HOLES IN EVOLUTION! (as described by my university Invertebrate Zoology textbook)

by Richard Peachey

During my studies at University of the Fraser Valley, Abbotsford, I enrolled in a two-semester upper-level course in "Invertebrate Biology" taught by Dr. Barbara Moon. Already an experienced biology instructor, Dr. Moon had recently completed her PhD in educational practice. An ardent evolutionist, she selected a strongly pro-evolution textbook for the course. The following quotations from that text, however, illustrate very well what a Swiss cheese evolutionary theory is! (Bold print indicates emphasis added.)

All quotations here are from: R. S. K. Barnes, P. Calow & P. J. W. Olive. 1993. The Invertebrates: a new synthesis. (Second edition.) Oxford, UK: Blackwell Scientific Publications. (This text presents most of the animal phyla as independently derived from flatworms — an evolutionist "lawn of grass" approach, as opposed to a typical Darwinian "tree." The flatworms themselves, along with just a few other phyla, are held to be direct descendants of one protist group or another.)

"Part 1 — Evolutionary Introduction

"Chapter 1 — Introduction: Basic Approach and Principles

"The main undercurrent which permeates our survey of invertebrate diversity (Part 2) and functional biology (Part 3) is that of the evolutionary pressures and advantages which have influenced these animals in the past and which continue to mould invertebrate biology today. In this introductory section, we describe briefly this all-pervasive evolutionary ethos." (p. 1)

"Chapter 2 — The Evolutionary History and Phylogeny of the Invertebrates

"Living animals are the products of their evolutionary pasts, and it is not possible fully to understand modern biology unless we have some appreciation of that past and of the constraints which it has placed upon their life styles and potentialities. In this chapter we describe the major features of the evolutionary history of the animal kingdom, including those of its origin.
  "All too often, phylogenetic reconstruction has appeared a rather sterile pursuit – an ingenious but largely irrelevant series of armchair attempts to juggle with various body plans in different combinations in order to find an intellectually satisfying picture, a sort of jigsaw-puzzle game with most of the pieces lost. Entirely hypothetical organisms have been designed so as to bridge gaps in these schemes, often with little regard to the necessity of postulating animals which could conceivably have survived, captured food, escaped predation and reproduced." (p. 10)

"It is certain [!] that the multicellular animals, like the two other multicellular kingdoms, the Fungi and Plantae, are the descendants of the unicellular (or acellular) eukaryote protists. But there certainty ceases. Most of the animal phyla that are represented in the fossil record first appear, 'fully formed', in the Cambrian, some 550 million years ago. These include such advanced, anatomically complex types as trilobites, echinoderms, brachiopods and molluscs. Precambrian fossil animals are not numerous, but it is generally accepted that cnidarians and segmented worms date back to that period, although not all forms can be accommodated in surviving groups. The fossil record is therefore of no help with respect to the origin and early diversification of the various animal phyla, except in so far as to indicate that these must have occurred in the Precambrian, probably between 1200 and 900 million years before the present day." (pp. 10-11)

"The first multicellular animals would presumably have been small, composed of relatively few cells, and without any hard parts. Since the fossil record is overwhelmingly one of organisms with hard tests, shells, plates or skeletons, it would therefore be unrealistic to expect that this record will ever be able to contribute to unravelling the ancestry of the animals; such ancestral forms are most unlikely to have been preserved. Zoologists have therefore been forced to argue solely on the basis of comparison of the structure and function of living members of the different animal and protist phyla, and to erect hypotheses of what existing characteristics of living organisms should be regarded as primitive features retained through to the present." (p. 11)

"To a modern zoologist, much of the early debate [about evolutionary relationships among animal phyla] was characterized by adherence to now discredited 'laws', such as 'ontogeny recapitulates phylogeny', by the wholesale invention of purely hypothetical intermediate stages which owed more to the necessities imposed by the hypothesis being advocated than to any requirements of successful survival, and by a succession of ingenious armchair speculations which, because of the nature of the quest, were essentially untestable and unfalsifiable. As a reaction against this early rash of speculation and counter-speculation, several modern biologists regard any attempt to reconstruct phylogenies as being futile and unscientific; we will never know if a given answer is correct, so it is pointless attempting the question! Although this attitude might strictly be correct, it is unlikely that the human spirit of enquiry would permit itself to be shackled by this constraint. If we adhered too strictly to a definition of biological science which excluded any area not amenable to experimental refutation of hypotheses, much current biological research, including all that directed towards events in the past, would become inadmissible.[!] Evidence from comparative study of living species and from the fossil record is available to render some suggested phylogenies more plausible than others, and it is upon such evidence that the following general account is based (much of it summarized by Willmer, 1990). The reader should note, however, that alternative interpretations are not only possible, but available in the phylogenetic literature." (pp. 11-12)

