Biogenetic Law Research Articles

Historical biogeography, the natural science

TAXONVolume 53, Issue 4 p. 899-903 Forum on Biogeography: IntroductionsFree Access Historical biogeography, the natural science Lynne R. Parenti, Lynne R. Parenti parenti@si.edu Division of Fishes, Department of Zoology, Smithsonian Institution, National Museum of Natural History, P.O. Box 37012, D.C. 20013 Rm. WG-12, MRC 159, Washington, U.S ASearch for more papers by this authorChristopher J. Humphries, Christopher J. Humphries cjh@nhm.ac.uk Department of Botany, The Natural History Museum, Cromwell Road, London, SW7 5 BD U.KSearch for more papers by this author Lynne R. Parenti, Lynne R. Parenti parenti@si.edu Division of Fishes, Department of Zoology, Smithsonian Institution, National Museum of Natural History, P.O. Box 37012, D.C. 20013 Rm. WG-12, MRC 159, Washington, U.S ASearch for more papers by this authorChristopher J. Humphries, Christopher J. Humphries cjh@nhm.ac.uk Department of Botany, The Natural History Museum, Cromwell Road, London, SW7 5 BD U.KSearch for more papers by this author First published: 01 November 2004 https://doi.org/10.2307/4135556Citations: 7AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Literature Cited Brundin, L. 1966. Transantarctic relationships and their significance as evidenced by midges. Kungl. Svenska Vetenskapsacad. Handl. (ser. 4) 11: 1– 172. Craw, R. C., Grehan, J. R. & Heads, M. J. 1999. Panbiogeography: Tracking the History of Life. Oxford Univ. Press, Oxford. Hallam, A. 1973. A Revolution in the Earth Sciences. From Continental Drift to Plate Tectonics. Clarendon Press, Oxford. Ladiges, P. Y., Humphries, C. J. & Martinelli, L. W. 1991. Austral Biogeography. CSIRO, Melbourne. Lomolino, M. V., Sax, D. F. & Brown, J. H. 2004. Foundations of Biogeography: Classic Papers with Commentaries. Univ. Chicago Press, Chicago. Morrone, J. J. & Carpenter, J. M. 1994. In search of a method for cladistic biogeography: an empirical comparison of Component Analysis, Brooks Parsimony Analysis, and Three-area statements. Cladistics 10: 99– 153. Williams, D. M. & Ebach, M. C. 2004. The reform of paleontology and the rise of biogeography—25 years after “ontogeny, phylogeny, paleonotology and the biogenetic law” ( Nelson, 1978). J. Biogeogr. 31: 685– 712. Citing Literature Volume53, Issue4November 2004Pages 899-903 ReferencesRelatedInformation

The ontogeny and physiology confirms the dual nature of sleep states

In the Jouvet's laboratory, as early as 1960 the study of the ontogenesis of paradoxical sleep (PS) named "sleep 'with jerks" began in the kitten and led to the first publication in 1961. Then, several species were studied, lamb, rat, human neonates, etc. These works showed that at birth sleep with jerks was preponderant in altricial (immature) species (cat, rat) and the first to appear during the second half of gestation in precocious species (guinea pig). For Jouvet, sleep with jerks is a immature form of PS. Why PS is so important at birth? The maturation of the central nervous system, based on the myelinization, starts in the spinal cord then forwards to the brainstem and forebrain. So, PS mechanisms located in the brainstem are the first to mature and the only one to function. Then the slow wave sleep (SWS) and waking structures become mature. Phylogenetic studies showed that in mammals and birds PS was present even in marsupials and monotremes. Until now only the one exception is the dolphin with a voluntary breathing. To sleep and breath, dolphin has developed an unilateral sleep without classical PS. In other animals, reptiles, amphibians, fishes, PS was not observed with the parameters used in mammals. The study at birth (not yet done) of reptiles would allow perhaps the observation of a temporary PS. Based on these findings, a schematic model of the sleep regulation can be elaborated. Haeckel's aphorism "Ontogeny recapitulates phylogeny" seems true for PS which appears in birds and mammals i.e. at the end of evolution as it appears at the end of gestation when PS cerebral structures are present and mature.

