Primer: ‘Sudden Appearance’

by TFN

This is Part II in a series of four posts in which TFN Insider had university scientists analyze problematic changes the State Board of Education made to science curriculum standards for Texas public schools in 2009. This year publishers will submit — and the state board will approve or reject — instructional materials based on these flawed standards. The following entry examines the current version of Texas Essential Knowledge and Skills (7)(B), which reads as follows

(7)  Science concepts. The student knows evolutionary theory is a scientific explanation for the unity and diversity of life. The student is expected to:

(B)  analyze and evaluate scientific explanations concerning any data of sudden appearance, stasis, and sequential nature of groups in the fossil record;

(Other entries in series: TEKS (3)(A) — All Sides of Scientific Evidence; TEKS (7)(G) — Complexity of the Cell; TEKS (9)(D) — Self-Replicating Life)


This standard was a new addition to the Texas science TEKS in 2009. It originated at the January 22, 2009, state board meeting in an amendment proposed by Don McLeroy, R-Bryan, a self-identified young earth creationist. The original wording of McLeroy’s amendment – approved by the board in January – was as follows:

(B) analyze and evaluate the sufficiency or insufficiency of common ancestry to explain the sudden appearance, stasis and sequential nature of groups in the fossil record;

At the March 27, 2009, board meeting, Lawrence Allen, D-Houston, moved to strike this standard entirely. In a final appeal to preserve his proposal, McLeroy stated that the purpose of his standard was to argue against:

“…the idea that all life is descended from a common ancestor by the unguided natural processes.

Despite McLeroy’s protestations, Allen’s amendment to strike the standard prevailed by an 8-7 vote, and it was removed from the standards. However, another member of the board’s anti-evolution faction, Cynthia Dunbar, R-Richmond, immediately offered new “compromise” language. An amendment by Bob Craig, R-Lubbock, slightly revised Dunbar’s “compromise.” Dunbar’s wording – as amended by Craig – was approved by a vote of 13-2. This compromise language was the final version adopted by the board.

Scientific and Pedagogical Problems with Standard

By Dr. John Wise, Research Associate Professor of Biological Sciences and Adjunct Associate Professor of Biological Sciences at Southern Methodist University in Dallas

Language referencing “sudden appearance” appears commonly in – and is closely associated with – the intelligent design movement.1 The inclusion of the expectation that students “analyze and evaluate scientific explanations concerning any data of sudden appearance … in the fossil record” parallels the major thesis of a book promoting intelligent design/creationism written by five members affiliated with the Discovery Institute’s Center for Science and Culture.2 Essentially the book, Exploring Evolution, promotes the hypothesis that the Cambrian Explosion, a geological period about 530 million years ago that revealed a great radiation of new animal body forms in the fossil record, can not be explained by current evolutionary science. The book extends this thesis by requiring that an intelligent, supernatural agent was required to create the new animal body forms. None of these hypotheses are supported by scientific evidence (as explained below).

The intelligent design/creationism thesis that the Cambrian Explosion occurred too “suddenly” to be explained by modern biological science completely ignores  a number of recent advances made in the science of evolutionary development that describe how animal bodies are made in a genetically modular way, thereby enabling rapid evolution.3 These intelligent design arguments also ignore many pre-Cambrian organisms that show relatedness to Cambrian organisms (see, for example, endnote 4).  In short, misleading claims about the Cambrian Explosion made in the intelligent design community have been specifically refuted on many detailed grounds and in many different places.5,6,7

This part of TEKS (7)(B) should therefore be deemed as an attempt to open the Texas public school educational system to old, refuted, religiously based, nonscientific intelligent design arguments. 
Likewise, the expectation that students analyze and evaluate scientific explanations of “stasis, and sequential nature of groups in the fossil record” is another use of language that can be traced to biased publications from anti-evolution, intelligent design/creationism proponents. The word “stasis” is used to describe the observation that fossil forms appear fully formed in the fossil record and remain relatively unchanged for long periods of time. In fact, these types of observations are fully compatible with evolutionary science. What other than fully formed organisms could be fossilized, for example? In addition, species that are well-adapted and exist in relatively stable environments would in many cases have the advantage of superior numbers over any organisms that would try to replace them. The predominant species would then be expected to dominate the fossil record over that period of time where its numbers predominated.

That fossils of transitional species (those species that are intermediate in characteristics between more widely separated organisms) are rare is a simple logical consequence of the time it takes the transition to occur versus the time of existence of the ancestor and descendant species. If the ancestor and then later the descendant species are well-adapted and are lucky enough to exist in stable environments, their total time on Earth can be very long. The transitions on the other hand can occur relatively quickly (in geologic time). The chance of finding a fossil of one of the transitional intermediates can therefore be low compared to finding a fossil of the stable ancestor or stable descendant species. Even though transitional fossils are rare and difficult to find, many transitional fossils species have been discovered by paleontologists. The existence of transitional fossils, as well as the general concept which these fossils support — namely, the sequential nature of descent from common ancestors — is so greatly supported by real scientific evidence that the vast majority of biological scientists and paleontologists accept these principles as fact.

