Aquatic Ape Human Ancestor Theory

Aquatic Ape Theory - What is it?

A Brief Summary of AAT - key arguments

A Brief History and Key Proponents of AAT

Current Aquatic Evolution Theories

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Alternative theories of human evolution

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. Anatomical Evidence
... Bipedalism
... Birth and babies
... Brain
... Breath control
... Fat
... Fingers, toes and feet
... Furlessness
... Hair and baldness
... Kidneys
... Menopause
... Nose
... Olfactory sense
... Pachyostosis
... Paranasal Sinuses
... Platycephaly
... Sexual features
... Surfer's ear
... Sweating
... Tears
... Underwater vision

. Diet
. Language & Song
. Sleep (USWS)
. Waterside environments
. Sea Gypsies

. Homo erectus - shallow diver

. Fossil evidence
. Paleoecological evidence

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Homo neanderthalis

Thinking a bit aloud, FWIW.
If the H/P-LCA lived in coastal forests &/or lagoons 5-4 Ma (Red Sea or
E.Afr.coasts? eg, Zambia mouth??), and after the split Homo populations
(why? innovation in shellfish opening??) spread along the coasts of the
Indian Ocean (still aquarboreal?), this can explain the retroviral data
(Yohn cs 2005 PLoS).
At the beginning of the Ice Ages, when sea levels dropped (1st drastic
drop c 2.6 Ma?), Homo was preadapted to colonise the drying continental
shelves, where they learned to dive for shellfish & to use stone
technology to open them. This explains most of the differences between P &
H: archaic Homo's huge brains, flat long heavy skulls, thick bones,
external nose, intercontinental coastal dispersal, stone tool industry,
early sites of Mojokerto etc.
I'd think they often lived in kelp forests during the glacials, but during
interglacials they waded more (more bipedal?) in estuaria etc.?
The sparks of the stone tool industry led to control over fire (already
1.5 Ma??) for opening shells, preparing foods, protection? This (or/&
other technol.innovations?) could have helped them to enter the land along
the rivers (esp.interglacially?). This could explain the shift from salt
water (renculi & vernix caseosa in human newborns) to fresh water
adaptations. Once a year, they still lived at the coasts ("holidays")
collecting seafood, but most of the time they gathered shallow freshwater
& waterside foods, diving & probably also wading (traces of cattails on
neandertals tools).
The discovery of composite (distance) weapons (harpoons...) made wading
more attractive than diving, which explains the the evolution of sapiens
from more archaic ancestors: longer legs, less heavy bones, higher skulls,
basi-cranial flexion (directing the eyes more downward) etc. According to
isotopic data, sapiens (in Europe at least) fed also on fish & fowl
(Richards cs 2001 PNAS). This preadapted to cooperation with wolves, eg,
sapiens wading in reedbeds chasing ducks, wolves waiting at the waterside.
Pups raised in floating huts (cf Marsh Arabs) became domesticated to dogs,
explaining why +-all dogs like to swim. The cooperation human+dog+weapons
preadapted them to leave the water (safer from felids, canids & ursids)
and to evolve from wader to walker.
Throughout this evolution, we probably ate more plant (incl.cane, papyrus,
cattails, rice etc.) than animal foods I'd think.

--marc

_________

HN Top Predator?

Reply to Fontes-Villalba et al.: On a reluctance to conjecture about
animal food consumption
Sponheimer M, Alemseged Z, Cerling TE, Grine FE, Kimbel WH, Leakey MG,
Lee-Thorp JA, Kyalo Manthi F,Reed KE, Wood BA & Wynn JG 2013
PNAS 110 E4056 doi 10.1073/pnas.1314368110

Fontes-Villalba cs (1) correctly observe that C isotope ratios in tooth
enamel do not speak directly to plant vs animal food ingestion.
C isotope ratio data are useful for quantifying the consumption of C3-or
C4-derived C, whether it comes directly from C3 or C4 plants, or
indirectly through consumption of animals that eat those plants.
Not only do we acknowledge as much in our recent series of papers, but we
have made this point in print many times over the past 2 decades (ref. 2 &
references therein).
However, to what extent can we speak to animal food consumption by early
hominins?
To address this question, we first note that "early hominin diet" is a
convenient abstraction at best, as the hominins discussed in our reports
spanned a period of greater than 3 My, and evinced major differences in
masticatory anatomy & associated archaeology.
Given this heterogeneity, and the likely corollary of marked diversity in
early hominin diets, it is not only plausible ― but probable ― that C4
food acquisition & consumption differed among hominin spp, eg,
given Par.boisei's high δ13C values, robust mandibles, low-cusped
cheek-teeth & diminutive incisors & canines, it is improbable that its
major C4 dietary input was meat:
even savanna carnivores may not attain such high δ13C values (3). It is,
therefore, most parsimonious to ascribe the preponderance of its C4
"signal" to the direct consumption of C4 plant foods.

