Star Larvae Hypothesis
The pre-programmed unfolding of the life cycle of an organism is admitted to be an example of programming in nature—that is, of teleology. Biologists call the programmed unfolding of an individual organism's life cycle the organism's ontogeny. Ontogeny reveals nature's potential to act planfully. Organisms develop with increasing complexity and move progressively away from equilibrium in accordance with a plan pre-programmed into their DNA.
Each organism begins life as a single cell. Some stay that way. Others grow into multicellular complexity, their cells progressively differentiating in form and function according to the instructions of its unique DNA coding. The progressive differentiation of tissue types is controlled by genetic "switches" and their protein-based regulatory networks. (Environmental factors exert an influence—for example, you cannot teach, reward, or with a special diet cajole a tadpole into maturing into a rhinoceros. But by controlling diet and other environmental factors, you can nudge it toward one extreme or another of its phenotypic potential. But the range is constrained by the genotype. Whether it exhibits a robust or an atrophied morphology, it remains a frog.)
"He expected to find that Anaxagoras would explain the world order as a work of design, not a result of blind mechanical necessity. The reason of that order would then be found, not in some previous state of things from which it had emerged, but in some end or purpose that it could be shown to serve. Reasons of that sort seemed to Socrates intelligible and satisfying."
F. M. Cornford
a suitable environment, an acorn develops according to its internal programming
into an oak tree; it will not mature into an adult mushroom or squid.
But science does not attribute the increasing complexity of a maturing
oak to a chance process that just happens to deviate from its simple beginnings
because it has enough time to and because its constituent cells merely
diversify, as in Gould's metaphor
of the drunkard's walk. Even science attributes the progressive development
of the oak, and of every other organism, to a directional program, specifically
one that is pre-coded into particular arrangements of chromosomal DNA
in an organism's cells.
The tadpole does not—cannot—mature into an adult walrus or the adult form of any other creature except that of a frog. The tulip bulb cannot sprout into a Norway pine. The caterpillar cannot metamorphose into a giraffe. Ontogeny is a progressive development operating in nature that is constrained to a predetermined plan.
And the juvenile form of a species might not at all resemble the adult form, as in the case of the lowly caterpillar that nature transforms into a high-flying butterfly. The metamorphosing insects demonstrate the potential of an ontogenetic program to encompass highly diverse forms and processes and release them into an organism’s life cycle according to a precoded sequence of stages.
This aspect of development, which involves DNA segments hitching a ride inside an organism until they are needed, might have implications for phylogeny, the evolutionary process. The received view of evolution theory has no place for "anticipatory" DNA that functions this way, lying in wait until it is needed. But the received view also is stumped by so-called junk DNA, sections of DNA preserved across generations but not expressed in the development of an organism. These unexpressed sections are also called "noncoding" DNA. Their origin and persistence remain a mystery. Why would evolution tolerate unproductive genetic baggage?
But if we look at the life cycle of a complex organism, such as a human being, we find a kind of ontogenetic, or developmental, counterpart to the junk DNA of the evolutionary biologists. And this genetic counterpart suggests an evolutionary role for junk DNA. It might be junk only in its immediate context.
To understand the ontogenetic counterpart to evolutionary junk DNA, consider the cells of a particular tissue type in a human body, such as muscle cells. Each muscle cell in a person contains the person’s entire genome, which each cell inherits from the zygote (fertilized egg cell) from which it is descended. During the course of development the zygote divides over and over again into the many cell types that make up an adult human being. Each mature cell type expresses only part of its genome; unexpressed DNA rides along as "junk." (A complete genome being present in each specialized cell type is what makes cloning possible.) So, in the case of a muscle cell, DNA for all the other cell types is present. It’s just not expressed.
As an extreme case, consider the phenotype of the zygote itself, which contains unexpressed DNA for all cell types that make up an adult body, though only a tiny portion of that genetic potential is expressed in the functioning of the zygote’s unicellular physiology. All the rest of the zygote’s DNA is "junk", until ontogenetically useful sections get expressed during development. The DNA for wings is "junk" in a caterpillar, but sheds that status when used to build a butterfly.
The star larvae hypothesis proposes that biological evolution on Earth and Earthlike planets is only a particular phase in a complex lifecycle: It is the larval phase of the stellar life cycle. In the context of the hypothesis, in which phylogeny is a subroutine within an overarching ontogeny—the mystery of junk DNA looks less mysterious. Junk DNA might have a function in the future—as does wing DNA that lies dormant in a caterpillar. Because anticipatory DNA is to be expected in the context of ontogeny, it poses no problem for evolution, if phylogeny is repositioned as a subroutine within the ontogenetic life cycle of an organism. Otherwise evolutionists are left to explain the persistence of junk DNA.
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
|Tweets by @Starlarvae|