Friday, July 07, 2006
The Organosubstrate and the Symbiotic Planet
I once asked the eloquent and personable paleontologist Niles Eldredge whether he knew of any case in which the formation of a new species had been documented. I told him I'd be satisfied if his example were drawn from the laboratory, from the field, or from observations from the fossil record. He could muster only one good example. Theodosius Dobzhansky's experiments with Drosophila, the fruit fly. In this fascinating experiment, populations of fruit flies, bred at progressively hotter temperatures, became genetically separated. After two years or so the hot-bred ones bould no longer produce fertile offspring with their cold-breeding brethren. "But," Eldredge quickly added, "that turned out to have something to do with a parasite!" Indeed, it was later discovered that the hot-breeding flies lacked an intracellular symbiotic bacterium found in the cold breeders. Eldredge dismissed this case as an observation of speciation because it entailed a microbial symbiosis! He had been taught, as we all have, that microbes are germs, and when you have germs, you have a disease, not a new species. And he had been taught that evolution through natural selection occurs by the gradual accumulation, over eons, of single gene mutations... From the long view of geological time, symbioses are like flashes of evolutionary lightning. To me symbioses as a source of evolutionary novelty helps explain the observation of "punctuated equilibrium," of discontinuities in the fossil record. [Margulis, Symbiotic Planet 7-8]
At the last ICC, Joe Francis submitted a paper describing what he called the organosubstrate -- the microbes and viruses which act as the link between the inert physical world and the higher organisms. According to Francis, "microbes and viruses could also be thought of as a single, complex, massive, multicellular, multitaxon organism with incredible and powerful life supporting properties."
Francis argues that the design of the organosubstrate is evident from the reproductive efficiencies and the adaptability of its members. The ability to adapt to a variety of environments, efficiently extract nutrients needed by macro-organisms, and establish a variety of symbioses is what allows it to function as the organosubstrate. Many members of the organosubstrate also have dispersal mechanisms that allow them to get to remote environments.
Most interesting to me, however, is the ability of microbes to form symbioses. Francis gives numerous examples of very interesting, highly intricate symbioses that microbes can form, some of which are so integrated as to suggest properties of multicellular organisms. But they can form symbioses with not only other microbes, but with macro-organisms as well. Digestive systems are the most obvious.
Interestingly, the concept of the organosubstrate has a number of similarities with the Gaia hypothesis as proposed by Lynn Margulis. First of all, please don't confuse Margulis's Gaia hypothesis with the New Age ideas of similar names. Margulis's hypothesis is simply that the earth behaves in a systems fashion. In fact, Margulis's book shares numerous similarities with Francis's hypothesis. [Note that Margulis's hypothesis also carries with it a lot of old-Earth, atelic baggage as well, but as a current, operational view they are largely similar]
However, Francis goes even further with a very interesting hypothesis about the creation of symbioses with macro-organisms. Francis speculates:
Further investigation into the symbiotic relationships between microbes and mammals may also lead to insight into the originally created purpose of the immune system. For instance, among microbes phagocytosis can function as a non-destructive mechanism to acquire symbionts and is common among unicellular and multicellular pond organisms. In contrast, phagocytosis in macro-organisms is an immune response that participates in destruction of pathogens. I predict that future investigation of this phenomenon will lead to a hypothesis that the immune system may have been originally created as an environmental sensing device that received data about the environment through the phagocytosis of beneficial microbes. Indeed the mammalian immune system possesses very specific and complex mechanisms that interact with microbes, often causing inflammation and tissue-destructive autoimmune responses and therefore appear to make little sense in the context of evolutionary biology. [emphasis mine]
In Francis's recent talk at the 2006 BSG meeting, he discussed a particular symbiosis with
Furthermore, Vibrio fischeri (a bacterium similar to V. cholera) also uses virulence factors, similar to several found in V. cholera and other pathogens, to establish a beneficial symbiotic relationship with the Bobtail squid (Euprymna scolopes). In this symbiotic relationship, virulence factors are involved in tissue remodeling and morphogenesis of an elaborate light-producing organ. Interestingly, not only do these bacteria appear to be more fit for their beneficial ecological roles, but inflammation, tissue degradation and toxin production that cause pathogenesis in some ecological settings play beneficial roles in other ecological settings.
Francis discussed the fact that the inflammation response of the squid was used to isolate the specific microbe that it wanted to establish a symbiosis with.
As the Margulis quote indicated above, perhaps the genes are not the primary originating factors of speciation, but instead symbioses and ecological factors. Indeed it appears that the largest-scale changes that have been observed to take place revolve around symbioses. In a personal conversation, Francis related another symbiosis in which the organisms literally changed form in the presence or absence of the symbionts.
An interesting Creationist research possibility would be to attempt to catalog and systematize the types of symbioses available and the methods by which they are established. I hypothesize, as I believe does Francis, that we will find specific mechanisms that act to sense the available organisms in the environment, what sort of symbioses would be available, and can decide whether and how to establish that relationship.
Historically, I think Creationists have assumed that complex symbioses must have been original creations. However, as has been pointed out here repeatedly, complex interrelated processes need not be originally established, but can have the ability to assume those processes pre-coded for later activation. Therefore, we need not balk at the idea of the development of complex symbioses through time. Using an informationally-driven model we can see both the origination of the symbiosis as occuring post-flood, but also that the ability to form it was established as a part of the organism. Because of the short time span needed to establish a symbiosis, it can help explain the rate at which intrabaraminic diversification took place.
I think that a systematic researching of symbiosis could be a place where a Creationist could persue work that is both Creationist as well as usable (and possibly fundable) by non-Creationists. This is a wide-open field, especially with researchers such as Margulis concentrating so much on the origin-of-life/origin-of-eukaryote issues, the really interesting parts (systematic study of speciation through symbiosis) remains largely untouched (if this is in error, I would love to know of a good reference for a systematic treatment of mechanisms of symbioses -- please post in the comments).
Francis, J. 2003. The Organosubstrate of Life: A Creationist Perspective of Microbes and Viruses. Proceedings of the Fifth International Conference on Creationism.
Franics, J. 2006. The Role of Virulence Factors in the Establishment of Beneficial Ecological Relationships of Vibrio cholera and Vibrio fischeri. OPBSG 8:14-15.
Margulis, L. 1998. Symbiotic Planet: A New View of Evolution. Basic Books.
We've talked about this subject a little bit before. I thought I'd link to the other posts we've done on the topic:
Creation, Ecological Diversification, and Symbioses
Stasis of the Baramin, Purpose, and Inheritance Mechanisms
The New Science of Eco-Devo
How long did it take the eye, the brain and the optic nerve to evolve?
Aren't Darwinists cry babies!
Of course, the proprieter of this blog thinks that it would have taken 40 million mutations just to produce obligate bipedalism from an ancestral species that engaged in opportunistic bipedalism, so it is no surprise how little his commenters understand...
He also likes to run around making comments on creationist boards about other bloggers or people whose claims he cannot substantively address. Crybabies? Look in the mirror, pally.