See below for Teeth & Armor and Parallel Convergence Speculations and much more.
I have some things to clean up and a few hundred newsletters to fold and insert, so I'm off.
Any lurking visitors, feel free to drop a question or two or leave a message.
May the arc be with you! (^u^) Peace be within you ~ salamalaikumsalam ~ shalomelaichemshalom
Really nice free diving video with Tanya Streeter, flying penguins etc.
http://www.youtube.com/watch?v=xsyHt0WHqb4
Wednesday, October 31, 2007
Tuesday, October 30, 2007
Parallel Convergence
Parallel Convergence, Generally speaking:
Anurans: Throat sac buoyancy, vocal mate selection, no tail
Salamanders: no, no, long tail
Hominoids: Laryn. air sac buoyancy, vocal mate selection, no tail
Monkeys: no, no, mid to long tail
Aves: Resp. air sac buoyancy, vocal mate selection, short tail
Reptiles: no, no, long tail
Walruses: Pharyn. air sac buoyancy, vocal mate selection, short tail
Mustelids: no, no (scent), long tail
Pterodons: soft tissue air sac, vocal mate sel.?, reduced tail later
Dinos: no, no, long tail
Anurans: Throat sac buoyancy, vocal mate selection, no tail
Salamanders: no, no, long tail
Hominoids: Laryn. air sac buoyancy, vocal mate selection, no tail
Monkeys: no, no, mid to long tail
Aves: Resp. air sac buoyancy, vocal mate selection, short tail
Reptiles: no, no, long tail
Walruses: Pharyn. air sac buoyancy, vocal mate selection, short tail
Mustelids: no, no (scent), long tail
Pterodons: soft tissue air sac, vocal mate sel.?, reduced tail later
Dinos: no, no, long tail
Teeth & Armor Speculations
[further discussion on this at:]
http://forums.deeperblue.net/674527-post20.html
Introversion of external hair (armor) to internal "teeth"
Baleen whales (blue, humpback, right whales) developed their baleen (whalebone stringy teeth) on the upper jaw, because their fish & mollusc eating ancestors had had walrus-like mustache whiskers which gradually migrated from the upper lip into the upper gums (over a period of a million years), changing from nerve-rich sensory bristles to long net-like filters, straining krill and small fish while allowing water to escape the mouth. (This is one of my hypotheses, haven't seeen any confirmation from others.)
Extroversion of internal teeth to external scales (armor):
Lamphrey (and hagfish?) types lack jaws, but have replaceable teeth which are used to grasp. Is it possible that fish scales derived from multiple teeth replacing (like in sharks, but non-jawed) in a previously non-scaled lamphrey-like ancestor? Various fish scales do resemble teeth in some way, although many have become ultra-smooth for high-speed hydrodynamics. Do fish embryos develop their scales in a cephalo-caudal direction starting at the head? Do primitive scaled fish have more dental-like scales?
Is this a new idea, or has anyone heard of it before? (This is another hypothesis)
Anyway, just seems cool that the opposite actions may have happened in fish and whales.
[Now consider that birds have feathers, which have bloodflow in the plume, do feathers derive from vestigial teeth in early aves which were developing beaks and bills and reducing their ancestral dentition? Are feathers malformed teeth with roots? Where did the beak come from? I don't know.]
DDeden
__________________
"Dive well and come up for more"
The-Arc-of-a-Diver: http://the-arc.wikispaces.com/ / http://the-arc-ddeden@blogspot.com
http://forums.deeperblue.net/674527-post20.html
Introversion of external hair (armor) to internal "teeth"
Baleen whales (blue, humpback, right whales) developed their baleen (whalebone stringy teeth) on the upper jaw, because their fish & mollusc eating ancestors had had walrus-like mustache whiskers which gradually migrated from the upper lip into the upper gums (over a period of a million years), changing from nerve-rich sensory bristles to long net-like filters, straining krill and small fish while allowing water to escape the mouth. (This is one of my hypotheses, haven't seeen any confirmation from others.)
Extroversion of internal teeth to external scales (armor):
Lamphrey (and hagfish?) types lack jaws, but have replaceable teeth which are used to grasp. Is it possible that fish scales derived from multiple teeth replacing (like in sharks, but non-jawed) in a previously non-scaled lamphrey-like ancestor? Various fish scales do resemble teeth in some way, although many have become ultra-smooth for high-speed hydrodynamics. Do fish embryos develop their scales in a cephalo-caudal direction starting at the head? Do primitive scaled fish have more dental-like scales?
Is this a new idea, or has anyone heard of it before? (This is another hypothesis)
Anyway, just seems cool that the opposite actions may have happened in fish and whales.
[Now consider that birds have feathers, which have bloodflow in the plume, do feathers derive from vestigial teeth in early aves which were developing beaks and bills and reducing their ancestral dentition? Are feathers malformed teeth with roots? Where did the beak come from? I don't know.]