The reform of palaeontology and the rise of biogeography – 25 years after ‘ontogeny, phylogeny, paleontology and the biogenetic law’ (Nelson, 1978)

AbstractAim To document the historical development of cladistics and the roles palaeontology and biogeography played in establishing coherent concepts of phylogenetic relationships focusing on some aspects of the contributions of Gareth Nelson.Conclusions Nelson's reformulation of the threefold parallelism provides a rationale for investigating phylogeny, replacing the central role palaeontology once played with biogeography, adding a spatial dimension to the concept of phylogeny. This approach to phylogeny replaces the old ‘transformationist’ view with the cladistic view, the latter dependent on discovering relationships among taxa. Numerical phylogenetic methods are inherently ‘transformationist’ and have replaced stratigraphy as the key to phylogenetic relationships. Numerical methods in systematics and biogeography are inherently transformational and suffer the same problems as the old palaeontology.

Recapitulation and Chronological Progression in John's Apocalypse: Towards a New Perspective

Most critical scholars have adopted some form of recapitulation theory to explain the chronological relationship between the seven seals, trumpets and bowls, but John was more interested in the chronological progression within the last days than is usually acknowledged. The seventh (or sixth) seal does not describe the ‘end’, but ushers in the Day of the Lord, which culminates in the seven bowls. While John does use the technique of recapitulation, he does not do so in the key texts usually adduced in support of the theory.

Leeches.

Real worms don't eat bacteria. Leeches are segmented, eucoelomate worms of the phylum Annelida, distinguished from other annelids by anterior and posterior suckers used for locomotion and feeding – on blood or soft body parts of other animals. They are not to be confused with nematodes, which lack these (and most other) features. Leeches are mainly aquatic, but the Asian land leeches are well known to trekkers. Annelid systematics is messy, but leeches are clearly united with earthworms and their ilk into a monophyletic grouping of hermaphroditic annelids, Clitellata, named for the specialized midbody segments (clitellum) that secrete a cocoon to surround the eggs. Blood sausage and escargot. Sanguivory evolved independently in different groups of leeches. Hirudinid species – traditionally used for bloodletting and still used to treat vasocongestion after reconstructive surgery – incise a delicate three-pronged wound, and are reared in the lab on heparinized blood presented in sausage casing or lambskin condoms. Glossiphoniid species have an evertable proboscis that penetrates more than a centimeter into the vertebrate host. Potent anticoagulants are secreted to assist in feeding in both groups. Other leeches prey on invertebrates, including crustaceans, snails and other annelids. Most leeches show clear species preferences in feeding, and some have strong preferences as to the anatomical site of attack – delicacy forbids further details. Why leeches? Leeches have distinguished pedigrees as preparations for embryology and neurobiology. C. O. Whitman, first director of the MBL (Woods Hole, Massachusetts), used glossiphoniid embryos for pioneering studies of embryological cell lineages in the 1870s, in part to test the predictions of Haeckel's Law – the notorious “ontogeny recapitulates phylogeny”. Whitman found that leech embryos do not pass through a ‘colonial stage’, but instead develop via stereotyped lineages, so that cells can be uniquely identified from the first cleavage. Later that century, G. Retzius in Sweden drew neurons of the medicinal leech (Hirudo) with detail rivaling that obtained by modern intracellular dye injections. What have they done for us lately? Beginning in the 1960s with standard electrophysiological techniques, and more recently using optical methods, scientists have been able to explain the sinuous swim movements and other leech behaviors in terms of networks of identified neurons in Hirudo. Studies of Hirudo neurodevelopment have revealed wonderful phenomena, including: baroque muscle scaffolding cells, each of which projects about 70 parallel growth cones obliquely to the animal's anteroposterior axis; and ‘isoneuronal’ avoidance, in which peripheral neurites of a developing sensory neuron avoid other processes of the same cell and yet fasciculate with those of equivalent neurons from other segments, apparently on the basis of synchronous activity in contiguous processes. Regeneration, and synapse formation by identified neurons in culture are also studied in Hirudo. Studies of early development resumed in the 1970s, using the large embryos of glossiphoniid species such as Helobdella. More unexpected phenomena include: stochastic expression of notch and wnt class genes in the two cell embryo, despite the unique identities of the cells; mitotic transcription of a hes class gene; and inductively regulated fusion of endodermal precursor cells. Amputated arthropods? Unlikely. Updated versions of Cuvier's (1817) ‘Articulata hypothesis’ hold that annelids and arthropods evolved from a segmented common ancestor. But recent molecular phylogenies suggest that arthropod and annelid lineages separated well before the Cambrian (more than 600 million years ago); annelids are assigned to a clade of largely unsegmented taxa, including mollusks, flatworms, brachiopods and other truly obscure phyla, collectively designated ‘Lophotrochozoa’. While most biologists focus on Deuterostomes (such as vertebrates and echinoderms) or Ecdysozoans (arthropods, nematodes and so on), the Lophotrochozoans are a relatively unexplored ‘third way’ of bilaterally symmetric animals. It's not how long you make it. Leeches make precisely 32 segments from five bilaterally paired stem cell lineages. Lineage tracing and ablation studies suggest ‘no compartments’, and analyses of Drosophila segmentation gene homologs provide little support for the Articulata hypothesis. In contrast to leeches, other annelids may add segments continuously throughout life, regenerate segments at one or both ends, or even reproduce by fission, continually respecifying segment identities. Rich grounds for comparative studies. Where can I find out more?http://mcb.berkeley.edu/labs/weisblat/ http://www.biology.ucsd.edu/faculty/macagno.html http://www.biology.ucsd.edu/faculty/kristan.html http://www.biosci.utexas.edu/mcdb/shankland.html http://www.umsl.edu/%7Ebiosbiss/ http://homepages.wmich.edu/~jellies/ http://www.anat.ox.ac.uk/groups/sblackshaw.htm http://calabreselx.biology.emory.edu/ http://www.people.virginia.edu/%7Ewof/home.html

