Thursday, July 31, 2008

Diving-Surfacing: Parallel Convergence

The blue whale's nose resembles the human nose and sea otter nose during backfloating.

Backfloating & Swimming: Infant 15 months old: Breathe on back, Swim on stomach

The Aquaphotic Respiratory Cycle (ARC)


The Aquaphotic Respiratory Cycle (ARC) contains two components, relying upon the trigeminal cranial nerve:

1) submergence - Mammalian Divers Reflex (MDR) (stifled inhale)
2) emergence - Photic Sneeze (PS) (explosive exhale)

The MDR (from air surface to ~2m+ water depth) occurs when the face is
suddenly pressured, chilled and darkened which results in a inhale
reflex BUT since the face is submerged underwater, the inhaling reflex
is stifled and converted into O2 conservation or Mammalian Divers Reflex.

Human Physiology, Klinke, Silbernagel et al., 2006,
MDR: trigeminal cranial afferent nerve (V) relays the information that the
nasal and mouth cavities are submerged, which triggers the autonomus
nervous system to

* bradicardia, meaning a reduction of heart rate to about 4/5 of
normal rate
* blood "shift"(?) to the thorax to support the lung when under
pressure to keep it from collapsing (which would be bad for numerous
* vasoconstriction, first in the limbs to protect vital organs,
and later of everything except the heart and the brain, which creates
a heart-brain circuit

The PS (from ~2m+ water depth to air surface) occurs when the face is
suddenly well lit after dark adaptation (accomodation for improved vision), (pressure and thermal changes
increase neural stimulus) -> fast forced CO2 exhale reflex and
"instant" oxygenation of tissues.

DDeden [AAT, Deeper Blue, The ARC blog]

The Ear-Popper is a handheld, battery-powered device that delivers a
constant, controlled stream of air pressure and flow into the nasal
cavity, diverting air up the Eustachian tube when the patient
swallows. This "pops" the ear so the fluid can drain, unblocking the
ear and restoring hearing.

Chapter five, appropriately called "Getting Ahead", begins with Shubin
studying cranial nerves several days before an anatomy test. Most
cranial are easy because they have only one function and attach to one
muscle or organ. Four, however, are a bit more difficult to trace.
Shubin focuses on two of the four - the trigeminal and the facial.
Each breaks up into a number of smaller branches that take a complex
path through the head. The trigeminal nerves controls some of the
muscles we use for chewing, innervate teeth, control some muscles in
the inner ear, and is responsible for facial sensation. The facial
nerve controls the muscles used in making facial expressions and like
the trigeminal, it also controls some muscles in the inner ear. The
question is why? As Shubin puts it:

Nothing about them seems to make any sense. For example, both the
trigeminal and the facial nerves send tiny branches to muscles inside
our ears. Why do two different nerves, which innervate entirely
different parts of the face and jaw, send branches to ear muscles that
lie adjacent to one another? Even more confusing, the trigeminal and
facial almost crisscross as they send branches to our face and jaw. Why? To answer that we need to look at the developing embryo. Part of the answer lies in the four arches that for roughly 3-4 weeks after
conception. The first arch tissues, ultimately, form the upper and
lower jaws, the malleus and incus, and all the muscles that supply
them. The second arch forms the stapes, the hyoid and the muscles that
control facial expression. The trigeminal comes from the first arch,
while the facial nerve comes from the second. But there is more. In
sharks, the first arch forms the jaws, which are enervated by the
trigeminal. The second arch, in sharks, forms a cartilage rod that
eventually breaks up to form to bones that support the jaws. The first
bone is the equivalent to the hyoid in humans and supports the lower
jaw. The second bone, which supports the upper jaw is equivalent to
the stapes in humans. oing a step further, if we look at Amphioxus we
can see a notochord. Humans have one too, but ours breaks up early in
embryology and, according to Shubin, becime part of the intervertebral
disks. Like humans, Amphioxus also has arches. In this case, the
arches form cartilage that support the gill slits. Going back in time,
say 500 million years, we can see the notochord preserved in some of
the earliest worm fossils.

Wednesday, July 30, 2008

Chauvet cavern @ Pont d'Arc

People have always preferred to live very near to water. This cave has paintings from 30,000 years ago. It is near this river which flows under the natural stone arc and out to the Mediterranean Sea (I guess). Now it is a gorge (steep valley) with many hiking trails.

human migration

Monday, July 28, 2008

Biggest pool

Nice place to swim, dive & backfloat, but they need a reef with pretty fish, clams, crabs, seahorses to make it interesting and more fun!

Saturday, July 12, 2008

Seashores, volcanoes & humanity

Sedimentol.& paleogeogr.context of the Mojokerto hominin site, E.Java p.92 abstr.67th Vert.Paleontol. F Huffman, R Buffler, J Kappelman, D Ruez & Y Zeim 2007

... the discovery site lies above marine Mollusk Mbr II & within a fossiliferous pebbly sandstone in the upper Pucangan Fm. The sandstone is a fluvial deposit with a broad channelized base, prominent cross-bed sets & other bedding indications of mid-Channel river bars incl.preserved dune surfaces (mega-ripples) on the bars , is confortably overlain by a 4�5 m paleosol developed in a mudstone. This bed is, in turn unconformably overlain by sand+mudstone containing burrows & marine mollusks representing the basal bads of Mollusk Mbr III. These lithofacies represent a variety of deposit.environment s ranging from flood plain to delta slope , together
preserve evidence of the localized progradation of a delta lobe into a shallow water marine embayment. ... present-day deltas in this region can experience very rapid progradation rates, the Perning lobe may have been deposited in <10*4 yrs , not necessarily linked to a glacio-eustatic sea-level lowstand. Given that the Moj.hominin spm appears to have experienced min.transport, we conclude that H.erectus inhabited seacoast environment. This paleoenvironmental reonctruction is in strong contrast to the more typical savanna-woodland setting of this sp in Africa , suggest that He had a broad adaptive niche.
Where did Earth's water come from? Natl' Geographic Magazine video.

Saturday, July 5, 2008

Local - Eureka, Humboldt, California coast

Local beaches & lagoons geology/hydrology (note photos at bottom right)

Local swimming pools closing?

Swimming great exercise, but doesn't reduce fat, so cross-train with jogging, walking.

Eureka is 8th best town in America? (BUT water is too cold! I'd rather be tropical.)

Thursday, July 3, 2008

Puffins and Penguins

Puffins (left pic) live north of the equator along the coasts, they both dive and fly, and tend to walk like a duck (horiz. axis).
Penguins (right pic) live south of the equator along the coasts, they only dive, and tend to hop or walk (vertical axis) somewhat like a human. Some species of puffins & penguins may look similar due to eco-niche convergent parallels, but they are not closely related.

Penguin ice island, they flock tightly to avoid the seals, orcas and sharks of deep water.

Petrol penguins

Why diving birds have small wings

Penguinology (Antarctica)

thanks to jewel for noticing my marine mammal center 'penguin' t-shirt was actually a puffin t-shirt (my oops), got me checking out the difference between the two. But why does the marine mammal center feature birds anyways?