DDeden
__________________
"Dive well and come up for more"
The-Arc-of-a-Diver: http://the-arc.wikispaces.com/ / http://the-arc-ddeden@blogspot.com
Tuesday, October 23, 2007
thoughts
Unfinished thoughts to be cont'd.
[QUOTE=naiad;673130]Fascinating. The AAT sounds plausible enough. There are still some things that I don't understand about it though. These are:
Nostrils which cannot be closed. Most aquatic mammals close their nostrils when diving. No animal uses a noseclip or pinches its nose, and few use sinus flooding.[/QUOTE]
True. First, our ancestors went through two different stages.
The first (amphibious) was transitional from a tarsier-like mammal with tail to a vertical-oriented part-time awkward bipedal upright wader/walker/floater (amphibious tree-frog-like) which lost the tail due to large laryngeal air sacs that inflated upon cool-water immersion due to a gasp-like reaction, allowing plucking foods on the water surface and shallow snails etc. but which did not swim well and did not dive at all, about 15 to 5 million years ago, along coastal lowland forests often flooded, this included all ape ancestors. But while human ancestors remained there, other apes moved inland into Asia and African into various swamps and riverine gallery forests, moving deeper and deeper into tropical rainforests, and because of large inland predators became more and more tree dependent, and when walking on the ground, tended to knucklewalk for more speed and stability. About 5 million years ago, when the chimps finally permanently split, chimps followed the path that a million years previously gorillas had gone, into the Rift valley and Congo. At this time all hominoids had air sacs, used for floating vertically with the face out of water, and for calling loudly. So now only the human ancestors were left at the seashores, they never knucklewalked (but the infants kneecrawled on the soft sands), they climbed easy-to-climb fig trees, mangroves and coconut palms, but not the tall forest trees. They adapted more to coastal pocket beaches surrounded by cliffs with caves and rockshelters, and slowly became better surface swimmers but not divers, mostly beachcombing and peeling molluscs from mangroves and rocks at low tide, in addition to fruits and seabird eggs. At this time, the nose was shaped like a baby's pug nose, the bell jar shape keeping water out during the rare dunkings. Since the nose was usually kept above the water by the air sacs, there was no natural selection for closable nostrils. This was completely unlike other aquatic animal ancestors, none of which had inflated laryngeal air sacs keeping the nose above water.
The second phase (aquatic) was only human ancestors, not apes, and seems to have occurred about 3 - 1 million years ago, when they gained a fat layer under the skin, the air sac was reduced to a vestige, lost most of the fur coat, but retained hydrodynamic hair in the voids of the body (throat, neck, armpits and pubic areas), and changed from surface floating and plucking to deeper diving, and eventually at some point developed a backfloating-diving cycle somewhat like a sea otter. Up until then, the pug-nose shaped like a bell jar was enough to keep water out of the airways as long as the mouth was closed or the tongue or velum closed the airway, this worked fine at the surface with the inflated air sac just under the throat, but only allowed plucking food below at arm's length. The air sac interfered with face submersion, and was slowly selected against, allowing deeper dipping, while the nose was selected for longer length. so during backfloating breathing was done through the nose when head was tilted back.
Until this time, the nostrils would not have been selected for closing, since the air sacs always kept the face above water. But with deeper diving, came water pressure problems and breath holding, which no ape had ever had before.
[QUOTE]
Poor underwater vision. Although some people are apparently better off than others, including tribes who dive regularly, most aquatic animals have much better underwater vision than we do. Those which do not, or live in murky water, have other adaptations such as long whiskers (seals), echolocation (dolphins and whales), lateral line (aquatic amphibians).[/QUOTE]
[QUOTE=naiad;673130]Fascinating. The AAT sounds plausible enough. There are still some things that I don't understand about it though. These are:
Nostrils which cannot be closed. Most aquatic mammals close their nostrils when diving. No animal uses a noseclip or pinches its nose, and few use sinus flooding.[/QUOTE]
True. First, our ancestors went through two different stages.
The first (amphibious) was transitional from a tarsier-like mammal with tail to a vertical-oriented part-time awkward bipedal upright wader/walker/floater (amphibious tree-frog-like) which lost the tail due to large laryngeal air sacs that inflated upon cool-water immersion due to a gasp-like reaction, allowing plucking foods on the water surface and shallow snails etc. but which did not swim well and did not dive at all, about 15 to 5 million years ago, along coastal lowland forests often flooded, this included all ape ancestors. But while human ancestors remained there, other apes moved inland into Asia and African into various swamps and riverine gallery forests, moving deeper and deeper into tropical rainforests, and because of large inland predators became more and more tree dependent, and when walking on the ground, tended to knucklewalk for more speed and stability. About 5 million years ago, when the chimps finally permanently split, chimps followed the path that a million years previously gorillas had gone, into the Rift valley and Congo. At this time all hominoids had air sacs, used for floating vertically with the face out of water, and for calling loudly. So now only the human ancestors were left at the seashores, they never knucklewalked (but the infants kneecrawled on the soft sands), they climbed easy-to-climb fig trees, mangroves and coconut palms, but not the tall forest trees. They adapted more to coastal pocket beaches surrounded by cliffs with caves and rockshelters, and slowly became better surface swimmers but not divers, mostly beachcombing and peeling molluscs from mangroves and rocks at low tide, in addition to fruits and seabird eggs. At this time, the nose was shaped like a baby's pug nose, the bell jar shape keeping water out during the rare dunkings. Since the nose was usually kept above the water by the air sacs, there was no natural selection for closable nostrils. This was completely unlike other aquatic animal ancestors, none of which had inflated laryngeal air sacs keeping the nose above water.