"The structure of sponges is so individual that it is impossible to derive any of the other living animal phyla from their body plan. This has led some people to regard sponges as an early, unsuccessful 'attempt' at multicellularity. Nothing could be further from the truth. Sponges are an extremely successful marine group, with more living species than the echinoderms and almost as many as those of the marine annelids; they have also been a prominent part of the marine fauna since the Cambrian. Their apparent simplicity need not be viewed as the result of some inability to evolve the organ systems found in other groups of animals, however, but can be related directly to their un-animal-like life style.
  "They are attached, sessile and completely immobile suspension feeders. Indeed, the function of their skeletal apparatus is the very antithesis of that in all other types of animal: in effect, it serves to prevent movement and to provide a rigid support for the body. Environmental water is induced to flow through the channels and chambers of the sponge mass by the (unorganized) beating of the choanocyte flagella; were the tubes not rigid and immovable, local reductions in water pressure could cause the tubing to constrict rather than serve to draw more water through. Granted that the body is incapable of movement, a nervous system, for example, would be functionless. Protection from predators is not brought about by detection and escape, but by distasteful chemicals or the spicular or fibrous nature of the skeleton. Seen in the same light, it is difficult to imagine how any of the other organ systems possessed by more organized animals could in any way increase sponge efficiency or survival. . . .
  "The sponge is therefore an alternative animal, not a reject." (p. 14)

"Like the sponges, the coelenterates (i.e. the Cnidaria and Ctenophora) are generally regarded as a highly individual and dead-end group. The supposition that they did not give rise to any other phyla is – again similarly to the sponges – only another way of stating that their general body plan is so successful that no basic change to it would be likely to lead to greater success. The peculiarities of the coelenterate body plan are their radial symmetry, their generally tissue-grade of organization with co-ordination of the cells being achieved by a diffuse network of naked nerve-cell fibres, and the occurrence of only two layers of cells, one on either side of a gelatinous and often non-cellular mesoglea. Equally characteristic are the intracellular organelles, the nematocysts (in the Cnidaria) or colloblasts (in the Ctenophora), responsible for offence and defence." (p. 14)

"By the same token, the basic body plan of the coelenterates is such as to make it unlikely that they were derived from any other known animal group. The ancestry of these animals is, therefore, most realistically to be sought amongst the Protista, although it is not possible to conclude which, if any, surviving type of protist is nearest to their origin. Because the cells of cnidarians are typically flagellated, rather than ciliated like the majority of animals, and because food particles are ingested by amoeboid phagocytosis, it has been suggested that the protists concerned are most likely to have been a group of heterotrophic flagellates. Although questions such as the precise bodily form of the colonial protist or protocoelenterate which could have been ancestral to the group, and whether the polyp or medusoid phase is the more primitive, have been much debated, all is here conjectural and little point would be served by attempting to argue the merits of any particular scheme." (p. 15)

"(Note that although we follow the traditional view here that the cnidarians and ctenophores are related groups, there is an increasingly held opinion that their resemblances are a result of convergence. The 'mesoglea' of the ctenophores may be more akin to the flatworm mesenchyme than to the system of that name in the Cnidaria, and ctenophore cells are also multiciliate rather than monoflagellate.)" (p. 16)

"A worm may be defined as any bilaterally symmetrical, legless and soft-bodied animal with a length greater than two or three times its breadth. On such a basis there are some sixteen animal phyla composed solely of worms (in addition to the flatworms) and several other groups that contain various vermiform species. Although evidence of the existence of worms, such as burrows, tubes and crawling traces, is abundant in the fossil record, including in the Precambrian, soft-bodied animals are not common as fossils. Priapulans and segmented worms are known to have been abundant in the Cambrian, but assignment of other fossil material to specific living phyla is fraught with contention. Be that as it may, representatives or evidence of several other phyla of worms have been claimed for the Cambrian and Precambrian. The fossil record is nevertheless of little assistance in disentangling the interrelationships of modern worms, and there is little general agreement on affinities within the group." (p. 19)

