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The Star Larvae Hypothesis
Nature's Plan for Humankind
Part 2. Star Larvae

Ontophylogeny, or Evelopment

Evolution’s Extended Synthesis dethrones natural selection as the primary shaper of phenotypes.

Since life first arrived on Earth, nature has been manufacturing (and occasionally retiring) species. The proper term for this process is phylogeny or, more commonly, evolution. The process proceeds without any program or plan, according to normal science. The form any species ends up having is ad hoc, contingent, being shaped by the vagaries of natural selection.

Unlike evolution, the differentiation of cells in a body follows a preferred direction. That process, ontogeny, or development, proceeds from the undifferentiated zygote to the diverse cell types characteristic of the particular species. For example, when a tadpole matures it does so predictably into an adult frog, being directed toward that end by some kind of inherent predisposition. (Or so it is believed. Maybe cells receive instructions from the quantum world. Who knows?)

Despite the differences that distinguish evolution and development, Darwin’s phrase, "descent with modification," describes both processes. And biologists have sought ways to unite the two processes in their theories. Ernst Haekel, in the nineteenth century, married development to evolution in his alliterative "biogenetic law," ontogeny recapitulates phylogeny. He proposed that as an organism develops it passes through the evolutionary stages of its ancestors. This view since has been replaced by the simpler one that as embryos develop, they generate increasingly specialized tissues and structures. The developmental sequence no longer is believed to be a telescoping of the species' evolution.

Recent discoveries in comparative genomics are rekindling interest in relating evolution to development, but this time it looks like development is the process being recapitulated. The rekindling already has ignited a new discipline within evolutionary biology, called evolutionary developmental biology, or evo-devo. The new discipline views evolution through the lens of development, seeing behind evolutionary change primarily the same mechanisms that underlie development, including genetic "switches" and "toolkits".

A theoretical shift is being visited upon the biological sciences, and evo-devo is only one of its several calling cards. Peering into DNA, researchers are finding genetic anomalies and unsuspected regulatory mechanisms. The data from DNA sequencing and analysis and related research suggests that natural selection plays a minor role in evolution. The new data suggest that evolution itself is an instance of development.

From Modern Synthesis to Extended Synthesis

When, in the early-to-mid twentieth century, biologists supplemented Darwinian theory with Mendelian genetics, the discovery of DNA, and the role of genes in inheritance, the enhanced model became known as the Modern Synthesis. Today the Modern Synthesis itself is being modernized. New work in epigenetics, niche construction, phenotypic plasticity and other fields are challenging the Darwinian legacy. In July 2008 a group of researchers exploring these new fields convened at the Konrad Lorenz Institute in Altenberg, Switzerland, to formalize a so-called Extended Synthesis of evolutionary theory. MIT Press published the conference papers as a sourcebook, Evolution - the Extended Synthesis. Many of the book's contributors reassure their readers that the new findings pose no fundamental threat to the Darwinian framework. The collective attitude seems to be that the new discoveries complicate but do not undermine the theory of natural selection.

But the star larvae hypothesis takes a different view. The sticking points of the Extended Synthesis point to a reconfigured, not extended, model of evolution. The star larvae hypothesis is particularly interested in the Extended Synthesis' recognition of endogenous factors—those internal to the organism—as primary, and of environmental factors as supplementary, in the shaping of phenotypes during evolution. This excerpt from the book’s introduction underscores this inversion of causal roles:

“[In the Modern Synthesis] organismal shape and structure were interpreted as products uniquely of external selection regimes. All directionality of the evolutionary process was assumed to result from natural selection alone. The inclusion of EvoDevo in particular, as shown in section five of this volume, represents a major change of this paradigm by taking the contributions of the generative processes into account as entrenched properties of the organism that promote particular forms of chance rather than others. On this view, natural selection becomes a constantly operating background condition, but the specificity of its phenotypic outcome is provided by the developmental systems it operates on. Hence the organisms themselves represent the determinants of selectable variation and innovation. At the theoretical level, this shifts a significant portion of the explanatory weight from the external conditions of selection to the internal generative properties of evolving phenotypes.”

The star larvae hypothesis draws attention to elements of the Extended Synthesis and proposes relationships among them to present a fully developmental model of evolution, as follows.