The second phase (aquatic) was only human ancestors, not apes, and seems to have occurred about 3 - 1 million years ago, when they gained a fat layer under the skin, the air sac was reduced to a vestige, lost most of the fur coat, but retained hydrodynamic hair in the voids of the body (throat, neck, armpits and pubic areas), and changed from surface floating and plucking to deeper diving, and eventually at some point developed a backfloating-diving cycle somewhat like a sea otter. Up until then, the pug-nose shaped like a bell jar was enough to keep water out of the airways as long as the mouth was closed or the tongue or velum closed the airway, this worked fine at the surface with the inflated air sac just under the throat, but only allowed plucking food below at arm's length. The air sac interfered with face submersion, and was slowly selected against, allowing deeper dipping, while the nose was selected for longer length. so during backfloating breathing was done through the nose when head was tilted back.
Until this time, the nostrils would not have been selected for closing, since the air sacs always kept the face above water. But with deeper diving, came water pressure problems and breath holding, which no ape had ever had before.
[QUOTE]
Poor underwater vision. Although some people are apparently better off than others, including tribes who dive regularly, most aquatic animals have much better underwater vision than we do. Those which do not, or live in murky water, have other adaptations such as long whiskers (seals), echolocation (dolphins and whales), lateral line (aquatic amphibians).[/QUOTE]
Friday, October 19, 2007
Celebes Sea: rare marine species
(Photo not linked to article)
http://scienceblogs.com/pharyngula/2007/10/friday_cephalopod_free_octy.php
http://news.yahoo.com/s/ap/20071016/ap_on_sc/new_marine_species
Project leader Dr. Larry Madin said Tuesday that U.S. and Philippine scientists collected about 100 different specimens in a search in the Celebes Sea south of the Philippines. Madin, of the Massachusetts-based Woods Hole Oceanographic Institution, said the sea is at the heart of the "coral triangle" bordered by the Philippines, Malaysia and Indonesia — a region recognized by scientists as having a high degree of biological diversity.
The deepest part of the Celebes Sea is 16,500 feet. The team was able to explore to a depth of about 9,100 feet using a remotely operated camera. "This is probably the center where many of the species evolved and spread to other parts of the ocean, so it's going back to the source in many ways," Madin told a group of journalists, government officials, students and U.S. Ambassador Kristie Kenney and her staff. The project involved the Woods Hole Oceanographic Institution and National Geographic Magazine in cooperation with the Philippine government, which also provided the exploration ship. The expedition was made up of more than two dozen scientists and a group from National Geographic, including Emory Kristof, the underwater photographer who was part of the team that found the wreckage of the Titanic in 1985. The group returned to Manila on Tuesday after spending about two weeks in the Celebes Sea off Tawi-Tawi, the Philippines southernmost provincial archipelago nearly 700 miles south of Manila.
Madin said the specimens they collected included several possibly newly discovered species. One was a sea cucumber that is nearly transparent which could swim by bending its elongated body. Another was a black jellyfish found near the sea floor. The most striking creature found was a spiny orange-colored worm that had 10 tentacles like a squid, Madin said. "We don't know what it is ... it might be something new," he said. He said it would take "a few more weeks" of research to determine whether the species are newly discovered. He expects to release a report by early next month.
Madin said the Celebes Sea, being surrounded by islands and shallow reefs, is partially isolated now and may have been more isolated millions of years ago, leading scientists to believe that "there may be groups of organisms that have been contained and kept within" the basin since then.
Monday, October 15, 2007
Simplest Proof
http://edition.cnn.com/2007/TECH/science/10/17/early.seafood.ap/index.html
Editor's Summary: Nature | 18 October 2007 | Life was a beach
It's been suggested that the first thing Homo sapiens did once he and she had evolved was head for the beach. This is demonstrated in dramatic fashion by a series of discoveries in Middle Pleistocene sediments from a South African sea cave near Pinnacle Point. The finds suggest that by around 164,000 years ago, the residents were on a diet that included shellfish — the earliest evidence for the exploitation of coastal resources by some 40,000 years. There is also evidence that they used pigments such as red ochre for symbolic behaviour. This was at a time when the world was going through a cool, dry spell, and Africa was mostly desert. Perhaps this environmental stress drove small bands of hunter–gatherers down to the sea in search of new food
sources and lifestyles.
