site author: Anthony Wheeler email: firstname.lastname@example.org
Dear Dr. Margulis,
Thank you so much for the wonderful package you sent me in October in response to my email that I originally addressed to Dr. Shermer. You sent me books! You know the way to a thinking man’s heart.
I finished reading all the material and have taken some time to think about it. Hopefully what follows will be worthy of your attention. Your work has significantly broadened my understanding of the micro-world, and changed my perspective to see the multiplicity of macro-organisms.
It surprises me that your insights weren’t respected far sooner. The inclusion of mitochondria and chloroplasts into modern cells from independent sources eons ago simply makes too much sense not to take seriously. The conservative nature of the scientific community is perhaps understandable, but you would think every thinker would be dying to expand the boundaries of the current orthodoxy, if not transcend them altogether, and your work certainly provide such opportunities to the reasonably adventurous.
And the article “The Origins of Larvae” by Williamson/Vickers is certainly intriguing, and again, directionally almost obvious once the facts are considered without prejudice. Even on the surface, say without the weight of authority, that is, in the beginning of biological science, it would have made sense to consider those creatures with radically different larvae and adult forms to somehow represent a combination of two independent forms sometime in the past, even if the mechanism for such a union remained a mystery.
But now for my big question, the one that relates to the on-going evolution of macro-fauna. As an example of such development, I would like to present a model of one possible evolutionary path of hominids, and ask along the way what mechanism might be responsible for the sequential changes in hominid physiology. This model is based on the original idea of the aquatic ape as presented by Alister Hardy in the 30’s, and later made current by Elaine Morgan. (I take full responsibility for the speculation that wanders beyond their scientific theory.) The point of the following is not to argue for this particular theory, but instead, to provide an example that will serve to base my questions upon.
Assume that the Last Common Ancestor of modern humans and Chimpanzees lived 7mil years BP, and that LCA resembled chimps far more closely than humans. In my model, around 7mil YBP, a shrinking zone of rain forest isolated a group of LCAs somewhere near a rocky sea shore. Once the trees completely disappeared, the only option these creatures had was to survive by gathering food in tidal zones. This zone would have been hot, and the sea warm. The shifting tides would provide isolated pools rich with possible food sources. Immediate adaptive pressure would be applied to stand up straighter, lengthen the legs, lose body hair, and gain subcutaneous fat. This is so because when you throw a chimp into deep water today, it sinks and then drowns in short order, whereas modern humans are buoyant due to their body fat.
So first question: do we accept current Neo-Darwinistic explanations to bring about these changes in the first stage of hominid development? Given that all these changes are increase/decrease of something already in place, this seems plausible to me, although I wouldn’t be surprised at the discovery of additional mechanisms involved.
Now comes the striking change, the one that makes all the difference: somehow, these creatures become mouth-breathers. All sea-mammals are mouth-breathers. This allows two things not possible by terrestrial nose-breathers: one, it allows the rapid exhalation and inhalation necessary when diving beneath the surface. More importantly for our case, though, is it allows the creature to consciously control breathing.
Another reason why the chimp quickly drowns when thrown into a pool is that it can’t hold its breath; its breathing is as automatic as its heartbeat, whereas in mouth-breathers the chest/lungs/throat/mouth is coordinated by semi-voluntary systems. In order for this physiological change to come about, at least two things have to change: one, the larynx has to drop in the throat, and secondly, the behavior of the creature has to change to adopt the new capability. In other words, this is a new system, and while it has occurred in many animals (hippos, seals, whales, etc.) I don’t understand how Neo-Darwinist mechanisms can account for the gradual changes necessary to create a system that either works in total, or not at all. One other note: once the larynx drops, the creature can now choke to death, an obvious disadvantage, one that must be offset by significant advantages of some kind.
Anyway, now that these hominids are mouth-breathers, something else becomes possible: language. Evidence suggests that the first hominids walked up-right long before their brains expanded, and if my model is correct, brain size increased with the advent of language, something that would have become more valuable for the social hominid. Living a semi-aquatic life would also encourage growing intelligence and potential tool-use (witness sea otters).
If this is correct, hominids would have remained by the seashore as the naked ape until three more developments took place and allowed them to expand their range into non-aquatic environments, all of them based on increased intelligence: tool use, fire and clothing. Until these are developed, the hominid would be restricted to warm sea-sides, but once they can keep warm and develop tools/weapons, they can expand their range into something similar to traditional hunter-gathering societies. If I am not mistaken, this would have taken place no more than 200,000 to 400,000 years BP – in other words, not all that long ago. In some ways, paleontological evidence supports this possibility, as virtually all hominid fossils have been found near ancient river/lake/seas. On the other hand, almost ALL fossils are found in such places due to the favorable conditions for fossil preservation, so perhaps this means nothing.
But again the question: can the use of language and increasing brain capacity be explained using traditional Neo-Darwinist theory? Presumably the LCA could make noises, not un-like modern chimps, and many of these vocal expressions mean something (warning, anger, etc.). But the use of complex language requires significant changes in brain physiology for creating and understanding verbal signs, in addition to changes in the vocal and auditory systems. Does it seem reasonable that these developed with discrete, incremental changes, either through variation created within living populations, or chance mutations?
If not, if the significant changes we can identify between the LCA 7mil ago and modern humans cannot be easily explained using current evolutionary theory (and this is simply one example among countless that might be used) than what explanation do we employ?
The sharing of genomes and/or merging of entire biological systems between single cells (symbiogenesis) or the merging of genomes between simple organisms as presented in Williamson’s “Origins of Larvae” doesn’t seem to pertain. It seems to me that the only comparable process would have to entail some kind of virus infection of sex cells prior to—or right after—conception. But in all the examples you have provided, the biological systems have already developed their unique capability (the merged genome expressing the adult version as larvae, for example, or the chloroplast incorporated wholesale in plant cells) so what kind of existing virus could provide a living hominid with the genome necessary to express an entire physiological system such as the change we have seen between nose-breathing animals and mouth-breathers?
So that remains my most basic question to the scientific community: if no detailed explanation exists, than simply say so, and allow the scientific culture to respect further research and the funding of such research in order to find one that serves evolutionary science better than the current Neo-Darwinist orthodoxy.
Finally, I would like to address something close to your heart – the Gaia hypothesis. The insight that the entire Earth is a living system that breathes, grows, and can grow ill and die is important, and should be readily accepted by anyone exposed to the perspective. But to assert that “Gaia” is a singular and unique “organism” in the same way a deer, snail or pine tree seems to me a step too far. Insisting on this view invites needless debate, in my opinion, as it ultimately comes down to an argument about language and definitions.
Earth is a planet, not an organism. More specifically, it is a rocky planet, making it different from the gas giants. It is a living planet, sure, in contradistinction from dead planets such as Venus, Mars and the moon, and as far as we know, the ONLY living planet, and that makes it special. As the only known member of its ‘species’, it simply cannot be considered in the same category that we generally accept as ‘animals’ or ‘plants’, despite your wonderful insight on how anything we normally consider ‘one’ organism is actually a congregation of millions – if not billions – of separate identifiable creatures.
Anyway, that’s all I have to say. You can’t imagine how pleased and surprised I was to receive your package, and the pleasure continues to this day.