Conservation of DNA

It turns out that genetic material varies much less across species than phenotypic—observable—differences would suggest. DNA is highly conserved. The discovery early in this century that DNA differs relatively little across species ushered in the new discipline of evolutionary developmental biology, or evo-devo. In their article, Regulating Evolution (Scientific American, May 2008) researchers Sean B. Carroll, Benjamin Prud’homme, and Nicolas Gompel explain why a new perspective was needed.

"For a long time, scientists certainly expected the anatomical differences among animals to be reflected in clear differences among the contents of their genomes. When we compare mammalian genomes such as those of the mouse, rat, dog, human and chimpanzee, however, we see that their respective gene catalogues are remarkably similar. [. . . .] When comparing mouse and human genomes, for example, biologists are able to identify a mouse counterpart of at least 99 percent of all our genes."

". . . to our surprise, it has turned out that differences in appearance are deceiving: very different animals have very similar sets of genes."

"The preservation of coding sequences over evolutionary time is especially puzzling when one considers the genes involved in body building and body patterning."

"The discovery that body-building proteins are even more alike on average than other proteins was especially intriguing because of the paradox it seemed to pose: animals as different as a mouse and an elephant are shaped by a common set of very similar, functionally indistinguishable body-building proteins."

Surprise? Puzzle? Paradox? Why does evolution theory suffer so many bouts of the unexpected now that researchers are mapping and comparing genomes? If the received theory was solid, wouldn’t new genetic details have slots waiting for them in it? Shouldn’t new genetic data bolster the existing model, rather than hand it surprises, puzzles and paradoxes? Nobody saw it coming. It was an empirical surprise.

But if evolution is a developmental process, then there's no surprise. The situation parallels the cellular side of ontogeny. During development, all cells in the body of a complex organism inherit the same genes from their common ancestor, the zygote. DNA is highly conserved among the cells in a body. But, despite all possessing the same genes, a body’s nerve, muscle, skin and other cells distinguish themselves phenotypically. Ontogeny demonstrates that diverse phenotypes, or morphologies, need not correspond to any proportionate diversity of genotype. "Adaptive radiation" of cell types in a body proceeds just fine without genetic variation, because during development regulatory genes switch on and off the genes that code for the body-building proteins.

In both cases, evolution and development, highly conserved DNA uses genetic switches to create diverse phenotypes. But instead of spinning off various tissues, as in development, the cycling on and off of genetic switches during evolution creates the various species. This discovery, of the importance of genetic switches in controlling gene expression, provides the empirical foundation for evo-devo. Under the Modern Synthesis, evolution theory cast phenotypes in the passive role of protoplasmic clay, to be shaped by exogenous, environmental factors. The Extended Synthesis underscores the importance in evolution of endogenous factors, including regulatory genes. It recognizes that endogenous factors severely compromise selection’s ability to shape phenotypes.

Epigenetic regulatory networks and junk DNA

A relatively small set of genes can produce an abundance of phenotypes, because genes can be switched on and off to produce unique combinations of gene activity. The switch settings for the various cell types in a body are stabilized by epigenetic mechanisms, so that each specialized type reproduces its own kind. It looks now like evolution stabilizes phenotypes using the very same mechanisms. In "Evolution in Four Dimensions: Genetic, Epigenetic, Behavioral, and Symbolic Variation in the History of Life", Researchers Eva Jablonka and Marion J. Lamb make just this case:

"A person’s liver cells, skin cells, and kidney cells, look different, behave differently, and function differently, yet they all contain the same genetic information. With very few exceptions, the differences between specialized cells are epigenetic, not genetic. They are the consequences of events that occurred during the developmental history of each type of cell and determined which genes are turned on, and how their products act and interact. The remarkable thing about many specialized cells is that not only can they maintain their own particular phenotype for long periods, they can also transmit it to daughter cells. When liver cells divide their daughters are liver calls, and the daughters of kidney cells are kidney cells. Although their DNA sequences remain unchanged during development, cells nevertheless acquire information that they can pass to their progeny. This information is transmitted through what are known as epigenetic inheritance systems (or EISs for short). It is these systems that provide the second dimension of heredity and evolution [the first being the genetic dimension]"

Epigenetic regulatory mechanisms include feedback loops in which a gene’s product (a particular protein) keeps the gene actively producing that product. Chromatin marking is another epigenetic mechanism, as in DNA mutilation in which methyl groups attach directly to DNA and activate or suppress gene expression. RNA interference (RN Ai) is another regulatory mechanism. In addition, some proteins, such as prisons, can convert the structure of other proteins to their own, in effect subverting the will of the genes that produce the other proteins. This is a new field of research, and many details remain to be worked out. But what is clear is that a DNA sequence or genotype is only part of the story of phenotypic expression. Epigenetic mechanisms are another essential part of the story.