News and Views: Palaeoanthropology: The coast in colour
A South African cave overlooking the Indian Ocean was apparently a desirable residence for early humans. The site has provided rich evidence for the early use of colour and marine resources.
Sally McBrearty & Chris Stringer
doi:10.1038/449793a Full Text | PDF (584K)
Letter: Early human use of marine resources and pigment in South Africa during the Middle Pleistocene
Curtis W. Marean, Miryam Bar-Matthews, Jocelyn Bernatchez, Erich Fisher, Paul Goldberg, Andy I. R. Herries, Zenobia Jacobs, Antonieta Jerardino, Panagiotis Karkanas, Tom Minichillo, Peter J. Nilssen, Erin Thompson, Ian Watts & Hope M. Williams
doi:10.1038/nature06204
Re: 1998 AAT videos
http://www.youtube.com/watch?v=VFsgtLxALac
http://www.youtube.com/watch?v=jTPQUU0KxMY
http://www.youtube.com/watch?v=kKSBWHGA5KI
http://www.youtube.com/watch?v=-88v2pLSYCk
http://www.youtube.com/watch?v=OnPJBuWPt0Y
A fine presentation!
Thanks to Algis for putting these videos on You-Tube for all to see.
Good to see Sir Alister Hardy, Dr. Morgan, Dr. Verhaegen, Dr. Tobias, Dr. Brain, Dr. Crawford, and more contributing to our knowledge of the human ancestral condition in relation to water.
DD
Editor's Summary: Nature | 18 October 2007 | Life was a beach
It's been suggested that the first thing Homo sapiens did once he and she had evolved was head for the beach. This is demonstrated in dramatic fashion by a series of discoveries in Middle Pleistocene sediments from a South African sea cave near Pinnacle Point. The finds suggest that by around 164,000 years ago, the residents were on a diet that included shellfish — the earliest evidence for the exploitation of coastal resources by some 40,000 years. There is also evidence that they used pigments such as red ochre for symbolic behaviour. This was at a time when the world was going through a cool, dry spell, and Africa was mostly desert. Perhaps this environmental stress drove small bands of hunter–gatherers down to the sea in search of new food
sources and lifestyles.
News and Views: Palaeoanthropology: The coast in colour
A South African cave overlooking the Indian Ocean was apparently a desirable residence for early humans. The site has provided rich evidence for the early use of colour and marine resources.
Sally McBrearty & Chris Stringer
doi:10.1038/449793a Full Text | PDF (584K)
Letter: Early human use of marine resources and pigment in South Africa during the Middle Pleistocene
Curtis W. Marean, Miryam Bar-Matthews, Jocelyn Bernatchez, Erich Fisher, Paul Goldberg, Andy I. R. Herries, Zenobia Jacobs, Antonieta Jerardino, Panagiotis Karkanas, Tom Minichillo, Peter J. Nilssen, Erin Thompson, Ian Watts & Hope M. Williams
doi:10.1038/nature06204
Re: 1998 AAT videos
http://www.youtube.com/watch?v=VFsgtLxALac
http://www.youtube.com/watch?v=jTPQUU0KxMY
http://www.youtube.com/watch?v=kKSBWHGA5KI
http://www.youtube.com/watch?v=-88v2pLSYCk
http://www.youtube.com/watch?v=OnPJBuWPt0Y
A fine presentation!
Thanks to Algis for putting these videos on You-Tube for all to see.
Good to see Sir Alister Hardy, Dr. Morgan, Dr. Verhaegen, Dr. Tobias, Dr. Brain, Dr. Crawford, and more contributing to our knowledge of the human ancestral condition in relation to water.
DD
Blog Action Day: Environmental Stability
Today is World Environmental Sustainability Day on the Blogosphere.
Links to sites:
http://www.blogactionday.org/
http://www.blogactionday.org/my
Replacement of primary rainforest ecosystem with large-scale oil palm plantation improves short-term economic development but may result in silt erosion of coral reefs and major reduction of biodiversity. What is the optimal path of development? Ecosystem collapse benefits no-one, forest preserves benefit future generations sustainably.
http://www.youtube.com/watch?v=Qv8NlidN2wg&NR=1
Ecosystemic Society Collapse Symptoms: (As the world turns)
http://www.logic-fu.com/archive/archive/collapse.html
Links to sites:
http://www.blogactionday.org/
http://www.blogactionday.org/my
Replacement of primary rainforest ecosystem with large-scale oil palm plantation improves short-term economic development but may result in silt erosion of coral reefs and major reduction of biodiversity. What is the optimal path of development? Ecosystem collapse benefits no-one, forest preserves benefit future generations sustainably.
