Science in Christian Perspective
Response to Reviews of Teaching Science in a Climate of Controversy: "Did the Universe Have, a Beginning?" and "Where Did the First Animals Come From?"
Co-author of Teaching
Science in a Climate of Controversy
7820 Santa Rosa Road
Bueliton, CA 93427
From: PSCF 40 (September 1988): 162-165.
The questions in the title above were two of four "open" questions covered in Teaching Science in a Climate of Controversy (TSCC), a 1986 booklet distributed by the American Scientific Affiliation (ASA) to 50,000 high school science teachers.' This article is a response to the scientific content of seven critical reviews (references 2a-2g) of the two questions in an attempt to ascertain what corrections or additions should be made in this section of ASA's booklet.
One critic, Juliana Texley, compares TSCC unfavorably to two other publications for teachers, both of which are recommended in the second printing of TSCC.' These are the 1984 'National Academy of Science (NAS) booklet Science and Creationism. and the 1986 National Science Teachers Association (NSTA) booklet Modern Science and the Book of Genesis by James W. Skehan. Texley also recommends the 1986 book aging by Robert Shapiro. The authors of TSCC also endorse her recommendation of Shapiro's book, which is subtitled "A Skeptic's Guide to the Creation of Life on Earth."
A recurring criticism of the "open questions" posed in TSCC is that they are selective; that is, they emphasize the unknown rather than the known areas of evolution. Although the questions are clearly labeled as "open," the criticism of selectivity is valid if one expects TSCC to stand by itself as a text on evolution. That was not the booklet's intent, however. It was intended as a supplement to biology textbooks and to the NAS publication, in which the relatively well-established areas of evolutionary biology are adequately covered. The NAS booklet is especially helpful in presenting evidence from biogeography and biochemistry which we saw no need to duplicate.
Most teachers on the firing line of the creation/evolution controversy seem to have little trouble recognizing the supplemental nature of TSCC, as indicated by the 70% A and A-plus grades on reader response cards. Nevertheless, it would have been wiser for us to label TSCC as a "supplement" to avoid misunderstanding on the part of some scientists concerned with the defense of evolution.
The authors of TSCC believe that unsolved problems and "open questions" deserve an important place in science education. Unsolved problems are an integral part of science and can be used to provide stimulation and inspiration in the classroom. The primary reason the authors chose the questions on the beginning of the universe and the origin of the first animals was that these areas are not covered in high school biology textbooks or in the NAS booklet.
Did the Universe Have a Beginning?
In scanning the critiques by nine prominent scientists assembled by William Bennetta, we note that not one of them presents a scientific criticism of this questions The following scientific criticisms have been made by others:
1. Bennetta states that our discussion contains "the implicit notion that time exists independently of the universe."' What we actually say is: "Although the idea of an eternal universe has satisfied many thinkers, modern discoveries have made that idea more difficult to accept. Today the best scientific evidence points to a real beginning, not only of the matter and energy of the universe but of time and space as well."
2. David Wake asks, "What do they accept as evidence? On the very day I read [in TSCCI that 'no trace of newly appearing or extinct galaxies' had been detected, the discovery of a spectacular new supernova was announced."' We think Wake (a professor of zoology) has mistakenly confused stars with galaxies. Supernovas signal the death of stars and provide the material for new stars and planets within galaxies. The question being addressed in TSCC is whether Hoyle's model of continuous creation is valid; we say no, for the reason that astronomers see no evidence of new galaxies. In other words, the universe is evolving from an initial beginning; it is not being continuously created.
3. Steven Schafersman says that "the Big Bang was not the beginning of matter and energy, only of its present form in our Universe."* He gives no scientific evidence to back up such a firm conclusion. In TSCC we point out that "The vacuum from which Guth's universe theoretically arises, however, is not a true vacuum; it contains energy. Attempts to derive a truly ex nihilo origin for the universe by what is known as 'quantum tunneling' have so far been frustrated. Quantum mechanics places severe limitations on 'virtual particle production,' and general relativity places demanding limits on the origin of time and space."
Schafersman (a geologist) cites no source for his statement that "much empirical evidence supports it [the oscillating universe hypothesis] over the hypothesis that the universe had only one origin." Although an oscillating universe is very appealing to some people for religious reasons, current scientific evidence and theory argue not for it, but against it. At the present time the observed density of the universe is at most only three-tenths of what is needed to force a collapse. Further, the density implied by the inflationary model will not force a collapse. Even if the universe were to collapse, a bounce would be unlikely, if not impossible, because of the huge entropy in the universe. Further, there is no known physical mechanism that can reverse a cosmic contraction. In final response to Schafersman's assertion that the oscillating universe hypothesis is "strongly supported," we note Tony Rothman's statement in the July 1987 issue of Discover: "There are models of the universe that bounce without resorting to quantum gravity, but they're not very realistic in their details. To date, all reasonable models of closed universes end in singularity."
