Licensed under
CC BY-SA 4.0
: also see my full Copyright statement.
HELP REQUIRED! This website/book has (for technical issues) been written using a plain ASCII text editor, and so contains quite a few typo's.
If you find any and have a couple of minutes you can report them - see
contact page!
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") - who were already mass-producing obsidian hand axes at 1.2 million years BP and probably had already some mastery of codage and knots. So far as we currently understand, Homo Sapiens is the result of interbreeding of several descendents of Homo Erectus, including Neanderthals and Denisovans [13] 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 [12]. 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, and a more sensitive, more easily overloaded nervous system [8]. 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, dietary, climate and terrain-specific adaptations. [9].
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.
When despair grows in me
and I wake in the middle of the night at the least sound
in fear of what my life and my children's lives may be,
I go and lie down where the wood drake
rests in his beauty on the water, and the great heron feeds.
I come into the peace of wild things
who do not tax their lives with forethought
of grief. I come into the presence of still water.
And I feel above me the day-blind stars
waiting for their light. For a time
I rest in the grace of the world, and am free.
Wendell Berry
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 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. (See extended discussion in endnote [3] .) 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 most [10] other mammal (such as a horse or dog) - include
Today the only things you can enter into relationship with are other
humans. Yet the human nervous system still needs the nourishment that
it once got from being in reciprocity with all these other shapes of
sensitivity and sentience. And so we turn toward each other, toward our
human friends and our lovers, in hopes of meeting that need. We turn
toward our human partners demanding a depth and range of otherness that
they cannot possibly provide. Another human cannot possibly provide
all of the outrageously diverse and vital nourishment that we once got
from being in relationship with dragonflies and swallowtails and stones
and lichen and turtles. It’s just not possible. We used to carry on
personal relationships with the sun and the moon and the stars! To try
and get all that, now, from another person — from another nervous
system shaped so much like our own — continually blows apart our
relationships, it explodes so many of our marriages, because they can’t
withstand that pressure.
David Abram[5]
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].
Teach the children. We don't matter so much, but the children do.
Show them daisies and the pale hepatica. Teach them the taste of
sassafras and wintergreen. The lives of the blue sailors, mallow,
sunbursts, the moccasin flowers. And the frisky ones – inkberry,
lambs-quarters, blueberries. And the aromatic ones – rosemary,
oregano. Give them peppermint to put in their pockets as they go to
school. Give them the fields and the woods and the possibility of the
world salvaged from the lords of profit. Stand them in the stream,
head them upstream, rejoice as they learn to love this green space they
live in, its sticks and leaves and then the silent, beautiful blossoms.
Mary Oliver
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.
References & Notes