There is a clear danger that the “stasis, and sequential nature” part of TEKS (7)(B) will be used to introduce discredited, scientifically falsified accounts from intelligent design/creationist publications that species appear in the fossil record without any transitional fossil evidence. Examples of these types of discredited arguments in intelligent design publications include the textbook supplement Of Pandas and People, which was the book at the center of the Dover trial8, and Icons of Evolution9, which pursues the discredited idea that major phylogenic groups in biology arose without any connection through descent from a common ancestor. In the age of modern biology, the hypotheses that fossil transitions are not evident in the fossil record as presented in Pandas and Icons has been fully refuted by many legitimate fossil transition discoveries. These real discoveries fully support modern evolutionary theory.

Unfounded doubts about the cornerstone of evolutionary theory, namely descent from common ancestors, introduced into students’ learning expectations via the use of intelligent design/creationism language like “sudden appearance” and “stasis, and sequential nature” have absolutely no place in biology classrooms or biology textbooks in Texas or anywhere else.

How Publishers Can Responsibly Address Standard

By Dr. Ben  Pierce, Professor of Biology and holder of the Lillian Nelson Pratt Chair at Southwestern University in Georgetown

To meet this new standard, publishers need not and should not introduce creationist arguments, as they do not meet the requirement that students analyze and evaluate “scientific explanations.”

One way for publishers to satisfy this new standard is to include a discussion of evidence for and against the theory of punctuated equilibrium. This idea, first proposed by evolutionary biologists Niles Eldredge and Stephen Jay Gould in 1972, is a scientific explanation for long periods of no evolution (stasis) followed by the sudden appearance of new organisms in the fossil record.10

Punctuated equilibrium proposes that major evolutionary change occurs when new species arise and that, between these speciation events, many organisms undergo little change. Evolutionary biologists have long debated whether evidence supports or refutes the theory of punctuated equilibrium. The fossil record of some organisms does indeed suggest a pattern of stasis followed by bursts of rapid evolution,11 but this pattern is not seen in other organisms.12 A review of 58 different studies that examined the theory of punctuated equilibrium across a range of organisms and geological periods concluded that sometimes evolution is gradual and sometimes punctuated — neither pattern is characteristic all of evolution.13 There is considerable disagreement over what processes are responsible for stasis in evolution.14


1 accessed on February 18, 2011 at the Discovery Institute’s Center for Science and Culture webpage, “The Theory of Intelligent Design: A Briefing Packet for Educators” – see, for example, page 15.
See Discovery Institute website, (accessed Feb. 18, 2011).
3 Carroll, S.B. 2005 Endless Forms Most Beautiful: The New Science of Evo-Devo, Norton and Co. New York.
4 Derek E. G. Briggs and Richard A. Fortey, 2005 “Wonderful strife: systematics, stem groups, and the phylogenetic signal of the Cambrian radiation” Paleobiology 31:94-112
5 A detailed analysis of fallacious “sudden appearance” arguments from the National Center for Science Education, (accessed Feb. 18, 2011).
A paleontologist’s response to fallacious intelligent design arguments about the Cambrian Explosion, (accessed Feb. 18, 2011).
A listing of problems with intelligent design/creationism’s claims about the Cambrian Explosion and other assertions, (accessed Feb. 18, 2011).
8 For a critique of the anti-evolutionary theory, pro-intelligent design Of Pandas and People’s treatment of the fossil record, see the National Center for Science Education (accessed Feb. 18, 2011).
9 For a critique of creationist-intelligent design Icons of Evolution, see the National Center for Science Education, (accessed Feb. 18, 2011).
10 Eldridge, N. and S. J. Gould.  1972.  “Punctuated equilibria: An alternative to phyletic gradualism.” In T. J. M. Schopf, ed. Models in Paleobiology.  Freeman, Cooper, and Company,San Francisco.
Jackson, J. B. C. and A. H. Cheetham. 1994. “Phylogeny reconstruction and the tempo of speciation in cheilostome Bryozoa.”  Paleobiology 20:407-423.
Chaline, J. and B. Laurin.  1986. “Phyletic gradualism in a European Plio-Pleistocene Mimomys lineage (Arvicolidae, Rodentia). ” Paleobiology 12:203-216.
Erwin, D. H. and R. L. Anstey. 1995. ” Speciation in the fossil record.”  In D. H. Erwin and R. L. Anstey, ed.  New Approaches to Speciation in the Fossil Record.  Columbia University Press, New York.
Futuyma, D. J.  1987.  “On the role of species in anagenesis.”  American Naturalist 130:465-473.