Re: Facial reactions
- Since camels can close their nostrils during windstorms, and virtually
all aquatics can close their nostrils when immersed, the human nose
seems inadequate both in water and on the savanna, but ok in a
rainforest, where rain is kept out of the nose. Yet the rainforest
chimps, orangs and gorillas don't have the protruding nose.
If human ancestors spent days wading and sitting in shallows, a
protruding hooded nose would be sufficient to keep out the water.
This would work as well backfloating and stomach-down swimming if nose
was (partly) in front.
It doesn't work in vertical dives or somersaults. That's where the
pinched nostrils are used by small kids, who haven't well developed
the velum valve, since their larynx/hyoid/paranasal sinuses are still
changing from suckling to weaned feeding.
The closed velum produces the same effect as the pinched nostrils, I
think vertical dive-foraging was generally done by adults.
Hard to tell if slit-like nostrils were self-closing previously, or
the upper lip curled up to seal the nostrils despite a mustache.
No doubt the velum closure and glottis closure was significant in
diving. Possibly valve closure was done while backfloating as well,
perhaps a form of sleep apnea in between dives, to maintain the
oxygen-conserving MDR divers reflex while warming at the surface?
This means that rather than inhaling much air upon surfacing, they
would just backfloat with partial apnea, maintaining O2 low rate,
rather than changing to surface aerobic breathing. (A low O2
consumption rate means a longer dive.)
--- In AAT@yahoogroups.com, "Dan G." <dgplexus1@...> wrote:
> Speaking of these cartilaginous flaps, I recall that, before I'll
used bromelain to shrink them, I could easily seal both sides enough,
that air and water couldn't enter, even with suction (inhalation
function blocked totally, in the nose.) I didn't hold the seal
constantly, while swimming, but only when it seemed advantageous, to
block water intrusion. Now, I can still seal the right side in this
way, but only partially seal the left side. I imagine this valve
feature, and muscular function, developed in our ancestry for swimming
advantage. It appears that the trait is not so common, now.
> --- In AAT@yahoogroups.com, "Dan G." <dgplexus1@> wrote:
> > This may seem odd, or not... But I've wondered, since I first
> > noticed them, why I have flaps of what seem to be cartilage, that
> > protrude from the sides of my nasal passages, on both sides of my
> > nose, about 1 or 1.5 cm beyond the nostril openings. They are on
> > the side of the nostrils, opposite the nasal septum. I think they
> > press up against the septum, when I seal (or nearly seal) my nasal
> > passageways. Their form reminds me a bit of a coronary valve
> > structure. I know I have some strange features... I've never seen
> > this particular feature in any anatomy sketches, so I wonder how
> > many people out there actually have these. Note, these cartilage
> > flaps used to be larger/longer, but I felt they were inhibiting my
> > nasal breathing to some extent, so I experimentally reduced them in
> > size by applying a bromelain enzyme solution to them, twice a day,
> > for a couple months. It worked, they're smaller now, but I don't
> > seem to breather much better, LOL. Note that, my nose is
> > basicallly "Celtic" in morphology, basically projecting but narrow,
> > which produces a kind of slit-like nostril form, that is easier to
> > close (or partly close) by using those muscles I mentioned.
> > Other oddities I have, include an atypical lumbar vertebra count,
> > and what might be called a parital saggital crest (which may have
> > something to do with my mother being administered relatively high
> > levels of synthetic progesterone, when she was pregnant with me.
> > This probably affected my development in other ways, as well.) I'm
> > one of those people who can voluntarily control the muscles in his
> > nose, ears, etc., to a greater than typical degree. It's kind of
> > funny, what can be done by manipulating the nose muscles in all the
> > possible combinations; you can even twirl the tip of the nose around
> > in circles.
> > Dan
- --- In AAT@yahoogroups.com, Marc Verhaegen <m_verhaegen@...> wrote:
> >>>>>> Downward noses are seen in OWM, gorillas and chimps
> >>>>>> (nostrils may open downwards or forwards) difference
> >>>>>> is in the shape the jaw ... m3d
> >>>> Catarrhines have the nostrils close to one another.
> >>>> NWMs have the nostrils directed sideward.
> >>>> I have no idea why. MV
> >>> One reason for the difference has to do with the cartilaginous
> >>> wings that support the nostrils...
> >>> Basically in OW primates it separates into two parts, in NWM
> >>> it splits (clefts) but does not separate into two parts, instead
> >>> it sort of folds sideways ... result in NWM the nostrils are
> >>> much further apart.
> >> Yes, possible.
> >> We need detailed comparisons of nosal cartilagines of primates.
> > The platyrrhini (the wide noses) and the catarrhini (the
> > downward noses) seem to have parted company 30 million
> > years ago.
> Yes, at least, possibly 40 Ma.
> >>> The Catarrhini have narrow downward noses, with the
> >>> nostrils facing downwards (or forwards) ... while
> >>> the Platyrrhini have wide noses with nostrils
> >>> facing more to the side.
> >>> Platyrrhini = wide-nosed
> >>> Catarrhini = down-nosed
> >>> Why the difference?
> >>> Possibly to allow the eyes to be closer together, face
> >>> more in a forwards direction? ---m3d
> >> Yes, or else, to the contrary, NWM eyes were further apart for better
> >> binocular vision, which was perhaps more important in the branches (NWMs are
> >> more arboreal than OWMs).
> > Think it is closer for binocular vision.
> No, no: wide apart, but both looking forward.
> The wider apart, the better binocularity.
A narrow downward catarrini nose with nostrils directed
downwards, probably has some other advantage.
(certainly an advantage, when you swimming)
"Catarrhini means narrow nose, and the term describes
their narrow, downward pointing nostrils. Unlike the
Platyrrhini, they are generally diurnal and their tails
(if they have tails at all) are not prehensile.
They have flat fingernails." (Wikipedia)
> > Wide spaced eyes, eyes on opposite sides of the head are
> > usually seen in prey species ...
> > Forward facing, closer together, eyes that work together
> > increases visual depth, improving the ability to pick a
> > particular fruit, grab a branch not a snake ... when
> > swinging through the trees.
> > Humans, most primates have binocular vision. ---m3d
> >> Or NWMs had once larger PNSs between the eyes,
> >> which later got reduced. Or...