The situation for contemporaneous Homo might well be different.
Its dental morphology, the general belief that it made & wielded stone
tools, & arguments derived from energetics are consistent with Homo having
consumed greater amounts of animal protein.
Nevertheless, these lines of evidence tell us little about the abundance
of animal products consumed, eg,
although the archaeological record unquestionably informs us about the
technical capacities of early hominins, it cannot discriminate between
diets that comprise 5 or 50 % animal foods. In addition, the "expensive
tissue hypothesis" cited by Fontes-Villalba cs (1) does not speak directly
to animal food consumption, but rather to an increase in the consumption
of "high-quality" (nutritionally dense) foods by Homo.
These foods include not only animal tissues, but also "nuts or underground
tubers" (4).

We are reluctant to speculate about the fatty acid & micro-nutrient
requirements of early hominins & their dietary implications.
We simply note that most primates (incl.some Hs) flourish on diets that
are dominated by plant foods:
among extant catarrhines, it is only Hs with a technologically
sophisticated hunting armamentarium that have been documented to subsist
(under certain conditions) on large amounts of animal flesh (5).
We agree with Fontes-Villalba cs (1) that it would be surprising if most
early hominins did not consume animal foods to some extent, given our
knowledge of the diets of Pan spp & the observed behavior of other savanna
primates (6).
We caution, however, that it is not possible at present to meaningfully
address the relative importance of faunivory for any Plio- or
early-Pleistocene hominin species, incl.those attributed to Homo.
It is for this reason that we eschewed conjecture about animal food
consumption in the 11 or so taxa discussed in our papers.

______

IOW, the belief that Homo ate a lot of meat rests only on
- Homo's dental morphology (bunodont = omnivorous cf swine)
- Homo's tool use (sea-otter: seafood, chimp: nuts)
- energetics arguments (seafood etc.)

IOW, Hn were no "top predators": their taurodonty, traces of cattails on
tools & of waterlilies in dental plaque, rel.small canines, bunodont
teeth, heavy weight etc suggest Hn mostly ate plant food.

--marc

==================================

'Homo' is the only primate whose tooth size decreases as its brain size
increases.

Andalusian researchers (BioMed Research International) have discovered
that the genus Homo are the only primates where, throughout their 2.5-My
history, the size of their teeth has decreased in tandem with the increase
in their brain size.
The key to this phenomenon, which scientists call "evolutionary paradox",
could be in how Homo's diet has evolved.

Digestion starts first in the mouth and, so, teeth are essential in
breaking food down into smaller pieces.
Therefore, the normal scenario would be that, if the brain grows in size,
and hence the body's metabolic needs, so should teeth.

However, in the case of Homo, this has not been the case:
Juan Manuel Jimenez Arenas:
"This means that significant changes must have occurred in order to
maintain this trend."

A change in diet, incorporating a higher amount of animal food, must have
been one of the keys to this phenomenon.
The quality leap in Homo's diet (a greater intake in animal proteins, fats
& certain oligo-elements) is essential for a correct working & maintenance
of the brain.
A larger brain allows greater social & cultural development, which led to
the achievement of important technological innovations.

The researchers evaluated the relationship between the size of post-canine
teeth & the volume of the endocranium in a wide set of primates, incl. the
main representatives of Homo fossils.
"Before we started the study, it was well known that, throughout the
evolution of humans, tooth-size diminished, and brain-size increased.
We have established that they are 2 opposing evolutionary trends that have
been linked for 2.5 My, when our first ancestors within the Homo genus
first appeared on the evolutionary stage."

The authors also relate these changes to the inactivation of gene MYH16,
linked to temporalis musculature, which fell in size c 2.4 Ma.
This would do away with an important barrier for encephalization (a
hypertrophied temporalis prevents the development of the cranial dome).
Likewise, they analyzed their relationship with the inactivation of gene
SRGAP2, which helps towards the evolution of the neo-cortex, playing a
principal role in human brain development.

________________________________________

I just sent this comment:

Thanks a lot, your study confirms my recent papers based on comparative
data (see below) that most or all East-African australopiths were
herbivores in wetlands (feeding predom.on papyrus sedges etc.?), that the
South-African australopiths were more omnivorous, and that
early-Pleistocene Homo populations trekked intercontinentally along the
coasts as far as Indonesia, Angola & England (coastal sites of Mojokerto,
Dungo V & Happisburgh resp.) & from the coasts inland along the rivers,
feeding on waterside & shallow aquatic foods.