Jablonka and Lamb describe three mechanisms by which germ cells can acquire an epigenetic variation and hence ways in which epigenetic differences can become heritable from parent to offspring:

• A variation can originate in the germ line.
• A somatic cell can pass on variations to germ cells when somatic cells develop into germ cells.
• A somatic cell can exchange information with germ cells, as appears to happen with RN Ai mechanisms.

The researchers elaborate the details of these and other epigenetic inheritance systems in Trans generational Epigenetic Inheritance, their contribution to Evolution - the Extended Synthesis.

Epigenetic mechanisms not only operate concurrently during development and evolution, like DNA, but also, like DNA, they appear to be conserved through evolution. Research at the University of Chicago has turned up epigenetic mechanisms in fish that regulate development of fins and that, when transplanted into mice, function as the native mechanism that mice use to regulate limb development. A press release from the university explains:

"The genetic switches that drive the expression of genes in the digits of mice are not only present in fish, but the fish sequence can actually activate the expression in mice," said Igor Schneider, PhD, postdoctoral researcher in the Department of Organismal Biology and Anatomy at the University of Chicago [.] "This tells us how the antecedents of the limb go back in time at every level, from fossils to genes."

This discovery would seem to compound problems for the Darwinian account. If both genetic and epigenetic mechanisms across species are so similar, then what is the source of the vast differences among species’ phenotypes? Increasingly it looks like evolutionary history was packaged already in the early species and unfolded over time.

Epigenetic mechanisms also shed light on so-called junk DNA. Because all cells that develop from the same zygote inherit the same genotype, they necessarily inherit many genes that they do not need. Skin cells don't express genes specific to the functioning of liver cells, for example. Neither do muscle cells express genes specific to the functioning of brain cells. And so on. The excess DNA in each cell type includes genes needed to create and operate all the other types. But from the point of view of a given type of cell, the DNA specific to the other types is junk. Nonetheless, all the cells inherit all the genes of their common ancestor, the zygote, whether they need them or not.

The received view of evolution is stumped by junk DNA at the species level, which is preserved across generations of a given species but not expressed. These unexpressed sections are also called "noncoding" DNA. Their origin and persistence at the species level remain a paradox.

What aspect of evolution theory predicts that long stretches of DNA would coast along inside organisms, seemingly contributing nothing to survivability? Nobody saw it coming. It was an empirical surprise. But it makes perfect sense, and would be expected, if evolution itself is an instance of development.

And, if evolution is an instance of development, then the species of the Earth ought to share a common genome, just as the cells in a body share a common genotype. In Universal Genome in the Origin of Metazoa (Cell Cycle 6:15, August 2007) researcher Michael Sherman argues precisely for such a common genome. His case rests largely on the presence of anomalous genes in older species that are needed by more recent species. Instances of such "anticipatory" genes are described below.

Sherman's insight was anticipated already in 1999, in an article by researcher W. H. Holland that appeared in Nature (Vol 402, Supplement, December 2, 1999) titled The Future of Evolutionary Developmental Biology. Holland says,

"So many examples of [DNA] conservation have now been found that it is no longer considered surprising. We can now state with confidence that most animal phyla possess essentially the same genes, and that some (but not all) of these genes change their developmental roles infrequently in evolution [emphasis added]."

If the traits characteristic of a species are determined by patterns of genetic switch settings, epigenetically stabilized, then what determines those settings? The Darwinian model assigns that responsibility to natural selection. In the Darwinian model, environments decide which genetic and epigenetic combinations are sufficiently adaptive to be fit for reproductive success. But the Extended Synthesis challenges the way in which the Modern Synthesis characterized environments, and in doing so it weakens the explanatory power of natural selection.

Niche construction

If Darwin got it right, and the phenotypic traits characteristic of each species have been set by the environment in which each species evolved, then evolution theory needs explicitly to characterize the relationships that link environments to their inhabitants. In the Modern Synthesis environments were treated as extrabiological givens that determine which random phenotypic variants from among the members of a local population will enjoy greater reproductive success. In his contribution to Evolution - the Extended Synthesis, researcher John Odling-Smee argues that the process is complicated by behaviors of organisms that alter their environments.

