Wednesday, November 18, 2009

Note to a colleague re. the ARC

A fine diving spot: Deans Blue Hole, Bahamas
Divers paradise
Myostatin protein regulates muscle build, effect on myoglobin, brain, jaws?
myostatin vs follistatin
nose nerves, inf conchae, PSR
Physis: a marine journal, CIEE in Bonaire
Blue planet divers site, diver list
Blue Planet Divers
Shoal/slow/shallow, sandbar, reef, wave patterns at shallows
Shoal, lagoon, Ayre/lake/laut/loch

The derivation of the word ayre is from Old Norse. It refers to a shallow bay/lake being separate from the sea by a sandspit. This may partly cut off a sheltered stretch of water from the sea to form a shallow freshwater loch.[2] This word is still in use for the particular landform in the Northern Isles of Scotland.

In Malay/Indonesian, ayer or air means water, laut means lake or sea.

The post-coastal Hadza Hunter/Gatherer camps

Isotope markers in bone: Seal (high) vs mollusk (low) in human diet, iris bulbs, at South African coastal Holocene sites
South Africa coastal hunting and gathering diet
Through chemical analysis of bone collagen from 69 skeletons dated from 4,500 to 2,000 years before present, what foods were you able to determine that Holocene populations in Robberg/Plettenberg and the Matjes River Rock Shelter were consuming?
In this area, people were able to choose from a long menu of foods including venison and the meat of other wild animals, berries, edible roots and corms, particularly of plants in the iris family, seafood including shellfish, fish, seabirds, stranded dolphins or whales, and much else. All these items have been identified in excavated food remains. It is, however, harder to know their relative importance. Neither conventional archaeological techniques nor isotope analysis (for different reasons) permit precise quantification of individual foods, but it is clear from the high ratios of 15N/14N in their bones that people buried at Robberg/ Plettenberg Bay ate unusually large quantities of high trophic level [animals high on the food chain] marine foods, very likely the meat of seals and large predatory fish caught in the deep waters surrounding the Robberg Peninsula. Bone tissue accumulates over many years, so this was a long-term dietary pattern. People buried at Matjes River Rock Shelter, on the other hand, ate much more mixed diets, with more terrestrial food or low trophic level [low on the food chain] marine foods, such as shellfish.

Why do you think their diets were different? Why is this finding important or surprising?
Today, there is a seal colony on the Robberg Peninsula, and it was probably there in the past as well. (This inference is based on the age distribution of seals that ancient people butchered and ate.) Mainland seal colonies are relatively rare (most colonies are on offshore islands, which offer protection from predators), so this would have been a special opportunity for hunter-gatherers--a type of living larder. In addition, the peninsula juts out into deep water, allowing access to fish not usually caught by shore-based anglers. People who lived at Robberg/Plettenberg Bay made the most of their good fortune, while people who lived at Matjes River Rock Shelter didn't have these advantages. What's surprising about it is the degree of specialisation in local resources, from which we can infer that these people were living within relatively small areas, rather than trekking regularly across large areas of landscape. This is unexpected, given the very mobile lifestyle of most recent southern African hunter-gatherers.

How does ethnographic research contribute to the analysis of Stone Age societies in South Africa?
Later Stone Age societies were the ancestors of communities who continued to live a foraging lifestyle, in the Kalahari and elsewhere, into the nineteenth and twentieth centuries. Studies of Kalahari foragers have been of enormous importance in anthropology in recent decades. In some respects, there are clear similarities between recent and ancient southern African hunter-gatherers, and the ethnographies have provided valuable insights into earlier societies. For example, aspects of belief systems recorded in the Kalahari in the twentieth century are also expressed in rock paintings that may be several thousand years old.

What does the painted seal scapula found in the cave at Knysna tell us about the hunter-gatherer society that created it?
This is a unique artifact--it's the only painted bone we have from South Africa, so interpretation must be cautious. Paintings on the walls of caves and rock shelters, however, expressed aspects of people's belief systems, including ideas about relationships between animals and humans in this world and in the spirit world. The animals depicted are usually larger species charged with symbolic power. The choice of a seal scapula and the images painted on it, of which the left-hand one, at least, looks very seal-like, hints that seals may have been important in a spiritual, as well as an economic sense.

You describe the societies as succumbing to "opportunistic sedentism." What do you mean by this, and why is it significant? How might being sedentary affect other aspects of life?
The idea is that people might initially have practiced a degree of sedentism in areas where there were rich resources, because there was no need to move. Early on, this is likely to have been a flexible pattern. When population densities rose, and there were limited options for moving, settlement patterns became more fixed--increasing our chances of recognizing them in the archaeology. Cross-culturally, more settled lifestyles require people to develop new methods of dealing with conflict, they allow storage of food or other commodities, opening up the possibility of differential access to resources and thus to social inequality. Southern Cape peoples probably didn't go very far down this road, but these are interesting questions.

