Homo erectus early childhood
Mammal species usually have one of two patterns for growth of their
offspring. The first pattern is called altriciality. In this pattern
the animal is born helpless and extremely immature. Because of this it
takes lots of parental effort to raise the young. Animals following this
pattern usually have litters and perform this care for multiple
offspring at once. Cats, with their blind and helpless kittens are
altricial. The other pattern is precocial. In this pattern the
offspring are usually born single and from birth the young are able to get
around quite well. They are alert and all their organs are functioning.
An example of this pattern is the horse, the wildebeest,antelope etc.,
where the young will run with the herds within minutes.
Humans follow neither pattern. We do not have litters yet our young are
helpless and extremely immature. They do are unable to stand and
locomote like precocial species. What is the explanation?
"In 1941 Adolf Portmann, a Swiss zoologist, considered the quandary and
suggested that humans are secondarily altricial. That is, he sees
humans as fundamentally precocial mammals (in terms of our brain
development and sensory systems) with an overlay of altriciality that
accounts for the incomplete development or retardation of our motor
system. Portmann makes some powerful points about the extraordinary
differences between humans and other precocial mammals. From the moment
of birth, chimpanzees and gorillas (not to mention antelope or whales)
closely resemble adults in limb proportions, body postures, and motor
patterns, even if these may be clumsy and labored at first. But newborn
humans are incapable of assuming the species specific upright posture
that characterizes their kind. Baby humans simply do not have the
physical equipment to stand and walk at birth; the limb proportions
must change and the vertebral column must alter until the typical S-
curve develops that allows it to act as a support and shock absorber for
an upright biped.. . . Astonishingly, although humans are a strongly
social species, we are born lacking even the rudiments of the species
means of communication (speech and gesture)."~Alan Walker and Pat Shipman,
_The Wisdom of the Bones_, p. 220.
Now, according to Walker and Shipman, altricial species almost never
have bigger brains than precocial species. The reason is that for all
mammals save one, the brain grows rapidly during gestation but then
grows less rapidly after birth. There is a kink in the graph of brain
size vs. time which occurs at birth. Altricial species whose immature
state at birth and subsequent slow down in the rate of growth forever
remain behind the more maturely born precocial species.
What humans seem to have accomplished is the trick of keeping the brain
growing at the embryonic rate for one year after birth. Effectively, if
humans are a fundamentally precocial species, our gestation is (or
should be) 21 months. However, no mother could possibly pass a year old
baby's head through the birth canal. Thus, human babies are born
"early" to avoid the death of the mother. Walker and Shipman write:
"Humans are simply born too early in their development, at the
time when their heads will still fit through their mothers' birth
canals. As babies' brains grow, during this extrauterine year of fetal
life, so do their bodies. About the time of the infant's first
birthday, the period of fetal brain growth terminates, coinciding with
the beginnings of speech and the mastery of erect posture and bipedal
walking."~Alan Walker and Pat Shipman, _The Wisdom of the Bones_, p. 222
This pattern of growth has huge implications. Every other primate
doubles their brain weight from birth to adulthood. But due to the
early birth of humans, we triple our brain's birth rate. Our last 12
month of fetal growth rate of the brain occurs outside the sensorially
deprived womb. The vast quantities of sensory input during the first
year of life affects the rate and nature of the neural connections.
Because of this year of helplessness, parents must provide close
physical and emotional support for the infant. Unlike chimp babies who
can cling to their mother's fur, human infants cannot even hang on to
mother in spite of having the hand reflex.
What does this have to do with Mother erectus' love? The question can be
asked, what pattern of growth did Homo erectus have? The Nariokotome
boy's pelvis was the first normal Homo erectus pelvis ever found. From
the scaling laws applicable to primates, the width of the female H.
erectus birth canal can be estimated. This knowledge allows an estimate
of the size of the H. erectus brain at birth.
Remember that primates double their brain size from birth to adulthood;
humans triple that size. Which pattern did the erectus have? Well the
adult erectus brains from the time of the Nariokotome boy, had brains
averaging 880 cc. So if the erectus birth canal allowed a 440 cc brain
to pass through, then erectus was raised in the primate pattern. If the
birth canal only allowed a 300 cc or less brain to pass, then he had the
human growth pattern. The birth canal would only allow a 231 cc brain to
pass through. This means that Homo erectus had the same birth pattern
as modern men! It means that they, like us, were fundamentally precocial
with an overlay of altriciality. They were born too early.
Could the female birth canal have a lot larger? It is highly unlikle for
mechanical reasons associated with bipedal walking. Wider hips would move
the legs further apart making it almost impossible to walk bipedally. Thus
the birth canal estimate is quite reasonable given the two conflicting
requirements: walking and birthing big brained babies.
The obvious implications are that Mother erectus, like your mother, had
to take care of an extremely immature infant.The care was for some
extended period of time. The early birth meant that the
erectus brain, like ours, finished its fetal growth in the stimulating
outside world rather than the boring womb. This would affect the neural
connections of the growing child. Once again we come face to face with
fact that Homo erectus was quite like us.
Walker and Shipman write:
"The human evolutionary 'trick' of growing a brain at fetal rates after
birth was obviously well in place by 1.6 million years ago. In fact it
seems likely that the change in the pattern of brain growth from apelike
to humanlike must have accompanied the evolution of Homo habilis."~Alan
Walker and Pat Shipman, _The Wisdom of the Bones_,, p. 228.
and
"Our findings about brains and pelvises implied an additional
characteristic even more evocative. Somehow, Homo erectus had managed
to rear babies whose senses were going full tilt while their motor
abilities were undeveloped. More than ever, this convinced me that Homo
erectus was an intensely social creature, with strong cooperative ties
to others of its species. I also knew that Homo erectus had faced and
solved a major dietary problem, for nursing babies with rapidly growing
brains demanded a significant upgrade in diet. Becoming an effective
hunter is the most obvious way to increase the amount of protein in the
diet--and protein is what is needed for big brains and big bodies."~Alan
Walker and Pat Shipman, _The Wisdom of the Bones_,, p. 228-229
The childhood growth patterns of a Homo erectus are quite similar to
those of modern humans. When this is combined with the evidence of human
technological activities, love and compassion shown two nights ago, one
must seriously reconsider the traditional approaches Christians have taken
to dealing with fossil man. The suggestion I have made, that Adam must
have been either a habilis or an erectus is supported by the birth and
growth patterns applicable to those species. They had a human pattern.
glenn
Foundation,Fall and Flood
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