He points out that the Modern Synthesis took selection pressures to be autonomous forces that mold organisms to fit niches, with niches taken to be "preexisting environmental templates," like keyholes waiting for keys or labeled folders in a file cabinet. The templates always were acknowledged as being dynamic, however, being subject to geological, climactic, chemical and other influences, and nature imposed such influences willy-nilly regardless of whatever organisms happened to be around or what those organisms did. Odling-Smee notes that in the Modern Synthesis, "the changes that organisms bring about in their own environments are seldom thought to have evolutionary significance." But this aspect of the Modern Synthesis is giving way to the notion of niche construction, which recognizes that organisms engineer the environments that they need. Odling-Smith explains the concept,

"[A]ll organisms, through their metabolisms, movements, behavior, and choices, partly create and partly destroy their environments. In doing so, they transform some of the selection pressures in the environments that subsequently select them. Therefore the adaptations of organisms cannot be exclusively consequences of organisms responding to autonomous selection pressures in environments. Sometimes they must involve organisms responding to selection pressures previously transformed by their own, or by their ancestors’ niche-constructing activities."

"A major feature of multicellular animals is the use of morphogen gradients, which in effect provide a positioning system that tells a cell where in the body it is, and hence what sort of cell to become. A gene that is turned on in one cell may make a product that leaves the cell and diffuses through adjacent cells, entering them and turning on genes only when it is present above a certain threshold level. These cells are thus induced into a new fate, and may even generate other morphogens that signal back to the original cell. Over longer distances morphogens may use the active process of signal transduction. Such signaling controls embryogenesis, the building of a body plan from scratch through a series of sequential steps. They also control maintain [sic] adult bodies through feedback processes, and the loss of such feedback because of a mutation can be responsible for the cell proliferation that is seen in cancer."

Cell types differentiating during development construct their niches using morphogens to condition their environments to suit their needs. Again, evolution and development leverage parallel mechanisms to manage descent with modification. What remains to justify treating evolution and development as distinct processes?

When organisms modify their environments, effectively shaping the selection pressures to which they, their progeny, and their neighbors are subjected, cause and effect enter into a feedback relation. As with all feedback loops, this one presents the prospect of positive feedback, which can run away until countered by physical barriers. This prospect is explored in the context of human industry in Cyberfetus Rising.

To summarize: To meet their needs, organisms construct niches. This is a very different understanding of the organism-niche relationship than was had under the Modern Synthesis. There the niche was regarded as an environmental given that organisms competed with each other to occupy. By granting a degree of causal agency to the organism in shaping its environment, niche construction further marginalizes the environment as a causal agent that shapes phenotypes. And in doing so the concept of niche construction further undermines the explanatory power of natural selection to account for how phenotypes get to be how they get to be.

Pre-Adaptation, or "Anticipatory" Genes

This is how things work in a developing organism.

Now, it turns out that ancient species also carry genes that seem to anticipate the needs of descendants. A news article in Nature covering the sequencing of the genome of the Great Barrier Reef sponge Amphimedon queenslandica, reveals that the hoary creatures harbor a "toolkit" of metazoan genes:

"The genome also includes analogues of genes that, in organisms with a neuromuscular system, code for muscle tissue and neurons."

"According to Douglas Erwin, a paleobiologist at the Smithsonian Institution in Washington DC, such complexity indicates that sponges must have descended from a more advanced ancestor than previously suspected. 'This flies in the face of what we think of early metazoan evolution,' says Erwin."

"Charles Marshall, director of the University of California Museum of Paleontology in Berkeley, agrees. 'It means there was an elaborate machinery in place that already had some function,' he says. 'What I want to know now is what were all these genes doing prior to the advent of sponges.'"

The conundrum for normal evolution theory is clear. Why would a common ancestor of animals with neuromuscular systems and sponges have needed such genes? And the ancestor must have arisen within a very narrow window. Fossil evidence of sponges goes back 650 million years; it constitutes, the authors note, "the oldest evidence for metazoans (multicellular animals) on Earth." So, what use would any species even more primitive than sponges have for orthologs of neuromuscular genes? Nobody saw it coming. It was an empirical surprise.