Owl monkeys, Aotus spp: nocturnal, huge tarsier/lemur-like eyes, thyroid, low metabolism, retro? Have same NeuA5 sialic acid as humans, so susceptible to human type malaria but brains small, and furry, retro? Original morph of NWM/OWM/apes, before malaria?

Java man
Prehistory of leprosy

"How long should a dive last? A simple model of foraging decisions by breath-hold divers in a patchy environment" Authors: Thompson D.; Fedak M.A.
Source: Animal Behaviour, Volume 61, Number 2, February 2001, pp. 287-296(10) Pub: Elsevier

Effects of increased swimming costs on foraging behavior and efficiency of captive Steller sea lions: Evidence for behavioral plasticity in the recovery phase of dives
Journal of Experimental Marine Biology and Ecology, Volume 333, Issue 2, 13 June 2006, Pages 306-314 L.A. Cornick, S.D. Inglis, K. Willis, M. Horning

Why do macaroni penguins choose shallow body angles that result in longer descent and ascent durations? Authors: Katsufumi Sato, Jean-Benot Charrassin, Charles-André Bost, Yasuhiko Naito1
Repetitive paired stimulation of nasotrigeminal and peripheral chemoreceptor afferents cause progressive potentiation of the diving bradycardia.
Am J Physiol Regul Integr Comp Physiol. 2008 Nov 5;
Authors: Rozloznik M, Paton JF, Dutschmann M
The hallmarks of the mammalian diving response are protective apnea and bradycardia. These cardio-respiratory adaptations can be mimicked by stimulation the trigeminal ethmoidal nerve (EN5) and reflect oxygen conserving mechanisms during breath-hold dives. Increasing drive from peripheral chemoreceptors during sustained dives was reported to enhance the diving bradycardia. The underlying neuronal mechanisms, however, are unknown. In the present study, expression and plasticity of EN5-bradycardias after paired stimulation of the EN5 and peripheral chemoreceptors was investigated in the in situ working heart-brainstem preparation. Paired stimulations enhanced significantly the bradycardic responses compared to EN5-evoked bradycardia using sub-maxim…

Bubbles and bubble rings:

Prevalence and severity of external auditory exostoses in breath-hold divers
To explore the prevalence and severity of external auditory exostoses in a population of experienced breath-hold divers, and to compare these to the same parameters within surfing and self-contained underwater breathing apparatus diving populations.

Indirect evidence for arterial chemoreceptor reflex facilitation
by face immersion in man
It is concluded that the intensification is caused by chemoreceptor reflex facilitation, due to stimulation of trigeminal receptors in the face.

The initiation and maintenance of bradycardia in a diving mammal
the muskrat, Ondatra zibethica

Extremes in human breath hold facial immersion bradycardia
Although the average human response to apneic facial immersion in ice water is a reduction in heart rate from 70 to 45 beats/min, a small proportion of healthy subjects develop diving bradycardia to less than 20 beats/min. Twenty-seven healthy subjects performed resting, seated, 30-s mid-inspiratory breath hold, facial immersion in a basin of water. Heart rate dropped more when the water temperature was 1 degree C than at 24 degrees C. Five subjects developed asymptomatic diving bradycardia to less than 15 beats/min. One physically active individual consistently had dive heart rates as low as 5.6 beats/min.

The nose is the source of many powerful reflexes, including the diving response, sneeze and sniff reflexes, and reflexes affecting autonomic nervous function to the cardiovascular system, airways in the lungs, the larynx, and other organs. The physiology of the nose 1986

The water content and glucose concentration in the whole blood of marine mammals were found to be correlated to red blood cell concentration. Because hematocrit (Hct) undergoes significant periodic shifts in these mammals during periods of apnea and/or diving, the measured values of whole blood glucose change due to alterations in Hct, independent of shifts in metabolite regulatory pathways. In contrast to humans, where red blood cell and plasma glucose concentrations are equivalent, in most other mammalian species red blood cell glucose concentration is much lower than that in plasma.
Influence of hematocrit on whole blood glucose levels: new evidence from marine mammals

Passive Flooding Of Paranasal Sinuses
And Middle Ears As A Method Of Equalisation In Extreme Breath-hold Diving
We describe a diver who, by training, is capable of allowing passive flooding of the sinuses and middle ear with (sea) water during descent, by suppressing protective (parasympathetic) reflexes during this process.