The Road from Haeckel: The Jena Tradition in Evolutionary Morphology and the Origins of “Evo-Devo”

With Carl Gegenbaur and Ernst Haeckel, inspired by Darwin and the cell theory, comparative anatomy and embryology became established and flourished in Jena. This tradi- tion was continued and developed further with new ideas and methods devised by some of Haeckel's students. This first period of innovative work in evolutionary morphology was followed by periods of crisis and even a disintegration of the discipline in the early twentieth century. This stagnation was caused by a lack of interest among morphologists in Mendelian genetics, and uncertainty about the mechanisms of evolution. Idealistic morphology was still influental in Germany, which prevented a full appreciation of the importance of Darwin's theory of natural selection for comparative morphology. Evolutionary morphology and embryology failed to contribute significantly to the modern synthesis of evolutionary biology, thereby probably delaying the integration of developmental biology into modern evolutionary biology. However, Haeckel's student Oscar Hertwig, as well as Victor Franz and Alexej N. Sewertzoff from a younger generation, all tried to forge their own synthetic approaches in which (inspired by Haeckel's work) embryology played an important role. Important for all three researchers were attempts to refine, and sometimes redefine, the biogenetic law, and to find new scientific explanations for it (and for the many exceptions to it). Their research was later more or less forgotten, and had little influence on the architects of the modern synthesis. As the relationship between evolutionary and developmental biology is now again rising in importance in the form of "Evo-Devo", we would like to draw attention to how this earlier research tradition grappled with similar questions to those now on the agenda, albeit from sometimes quite different perspectives.

Homeosis and atavistic regeneration: the 'biogenetic law' in Entwicklungsmechanik.

