Star Larvae Hypothesis
“[T]here is no obvious reason to suppose, as proponents of natural selection do, that phenotypic properties are by and large the effect of adaptation to exogenous variables."
Jerry Fodor and Massimo Piattelli-Palmarini
In the scientific account, evolution is shaped by natural selection, which acts on the variation that occurs among individuals in the local population of a species. Environments "select" for survival those individuals endowed by nature with a "selective advantage," that is, with adaptive traits that enable it to survive and beget fertile, viable offspring.
Individuals selected by the environment to survive and bear progeny skew the genetic profile of generations down the line. As a result, successive generations of a species might bear little resemblance to their ancestors, because they represent only that slice of the original gene pool, supplemented by mutations, horizontal gene transfer, and possibly other sources of genetic novelty, that possessed the characteristics necessary for survival and reproduction. For generations sufficiently far down the line, the genome of any descendant species is up for grabs. Its makeup will depend on the particular demands made by the environment, which can change significantly as environments themselves change.
"The idea that adjustments are the result of natural selection among unpurposed or blind variations is not incompatible with that of cosmic purpose. For the maintenance of the general conditions under which chance and competition will produce evolution may itself be purposive. Darwinism derives generally higher forms of interadjusted species from lower; but interadjustment itself and as such is assumed, not explained. Interadjusted atoms or particles involve the same essential problem. Theism can explain order as a general character of existence; can any other doctrine? And an order capable of evolving such a vast variety of mutually compatible creatures seems all that providence could guarantee, granting that freedom is inherent in individual existence as such."
No amphibian hatchling can mature into a wolf, but amphibians as a class can sprout a family tree that eventually includes wolves and many other unamphibious descendants. The divergences can become so pronounced, that humankind for the longest time failed to develop any widely held concept of species descent. However, as the theory of evolution gained currency, hypotheses arose that sought to relate phylogeny and ontogeny in meaningful ways. As different as they are in scale, both can appear to be processes of development. Both are certainly processes of, in Darwin's words, descent with modification.
One influential unification of the two concepts was the "biogenetic law" of German biologist Ernst Haekel in the nineteenth century. Haekel's alliterative law, "Ontogeny recapitulates phylogeny," was widely adopted as a scientific principle, its influence reaching well into the twentieth century. Haeckel proposed that a complex organism passes through the stages of its ancestral phylogeny, through the various steps from simple unicellular creature through stages that repeat its evolutionary history.
The ontogeny of an individual organism appears to be an example of ends being imminent in a natural process—that is, of a natural teleology. But, in the received view, ontogeny is embedded in the larger context of nonteleological, unprogrammed phylogeny. The star larvae hypothesis challenges this view. The hypothesis reconceptualizes the relationship between ontogeny and phylogeny. It locates phylogeny—biological life’s evolutionary history—within an overarching ontogeny—the stellar life cycle—making the former subordinate to the latter. It inverts the received relationship between ontogeny and phylogeny; it assigns to evolution an ontogenetic plan.
“[M]orphological explosions may well reflect major changes in internal constraints as crucial components in speciation. If so, then the effects of natural selection may well consist largely of post-hoc fine-tuning in the distribution of supspecies and variants: quite a different account from the one of gradual selection of randomly differing small variations.”
Jerry Fodor and Massimo Piattelli-Palmarini
"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 indentify a mouse counterpart of at least 99 percent of all our genes."The perplexed authors elaborate on the new findings:
". . . 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? Puzzling? Paradox? Why does evolution theory suffer so many bouts of the unexpected now that genomes are yielding their secrets? If the received theory of evolution were solid, wouldn’t new genetic details have slots waiting for them in it? Shouldn’t new genetic data bolster the theory, rather than generate surprises, puzzles and paradoxes for it to resolve?
“We think that this is important, so we’ll say it again: you don’t need the theory of evolution to explain why a creature’s phenotype is well adapted to its environment (i.e. to the world); that follows simply from the fact that there are creatures with that phenotype."
Jerry Fodor and Massimo Piattelli-Palmarini
"The genome also includes analogues of genes that, in organisms with a neuromuscular system, code for muscle tissue and neurons."A curious finding. The article continues:
"According to Douglas Erwin, a palaeobiologist 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. But, rather than propose that the genes needed by organisms with neuromuscular systems are in the sponge for the anticipatory purpose of providing those genes to descendants who will need them, the scientists invent an imaginary ancestor of the sponge that needed the genes. But the ghostly ancestor would have had to 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 the neuromuscular genes? Nobody saw it coming. It was an empirical surprise.
