparently, judging from Icons of Evolution, they should teach the familiar old YEC saws about the weaknesses of evolution. Evolution is bad science, they say. So to my way of thinking, ID does not rise above familiar anti-evolutionism, though it may be served up in probability theory and information theory with a side order of biochemistry. There is no coherent ID model of what happened for teachers actually to teach.

This invites the question of what, according to the proponents of ID, should teachers teach about the following issues?

1) Is the universe a few thousand years old or billions? Most ID proponents will, if forced, uncomfortably confess that they accept an ancient age of the earth, but they are quick to dismiss the question as unimportant, presumably to keep the YECs in their anti-evolution tent. But should a teacher teach that the earth is millions or thousands of years old? You cannot have it both ways if you are proposing a K–12 curriculum. What is the ID model? What happened?

2) Is the geological column, which shows a succession of species through time, “real” or an artifact? At least the YECs present a model of what happened: the arrangement of species in the geological column is a result of sorting by Noah’s flood, rather than their appearance at different times. Does ID accept the geological column as “real”? This is a simple thing to agree to: it is still possible to argue (as Jonathan Wells does) that the arrangement of species through time does not represent descent with modification, but Dembski and his colleagues are going to have to come clean as to what this means. Minimally, it means the special creationists are wrong, but it also requires the progressive creationists and the theistic evolutionists to fight it out as to whether the succession of species through time represents separate creations or a genealogical pattern of related species.

3) Did living things descend with modification from common ancestors? This is what biological evolution is all about — and where the ID big tent starts showing the strain of trying to stretch over incompatible views. How is ID going to accommodate both theistic-evolutionist Michael Behe and special-creationist Paul Nelson? More important, what do proponents of ID expect teachers to teach? What happened?

I think that I know the answer. Teachers are supposed to teach that evolution did not happen. Of course, if they did, they would be teaching a view that is well outside the scientific mainstream, and be doing their students no favors. I like to remind people that evolution is taught matter-of-factly at every solid university in the nation, including Brigham Young, Notre Dame, and Baylor. But more importantly for our purposes here, ID does not present a coherent model of “what happened”, making it impossible for teachers to present ID as an alternative to evolution, as its proponents seek.

Now, maybe Dembski or other ID proponents will tell me that they are not trying to influence the K–12 curriculum, that they are merely trying to build a scholarly movement at the university or intellectual level, trusting that eventually ID will be validated and, like other intellectual movements, will trickle down to the K–12 level. If Dembski had attended my talk, he would have heard me advocate exactly this strategy. I do not think that ID will enter the academic mainstream, but if it does, then obviously it will eventually be taught in high school.

But I do not think that ID proponents are willing to wait until they get this validation: Jonathan Wells, whose book provides disclaimers to be copied and placed in K–12 textbooks, is obviously concerned primarily with the K–12 curriculum; Phillip Johnson’s Defeating Darwinism (1997) is explicitly aimed at high school students; and the CRSC’s Steven Meyer is an author of a substantial “Afterword” to teachers in the ID high-school textbook, Of Pandas and People (Davis and Kenyon 1989). Bruce Gordon, currently interim director of The Baylor Science and Religion Project, has correctly noted that ID “has been prematurely drawn into discussions of public science education, where it has no business making an appearance without broad recognition from the scientific community that it is making a worthwhile contribution to our understanding of the natural world” (Gordon 2001).

So, what happened, Bill? Will you go beyond “evolution is bad science” to give us an actual model of what happened?

[Dembski responded to my article on Meta (Dembski 2001b). Despite lavishing 2500-odd words on his response, he carefully avoided committing ID to any position on the age of the earth, the geological column, and common descent. The big tent continues to strain at the seams.]

Acknowledgments


I thank Glenn Branch for useful comments and William Grassie for the title.

References:

Davis P, Kenyon DH. Of Pandas and People, 2d ed. Dallas: Haughton, 1993.

Dembski W. What every theologian should know about creation, evolution, and design. Center for Interdisciplinary Studies Transactions 1995; 3 (2): 3.

Dembski W. Is intelligent design testable? 2001a. Available from , last accessed September 14, 2001.

Dembski W. Teaching intelligent design. 2001b. Available from , last accessed September 14, 2001.

Gordon B. Intelligent design movement struggles with identity crisis. Research News & Opportunities in Science and Theology 2001 Jan; 2 (1): 9.

Johnson PE. Defeating Darwinism. Downers Grove (IL): InterVarsity Press, 1997.

Scott EC. Two kinds of materialism. Free Inquiry 1998 Spring; 20. Wells J. Icons of Evolution. Washington (DC): Regnery Press, 2000.

About the Author(s): 
Eugenie C Scott
NCSE
PO Box 9477
Berkeley CA 94709-0477