But the sponge genome is only one example. Research is finding case after case of ancestral species that harbor genes essential for remote descendants. Another example: It turns out that a species of unicellular protozoan carries genes essential for metabolic processes specific to metazoans. The researchers who discovered the surprise genes (PNAS – 2010 107 (22) 10142-10147) explain,

"One of the most important cell adhesion mechanisms for metazoan development is integrin-mediated adhesion and signaling. The integrin adhesion complex mediates critical interactions between cells and the extracellular matrix, modulating several aspects of cell physiology. To date this machinery has been considered strictly metazoan specific. [. . . .] Unexpectedly, we found that core components of the integrin adhesion complex are encoded in the genome of the apusozoan protist Amastigomonas sp., and therefore their origins predate the divergence of Opisthokonta, the clade that includes metazoans and fungi. [. . . .] Our data highlight the fact that many of the key genes that had formerly been cited as crucial for metazoan origins have a much earlier origin." (emphasis added)

And the surprises keep coming. Science magazine (July 6, 2007) reports

"The newly decoded DNA of a few-centimeter-tall sea anemone looks surprisingly similar to our own," a team led by Nicholas Putnam and Daniel Rokhsar from the U.S. Department of Energy Joint Genome Institute in Walnut Creek, California, reports on page 86. "This implies that even very ancient genomes were quite complex and contained most of the genes necessary to build today’s most sophisticated multicellular creatures."

Newer (2007) sequencing and analysis results corroborate the anemone anomalies.

Another example comes from research at the European Molecular Biology Laboratory, which found human genes in a marine worm. The news release (11/24/2005) announcing the discovery is at http://www.embl.de/aboutus/communication_outreach/med ia_relations/2005/051124_heidelberg/index.html

Additional research has found that genes essential for human nerve cells to communicate with one another are present already in bacteria. This research is described in a NIH news release (6/1/2004) at http://www.nichd.nih.gov/new/releases/genes.cfm

Yale researchers recently found 1500 mammalian genes active only in placental mammals, but present also in marsupials. The genes are transposons that act as regulators. In a Yale press release, researcher Vincent J. Lynch, comments on the peculiarity of the "prefabricated" mechanism,

"These transposons are not genes that underwent small changes over long periods of time and eventually grew into their new role during pregnancy," Lynch said. "They are more like prefabricated regulatory units that install themselves into a host genome, which then recycles them to carry out entirely new functions like facilitating maternal-fetal communication."

Some protein-coding genes active in humans were present already when humans and chimps diverged, but did not become active until after the divergence. Some enhancer genes in vertebrates also preceded their expression. And new research data reveals that some aquatic plants were genetically "pre-adapted" for life on land. A report on this finding is available at http://www.biomedcentral.com/1471-2148/10/341.

These and other phylogenetically anomalous discoveries are collected at http://www.panspermia.org/oldgenes.htm. This page of Brig Klyce’s "Cosmic Ancestry" web site includes commentary on the relevance of these findings to panspermia. A summary of these peculiar findings appears also in the January 1, 2011, issue of The Scientist, in the article From Simple to Complex. Author Jef Akst observes,

"Conventional thought on evolutionary change has led researchers to believe that genetic innovations underlie the transition [from unicellular to multicellular life]. Advances in genomics research, however, are revealing that more and more of the genes associated with complex processes also exist in simpler animals and even in their unicellular cousins. This suggests that the appearance of new genes cannot fully explain the appearance of new traits that are key to multicellularity."

What is particularly striking about these findings, taken together—and what is particularly interesting to the star larvae hypothesis—is not only that they were unanticipated by the practitioners of the Modern Synthesis, but also that they make the evolutionary process look strikingly like a developmental process, like a stage, or stages, in the life cycle of a developing organism.

A Thought Experiment on the Philosophy of Natural Selection

All complex organisms begin life as a single cell, a zygote. The zygotes of seahorses, hummingbirds, and humans, for example, are phenotypically indistinguishable. They all look alike. The zygotes divide and divide until enough cells are present to trigger a specialization of labor. The collective labors of the resulting specialized cells constitute the physiology of the embryo that their cellular bodies, in aggregate, constitute. As each organism develops, the distinctive, specialized, adult features of the species emerge.

During embryological development, a cell that is a progenitor of a liver cell gives rise to a true liver cell; a cell that is a progenitor of a neuron gives rise to a neuron, and so on. Embryonic cells give rise to specific morphological types that behave in specific ways in their interlocking niches within the somatic ecology of the developing organism. Is this process of specialization—of descent with modification—guided or random? Teleological or Darwinian?

