Well, strong continuous complex changing
evolutionary pressure conditions exert forces stimulating certain aspects of
the evolution of a natural population of organism species through either the accumulation of gene-loss-
generated by inactivation- mutation duplications that have become
non-functional pseudo genes a.k.a. inactive-copies of protein-coding genes;
and/or through DNA segmental-duplications to generate new-alleles /
genetic-information material in the process of MOLECULAR-BIOLOGY –EVOLUTION
which contextually create new-primate-genes contributing to the shaping of
human-genetic-variation / diversity which in-turn clear genetic /
anatomic-constraints that bar or inhibit the path to the effectiveness of natural-selection
and thus turning into a mechanism that increases the
intensity-and-effectiveness of phenotype-traits
rather that create more phenotype-trait variation……..by effectively
selecting the optimum, upgraded, better-suited distinct-expression of
beneficial-alleles’ phenotype-traits that provide selective, reproductive,
survival-fitness performance / adaptive-values to the organism-species.
Hence, strong continuous, complex, changing
evolutionary-pressure-conditions exert forces stimulating certain aspects of
the evolution of an organism-species population through the accumulation of
gene-loss-inactivation-mutation duplications to clear genetic /
anatomic-constraints that bar / inhibit the path to the effectiveness of
natural-selection by enhancing-selection
through pressurizing cell-and-organisms to evolve by increasing the
cutting-edge intensity-and-effectiveness of heritable phenotype-traits of
beneficial-alleles rather than create new phenotypic-trait variation, like in ,
e.g. early-bipedal-ancestral-hominid-fossil-species’ continuous, complex, changing
evolutionary-pressure-conditions to increase their mental-capacity /
intelligence for COGNITION to
technologically-adapt the creation-and-use of advanced, elaborate
food-processing technology-tools to simplify-and-make efficient
hunting-and-processing of energy-rich
meat-and-plant food-products subsequently led to the hominid-dentition
fossil-record-evidence trend of smaller-molars and tooth-sizes increasingly in
the genus-Homo as one ancestral-hominid-fossil-species descended into the
next-generation; concurrently with skull-expansion / encephalization
facilitated by the accumulation of gene-loss inactivation-mutation duplications
of the SARCOMERIC-MYOSIN-GENE a.k.a. MYH16-gene which in turn stimulated developmental-changes in the morphology of
SMALLER-MASTICATORY-MUSCLES and MUSCLE-ATTACHMENT to the SKULL into allowing
more room for ENCEPHALIZATION, i.e. the continued expansion, increase in volume
and the development of a LARGER-BRAIN-SIZE gradually, successively over time to
the modern-form between 959-1800cc with a mean of 1330cc.
Thus, the hominid-dentition
fossil-record-evidence indicates that a DOMINANT-GENE for BIGGER,LARGER
MASTICATORY/MANDIBLE-MUSCLES, i.e. the SARCOMERIC-MYOSIN-GENE a.k.a.
MYH16-gene was lost in the human-lineage
due to accumulation of gene-loss inactivation-mutation duplications generating
inactive-copies of its protein-coding DNA leading to the morphology of
SMALLER-MASTICATORY-MUSCLES which acted as a CHANGED,STRONG,COMPLEX EVOLUTIONARY-PRESSURE-CONDITION
ending-up in turn exerting a force that
stimulated the aspect of the evolution of the human-skull, cranium, brain-size
and volume of the natural-population of the
early-bipedal-ancestral-hominid-fossil-species lineage and therefore resulting
in the period that followed to be marked
by a strong-increase in CRANIAL-CAPACITY, i.e. ENCEPHALIZATION through as well
the SEGMENTAL-DUPLICATION of SRGAP2-gene which produced a more rapid wiring of
the human FRONTAL-CORTEX indicating that
the MYH16-gene 2base-pair-deletion
gene-loss inactivation-mutation duplication removed thus the
genetic-anatomic-constraint on brain-size and volume in the genus-Homos’
early-bipedal-ancestral-hominid-fossil-species lineage.
Hence was encephalization
directly tied to the invention of the
technological ‘DEVELOPMENT-of-ELABORATION’ of stone-tools including cutters, choppers,
hunting/fishing-and-gathering tools; as well as tied to the subsequent
increasing emphasis of meat in the diet…………all interpreted as
signs-of-intelligence, a phenomenon
which in turn in itself again stimulated certain aspects of the
evolution of the human-brain through SEGMENTAL-DUPLICATION of the SRGAP2-gene
which produced a more rapid-wiring of the frontal-cortex equivalent to a rate
of each descending-generation having acquired an additional 125000 neurons more
than their parents in the FRONTAL-CORTEX! This was the time of transition of
the Homo habillis brain, an early-bipedal-ancestral-hominid-fossil-species
member of the genus Homo who evolved around 2.3m.y.a. and for whom there’s
positive-evidence for the use of stone-tools and development of the
OLDOWAN-LITHIC-TECHNOLOGY named after OLDUVAI-GORGE in TANZANIA. Homo habillis
brain were more or less the same size as the brains of chimpanzees at
approximately 400cc which then during the next million years underwent a
process of evolution of the skull, cranial-capacity, brain-size and volume such
that by the time of the arrival of the Homo erectus species in the
fossil-record between 1.8-and-1.3m.y.a. [ at least as early as 1.85m.y.a. for
Homo erectus georgicus of The Dmanisi-Skulls Georgia ] cranial-capacity had
doubled to 850cc from an average of
400cc catapulting them to be the first
hominine to use FIRE-and-COMPLEX TOOLS; a feat which clearly indicates
that INTELLIGENCE increased as a
response to increased-necessity for COGNITION, i.e. to solve important
social-problems of survival-and-reproduction as human-society became more and
more complex, civilized and advanced from pre-historic / pre-industrial to
historic / industrial.
Thus is COGNITION, the set
of all mental-faculties / processes composed of a FUNCTIONAL-STRUCTURE,
THE-BRAIN who’s PHYSIOLOGICAL-FUNCTIONS carries-out the operations of these set
of mental processes and just like other organs and the immune-system, the brain
is ENCODED / DETERMINED by genes meaning it evolved by natural-selection and
was thus acquired by gradation as has been showcased above in
transitional-series from early-bipedal-ancestral-hominid-fossil-species a.k.a. proto-humans including either Sahelanthropus
tchadensis or Orrorin tugenensis or Ardipithecus ramidus / kaddaba through to them Australopithecines to Homo
habillis to Homo erectus to primitive /
archaic / early-modern-man to the Neanderthal-and-Denisovan hominins to
anatomically-modern-humans; whereby in turn this ENCEPHALIZATION of the human-brain
underpinned humanity’s technological-adaptations, his moral-sensibilities and
pre-adaptation of speech [ i.e. language and literacy of which the world’s-languages
diversity totals a number of 7000 languages so far ] following on rudimentary speech.
Thus, this is the summary of
the MYH16-gene and SRGAP2-gene evolutionary-pressure-conditions that removed
the genetic / anatomic-constraints inhibiting the path to the brains
ENCEPHALIZATION. I’m next going to tackle the controversial
OLFACTORY-RECEPTOR-GENE-FAMILY vis-à-vis COLOR-VISION though I will fast go
through THE ADAPTATION OF BIPEDALISM as humanity’s basic defining ADAPTATION
which stimulated an interesting suit of skeletal-changes necessitating the
above developments and the controversies there-in as well as regards compelling
evidence.
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