"Molluscs have neither a coelomic hydrostatic skeleton, nor signs of metameric segmentation, yet because they share a type of larva – the trochophore – in common with the coelomic and segmented annelids, and because larval form was once held to be of overriding importance in establishing phylogenetic relationships, they were for many years assumed once to have had a coelomic body cavity and to have been segmented, only to have lost both in later evolution. It is certainly the case that some molluscs have multiple pairs of some organs (the monoplacophorans, for example, have eight pairs of foot-retractor muscles, six pairs of excretory organs, and five or six pairs of gills), but these multiple pairs of organs are not in any way associated with particular regions of the body which could be considered to represent segments. Several unsegmented animals have multiple pairs of organs in linear series without being regarded as having once been metamerically segmented: they are sometimes termed 'pseudo-metameric'. Molluscs do also have a coelomic cavity surrounding the heart, but this is more plausibly regarded as a space evolved by that group within which the heart can beat, than as a remnant of a once more extensive cavity which served as a hydrostatic skeleton.
  "There is, therefore, no compelling evidence for any such original presence and later great reduction or loss, and molluscs are no longer usually regarded as being closely related to the annelids." (p. 22)

"Somewhat paradoxically, although the four deuterostome phyla (the Hemichordata, Echinodermata, Chordata and Chaetognatha) form a closely knit group, sharing many common features, almost nothing is known of their interrelationships. . . .
  "The echinoderms are one of the many groups first to appear, clearly recognizable as to their phylum, in the Cambrian, although the early forms did not uniformly display the five-fold (pentaradial) symmetry that characterizes the surviving echinoderm classes. The ancestral body plan is purely a matter of conjecture. . . .
  "Besides the common features shown by all deuterostomes, echinoderms share with the chordates a hard, mesodermal, protective, calcium-based system of plates in the dermis, and some extinct echinoderms may have had the equivalent of pharyngeal clefts, a feature also found in the surviving hemichordates (and in some gastrotrichs). Not surprisingly, therefore, most attempts to derive the chordates from another animal group have implicated the echinoderms as being near to the point of origin. But, as with the hemichordate/echinoderm transition, all such suggested phylogenies come up against a lack of potential intermediate stages; no living species can serve as appropriate analogies and the fossil record is of no help unless the peculiar homalozoans of the Cambrian to Devonian, which lack any form of symmetry, are ancestral chordates as has been claimed. . . .
  "The fourth deuterostome phylum, the Chaetognatha, is as phylogenetically obscure as it is ecologically important; chaetognaths are perhaps the most important invertebrate predators of the marine plankton. The early embryology of these transparent, soft-bodied worms is typically deuterostome, and they possess a tripartite body plan of head, trunk and post-anal locomotory tail. Whether these three regions correspond to the hemichordate pro-, meso- and metasome, however, is more problematic, and some chaetognath features appear distinctly similar to those of the pseudo-coelomate groups. On present knowledge, nothing can be surmised as to their precise relationships with the other deuterostomes." (pp. 27-28)

"Living animals can be placed in a total of 35 phyla; a phylum being defined pragmatically as a group of organisms that appear to be related one to each other, but whose relationships with other such groups are debatable or purely conjectural. In essence, therefore, phylum status is an admission of our ignorance, although the foregoing sections have endeavoured to trace likely patterns of affinity. These 35 living phyla, however, are not the end result of a long, slow process of evolutionary divergence which has culminated in the diversity that we see today. It seems probable [to an evolutionist] that with very few exceptions, all the surviving animal phyla were in existence during the Cambrian, and that the diversification of the flatworm-like antecedents of the majority of groups occurred in the Precambrian. This presents something of a conundrum." (p. 28)

"The temptation to regard flatworms and coelenterates, for instance, as in some way inferior to crustaceans and chordates with their much more complex structure and behaviour is therefore to be avoided. The variety of animal types produced by the [alleged] great Precambrian and Cambrian radiations are all more or less equally ancient, alternative body plans; they do not form a ladder of increasing adaptedness or 'perfection'." (p. 36)

After posting the above article, I received this very kind email from Frank Sherwin, biologist at the Institute for Creation Research. I'm appending Frank's email to my article because he includes a good selection of citations from his own college textbook, and other sources, on the topic of holes in invertebrate evolution.

Hi Richard –

I immediately bookmarked your CSABC website with your most-excellent front page article – outstanding!