"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 just keep coming. A news release (11/24/2005) issued by the journal Trends in Genetics announces that
"Corals and sea anemones (the flowers of the sea), long regarded as merely simple sea-dwelling animals, turn out to be more genetically complex than first realised. They have just as many genes as most mammals, including humans, and many of the genes that were thought to have been "invented" in vertebrates are actually very old and are present in these "simple" animals."
text of the release is available at http://www.sars.no/resear
(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
and other phylogenetically anomalous results of genomic analysis are collected
This page of Brig Klyce’s "Cosmic
Ancestry" web site includes commentary on the relevance of these
findings to panspermia.
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 who engineered the current theory, but also that they make the evolutionary process look like a developmental process, like a stage, or stages, in the life cycle of a developing organism.
The findings are paradoxical only for a theory that sees evolution as pure contingency. If evolution is recognized as the developmental unfolding of a life cycle, then the findings
A complex organism begins life as a single cell of a morphologically generic sort. The fertilized egg cells of seahorses, hummingbirds, and humans, for example, are phenotypically indistinguishable. The all look alike. The fertilized egg divides into two cells, then into four, and so on, until enough cells exist for the cellular collective to initiate a specialization of labor. The various types of cells compete and cooperate to acquire the resources that they need to survive, and their collective labors constitute the physiology of the embryo that their bodies, in aggregate, constitute. As the process continues, the distinctive features of the species emerge.
At some point during embryological development, a cell that is only 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 organism's physical being. Is this process of diversification teleological or Darwinian?
"Let me now rephrase the central proposition in a somewhat stronger and more interesting form: if the genetic components of human nature did not originate by natural selection, fundamental evolutionary theory is in trouble. At the very least the theory of evolution would have to be altered to account for a new and as yet unimagined form of genetic change in populations."
Edward O. Wilson
Consider the counterintuitive argument: Insofar as there is variation among the individuals in the population of any particular cell type in the body of a complex organism, and insofar as not every cell survives to contribute its genetic predispositions to the next generation, there is a natural selection among cells during ontogeny. This thought experiment—fitting ontogenetic cellular differentiation into a model of Darwinian phylogeny—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 can also be seen as a phylogeny, a "cytophylogeny," in which a common ancestral starting point—a fertilized ovum—begets successive generations of increasingly diverse descendant forms.
Imagine the cells of a complex organism, having developed their own theory of evolution, marveling at the blind workings of mutation and natural selection that turned their common ancestor—the original ovum—into the diversity of interdependent cellular species in which they find themselves enmeshed. Fitness selects the survivors, they would say, as demonstrated by their survival! We would understand that these scientifically minded cells have missed the boat, that they live by a developmental program and that they are mistaken when they explain their situation in nonteleological terms. Their thinking, however, would be consistent with modern science's theory of human descent. The star larvae hypothesis argues that human beings have made the same mistake as these cells, in believing that nonteleological processes delivered them from their remote ancestors.
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 you 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 the 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 better understood as the undirected spread of mere variation. Increases in variation are sufficient to product 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:
“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.”
Again, 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 the result of wholly undirected, stochastic mechanisms that merely increase variance among cell types. The received view says no; explanations from phylogeny are inadequate to account for ontogeny. But the parallels are stiking: Some cell types, the early undifferentiated types of the blastula, for example, go extinct during human 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 model equally well explain the diversification of cells during ontogeny as it does the diversification of species during phylogeny? Empirically, the two processes are of a kind: multiform descent from a common ancestor.
To clarify: The star larvae hypothesis does not argue that ontogeny is a stochastic process that merely increases variance among cell types, but accepts the received view that ontogeny follows an inherent program. But it rejects the received view when it comes to phylogeny, which, it argues, also follows an inherent program. The applicability of phylogeny's supposed 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 reduce ontogeny to nonteleological processes, then perhaps we can consider that science has erred in reducing phylogeny to nonteleological processes.
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 reach 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. Once we assign the evolution of species to a subordinate position within the overarching ontogeny of the stellar life cycle, we effectively resurrect the Chain of Being, but 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.
The Star Larvae Hypothesis:
Stars constitute a genus of organism. The stellar life cycle includes a larval phase. Biological life constitutes the larval phase of the stellar life cycle.Elaboration: The hypothesis presents a teleological model of nature, in which
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