Here is a thought experiment: Insofar as the cells in the body of a complex organism vary phenotypically from one type to another and insofar as not every cell survives to contribute its epigenetic predispositions to the next generation, there is a natural selection among cells during embryonic development and, indeed, throughout the life of a complex organism. The thought experiment consists of fitting ontogenetic cellular differentiation into the Darwinian model of descent with modification via natural selection. The experiment underscores an early and continuing criticism of Darwinian logic, namely that it is tautological. When formulated as "survival of the fittest" the doctrine of natural selection identifies the fittest organisms as those that survive and the survivors as those most fit. Ontogeny also can be seen through such a lens, as a phylogeny, a "cytophylogeny," in which a common ancestral starting point—a zygote—begets successive generations of increasingly diverse descendants, the specialization of the types being shaped by natural selection, the survivors being the fit and the fit surviving.

Imagine, then, cognitively gifted and secularly inclined cells, living in a complex organism and having developed their own theory of evolution, marveling at the blind workings of chance variation and natural selection that turned their common ancestor—the original zygote—into the complex ecosystem of interdependent cell types to which they find themselves adapted. Fitness selects the survivors, they would announce, as demonstrated by their survival! We would understand that these scientifically minded cells had missed the boat, that they in fact live by an ontogenetic program and that they were fated from the start to be teased out of the genotype of their zygotic ancestor. But their thinking would be consistent with the Modern Synthesis.

The late Harvard paleontologist Stephen Jay Gould accounted for the apparent progress of evolutionary change with the metaphor of "the drunkard’s walk." In this thought experiment one must imagine a drunkard staggering along a wall. He ventures varying distances from the wall as he makes his way along it. The distance from the wall at any particular instant is just whatever it is. An increase in average distance over time is merely a function of time passing. The more time that passes, the greater the number of opportunities for the drunk to stumble even farther from the wall than he or she previously had ventured. Increasing distance from the wall corresponds to increasing complexity, with the wall representing the unicellular limit of biological simplicity. By this metaphor the apparent increase in complexity of organisms over evolutionary time, which suggests a direction to evolution, is understood to be the undirected increase of mere variation. Increases in variation are sufficient to produce increases in complexity. Gould lays out this model of pseudoprogress in Full House

Philosophers Kim Sterelny and Paul E. Griffiths, in Sex and Death: An Introduction to Philosophy of Biology, summarize Gould's argument (their book is reviewed on the starlarvae blog):

"Life starts off as simple as life can be. Mostly, it stays that way. Most living things have always been as simple as the first living things, for nearly every organism is a bacterium. Occasionally lineages split and a species appears that is more complex than its parent. No global evolutionary mechanisms make this impossible, but none make it more likely. Complexity increases by passive diffusion from a point of minimum complexity, then wholly undirected, stochastic mechanisms will increase the variance, and that variance must include a bias in the direction of increased complexity. Mechanisms that are blind to complexity suffice to produce an upward drift in average complexity. The fact that there is no bias in the mechanisms of adaptation, speciation, or extinction that favors increased complexity, together with the persistence of bacterial domination of the living world is fatal to any robust version of the idea that evolution over time has generated increased complexity."

When this line of thinking is applied to ontogeny, the shoe fits. We can ask whether cellular differentiation during the ontogenetic development of an organism is the result of wholly undirected, stochastic mechanisms that merely increase variation among cell types. The received view says no; explanations from phylogeny are inadequate to account for ontogeny. But the parallels are striking: Some cell types, the early undifferentiated types of the blastula, for example, go extinct during ontogeny. Though, some ancestral types persist, in the form of adult stem cells. And bacteria dominate the environment, comprising 90 percent of the cells in a human body So why assume an ontogenetic program? Doesn't Gould's evolutionary model explain equally well the diversification of cells during ontogeny? Empirically, evolution and development are of a kind: descent with modification from a common ancestor. How could one falsify either account in either case?

To clarify: The star larvae hypothesis does NOT argue the case proposed in this thought experiment that ontogeny is a stochastic process that merely increases variation among cell types, but accepts the received view that ontogeny follows inhering developmental instructions, of some sort. But the hypothesis rejects the received view when it comes to phylogeny, which, it argues, also follows an inherent developmental program. The applicability of phylogeny's supposedly stochastic mechanisms to account for ontogeny is meant as a reductio ad absurdum of the received view regarding phylogeny; i.e., if phylogenetic theory has such vast explanatory power, why assume programming anywhere? Cells cooperate and compete in an organism, and organisms cooperate and compete in an ecosystem. If we will not accept that ontogeny is shaped by the Darwinian process of natural selection, then perhaps we can consider that science has erred in asserting that phylogeny is shaped by that nonteleological process.

