A systems view of biological health

Section 2: Theory

41 : From Mammals to Hominids

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Humans have a small but significant physical adaptations that distinguish them from most other mammals. However, the majority of human anatomy and physiology is distinctly mammalian

The greatest influences that influenced the evolution of a healthy human nervous system were "soft" – i.e. social

The mammalian body plan provides both thermoregulation and rapid release of energy, allowing mammals to adapt to a vast range of environments - deserts, ice packs, frozen and tropical seas, and up to two kilometers deep in the ocean. Mammals run as fast as 70 miles per hour, fly, burrow, eat insects, plankton, meat, vegetation, are the largest creature in the seas (the blue whale reaching up to 30 metres long and 200 tons) and on land (elephants weigh about 6 tons) or can be as little as two inches long and (humans) may live over 100 years. Human physiology along with the arrangement of the ANS is broadly (allowing for that vast range of mammal behaviour and habitat ) equivalent to the physiology of most other mammals, with a few special adaptations.

Humans (Homo Sapiens, or "thinking man") started out about three million years ago as Australopithecus, which then developed into Homo Erectus ("upright man") by about one million years bp. So far as we currently understand, Homo Sapiens is the result of interbreeding of several descendents of Homo Erectus, including Neanderthals and Denisovans during at least two waves of migration out of Africa and many phases of East-West population migration across Asia, plus at least two major migrations through Alaska into the Americas. So although it is possible to generalise, all humans are not exactly the same, having varying ancestries and inherited adaptations. More Denisovan ancestry can give better adaptation to high altitude. More Neanderthal ancestry can result in a more square hip joint, less limb flexibility but greater body strength. There are further subdivisions of human metabolic range according to regional variations in gut microbiome – this and blood group types having been affected by many generations of ecosystem and clamate-specific diet.

But the vast majority of humans evolved as hunter-gatherers in small extended families, moving with the seasons, following food and water, just another migratory animal. As humans we have a few very specific adaptations. Pursuit hunting is a very arduous activity that requires we thermoregulate and move in a more energy-efficient way than our prey. Ungulates (hooved animals) are capable of sprinting much more rapidly than humans - but cannot so easily thermoregulate, and their rate of breathing and gait when running (and therefore energy usage) is rigidly linked together, one breath equating to one stride. So we have adapted to thermoregulate by sweating – something quite rare amongst mammals. Our upright gait provides an extremely energy-efficient [1] easy jogging pace in which gait and breath are de-coupled by upright biomechanics and a muscular diaphragm.

The human body is the least adapted of all animals (being very similar to the newborns of the great apes), having no hooves, claws, canines or heavy fur to speak of. This lack of hard adaptation allows us to adapt it by usingit differently – treating the whole body as if it is a tool - including the addition of actual tools as limb extensions, and clothing. We must have tamed fire a long time ago. Cooking (including fermentation) allows food to be softer; and it is only with the reduced mechanical effort to eat soft food that the temporalismuscle can shrink, the bones of the skull become less thick and dense, and the cranium expand to accommodate a larger brain. With softer food came less adapted teeth which also change the jaw angle and allow a finer balance of the weight of the head – making running more efficient. Our hands are a marvel of adaptability, allowing strong but also precise movement. But the adaptation is still general rather than specific. We have adapted to be as adaptable as possible.

At some point our ape ancestors started to sing [2] as a form of communication. The songs then developed common meaning and eventually turned into speech as we evolved both a voicebox and additional neural capacity to devise and vocalise and make sense of a broad vocabulary. We also managed to re-invent colour vision, most mammals seeing in black and white. Who knos what senses hang around in the subconscious – things we could hear, and see but cannot because we do not yet know we can. The lack of use of words for certain colours in ancient languages suggest [3] that whilst we may have been able to "detect" blues for maybe hundreds of thousands of years, this subliminal recognition only became conscious (such that we could name what our senses could discriminate) relatively recently in human history. Laurens van der Post in his book Heart of the Hunter (1961) reported that the Bushmen were sad for him that he could not hear the stars singing, and thought initially that he was telling them a bad joke:

So the traffic of meaning between the Bushman and the stars has gone on from the beginning right into the lives of his descendants in the desert of today, like that traffic of angels which Jacob saw in a dream during his own desert flight, ascending and descending a ladder pitched between him and the sky. Nor was the traffic visual only. I have already mentioned the sounds wherein the stars speak to the Kalahari Bushman today: nearly a hundred years ago a Bushman told Bleek about their voices; and he said too – a thing I had not heard in the Kalahari – that the sun had a great voice of its own. It made a ringing sound in the sky. When I read that, I thought instantly of the great chord [4] with which Goethe begins the music of Faust : "Die Sonne – tönt nach alter Weise."

And of course there is the "sapiens" part of being human. Some might say/have said the human mind, the ability to think, create, abstract, invent, employ language and tell stories is our great gift. Others might call it the "monkey mind" – something that takes over and causes trouble for no good reason other than the fun of it. I think this latter phrase is disrespectful to monkeys.

So far the specifics mentioned that might apply to how a human body-mind is supposed to be used any different from any other mammal (such as a horse or dog) - are in

• the use of breath, speech and particularly song,

• the way that we balance an upright posture

• the proper use of the human mind in adaptive cooperation with the "animal" body

• in stress-tolerance to levels of hydration and sodium, and

• maybe some facet of the vast adaptive range of the hands.

On top of this we have the vast relational-adaptive behavioural and symbiotic range. The three million years since Australopithecus and probably all of the ten million years before then saw us largely moving round in extended families – people of all ages from babies to the moderately old, in groupings of up to about 20 or 30 people[6]. The land was not farmed so much as tended – creating vast areas of ecosystem (e.g. the Amazon rainforest, the Pacific Northwest) that were essentially self-sustaining larders. If you live in such a group, then children are parented by the whole community and mutual trust - cemented by a social structure and ceremony based on an intimate perpetually renewed relationship with the living landscape - is the glue that binds everything together[7].

All this co-creative relationality that is so "human" also started tens or hundreds of millions of years before hominids graced the planet. Humans (and all of Live) being self-reflective, there is an internal relationality between attention and body that is directly equivalent to external relationality – that can at best be equal and supportive.