Hence, the authors of TSCC see no basis on which to make changes in the section "Did the Universe Have a Beginning?" although we remain open to new discoveries and constructive scientific criticisms.
Where Did the First Animals Come From?
Several criticisms have been leveled at this "Open Question."
1. A major objective of TSCC is to teach students and teachers that scientific conclusions should be based on evidence. We are therefore concerned when Juliana Texley, editor of The Science Teacher magazine, accuses us of "inaccurate misrepresentations" and "no balanced discussion," citing as evidence for her accusation our "ignoring the relatively recent evidence for the great variety in Precambrian life."" We invite interested readers to examine the booklet for themselves, and note the illustrations and caption on page 34. Further, a full paragraph entitled in bold print "The Known" contains a summary description of the late Precambrian Ediacara fossil complex. In addition, TSCC readers are given sources in footnotes 14 and 15 for more extensive reading on these relatively recent Precambrian discoveries. Perhaps Texley has confused our booklet with her alternative recommendations, which make no mention of these exciting discoveries.
2. William Bennetta accuses us of virtually ignoring "the whole post-Cambrian record, its overwhelming demonstration of evolutionary succession, its transitional forms, and the knowledge it has yielded."" Again, we invite readers to examine the evidence for themselves. With regard to transitional forms required by evolutionary theory, we state that the "'reptilian bird,' Archeopteryx, is one of many exciting discoveries that seem to fit the general picture. Further, in following the succession of fossilized life from ancient layers of rock to more recent ones, we see that, in general, increasingly complex life-forms have appeared" (p. 34). Also, we devote an entire page (25% of the space for the First Animals section) to an illustration of these increasingly complex life-forms as they appeared over the last 500 million years of geologic history (the post-Cambrian). This hardly squares with Bennetta's charge that we "virtually ignore the postCambrian" and his further accusation in the California Science Teacher's Journal that, "As far as the A.S.A. is concerned, the past 500 million years seem not really to have happened at all."
3. Bennetta claims that TSCC affirms that: "Scientists cannot reasonably infer 'where' animals came from, because the fossil record is sparse until the Cambrian period."' We cannot be held responsible for an inference made by Bennetta which we never intended or made. To clear up any misunderstanding on this score, we hereby affirm that it is indeed a logical scientific inference that the first animals as -ell as subsequent ones evolved from previous life-forms. The problem is that the origins and earliest evolution of the metazoan phyla cannot be currently documented from the fossil record. It is this missing evidence and the parameters of the unsolved problem that TSCC addresses.
4. Neil Wells charges that "the reader is deliberately left with the impression that everything in the Precambrian was blue-green algae and that 'real animals' suddenly appeared at the start of the Cambrian."" The following items from TSCC are in direct contradiction to Wells' assertion. After our description of the blue-green algae in the caption on page 34, we say that "The first cells with a nucleus (eukaryotes) appeared perhaps I billion years ago. Life was very simple until about 700 million years ago." In our text on pages 34 and 35 we say that "A few [of the earliest animals] have left their mark in rocks of late Precambrian time about 700 million years ago. Impressions found between sedimentary layers define some simple animals that had neither shells nor skeletons. Those earliest fossilized animals were first discovered in Australia about twenty years ago." We describe these first fossilized animals as the Ediacara fossil complex, date them as far back as 100 million years before the Cambrian, identify them as fully formed, soft-bodied animals many of which are unlike later animals. We cite two reference sources for further study by those interested. If this information about the general sequence of life between the blue-greens and the Cambrian animals constitutes deliberately leaving the reader with the impression Wells describes, somebody has a serious communication problem.
We are grateful to Wells for his helpful criticism that we improperly identified stromatolites as being formed by "floating mats." We should have said "algal mats," or more completely, "mats of blue-greens, properly called cyanobacteria, growing on the sediment surface." Our mistake is especially embarrassing to one of the co-authors, John Wiester, who has the correct description in his 1983 book The Genesis Connection (pp. 77-79).
5. Schafersman states that the authors of TSCC "conclude that the argument that the transitional forms were not preserved because they were soft-bodied is not convincing because numerous well-preserved soft-bodied fossils from Precambrian and Cambrian rocks have been found."'g We did not say the argument was "not convincing." We said the argument was "less convincing than it once was" because of the numerous recent discoveries of soft-bodied preservation from the Cambrian and Precambrian.