http://www.youtube.com/watch?v=Qv8NlidN2wg&NR=1
Ecosystemic Society Collapse Symptoms: (As the world turns)
http://www.logic-fu.com/archive/archive/collapse.html
Saturday, October 13, 2007
10 year old Chinese girl "dolphin swimming"
http://webcenters.netscape.compuserve.com/whatsnew/gallery.jsp?floc=g-wnew_huang_li1&gname=wnew_huang_li&pi=4&grurl=http%3A%2F%2Fwww.google.com%2Fsearch%3Fq%3Dhuang%2Bli%2Bdaosheng%26ie%3Dutf-8%26oe%3Dutf-8%26aq%3Dt%26rls%3Dcom.ubuntu%3Aen-US%3Aofficial%26client%3Dfirefox-a&photo=1&xad=true
http://www.cnn.com/2007/WORLD/asiapcf/10/04/china.swimmmer.ap/index.html?eref=rss_mostpopular
hands and feet bound, "dolphin swimming"
She intends to cross the English Channel this way I guess.
I'd think it would be better if the bindings were a simple loop, that she could remove.
3 hours in the river, 3 km / 1.8 miles downstream.
Thursday, October 11, 2007
Earth travelers
African mega-droughts:
http://www.physorg.com/news111083381.html
10.10.07
davina.quarter...@oxon.blackwellpublishing.com
Environmental setting of human migrations in the circum-Pacific Region
A new study by Kevin Pope of Geo Eco Arc Research and John Terrell of The Field Museum adds insight into the migration of anatomically modern humans out of Africa and into Asia less than 100,000 years before present (BP). The comprehensive review of human genetic, environmental, and archaeological data from the circum-Pacific region supports the hypothesis, originally based largely on genetic evidence, that modern humans migrated into eastern Asia via a southern coastal route. The expansion of modern human populations into the circum-Pacific region occurred in at least four pulses, in part controlled by climate and sea level changes in the Late Pleistocene and Holocene epochs. The initial "out of Africa" migration was thwarted by dramatic changes in both sea level and climate and extreme drought in the coastal zone. A period of stable climate and sea level
45,000-40,000 years BP gave rise to the first major pulse of migration, when modern humans spread from India, throughout much of coastal southeast Asia, Australia, and Melanesia, extending northward to eastern Russia and Japan by 37,000 years BP.
The northward push of modern humans along the eastern coast of Asia stalled north of 43°N latitude, probably due to the inability of the populations to adjust to cold waters and tundra/steppe vegetation. The ensuing cold and dry Last Glacial period, ~33,000-16,000 year BP, once again brought dramatic changes in sea level and climate, which caused abandonment of many coastal sites. After 16,000 years BP, climates began to warm, but sea level was still 100 m below modern levels,
creating conditions amenable for a second pulse of human migration into North America across an ice-free coastal plain now covered by the Bering Sea.
The stabilization of climate and sea level in the early Holocene (8,000-6,000 years BP) supported the expansion of coastal wetlands, lagoons, and coral reefs, which in turn gave rise to a third pulse of coastal settlement, filling in most of the circum-Pacific region. A slight drop in sea level in the western Pacific in the mid-Holocene (~6,000-4,000 year BP), caused a reduction in productive coastal
habitats, leading to a brief disruption in human subsistence along the then densely settled coast. This disruption may have helped initiate the last major pulse of human migration in the circum-Pacific region, that of the migration to Oceania, which began about 3,500 years BP and culminated in the settlement of Hawaii and Easter Island by 2000-1000 years BP.
http://www.physorg.com/news111083381.html
10.10.07
davina.quarter...@oxon.blackwellpublishing.com
Environmental setting of human migrations in the circum-Pacific Region
A new study by Kevin Pope of Geo Eco Arc Research and John Terrell of The Field Museum adds insight into the migration of anatomically modern humans out of Africa and into Asia less than 100,000 years before present (BP). The comprehensive review of human genetic, environmental, and archaeological data from the circum-Pacific region supports the hypothesis, originally based largely on genetic evidence, that modern humans migrated into eastern Asia via a southern coastal route. The expansion of modern human populations into the circum-Pacific region occurred in at least four pulses, in part controlled by climate and sea level changes in the Late Pleistocene and Holocene epochs. The initial "out of Africa" migration was thwarted by dramatic changes in both sea level and climate and extreme drought in the coastal zone. A period of stable climate and sea level
45,000-40,000 years BP gave rise to the first major pulse of migration, when modern humans spread from India, throughout much of coastal southeast Asia, Australia, and Melanesia, extending northward to eastern Russia and Japan by 37,000 years BP.