Seafood is rich in brain-specific nutrients (e.g. DHA, explaining Homo's
brain expansion, see the work of Stephen Cunnane, Michael Crawford, José
Joordens etc.), it's typically soft & slippery, can be processed without
much chewing (explaining MYH16 inactivation), but often requires stone
tools (explaining the beginning of human technology & fire use).

Some of our publications on this:
-with P-F Puech 2000 "Hominid lifestyle and diet reconsidered:
paleo-environmental and comparative data" Hum Evol 15:175-186,
-with S Munro 2002 "The continental shelf hypothesis" Nutr Health 16:25-27,
-with Puech & Munro 2002 "Aquarboreal ancestors?" TREE Trends in Ecol &
Evol 17:212-7, google "aquarboreal",
-with S Munro, M Vaneechoutte, R Bender & N Oser 2007 "The original
econiche of the genus Homo: open plain or waterside?" :155-186 in SI Muñoz
ed 2007 "Ecology Research Progress" Nova NY, google "econiche Homo",
-with S Munro 2011 "Pachyosteosclerosis suggests archaic Homo frequently
collected sessile littoral foods" HOMO J compar hum Biol 62:237-247, and
"Pachyosteosclerosis in archaic Homo" :82-105 in M Vaneechoutte cs eds
2011 "Was Man More Aquatic in the Past?" eBook Bentham Sci Publ,
-2013 "The aquatic ape evolves: common misconceptions and unproven
assumptions about the so-called Aquatic Ape Hypothesis" Hum Evol
28:237-266, google "unproven assumptions Verhaegen",
-S Munro 2010 "Molluscs as ecological indicators in palaeo-anthropological
contexts" PhD thesis Austr Nat Univ Canberra.

--marc verhaegen
http://groups.yahoo.com/group/AAT

________________________________________

On the Relationships of Postcanine Tooth Size with Dietary Quality and
Brain Volume in Primates:
Implications for Hominin Evolution
Juan Manuel Jiménez-Arenas, Juan Antonio Pérez-Claros, Juan Carlos Aledo &
Paul Palmqvist 2014 open access
BioMed Research International 2014 ID 406507, 11 pages
http://dx.doi.org/10.1155/2014/406507

Brain volume & cheek-tooth size have traditionally been considered as 2
traits that show opposite evolutionary trends during the evolution of
Homo.
As a result, differences in encephalization & molarization among hominins
tend to be interpreted in paleo-biological grounds, because both traits
were presumably linked to the dietary quality of extinct spp.

Here we show that there is an essential difference between the genus Homo
& the living primate spp:
Post-canine tooth size & brain volume are related to negative allometry in
primates, and show an inverse relationship in Homo.
However, when size effects are removed, the negative relationship between
encephalization & molarization holds only for platyrrhines & the genus
Homo.
There is no general trend for the relationship between post-canine tooth
size & dietary quality among the living primates.
If size & phylogeny effects are both removed, this relationship vanishes
in many taxonomic groups.
As a result, the suggestion that the presence of well-developed postcanine
teeth in extinct hominins should be indicative of a poor-quality diet
cannot be generalized to all extant & extinct primates.

------------------------------------------

Did Europeans Get Fat from Neanderthals?

<http://feedproxy.google.com/~r/TheArchaeologyNewsNetwork/~3/RwvStffEcJU/di
d-europeans-get-fat-from-neanderthals.html?utm_source=feedburner&utm_medium
=email
>
Contemporary European Hs have 3 times more Hn variants in genes involved
in lipid catabolism than Asians & Africans.

Neanderthal ancestry drives evolution of lipid catabolism in contemporary
Europeans


Ekaterina Khrameeva cs 2014
Nature Communications 5:3584 doi 10.1038/ncomms4584
free access

Although Hn are extinct, fragments of their genomes persist in Hs.
Here we show that while the genome-wide frequency of Hn-like sites is
+-constant across all contemporary out-of-Africa populations, genes
involved in lipid catabolism contain more than 3-fold excess of such sites
in contemporary Hs of European descent.
Evolutionally, these genes show significant association with signatures of
recent positive selection in the contemporary European, but not Asian or
African populations.
Functionally, the excess of Hn-like sites in lipid catabolism genes can be
linked with a greater divergence of lipid concentrations & enzyme
expression levels within this pathway, seen in contemporary Europeans, but
not in the other populations.
We conclude that sequence variants that evolved in Hn may have given a
selective advantage to Hs that settled in the same geographical areas.


Articles and papers:

Findings indicate existence of Neanderthals on Greek island of Naxos

http://archaeologynewsnetwork.blogspot.gr/2015/05/findings-indicate-existence-of.html#.VWg92UaRbyd



 
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