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Re: primers



Dann Pigdon (dannj@alphalink.com.au) wrote:

<Nonsense. Why this constant dichotomy between 'human' and 'natural'?
Humans are a species that evolved naturally, therefore anything they do
that provides selective pressure to other species is just as natural an
evolutionary process as climate change (or any other non-human process).>

  It's not about introduction of species, or migration, or expansion, or
habitat loss of an already existing species, but about species
_formation_, such as allopatry or sympatry. As an example, if a breed of
dog, say a pug, were out in the wild, would it be selectively breeding
with pugs? would the pug breed arise naturally? Feral dogs, horses, cats,
cattle, goats, etc., tend not to select for breed when mating, and this
only underscores the lack of utility in using artificial "species" as
examples of speciation, or even morphological diversity within a species,
since what features may normally be weeded out as ineffective or not
optimal would not be expressed in exclusive lineages; a small animal with
trouble breathing would not be a fit hunter, and thus may not live long
enough to breed, or be incapable of protecting or rearing young, so the
American bulldog, pug, and persians are largely "bad" breeds.

<Selective breeding by humans has enhanced the survival of many species.>

  And impaired it in many, many others.

<If humans hadn't entered into a symbiotic relationship with cattle then
they'd be far less numerous and occupy far fewer ecological niches than
they do today.>

  Human breeding in cattle resulted in destruction of habitat for the sake
of breeding the cattle as grazers, open range grazers for most varieties,
and thus the destruction of other ecological niches. Cattle, on the other
hand, occupy only two, maybe four, niches, given the geography (Indian
cattle tend to be more forested along with other South-Asian types than
African, American, and European/West/North/Central-Asian breeds).

<The way humans shape the evolutionary development of domesticated animals
is no different to other symbiotic relationships. The fungus that
leafcutter ants cultivate grows nowhere else but in their nests. Fig wasps
and fig trees are completely dependant on each other. There are many other
examples of species that are locked into symbiotic relationships, where
each has influenced the development and behaviour of the other. Human
selective breeding is no different - just a little faster.>

  See above.

  Cheers,

=====
Jaime A. Headden

  Little steps are often the hardest to take.  We are too used to making leaps 
in the face of adversity, that a simple skip is so hard to do.  We should all 
learn to walk soft, walk small, see the world around us rather than zoom by it.

"Innocent, unbiased observation is a myth." --- P.B. Medawar (1969)


                
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