The northward push of modern humans along the eastern coast of Asia stalled north of 43°N latitude, probably due to the inability of the populations to adjust to cold waters and tundra/steppe vegetation. The ensuing cold and dry Last Glacial period, ~33,000-16,000 year BP, once again brought dramatic changes in sea level and climate, which caused abandonment of many coastal sites. After 16,000 years BP, climates began to warm, but sea level was still 100 m below modern levels,
creating conditions amenable for a second pulse of human migration into North America across an ice-free coastal plain now covered by the Bering Sea.
The stabilization of climate and sea level in the early Holocene (8,000-6,000 years BP) supported the expansion of coastal wetlands, lagoons, and coral reefs, which in turn gave rise to a third pulse of coastal settlement, filling in most of the circum-Pacific region. A slight drop in sea level in the western Pacific in the mid-Holocene (~6,000-4,000 year BP), caused a reduction in productive coastal
habitats, leading to a brief disruption in human subsistence along the then densely settled coast. This disruption may have helped initiate the last major pulse of human migration in the circum-Pacific region, that of the migration to Oceania, which began about 3,500 years BP and culminated in the settlement of Hawaii and Easter Island by 2000-1000 years BP.
Monday, October 8, 2007
The arc of a diver
Lucia: Dive reflex not always helpful? I have been doing dry and pool {dive} training for a long time now, and my dry breath holding apnea performance is always significantly better than in the pool. I have tried to work out what the reason is, but nothing fully explains it. What a useless reflex, I don't know how it could possibly be good in any situation to gasp when falling into cold water.
DD: It helps to understand how the body reacts to temperature and pressure changes.
Feet first: gasp, wading in cool water
Face first: MDR, diving in cool water
It's actually the same reflex, maximizing oxygen retention, but face-first shuts off the inhalation phase, while feet-first exaggerates the inhalation phase.
Your best MDR response might be this approach:
(with a buddy at poolside watching and estimating time, not a small crowded pool)
1) NO wetsuit, just swim suit, warm and dry, no nose/ear plugs/mask/cap.
2) PLAN only ONE dive, (afterwards hit the hot shower, then dry and leave).
3) NO breathe up, just walk to the edge of deep end, casually deflate lungs while leaning forward, and pushing gently off into the water, entering face-first with arms down at your sides, to between 1/2 to 2 meters deep, glide down and forward until stopping, then casually but with strength, kick a few times while gliding hydrodynamically, then, when ready to climb, [*see note below] bring your arms forwards and SLOWLY power stroke laterally at sides (no more kicking) diagonally or vertically up to the surface, turn onto your back and inhale a few slow moderate breaths (not deeply) while laying flat like a board on the surface relaxing, backstoke over to the edge and climb up and leave pool. You did it. Shower, dry, go home, forget it.
4) It's not the length of time or distance, it's the technique, 20 seconds submersed is fine.
5) That night, dream the dive again, let the experience come back, learn from it subconsciously while sleeping, adjust little things (slower or faster kick, hear echoes under water, sense difference between surface temp. and depth temp. etc.).
6) Repeat pool dives often, after the first day, 2nd and 3rd dives are ok, but stay focussed on technique, hydrodynamics and sensing conditions. No more dry/wet statics until normal dives are smooth enough to make a dolphin smile.
* Assuming no lane intrusions and not close to wall, close eyes during ascent and allow face skin to inform you of your position. Your ears know the depth and body orientation via the eardrums and the 3 semicircular canals of the inner ear, your hair/forehead/eyebrows/eyelids/eyelashes know the speed and the difference between water and air temperature and pressure, rely on this sensitivity. Once in backfloating position and ready to scull to the edge, only then open the eyes and go.
Lucia: Maybe I will try the one-dive approach, with a buddy. I am still a bit scared of getting into cold water, because for me the gasp reflex happens even if I put my face only in the water. It is not so bad if I take a deep breath and hold it, and much worse with empty lungs.
DD: I fully empathise with the dislike of cold water immersion. The reason I mentioned it was because I assume your available pools aren't really warm and the pumps keep moving the water around. The ideal would be very very warm at the surface (6" 15cm) and quite cool just above the pool floor, with the water almost still and thermally stratified, like in a sunlit tropical lagoon completely surrounded by reefs.
By breathing up, and then filling the lungs with air, the body's sensors read "low CO2 so plentiful O2", and keep burning O2 at a regular aerobic non-MDR pace.
Then when the CO2 rises due to the fast O2 burning, contractions or air hunger starts.
OTOH, having the MDR/gasp occur right away with empty lungs forces O2 conservation, burns O2 slowly and builds CO2 slowly. This registers in your mind as discomfort because you haven't gradually habituated to it. The same physiological gasp that tries to suck in air to the lungs is actually pumping O2 from the extremities. By sealing the mouth and nose (with tongue in back), the coldwater gasp has nowhere to come from but the blood cells and muscle cells rich in O2 in the limbs, biochemically kicking them to move faster towards the core to ease the pH differential.
