Discussion on hypothesized ancestral human cyclical ARC dive-foraging

[wet]

Merry Fishmas

Excellent educational slide show from Neil Shubin's book:
Your Inner Fish: Teaching Tools

(I note the effect of hydrodynamics and oxygen /CO2 management in foraging, with changes to the limbs and respiratory systems. H/t to Brian @ Merry Fishmas! : Laelaps )

BBC News - Minute organs in the ear can alter brain blood flow
Minute organs hidden deep within the ear appear to directly alter blood flow to the brain, scientists have revealed. Until now, experts thought the inner ear's job was to control balance alone. But the Harvard Medical School team, working with Nasa, found the balance organs also affect brain blood flow in their study involving 24 people. They told BMC Neuroscience journal that the connection probably evolved to enable man to stand upright and still get enough blood up to the brain. This revealed that the utricle and saccule, also known as the otoliths, directly affected brain blood flow regulation, independent of other factors, such as blood pressure. [Per Shubin, both the trigeminal and facial nerves are routed very near to these otoliths, so they probably affect and are affected by postural (and external ambient pressure) changes. Note that postural and ambient water pressure change from deep dive to backfloat is far less physiologically stressful than from deep dive to climbing upright aboard a boat while wearing scuba or weights!]

Hey, its ant-a-claws, from the author of Swimming with the piranas at feeding time: Ants with opposable thumbs? strange behaviors

Efficient processing of 'volleyball-like' fruit by nimba chimps with cleavers & anvils
BBC - Earth News - Chimps use cleavers and anvils as tools to chop food

Cavemen/women roasted diving ducks for dinner 150ka
Cavemen Roasted Birds, Too : Discovery News

Supervolcano Mt. Toba caused 1,000 yr winter 73ka
Supervolcano eruption -- in Sumatra -- deforested India 73,000 years ago

Mediterranean whale fossil 4.5ma in Spain: deposited on seafloor 50m deep, now 80m above ground 24km inland. So 4.5ma Medit was high and/or seabottom tectonic uplift.
Story of 4.5-million-year-old whale found in Spain

Dwarf Australian mud-sucking whale
BBC News - Ancient whale sucked mud for food
(Whale picture lacks upper lip mustache which inverted to become baleen)

Did shellfish save the human race?
How shellfish saved the human race Boing Boing
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{That's 220 posts of mine here, total 400, 11000 views, time to take a break.}

*Snowflakes are falling on my thread *
(cf. Raindrops are falling on my head)

Happy Winter Solstice/Azhura/Hanukkah/Kwanzaa/Boxing Day/Christmas/New Year!

 

[wet]

"Known from a partial skull discovered near the Red Sea coast in Saudi Arabia, Saadanius lived in a freshwater mangrove swamp about 29-28 million years ago. As Iyad Zalmout and co-authors state in the introduction of the paper, it is the most substantive discovery of its kind for this part of earth's history - the later part of the Oligocene - " from Laelaps blog

That sounds very similar to what I had written earlier at the AAT forum, near the coast but not marine-adapted, (some surface swimming and shallow wading, no forage-diving) with very gradual enlargement of laryngeal air sacs and complete tail loss, more upright posture but not bipedal. Must have had more wetter weather then, the Red Sea was then connected to the Mediterranean and was much smaller.

 

[wet]

1,800,000 years ago toothpicks indicate possible proto-speech capability, possibly links trigeminal nerve development and associated photic sneezing (as part of dive cycle?), changes in brain and tongue dexterity (suction feeding, low-volume communication, clicking-humming, dive song?). [Note that crab eating/diving macaque monkeys have been seen using human hairs as dental floss to clean teeth.]
-

L.Hlusko (2003): there is suggestive evidence of toothpicking going back to
>>>> c 1.8 Ma (Omo L-894-1 RP3).
>>>> ... Agger cs (2004:403): "tooth-picking behavior may represent indirect
>>>> evidence for the evolution of the biological capacity for language."
>>>> The largest branch of the cranial nerve V (trigeminal) controls (among other things)
>>>> lingual movement & makes the teeth & gums extremely sensitive to various
>>>> irritants. Tooth-picking is one way to remove small irritants lodged
>>>> between the teeth & the gum:
>>>> "... small pieces of food caught between his or her teeth ... cause a
>>>> sensation out of proportion to the size of the food matter or tooth defect.
>>>> This exquisitely sensitive neural pathway for conveying proprioceptive
>>>> information to higher brain centers can only be routed via a developed and
>>>> functioning cranial nerve V. As a result, oral dental sensations promote
>>>> the obligatory postprandial toothpick, at least in modern times & plausibly
>>>> in early hominids. The proprioceptive information is not only protective
>>>> but critical feedback for the tongue posturing necessary for speech.
>>>> Thus it appears that both a highly developed trigeminal nerve (V) &
>>>> auditory
>>>> nerve (VIII) are needed for input to the Brodmann's area along the
>>>> peri-sylvian fissure of the human brain (brain region critical for the
>>>> formulation of speech). We hypothesize that the ability to sense & remove
>>>> food particles between teeth occurred c 2 Ma, as a result of selective
>>>> pressures driving the evolution of complex vocalization of the hominid
>>>> frontal-parietal lobe."

A Very Remote Period Indeed: Clean-toothed Neanderthals

 

[wet]

On Ears: why don't "post-aquatic" humans have internalized ears like dolphins & dugongs?

Generally aquatics that lose their hair then lose their pinnae (external ears) for improved hydrodynamics, those that retain their hair retain their pinnae (sea otters, sea lions), humans retain scalp hair including sideburns which covers the ears during forward swimming.

Human ears are smaller than chimp ears, while human brains/skulls are relatively much larger than chimp brains/skulls. Gorilla & orangutan ears are smaller than chimp ears, but their brains/skulls are relatively smaller.

 

[wet]

Small penguins "cheat" to stay warm in ice water
Penguins ?Cheat? to Stay Warm in Icy Waters March of the Fossil Penguins

 

[wet]

Abstract

A possible function of laryngeal air sacs in apes and gibbons was investigated
by examining the relationships between air sac distribution, call rate, call
duration and body weight in a phylogenetic context. The results suggest that
lack of sacs in the smaller gibbons and in humans is a derived feature. (their interpretation Call
parameters in primates, such as rate and duration, scaled to resting breathing
rate (and therefore to body weight) only in species without air sacs, which
appear to modify these relationships. Apes and larger gibbons may be able to
produce fast extended call sequences without the risk of hyperventilating
because they can re-breathe exhaled air from their air sacs. Humans may have
lost air sacs during their evolutionary history because they are able to modify
their speech breathing patterns and so reduce any tendency to hyperventilate.
-
(my interpretation: diving & backfloating preceded & resulted in speech (clicking-humming dive song), loss of ape-like primitive air sacs due to switch from shallow floating-food foraging (cf wetland gorillas) to benthic foraging & backfloating (cf sea otter), parallels with xenopus & gibbons due to loss of water surface nose-above mouth foraging/resting)

 

[wet]

re. article citing gorillas humming while gathering floating wetland plants (Hydrocharis). [possible link to backfloating & humming?]

humpback whale backfloating while protecting seal from Orcas, cf sea otter mother and pup
https://www.yahoo.com/news/saved-whale-humpbacks-play-hero-orcas-attack-134350097.html