Homeosis is a developmental abnormality corresponding to the transformation of a part of the body into another one. This term was introduced in 1894 by William Bateson, who aimed to make an inventory of all kinds of biological variation in order to understand how evolution proceeds. But, immediately afterwards experimental embryology, or Entwicklungsmechanik in Germany, adopted and redefined this term to refer to abnormal regenerations in which the newly developed organ was not identical to the initial one but rather resembled another part of the body. At that time, many experimental embryologists, such as Wilhelm Roux, were calling for the elimination of any phylogenetic explanation of development and were attempting to promote more mechanistic, proximate explanations. Despite these recommendations, several biologists continued to account for developmental processes by turning to phylogeny instead of mechanical forces. The case of homeosis is representative. Indeed, abnormal regenerations were often seen as examples of atavisms, or recurrence of ancestral characteristics, and many embryologists appealed to Ernst Haeckel's 'fundamental biogenetic law' to explain these strange phenomena. The break between Haeckelian tradition and Entwicklungsmechanik is thus less radical than often assumed, and the homeosis concept represents one of the factors of this continuity.

Haeckel's ABC of evolution and development.

One of the central, unresolved controversies in biology concerns the distribution of primitive versus advanced characters at different stages of vertebrate development. This controversy has major implications for evolutionary developmental biology and phylogenetics. Ernst Haeckel addressed the issue with his Biogenetic Law, and his embryo drawings functioned as supporting data. We re-examine Haeckel's work and its significance for modern efforts to develop a rigorous comparative framework for developmental studies. Haeckel's comparative embryology was evolutionary but non-quantitative. It was based on developmental sequences, and treated heterochrony as a sequence change. It is not always clear whether he believed in recapitulation of single characters or entire stages. The Biogenetic Law is supported by several recent studies -- if applied to single characters only. Haeckel's important but overlooked alphabetical analogy of evolution and development is an advance on von Baer. Haeckel recognized the evolutionary diversity in early embryonic stages, in line with modern thinking. He did not necessarily advocate the strict form of recapitulation and terminal addition commonly attributed to him. Haeckel's much-criticized embryo drawings are important as phylogenetic hypotheses, teaching aids, and evidence for evolution. While some criticisms of the drawings are legitimate, others are more tendentious. In opposition to Haeckel and his embryo drawings, Wilhelm His made major advances towards developing a quantitative comparative embryology based on morphometrics. Unfortunately His's work in this area is largely forgotten. Despite his obvious flaws, Haeckel can be seen as the father of a sequence-based phylogenetic embryology.

2001 NAPS Presidential Address: The Christian Reception of the Pentateuch: Patristic Commentaries on the Books of Moses

The interpretation of the "Old Testament" posed a theological problem for early Christians. They would not reject it (with Marcion) or interpret it only figuratively (with Barnabas). Irenaeus' theory of recapitulation solved the problem in theory, and Origen's exegetical writing provided the first Christian interpretation for most of the Bible. The Pentateuch could be a stubborn text, and in many cases the Fathers had to work to find any Christian application at all for some passages. Their methods of interpretation depended heavily upon the techniques of literary study they had learned. Passages in the Pentateuch provided opportunities for creative interpretation, which range from the profound to the playful. A series of examples offers illustrations of the many ways the Fathers tried to find some Christian application for passages in the Pentateuch.

Learning from history: morphology's challenges in Germany ca. 1900.

A century ago, Carl Gegenbaur's program of vertebrate evolutionary morphology faced its greatest challenges. The controversy over the evolutionary origin of the vertebrate paired limbs between 1875 and 1906 illustrates the failure of the traditional methods of comparative anatomy and embryology (supported by Haeckel's biogenetic law) to choose between different phylogenetic hypotheses. The controversy over morphology's status as science intensified at the turn of the twentieth century, when the legitimacy of historical explanation itself as a mode of scientific understanding came under fire. Gegenbaur's intellectual grandson, Hermann Braus, sought to defend the legitimacy of phylogenetic reconstruction while updating it to include experimental and causal-analytical approaches, but was unable to sustain a viable synthetic research program. The article concludes with reflections on approaches to the past used by historians and evolutionary morphologists.

