Tweet   Home | Blog | About | Videos | Contact

The Star Larvae Hypothesis
Nature’s Plan for Humankind
Part 1. Metabolic Metaphysics

Symbiosis

Organisms become harder to define when they extend their metabolisms through, and become dependent upon, one another.

A mutually beneficial relationship among organisms is called symbiosis.

The concept of symbiosis can blur the distinction between organisms and their environments. For example, if a plant requires the participation of an organism of a different type, a bee, say, to reproduce, then the bee is a part of the plant’s reproductive cycle. And if the bee requires the pollen from the plant to feed its larvae, then the plant participates in the bee’s reproductive cycle, and the organisms enjoy a symbiosis. The organism is the beeplant. To where the bee flies, the plant might extend its range. To where the plant’s seeds light, perhaps due to the intervention of a bird, a new beehive might be established. (And the bird adds its own layer of complication.) Symbiotic organisms extend one another's metabolisms.

A lichen appears to be a single type of organism, but lichens are integrated symbiotic communities of bacteria and fungi.

A micro-organism that lives in the gut of the termite is another example of symbiosis. It produces an enzyme that enables the termite to digest cellulose (wood fiber).

The human body by cell count consists mostly of symbiotic bacteria—about 90 percent of a human body’s cells are bacterial. Although this population of microbes, the human microbiome is a topic of ongoing research, its dynamics have been mapped sufficiently to expose the hjuman body as a complex ecosystem.

The figure at left shows the human body and its many microbial communities. (Illustration by Patricia J. Wynne, from Welcome to the Microbiome, by Rob DeSalle and Susan L. Perkins, Yale University Press, 2015.) The authors observe,

“[P]erhaps as many as 90 percent of the cells in a typical healthy human body are microbes, and that up to 3 percent of our body mass is made of microbial interlopers. [. . . .] As unbelievable as it may seem, our genomes have evolved to cope with and even cooperage with these microbial residents.”

Moreover, this population of micro-organisms evolves by ecological succession. Summarizing a study of the effects of handwashing on bacterial communities that live on human skin, the same authors note that, surprisingly,

“[I]t turns out that time since last handwashing was not correlated with diversity [of microbes on the skin] and, in fact, the degree of diversity is pretty much the same regardless of time since washing. What did change over time were the kinds of bacteria found on the hand since the last washing, implying that there is a kind of succession of bacteria that colonize a clean hand. Certain types of bacteria jump on at first and establish themselves, and then a little later others take over.”

Bodies of complex organisms are themselves ecosystems that host rotations of symbiotic populations and otherwise display the same dynamics as characterize macro-ecosystems.

Furthermore, researcher Anna Skalka, Director Emeritus, Institute for Cancer Research, Fox Chase Cancer Center, and colleagues estimate that at least 8 percent of the human genome is of viral origin. She is interviewed about the work on National Public Radio HERE. Symbiosis raises the question: When organisms cooperate for mutual benefit, whose metabolism is whose?

The ambiguities encountered when trying to distinguish organisms from one another is a problem for evolution theory, because the theory needs to define something discrete for nature to "select" from among her interwoven metabolic processes. Which is a discrete unit of evolutionary selection, a gene, a trait, an individual organism, a species? This "granularity problem" plagues the Darwinian model.

Endosymbiosis

The ambiguities take a dramatic turn in the case of endosymbiosis. This occurs when varieties of unicellular organisms merge to form a new kind of cell, which, being a conglomerate of symbionts, has a structure more complex than any of its formerly independent constituents. According to normal evolution theory, various species of bacteria, or prokaryotes, merged to create the more complex, eukaryotic, cells that make up the bodies of multicellular plants and animals. The notion that this is how complex cells arose, through a communal pooling of resources on the part of bacteria, was greeted with scorn when researcher Lynn Margulis proposed the idea in the 1960s. But she got the last laugh. Endosymbiosis is accepted today by most evolutionary theorists as the most plausible path to eukaryotic cells.

Although tightly coupled anabolic and catabolic subprocesses create the illusion that bodies are fundamentally discrete biological units, with tthe metabolic process per se being the dynamic structuring pattern. But organism is a conceptual convenience that designates a relatively stable cross-section of overlapping, interdependent metabolisms. Organisms make their ways among other organisms, making and breaking bonds of various kinds, forming new entities in their combinations and recombinations of metabolic interveavings.

Technology: Humankind's Extended Symbiont

Is the coral of the reef distinct from, or part of, the living polyp that excretes the coral? Is the coral an artifact of polyp technology, a component of the polyp's physical environment, or the true skin of the polyp body? Can the reef's coral be part of the organism and itself not be living? If so, it suggests that an organism can have two parts, one possessed of livingness and one not, the two being interwoven in the body of the thing. But are the molecules themselves possessed of livingness? Are the iron atoms that ride along in the hemoglobin molecule that keeps humans alive, alive?

The concept of symbiosis can be abstracted to include social behaviors, as forms of intraspecific symbiosis. Microbiologist Bonnie Bassler describes symbiotic/social behaviors among bacteria and the chemical signaling involved to keep their societies thriving.

Something as intuitively nonliving as atoms of iron turn out to be essential to the lives of certain organisms, but it seems doubtful that any iron atom distinguishes between participating in living processes and nonliving ones. During its lifetime an iron atom will make and break bonds with countless other atoms, in iron ore, hemoglobin molecules and rusty nails. Nature's matter and energy exchanges crisscross seamlessly between the organic and the inorganic. Nature seems uninterested in maintaining walls of separation between the two domains. This observation raises questions about the character of manufactured (organic and inorganic) artifacts and humankind's relationships with them.

NEXT > Technology, or Niche Construction

Home | Blog | About | Videos | Contact | Text Copyright ©2004-2017 Advanced Theological Systems. All Rights Reserved.