Schafersman also says that we make the "incorrect claim that transitional forms linking the Cambrian invertebrate phyla that did have hard parts should have been found since they 'should have contained hard parts.' " He then says that we are "wrong" because "the adaptive radiation that led to the appearance of the Cambrian phyla occurred in the late Precambrian before the various phyla had developed hard parts." The latest information shows that both we and Schafersman have made incorrect statements. Schafersman is incorrect to insist that the adaptive radiation that led to the appearance of the Cambrian phyla had to have taken place in the Precambrian. It could have taken place at the base of the Cambrian following the mass extinction of the Precambrian animals. He is also incorrect in his assumption that the adaptive radiation that led to all the Cambrian phyla would have been entirely without hard parts. We are wrong in assuming that links between invertebrate phyla should exist that contain hard parts.
The real issue in dispute is whether there should have existed transitional forms with durable parts leading to at least some of the phyla and subgroups that make their appearance in the Cambrian. We note that James W. Valentine and Douglas H. Erwin state that "The Echinodermata particularly, and the Mollusca as well, contain classes that are, to the level of certainty possible in such cases, descended from durably skeletonized ancestors that were not usually minute. Yet we have no intermediates in these cases. The missing intermediates may be regarded as data, and these data indicate that ancestors of high-level taxa may be missing even if they are not soft bodied or minute."' They also state that "The evidence presented concerning the brachiopods suggests that the phylum could not have gradually evolved without hard parts and then acquired them, leading to the rapid appearance of these groups in the fossil record; rather the hard and soft parts of these groups are intimately coevolved."' A key point of the Valentine and Erwin paper is that it is time to regard the missing intermediate forms as real data and to look for "mechanisms of genome change that do not operate at the same intensity or with the same results today. ,4 It is this type of approach to unsolved problems that leads to the advancement of science.
6. We feel that Stephen Gould's charge that we have quoted him out of context is based on his inference concerning our motives.' Our motive is not to throw doubt on the record of the subsequent evolution of invertebrates, as Gould states. We agree that we should have avoided misunderstanding by clarifying his intent, which was to explain (in Gould's words) "why we should not expect progress as a major feature of the fossil record." Our objective in using his quote was to emphasize the importance of this pivotal point in biologic history (the origin of major body plans). Roger Lewin has also emphasized the importance of the origin of the major body plans: "Around 600 million years ago multicellular organisms appeared, and within a few tens of millions of years all the basic designs for complex life forms had been established. Since then life has again and again consisted of variations on a theme" (The Thread of Life, 1982, Smithsonian Books, p. 70). Gould and his co-workers have more recently called the base of the Cambrian a "crux in life's history" when "nearly all basic designs of invertebrate life entered the fossil record for the first time" (Science 236:1437-1441, 12 June 1987).
In conclusion, the section of the TSCC booklet dealing with the "open question" of "Where did the first animals come from?" concludes that the origins and earliest evolution of the invertebrate phyla remain essentially undocumented in the fossil record. The amazing amount of diversification that took place in the early Cambrian, producing almost all the animal phyla, is seldom appreciated by students as a major feature of evolutionary history. The booklet neither proposes an explanation nor accuses researchers of covering up our current lack of information regarding the origin of the invertebrate phyla. But why should high school textbooks inadequately depict this "crux in life's recorded history" (in the words of Gould et al.)? It is an excellent place not only to explore the role of mass extinctions and subsequent radiations in evolutionary theory, but also to present unsolved problems-all of which deserve (B) The major inaccuracy in your editorial and by most of an important place in science education.
I. Teaching Science in a CItimte of Controversy. A View from theAmerican Scientificc Affiliation, (1986). American Scientific Affiliation, P.O. Box 668, Ipswich, MA 01938.
2. Reviews of Teaching Science :
(a) J. Texley, The Science Teacher, 54(2):8 (1987).
(b) J. Texley, The Scientist, May 4, 1987, p. 20.
(c) D.B. Wake, The Scientist, May 4, 1987, p. 21.
(d) W.J. Bennetta et a]., The Teacher, 54(5):36-43 (1987),
(e) W.J. Bennetta, Creation/Evolution Newsletter, 6(6):6-7 (1987), and an almost identical article in California Science Teachers Journal, Spring 1987.
(f) N.A. Wells, CreatonlEvolution @ewslater, 7(2-3:4-5 (1987).
(g) S.D. Schafersman, Creation/Evolution Newsletter, 7(2-3):5-7 (1987).
3. J. W. Valentine and D. H. Erwin, "Interpreting Great Developmental Experiments: The Fossil Record. " In Development as an Evolutionary Process (R.A. and E.C. Raff, eds.), New York: Alan R. Lin, 1987, p. 87.
4. Ibid., p. 100.