The Myth of the “Biogenetic Law”

The Myth of the “Biogenetic Law”

THE BIOGENETIC LAW AND ITS INFLUENCE ON THEORIES OF LEARNING MATHEMATICS

Reference to the history of mathematics has been widely used in discussions of the development of curricula, the problems students have in learning mathematics, and the development of concepts in the individual. This paper examines the background to the "Biogenetic Law" [1] which has influenced so much thinking in educational theory, and the use of the "principle of parallelism" where individual development is claimed to mirror the historical development of the subject matter. Interpretations of the history of mathematics which are used to justify these claims are examined, and the universality of the supposed concepts is challenged. Questions are raised about some of the fundamental tenets of Piagetian epistemology.

Of Sequels and Sons: Tarzan and the Problem of Paternity

There is but one he said. There can never be another. -Edgar Rice Burroughs, The Son of Tarzan (1917) We have come to understand Tarzan of the Apes (1914), the opening volume of Edgar Rice Burroughs's immensely popular ape-man series, as a paradigmatic tale of racial recapitulation. Orphaned on the west coast of Africa, the infant son of the Lord and Lady Greystoke is adopted by an ape mother mourning the death of her own child, and then raised to puberty among the beasts of her tribe. Tarzan's jungle boyhood-in which he reenacts the developmental stages of his most primitive ancestors, from newborn to animal to savage-paradoxically prepares him, as no other sequence could, for the civilized white adulthood that is his birthright. As Gail Bederman has recently affirmed, a childhood in this primal environment makes Tarzan an exemplar of [the] perfect manhood anticipated by turn-of-the-- century recapitulation theorists (220-21). Wild child becomes savage boy becomes civilized man, who in due evolutionary turn outstrips even his own aristocratic forebears. For only by returning to racial origins, recapitulation theory argued, might one move the present race a step ahead. By dramatizing this developmental process in the figure of Tarzan, critics assert, Burroughs gave powerful imaginative shape to a widespread cultural belief. The problem with this account of the Tarzan story, however, is that within a few short years Burroughs would renounce the very recapitulation narrative that underwrote his introductory volume. After giving himself wholeheartedly to that narrative through not one but three Tarzan books, in the final pages of the fourth volume Burroughs suddenly recoiled from the most basic implications of his recapitulatory plot. He did so, I will argue, because of the limits that the demands of that plot posed to the future success of his series, even though the series' triumph had much to do with Burroughs's canny probing of the anxieties surrounding race and reproduction in early-twentieth-- century American culture. Tracking Burroughs's retreat from recapitulation, I believe, will prove as instructive for an understanding of the series as a whole as the initial awakening to the recapitulation narrative proved for readings of Tarzan of the Apes. More specifically, examining this retreat will shed new light on several crucial yet misunderstood aspects of the Tarzan volumes. It will make new sense, for example, of the series' fascination with repetition. It will also clarify the impetus behind Tarzan's emphatic embrace of racially motivated violence despite early narrative signals to the contrary. Most intriguing, it will help explain why Burroughs felt compelled to give Tarzan a son-and then almost immediately to pretend that son had never existed. What we will discover, in fact, is that it is the presence of Tarzan's son-a development virtually demanded by the recapitulation plot itself-that quite unexpectedly pushes the series not toward millennial perfection, but repetitive, if not regressive, mayhem. At stake is more than mere clarification of the series' concerns. Investigating this turn toward regression will illuminate popular American attitudes toward fatherhood at a time when paternal roles were under serious scrutiny. Accustomed by the growth of wage-employment under industrial capitalism to regard breadwinning as not simply a father's prerogative but his essence, yet disappointed by their diminished position in family life, many turn-of-the-century middle-class American men paid increasing attention to fatherly nurture and family companionship. An implicit goal of this attention was to provide more manly guidance for their sons, whom many feared were softening under their mothers' rule (Griswold 90). As we will see, Burroughs invents for Tarzan a child in need of precisely such rescue. But Burroughs simultaneously suggests that in order to preserve their own sense of virility and dominance, many men may have fantasized the disappearance of those selfsame sons. …

