A Specification for an XXT

Paul Crowley (Paul@crowleyp.demon.co.uk)
Wed, 11 Oct 95 23:07:01 GMT

I hope to post my personal "newly revised" version of the AAT in a
week or so. First I'd like to be clear about the matters that need
explaining which should be in any theory of human evolution. These
would be in two categories (a) essential: where the theory must
provide a reasonable explanation, and (b) optional: the more of these
items that the theory explains the better, but it could omit or be
uncertain about several.

I'm sure such a checklist has been produced before. It could be in
textbooks I haven't read, and it may have been posted in this group
but I've not seen one here in recent months.

Ideally, it would be desirable to get a consensus on this list, so
that every proposed theory could be measured against it.

Anyway here are my present crude ideas. It has not quite worked
out as well as I had hoped, so please post additions, corrections,
improvements in terminology, criticisms, revisions. If you have
another list, please post it.


The proposed theory (the XXT) should set out the same kind of
explanation as would be provided for the generation of any species.

e1 The ecological niche the species occupied should be clearly
delineated. The XXT must state what circumstances created this new
niche or, if it had existed before, why it was vacant. The XXT
must explain how the CA/new hominid was better adapted to occupy
it, as compared with other animals believed to be present at the

e2 The speciating event and its circumstances should be clearly
described. Preferably this should not involve any kind of natural
catastrophe, but should be the sort of event that would probably
have happened sooner or later, given the environment. If
geographical separation is proposed, possible locations should be
named and the barrier specified. The length of time that the
isolation persisted should be indicated and possibly also the
reasons for the absence of re-integration.

e3 The XXT should specify the type of diet and the sources it was
obtained from. It should state how much water would be needed in
the environment and indicate how the water would be obtained.

e4 The XXT should outline the probable predation problems the species
faced and depending on their estimated severity indicate probable
or possible ways in which the species coped with it. The severity
of predation is to be measured against forecast reproduction rates.
Predation by day and by night should be separately described, as
also predation of the young, females, and males if they were
generally in separate groups.

e5 The extremes of temperature, or other climatic conditions, that the
species would regularly encounter should be stated. Day and
night-time temperatures should be stated as should the manner in
which the species coped; the degree to which the species would
have to find additional shelter or greater food resources should be

e6 The manner of care of the young should be clearly described, both
in infancy and early childhood, and during the day and at night.

e7 The roles of each sex should be described and size, shape, and
physical features of each sex, and the varying degrees throughout
the time period (5mya-present) of sexual dimorphism should be
accounted for.

e8 Any possible competition with other species for food or other
resources should be indicated.

e9 The effect of competition within the species should be stated.

e10 The locomotion capabilites of the species throughout the relevant
period must be clearly specified, both on the ground, in trees or
in any other environment. The probably ability of the species to
escape likely predators in each environment should be described.

e11 The reasons for the development of bipedalism must be clearly shown.

e12 The effects of initial bipedalism on all aspects of the hominid's
activities must be described. This will include caring patterns
for the young, coping with predators and the location of food and
any other resources. The consistent pressure towards better
bipedalism over some 50,000 to 100,000 generations and the
selective advantages of this progression in *each* generation must
be explicitly stated.

e13 The XXT should clearly state how it fits in with the fossil record-
making reasonable allowance for current uncertainties and possible
misinterpretations of existing fossil data.


The XXT should provide an explanation for as many of these as possible.

o1. Nakedness
o2. Greater amounts of hair on males
o3. Distribution of hair on the body - male/females
o4. Descended Larynx
o5. Subcutaneous Fat
o6. No Estrous
o7. Menopause
o8. Different sweat glands
o9. Speciation of human flea
o10. Cry of human baby

--------- End of Specification ---------

I'm sure I've left out a lot.