Evolution is a slow, drawn out developmental process, just as development is a compacted, sped-up evolution. This is the picture emerging from the new discoveries in the biological sciences. The star larvae hypothesis is particularly interested in the prospective teleology that the integration of evolution and development injects into evolutionary theory.

The Great Chain of Being

Western thinking from Plato through The Elizabethan Age conceived of Creation as structured hierarchically in the form of a "Great Chain of Being." The chain ascended from the smallest germ up through the plants and creatures to humankind and ultimately through the spheres of the firmament to the throne of God. The extraterrestrial links in the chain were/are detailed in the form of the Orders of Angels. Few thinkers today would regard such metaphors as more than poetic, a primitive conception of the natural (and supernatural) order. But in the context of the star larvae hypothesis, the Chain of Being presents a more complete picture of evolution than does the standard scientific view. What the Chain lacks, and science provides, is the temporal, dynamic dimension of the process.

The Chain of Being represents a longitudinal section through a temporal progression—a developmental sequence that leads from the terrestrial to the extraterrestrial. The Chain was conceived of at a time when Creation was regarded as static, and the Chain provided a cross section of the whole structure. But assigning the evolution of species a subordinate position within the overarching ontogeny of the stellar life cycle effectively resurrects the Chain of Being in an ecological context. Evolution is the metamorphosis of stages in the life cycle of a genus of organism—the stellar organism. The apparent directionlessness of evolution is replaced by a processional sequence that, when viewed in a longitudinal section, takes the form of the Great Chain of Being. The intuition behind the Chain was essentially right, it just failed to take into account the underlying dynamic, temporal process.

Do the novelties that the Extended Synthesis introduces to the Modern Synthesis add up to anything? The editors of Evolution, the Extended Synthesis fail to use the new findings to compose any integrated theoretical revision of the Darwinian model. The new findings seem to be offered as odds and ends to be grafted here and there onto the existing theory. If any consistent wrinkle emerges, it is the shift of explanatory credit for shaping phenotypes from exogenous to endogenous factors. Does that causal shift stretch the Darwinian model to the breaking point? That's the position of Jerry Fodor and Massimo Piatelli-Palmarini in "What Darwin Got Wrong" (reviewed on the starlarvae blog). But those authors don't offer up any new model. And the collection of papers in Evolution—The Extended Synthesis doesn't seem to add up to a new model, unless they force a view of evolution as being an instance of development.

If the new data break or threaten to break the Modern Synthesis, then the stage is set for a Kuhnian scientific revolution. The star larvae hypothesis describes what a new theory of evolution might look like, because it puts endogenous factors front and center in evolution, because it puts development front and center. But it goes beyond the toe-in-the-water approach of evo-devo to subsume evolution altogether under development. In light of the Extended Synthesis, what’s going on in evolution looks so much like what goes on in development that it makes evolution distinguishable from development only in scale.

The Extended Synthesis plants a mastodon smack-dab in the middle of the room of evolutionary theory, because it forces the theory to face up to the ontogenetic concept of life cycle, with all of its teleological/programmatic implications. The many developmental mechanisms that evolutionary biologists borrow to explain evolution point to the unfolding of the life cycle of an organism. Even the Gaia hypothesis, in its strongest form, does not fully develop the entailed notion of life cycle. How long can evolutionary biologists keep borrowing explanatory mechanisms from developmental biologists before they are forced to admit that evolution is a developmental process and therefore the unfolding of a developmental life cycle?

The star larvae hypothesis proposes that biological evolution on Earth and Earthlike planets is only a phase in a complex lifecycle: It is the larval phase of the stellar life cycle. The hypothesis endorses the vocabulary of ontophylogeny, or evelopment, introduced in the quotations at the top of this page (though Kupiec would see ontogeny absorbed into phylogeny, and the star larvae hypothesis sees the integration going in the opposite direction). Ontophylogeny models descent with modification as a system of nested developmental cycles that accommodates phenotypic adaptation to environments at all levels in the nested structure and includes programmatic development at all levels, or adaptive life cycles within adaptive life cycles.

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