Visual Awareness Due to Neuronal Activities in Subcortical Structures: A Proposal

It has been shown that visual awareness in the blind hemifield of hemianopic cats that have undergone unilateral ablations of visual cortex can be restored by sectioning the commissure of the superior colliculus or by destroying a portion of the substantia nigra contralateral to the cortical lesion (the Sprague effect). We propose that the visual awareness that is recovered is due to synchronized oscillatory activities in the superior colliculus ipsilateral to the cortical lesion. These oscillatory activities are normally partially suppressed by the inhibitory, GABAergic contralateral nigrotectal projection, and the destruction of the substantia nigra, or the sectioning of the collicular commissure, disinhibits the collicular neurons, causing an increase in the extent of oscillatory activity and/or synchronization between activities at different sites. This increase in the oscillatory and synchronized character is sufficient for the activities to give rise to visual awareness. We argue that in rodents and lower vertebrates, normal visual awareness is partly due to synchronized oscillatory activities in the optic tectum and partly due to similar activities in visual cortex. It is only in carnivores and primates that visual awareness is wholly due to cortical activities. Based on von Baerian recapitulation theory, we propose that, even in humans, there is a period in early infancy when visual awareness is partially due to activities in the superior colliculus, but that this awareness gradually disappears as the nigrotectal projection matures.

Haeckel's Embryos in Question

Haeckel's Embryos in Question

Haeckel's Embryos & Evolution: Setting the Record Straight

N The Origin of Species Charles Darwin wrote that embryos of mammals, birds, fishes, and reptiles [are] closely similar, but become, when fully developed, widely dissimilar. He inferred that all vertebrates the modified descendants of some ancient progenitor, and that embryonic or larval stages show us, more or less completely, the condition of the progenitor of the whole group in its adult state (Darwin 1859, pp. 338, 345). Darwin's contemporary Ernst Haeckel called this the Law, according to which ontogeny recapitulates phylogeny. To illustrate the law, Haeckel (1891) produced drawings of vertebrate embryos which have been widely used in biology textbooks ever since (Figure 1). But Haeckel's Biogenetic Law was discredited by embryologists in Darwin's lifetime (Bowler 1989); recent work has shown that Haeckel's drawings misrepresent the embryos they purport to show (Richardson et al. 1997); and Haeckel entirely omitted the earliest stages of development in which the various classes of vertebrates are morphologically very different (Elinson 1987). Biology teachers should be aware that Haeckel's drawings do not fit the facts.

Evolution, development and complexity in Pere Alberch (1954–1998)

Evolution, development and complexity in Pere Alberch (1954–1998)

“His Mind Aglow”: The Biological Undercurrent in Fitzgerald's Gatsby and Other Works

They talked until three, from biology to organized religion, and when Amory crept shivering into bed it was with his mind aglow…(Fitzgerald, This Side of Paradise)Readers familiar with F. Scott Fitzgerald's early work might recall that in those years just before the Scopes trial he wrote of Victorians who “shuddered when they found what Mr. Darwin was about”; or that he joined in the fashionable comic attacks on people who could not accept their “most animal existence,” describing one such character as “a hairless ape with two dozen tricks.” But few would guess the extent to which his interest in evolutionary biology shaped his work. He was particularly concerned with three interrelated biological problems: (1) the question of eugenics as a possible solution to civilization's many ills, (2) the linked principles of accident and heredity (as he understood these through the lens of Ernst Haeckel's biogenetic law), and (3) the revolutionary theory of sexual selection that Darwin had presented in The Descent of Man and Selection in Relation to Sex (1871). As I hope to show in the following pages, his concern with these issues underlies such well-known features in the Fitzgerald landscape as his insecurity in the “social hierarchy” (his sense of its “terrifying fluidity”), his emphasis on the element of time, his interest in “the musk of money,” his interest in Spengler and the naturalists, and his negative portraiture of male violence. The principles of eugenics, accidental heredity, and sexual selection flow together as the prevailing undercurrent in most of Fitzgerald's work before and after The Great Gatsby, producing more anxiety than love from the tangled courtships of characters he deemed both beautiful and damned.