Adaptations to deep breath-hold diving: respiratory and circulatory mechanics
Respiration and circulation in diving mammals are characterized by interrelated adaptations of structure, function, and behavior that are incompletely described and understood. This speculative survey touches some of them. a) Arterial blood flow can be controlled by vasoconstriction not only in arterioles but also in large arteries. The latter physiology is not well known. b) Mechanisms that might regulate and limit nitrogen uptake are not clear, although Scholander's suggestion that airspaces become gas-free during deep dives is still accepted. c) Systemic arterial retes may be able to store oxygenated blood in some diving mammals. If so, O2 in the lung might be 'skimmed off' early in a dive, leaving the N2 behind. d) Variable clusters of interdependent adaptations in diving mammals include compliant chest walls that avoid thoracic squeeze; inspiratory breath holds that maintain high lung volumes; large tidal volumes that nearly empty the lung at end-expiration...

Renal response to head-out water immersion in Korean women divers
Head-out water immersion (HOI) induces a profound diuresis and natriuresis, which may endanger the body fluid balance of breath-hold divers during prolonged diving work.

An intact glutamatergic trigeminal pathway is essential for the cardiac response to simulated diving

Autonomic response to auditory stimulation
Autonomic and behavioral response to fear stimulation (sudden noise 80 dB) was studied in 12 sleeping infants at ages 8-50 weeks. The aim of the present study was to identify a possible passive defense response in infants. The response, which is widespread in birds and mammals, is characterized by apnea and bradycardia with circulatory changes as seen during the forced diving response.

Trigeminal mediation of the diving response in the muskrat
These data implicate trigeminal neurons in the medullary dorsal horn as modulators of autonomic activity, especially in the cardiorespiratory adjustments after nasal stimulation.
PMID: 1760738 [PubMed - indexed for MEDLINE]
h/t Ivo @

Hello (...) [slightly modified]

Do you have an opinion on these?

Chromosome 2 is unique to humans amongst hominoids, it contains the genes/SNP (Single Nucleotide Polymorphism) for:
- Photic sneeze (Dark adaptation, O2/CO2 apnea regulation?)
- Hypothyroidsm (Ecto/endo-thermic adipocity, Iodine regulation?)
- Hemochromatosis (Bone density, Iron regulation?)

I do not view that as mere coincidence.

Regarding baby backfloating in warm sunlit lagoons:
Human babies have full envelope of SC white fat (insulatory) but dorsal brown fat, which provides warmth to the only sun-shaded area that also is exposed to the coolest proximal water, infant humans (and seals) AFAIK don't shiver for warmth (not useful for hydrostatic backfloating in water). Breastfeeding human infants produce/accumulate Hydrogen (nature's most buoyant material) in the gut, and this, combined with (otherwise healthy) infant colic (GI gas entrapment while backfloating and associated crying) and abundant white SC fat, would provide sufficient buoyancy in dense warm calm saltwater to allow parental foraging without hindrance, in part resulting in loss of fur coat.

Regarding human endurance locomotion: At lagoons, dive foraging would be typical, but in between optimal lagoons, shoreline walking/wading/jogging would be typical due to hazards of rough surf, cold water, box jellyfish, sharks/crocs, etc. This would be maintained during inland seasonal migrations where diving was limited.

Regarding islanding: I think that similar to how Gibralter functioned as a gateway for EurAsian macaques into north Africa, I think the Afar-Eritrea-Yemen region functioned as a gateway to and from EurAsia. The 'bridge' linking Yemen is about 100m deep, about the depth of sea level drop at various glacial periods, (disregarding lack of data on local tectonic changes). I do not view the Danakil alps region as "the refuge", but rather as a periodic gateway, similar to Gibralter and Sinai, though it may have been a stopover with a residual population, similar to today's Barbary macaques at Gibralter.

I haven't found any evidence to contradict the dark adaptation-dive / sunlight surface exhale idea (Aquaphotic Respiratory Cycle), except that it is not used today by modern human divers. I consider it plausible that during the MSC human ancestors separated from the other apes due to being trapped in the Medit. basin, where a unique environment produced selection for a unique hominid different from the others. The low UV present, similar to today's Dead Sea, may have selected for light skin tone or less fur, and unusual eyes (exposed white eye sclerae), and plausibly the sun sneeze, and also increased availability of stone, both for tools and climbing. Later filling of the basin would send various human-types in different directions, to adapt to local conditions with different morphotypes, many would go extinct later.


ps. I've stepped away from AAT yahoogroup for a bit, but continue to skim the threads.

MSC refill
5.6 - 5.33ma MSC may have refilled in 2 years, H/P split 5 - 7ma
picture of Medit MSC refill 5.33ma

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