Lucia: Interesting. That makes sense. I remember that when I was a kid, if I was outside and there was a cold wind blowing, I would get an uncontrollable apnea reflex, which was unpleasant but bearable. It must have lasted for a few seconds. It still happens occasionally, but much less. It was very similar to the feeling I now get when I put my face in cold water.
DD: Right, the fast combined thermal and pressure change on the face, and also in the throat triggers the reflex.
When you hold your breath with full-lungs, I think you are getting about 1/2 of this effect due to air pressure on baroreceptors in the mouth/nose/throat/lungs.
When you did empty-lung breath hold, that 1/2 effect was missing, so you only felt the struggle phase, without the benefit of the 1/2 effect.
What I've been saying, is that by first being warm and dry, and knowing that soon you will again be very warm in the shower afterwards, then, casually diving in slightly cool water, that if you relax and accept the "switch-over" discomfort, knowing that it's just a temporary adjustment your body makes as it "becomes one with water" (no longer bothering to carry this huge "bubble" of excess air in the lungs down under the surface), and let your body feel the water as you glide through, and limbs smoothly power you along, and then rising up again to the surface, you are fully aware and sensitive to your immediate environment, and gracefully exchange the gift of air. Upon contacting the surface, you will want to exhale, but don't push it out, just exchange it gratefully.
As you climb out of the pool, your body which was adapted to the cool water during the dive, is now warming up due to the aerobic metabolism required to deal with moving in regular terrestrial gravity, so do a brief stretch of arms and legs and trunk, and a moderate aerobic breathe-up (no forced inhale, just a yawn), this should give a blush or flushed face and a tiny sweat reaction (the opposing reflex of the gasp), and then go take a warm shower and dry off.
Actually, I think that both of these reflexes release biochemicals into the bloodstream including micro-doses of endorphins and natural steroids, that help relax during stress.
Anyway, like I said, if something doesn't sound or feel right, don't do it, take time to figure out what's happening. Don't rush a dive, relax a dive. Those super-fast dolphin's ancestors 50 million years ago were once very slow divers too, as were our ancestors at the seashores 1 million years ago. It takes time. Dive with dolphins, backfloat with sea otters, blow bubbles with koi, breathe.
The thermoreceptors and baroreceptors of the face, mouth, throat are involved in the early part of the MDR empty lung dive.
The chemoreceptors in various places where blood flows through are involved in the next part of the dive. They are affected by the pH changes, as CO2 accumulates, diaphragmatic contractions and/or air hunger due to higher CO2 concentration gets stronger. It is the MDR gasp all over again, but this time triggered internally at the core, rather than externally at the skin surface of the face.
Since most people aren't used to making their blood send O2 more efficiently, we tend to get a "shock" when getting contractions. But the contractions simply move O2 towards the lungs. By propelling while matching these contractions to a whole body undulation or kick or arm stroke makes them less noticeable and might even add some extra oomph with no additional energy or oxygen consumption.
DD: It helps to understand how the body reacts to temperature and pressure changes.
Feet first: gasp, wading in cool water
Face first: MDR, diving in cool water
It's actually the same reflex, maximizing oxygen retention, but face-first shuts off the inhalation phase, while feet-first exaggerates the inhalation phase.
Your best MDR response might be this approach:
(with a buddy at poolside watching and estimating time, not a small crowded pool)
1) NO wetsuit, just swim suit, warm and dry, no nose/ear plugs/mask/cap.
2) PLAN only ONE dive, (afterwards hit the hot shower, then dry and leave).
3) NO breathe up, just walk to the edge of deep end, casually deflate lungs while leaning forward, and pushing gently off into the water, entering face-first with arms down at your sides, to between 1/2 to 2 meters deep, glide down and forward until stopping, then casually but with strength, kick a few times while gliding hydrodynamically, then, when ready to climb, [*see note below] bring your arms forwards and SLOWLY power stroke laterally at sides (no more kicking) diagonally or vertically up to the surface, turn onto your back and inhale a few slow moderate breaths (not deeply) while laying flat like a board on the surface relaxing, backstoke over to the edge and climb up and leave pool. You did it. Shower, dry, go home, forget it.
4) It's not the length of time or distance, it's the technique, 20 seconds submersed is fine.
5) That night, dream the dive again, let the experience come back, learn from it subconsciously while sleeping, adjust little things (slower or faster kick, hear echoes under water, sense difference between surface temp. and depth temp. etc.).
6) Repeat pool dives often, after the first day, 2nd and 3rd dives are ok, but stay focussed on technique, hydrodynamics and sensing conditions. No more dry/wet statics until normal dives are smooth enough to make a dolphin smile.
* Assuming no lane intrusions and not close to wall, close eyes during ascent and allow face skin to inform you of your position. Your ears know the depth and body orientation via the eardrums and the 3 semicircular canals of the inner ear, your hair/forehead/eyebrows/eyelids/eyelashes know the speed and the difference between water and air temperature and pressure, rely on this sensitivity. Once in backfloating position and ready to scull to the edge, only then open the eyes and go.