As a student of biology, I was routinely taught the party line of macroevolution, but was never told how it actually occurred. Editor Michael Allaby stated, “there is no agreement as to whether macroevolution results from the accumulation of small changes due to microevolution, or whether macroevolution is uncoupled from microevolution” (The Concise Oxford Dictionary of Zoology, 1992). Evolutionary biologists Jones & Blaxter at the University of Edinburgh said, “Despite the comforting certainty of textbooks and 150 years of argument, the true relationships of the major groups (phyla) of animals remain contentious” (Nature, Animal Roots and Shoots, 434:1076-77).

We used the 1974 edition of Integrated Principles of Zoology by Hickman, Hickman & Hickman at Western St College. Not a single fact of macroevolution was listed in those pages. Interestingly, the 1997 edition of Integrated Principles of Zoology by Hickman, Roberts & Larson seems to have even less to say in regard to macroevolution -

“The origin of the ciliates [e.g. the Paramecium] is somewhat obscure.” – p. 235

“Unraveling the origin of the multicellular animals (metazoans) has presented many problems for zoologists.” – p. 240

“. . . one of the most intriguing questions is the place of mesozoans in the evolutionary picture.” – p. 242

“The origin of the cnidarians and ctenophores is obscure.” – p. 275.

“Any ancestral or other related groups that would shed a clue to the [evolutionary] relationships of the Acanthocephala is probably long since extinct.” – p. 317

“The primitive ancestral mollusk [snails, clams, squids] was probably a more or less wormlike organism . . .” – p. 346

“The phylogenetic position of placozoans is uncertain . . .” – p. 242 (this phylum is now supposedly ‘the closest living thing to the ancestor of all animals’ – New Scientist 1/09)

“No truly satisfactory explanation has yet been given for the origins of metamerism and the coelom, although the subject has stimulated much speculation and debate over the years.” – p. 365

“What can we infer about the common ancestor of the annelids? This has been the subject of a long and continuing debate.” – p. 365

“Controversy on [evolution] within the Chelicerata also exists . . .” – p. 379

“The relationship of the crustaceans to other arthropods has long been a puzzle.” – p. 399

“The [evolutionary] affinities of the Pentastomida are uncertain. – p. 439

“The [evolutionary] position of the lophophorates [invertebrates] has been the subject of much controversy and debate.” – p. 447

“Despite the excellent fossil record, the origin and early evolution of the echinoderms [sea stars] are still obscure.” – p. 450 [see also: Zamora, “Middle Cambrian echinoderms from north Spain,” Geology, v. 38]

“Despite the existence of an extensive fossil record, there have been numerous contesting hypotheses on echinoderm [evolution].” – p. 465

“Hemichordate [evolution] has long been puzzling.” – p. 476

“ . . zoologists have debated the question of vertebrate origins. It has been very difficult to reconstruct lines of descent because the earliest protochordates were in all probability soft-bodied creatures that stood little chance of being preserved as fossils even under the most ideal conditions.” – p. 485 [In other words, there is no evidence for their evolution]

“However, the exact [evolutionary] position of the chordates within the animal kingdom is unclear.” – p. 480 [discoveries in Mexico now confirm “that all skeletalized metazoan phyla appeared in the Cambrian.” - Landing, English, & Keppie, “Cambrian origin of all skeletalized metazoan phyla—Discovery of Earth’s oldest bryozoans (Upper Cambrian, southern Mexico),” Geology, v. 38, no. 6]

“The evolutionary origin of insect wings has long been a puzzle.” – p. 429 [“Nobody knows where caterpillars came from” – retired zoologist Donald Williamson, U of Liverpool, New Scientist Aug. 29, 2009, p. 12]

“The fishes are of ancient ancestry, having descended from an unknown free-swimming protochordate ancestor.” [my emphasis] – p. 499

Trilobites (subphylum Schizoramia - at least 56 families) are fascinating creatures found in the Cambrian and Ordovician rocks and disappearing at the end of the Permian. One multimedia encyclopedia (Navify) stated, “When trilobites first appeared they were already highly diverse and geographically dispersed” - as predicted by creation science. Evolutionist David Raup said the trilobites" ... used an optical design which would require a well trained and imaginative optical engineer to develop today ... " (Raup, 1979). See also ‘Trilobites — The Eyes Have It’ by Sherwin & Armitage, 2003 Creation Research Society. CRSQ—Creation Research Society Quarterly, Vol. 40, No. 3.