Haeckel's embryos, continued.

I am concerned to find that I may have helped perpetuate a Creationist myth, as described by K. Sander and R. Bender (Letters, 17 July, p. 349). The claim that Ernst Haeckel was convicted of fraud was made in The Times ([1][1]). I relied on that statement in a subsequent publication ([2][2]) without seeking a primary source—clearly a mistake on my part. Nonetheless, the core scientific issue remains unchanged: Haeckel's drawings of 1874 ([3][3]) are substantially fabricated. In support of this view, I note that his oldest “fish” image is made up of bits and pieces from different animals—some of them mythical. It is not unreasonable to characterize this as “faking.” Later editions of Haeckel's drawings were somewhat more accurate, and showed significant variations among embryos of different species. Sadly, it is the discredited 1874 drawings that are used in so many British and American biology textbooks today. 1. [↵][4]1. T. J. Hamblin, 2. R. E. M. Moore , The Times 18 (18 August 1997). 2. [↵][5]1. M. K. Richardson , Physiol. Soc. Mag.(no. 29), 30 (1997). 3. [↵][6]1. E. Haeckel , Anthropogenie (Engelmann, Leipzig, 1874). [1]: #ref-1 [2]: #ref-2 [3]: #ref-3 [4]: #xref-ref-1-1 View reference 1 in text [5]: #xref-ref-2-1 View reference 2 in text [6]: #xref-ref-3-1 View reference 3 in text

A Test and Review of the Empirical Performance of the Ontogenetic Criterion

The empirical performance of the ontogenetic criterion for determining character po- larities was tested based on three published and one new data set originating from a study of larval Sepsidae (Diptera). The ontogenetic criterion polarizes about as many characters as does outgroup comparison. However, for the four data sets conflicting polarities were inferred for 4- 45% of all characters for which both polarization methods were applicable. Four different versions of the ontogenetic criterion were identified from the literature and were empirically tested. The version used by de Queiroz (1985, Syst. Zool. 34:280-299) and Wheeler (1990, Cladistics 6:225- 268) fared best, as determined by low levels of homoplasy and a small number of inferred equally parsimonious tree roots. For three of four empirical data sets, hypothetical ancestors based on outgroup comparison and the ontogenetic criterion resulted in identical tree roots. Hypothetical ancestors based on outgroup comparison implied less homoplasy than did those based on the ontogenetic criterion, so the ougroup method appears to be superior for character polarization. To test whether polarity decisions from both polarization methods should be combined into one hypothetical ancestor, two different composite ancestors were reconstructed. One comprised only the plesiomorphic states of the characters for which both criteria predicted the same polarity (consensus). It inferred multiple parsimonious roots without distinctly lowering the level of ho- moplasy. The second ancestor comprised the plesiomorphic states as predicted by one or both methods (composite). It tended to infer single roots, even for data sets for which very different rooting positions were identified by the two polarization criteria, thereby obscuring conflict be- tween the two methods. High levels of homoplasy in hypothetical ancestors based on the onto- genetic criterion are not due to the inclusion of presence /absence characters in the data set, for which the application of the ontogenetic criterion would require hypotheses of homology for absent character states across ontogenetic stages of different species. Instead, the ratio of ter- minal deletions to terminal additions is a better predictor for the success of the ontogenetic cri- terion for any particular data set. (Biogenetic law; heterochrony; Nelson's rule; ontogenetic crite- rion; outgroup comparison; recapitulation.)