Lucia: Maybe I will try the one-dive approach, with a buddy. I am still a bit scared of getting into cold water, because for me the gasp reflex happens even if I put my face only in the water. It is not so bad if I take a deep breath and hold it, and much worse with empty lungs.
DD: I fully empathise with the dislike of cold water immersion. The reason I mentioned it was because I assume your available pools aren't really warm and the pumps keep moving the water around. The ideal would be very very warm at the surface (6" 15cm) and quite cool just above the pool floor, with the water almost still and thermally stratified, like in a sunlit tropical lagoon completely surrounded by reefs.
By breathing up, and then filling the lungs with air, the body's sensors read "low CO2 so plentiful O2", and keep burning O2 at a regular aerobic non-MDR pace.
Then when the CO2 rises due to the fast O2 burning, contractions or air hunger starts.
OTOH, having the MDR/gasp occur right away with empty lungs forces O2 conservation, burns O2 slowly and builds CO2 slowly. This registers in your mind as discomfort because you haven't gradually habituated to it. The same physiological gasp that tries to suck in air to the lungs is actually pumping O2 from the extremities. By sealing the mouth and nose (with tongue in back), the coldwater gasp has nowhere to come from but the blood cells and muscle cells rich in O2 in the limbs, biochemically kicking them to move faster towards the core to ease the pH differential.
Lucia: Interesting. That makes sense. I remember that when I was a kid, if I was outside and there was a cold wind blowing, I would get an uncontrollable apnea reflex, which was unpleasant but bearable. It must have lasted for a few seconds. It still happens occasionally, but much less. It was very similar to the feeling I now get when I put my face in cold water.
DD: Right, the fast combined thermal and pressure change on the face, and also in the throat triggers the reflex.
When you hold your breath with full-lungs, I think you are getting about 1/2 of this effect due to air pressure on baroreceptors in the mouth/nose/throat/lungs.
When you did empty-lung breath hold, that 1/2 effect was missing, so you only felt the struggle phase, without the benefit of the 1/2 effect.
What I've been saying, is that by first being warm and dry, and knowing that soon you will again be very warm in the shower afterwards, then, casually diving in slightly cool water, that if you relax and accept the "switch-over" discomfort, knowing that it's just a temporary adjustment your body makes as it "becomes one with water" (no longer bothering to carry this huge "bubble" of excess air in the lungs down under the surface), and let your body feel the water as you glide through, and limbs smoothly power you along, and then rising up again to the surface, you are fully aware and sensitive to your immediate environment, and gracefully exchange the gift of air. Upon contacting the surface, you will want to exhale, but don't push it out, just exchange it gratefully.
As you climb out of the pool, your body which was adapted to the cool water during the dive, is now warming up due to the aerobic metabolism required to deal with moving in regular terrestrial gravity, so do a brief stretch of arms and legs and trunk, and a moderate aerobic breathe-up (no forced inhale, just a yawn), this should give a blush or flushed face and a tiny sweat reaction (the opposing reflex of the gasp), and then go take a warm shower and dry off.
Actually, I think that both of these reflexes release biochemicals into the bloodstream including micro-doses of endorphins and natural steroids, that help relax during stress.
Anyway, like I said, if something doesn't sound or feel right, don't do it, take time to figure out what's happening. Don't rush a dive, relax a dive. Those super-fast dolphin's ancestors 50 million years ago were once very slow divers too, as were our ancestors at the seashores 1 million years ago. It takes time. Dive with dolphins, backfloat with sea otters, blow bubbles with koi, breathe.
The thermoreceptors and baroreceptors of the face, mouth, throat are involved in the early part of the MDR empty lung dive.
The chemoreceptors in various places where blood flows through are involved in the next part of the dive. They are affected by the pH changes, as CO2 accumulates, diaphragmatic contractions and/or air hunger due to higher CO2 concentration gets stronger. It is the MDR gasp all over again, but this time triggered internally at the core, rather than externally at the skin surface of the face.
Since most people aren't used to making their blood send O2 more efficiently, we tend to get a "shock" when getting contractions. But the contractions simply move O2 towards the lungs. By propelling while matching these contractions to a whole body undulation or kick or arm stroke makes them less noticeable and might even add some extra oomph with no additional energy or oxygen consumption.
Monday, October 1, 2007
VISUALIZE
Flight of the Malaysian fruit bat
Xray of nose and paranasal sinuses of Chinese lady
http://www.sciencemag.org/cgi/content/full/317/5846/1858
Go to the site linked and enlarge the photos by clicking on them. Very unique "art".
Xray of nose and paranasal sinuses of Chinese lady
http://www.sciencemag.org/cgi/content/full/317/5846/1858
Go to the site linked and enlarge the photos by clicking on them. Very unique "art".
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